PANRE-LA Practice Portal

Mitral stenosis is a narrowing of the mitral valve that obstructs flow from the left atrium into the left ventricle during diastole, and rheumatic fever is its leading cause. The scarred, stiff leaflets snap open early in diastole (the opening snap), then blood squeezes through the tight orifice, producing a low-pitched rumbling diastolic murmur heard best with the bell at the apex in the left lateral decubitus position. Pressure rising in the left atrium backs up into the lungs (dyspnea, crackles) and stretches the atrium, which triggers atrial fibrillation. The rule: an opening snap followed by an apical diastolic rumble in a patient with a rheumatic history is mitral stenosis until proven otherwise. This woman's childhood illness (fever, migratory arthritis, then months of injections for prophylaxis), irregularly irregular pulse, and apical rumble fit exactly.

Board-Level Insight: Rheumatic heart disease typically presents with mitral stenosis, auscultated at the cardiac apex in the left lateral decubitus position as a loud S1, a high-pitched early diastolic opening snap, and a low-pitched rumbling mid-diastolic murmur with presystolic accentuation.

Classic Board Trap: The interval between the aortic closure sound (A2) and the opening snap (A2-OS interval) correlates inversely with stenosis severity: a shorter A2-OS interval indicates higher left atrial pressure and more severe mitral valve narrowing!

Incorrect answer explanations

• Aortic regurgitation – high-pitched early diastolic decrescendo murmur at the left sternal border, often with a wide pulse pressure; no opening snap or apical rumble.

• Aortic stenosis – systolic crescendo-decrescendo murmur at the right upper sternal border radiating to the carotids.

• Mitral regurgitation – holosystolic blowing apical murmur radiating to the axilla; a systolic, not diastolic, lesion.

• Tricuspid stenosis – rare; diastolic rumble at the left lower sternal border that increases with inspiration, with jugular venous distension and edema rather than pulmonary congestion.

Clinical Pearls

• Mitral stenosis with atrial fibrillation needs warfarin — direct oral anticoagulants are not indicated in this setting.

• Unusual board clues: hemoptysis from ruptured pulmonary vessels and hoarseness from a dilated left atrium compressing the left recurrent laryngeal nerve (Ortner syndrome).

• Symptoms often surface or worsen in pregnancy, when blood volume rises.

• Percutaneous mitral balloon commissurotomy is the procedure of choice for suitable valves (no heavy calcification or left atrial thrombus).

• In older adults without rheumatic history, mitral annular calcification is an increasingly common cause.

Blueprint Comparisons — Valvular disorders

Extra Challenge

• This patient's atrial fibrillation needs stroke prevention. Which anticoagulant class is indicated?

Answer: A vitamin K antagonist (warfarin); direct oral anticoagulants are not indicated in atrial fibrillation with mitral stenosis.

• What is the procedure of choice for symptomatic severe rheumatic mitral stenosis with pliable, noncalcified leaflets and no left atrial thrombus?

Answer: Percutaneous mitral balloon commissurotomy.

Stridor at rest with retractions in a toddler who has a barking cough after a viral prodrome defines moderate croup (viral laryngotracheobronchitis), most often from parainfluenza virus and worst at night in children 6 months to 3 years. Subglottic edema is the problem, so treatment targets the mucosa two ways: a single dose of dexamethasone (oral or intramuscular) reduces inflammation over hours and lowers return visits and admissions, while nebulized racemic epinephrine constricts mucosal vessels and shrinks the edema within minutes. Any child with stridor at rest, retractions, or distress should receive epinephrine in addition to the steroid; a child with only a barking cough and no resting stridor (mild croup) needs dexamethasone alone. Because epinephrine's effect wears off in about 2 hours, the child must be observed for at least 2 to 4 hours after the dose to catch a return of stridor before discharge.

Incorrect answer explanations

• Cool mist humidification – a traditional home remedy that has not been shown to improve outcomes; it is not a treatment for stridor at rest.

• Intravenous ceftriaxone – croup is viral; antibiotics belong to bacterial tracheitis or epiglottitis, which present with high fever, toxic appearance, and poor response to croup therapy.

• Intravenous methylprednisolone – a second steroid adds no benefit once dexamethasone has been given and, like all corticosteroids, takes hours to act.

• Nebulized albuterol – a beta-2 agonist for lower-airway bronchospasm (asthma, bronchiolitis in select cases); it does not treat subglottic edema and would worsen tachycardia.

Clinical Pearls

• Severity at a glance: mild = barking cough, stridor only when agitated (dexamethasone, home); moderate = stridor at rest with retractions (dexamethasone plus nebulized epinephrine, observe); severe = decreased air entry, hypoxemia, lethargy (epinephrine, steroid, oxygen, admit and prepare for airway).

• Diagnosis is clinical; an anteroposterior neck radiograph may show the steeple sign (subglottic narrowing), while a lateral film with a swollen epiglottis (thumbprint sign) means epiglottitis.

• Croup that fails to improve or that worsens after epinephrine and steroid, especially with high fever and a toxic look, is bacterial tracheitis until proven otherwise (Staphylococcus aureus most common).

• Do not agitate a child with stridor: keep the child in a parent's lap, defer throat examination and blood draws, and never force supine positioning.

• Spasmodic croup recurs suddenly at night without fever or prodrome and resolves quickly; it is treated the same way when symptomatic.

Blueprint Comparisons — Pulmonary infectious disorders (pediatric upper airway)

Extra Challenge

• What is the classic finding on an anteroposterior neck radiograph that supports the diagnosis of croup?

Answer: The steeple sign, a tapered subglottic narrowing of the tracheal air column.

• Two hours after nebulized epinephrine, a child with moderate croup is calm with no stridor at rest. What determines whether she can go home?

Answer: Sustained absence of stridor at rest and retractions after the observation period, normal oxygenation, ability to take fluids, and a reliable caregiver — the dexamethasone already given covers the next 2 to 3 days.

Nearly two weeks of pharyngitis with exudates, posterior cervical lymphadenopathy, profound fatigue, and splenomegaly in an adolescent with a negative streptococcal test is infectious mononucleosis caused by Epstein-Barr virus (EBV). EBV infects B lymphocytes, and the immune response is a surge of activated CD8+ cytotoxic T cells that appear on the smear as atypical lymphocytes (Downey cells): large cells with abundant pale-blue cytoplasm that seems to wrap around neighboring red cells. The classic hematologic picture is an absolute lymphocytosis (more than 50% of leukocytes) with at least 10% atypical lymphocytes, often up to 30%, which is the best initial laboratory clue before serologic confirmation.

Incorrect answer explanations

• Hypersegmented neutrophils – neutrophils with six or more lobes are the smear hallmark of vitamin B12 or folate deficiency (megaloblastic anemia), a defect in DNA synthesis, not a viral response.

• Hypochromic red blood cells – enlarged central pallor reflects reduced hemoglobin per cell, as in iron-deficiency anemia or thalassemia; red cell morphology is normal in mononucleosis.

• Schistocytes – helmet cells and fragments are produced by mechanical shearing in microangiopathic hemolytic anemia (thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, disseminated intravascular coagulation) or by prosthetic valves.

• Target cells – excess membrane relative to hemoglobin, seen in liver disease, thalassemia, hemoglobin C disease, and post-splenectomy states.

Clinical Pearls

• The heterophile antibody (Monospot) test is falsely negative in about 25% of patients during the first week and in most children under 4; if negative with high suspicion, repeat it or send EBV viral capsid antigen (VCA) IgM, which confirms acute infection (EBV nuclear antigen IgG appears only 2 to 4 months later and means past infection).

• A diffuse maculopapular rash after amoxicillin or ampicillin is a classic mononucleosis clue and is not a true penicillin allergy.

• Mild transaminase elevation occurs in most patients; jaundice is uncommon.

• No contact sports or heavy lifting for at least 3 to 4 weeks because of splenic rupture risk; corticosteroids are reserved for airway obstruction from tonsillar hypertrophy, severe thrombocytopenia, or hemolytic anemia.

• A heterophile-negative mononucleosis syndrome should prompt testing for cytomegalovirus, acute human immunodeficiency virus (HIV) (fourth-generation antigen/antibody plus RNA), and toxoplasmosis.

Blueprint Comparisons — Viral diseases

Extra Challenge

• A patient with mononucleosis develops sudden left upper quadrant pain radiating to the left shoulder and becomes hypotensive. What has happened and what is the next step?

Answer: Splenic rupture (Kehr sign from diaphragmatic irritation); emergent computed tomography or focused ultrasound and surgical consultation, with splenectomy for hemodynamic instability.

• Which EBV antibody pattern indicates a past, resolved infection rather than acute disease?

Answer: Positive VCA IgG with positive EBNA IgG and negative VCA IgM; EBNA antibodies take 2 to 4 months to appear and persist for life.

Pain out of proportion to the injury, pain with passive stretch of the fingers, and a tense, firm compartment after a forearm fracture and fixation are the early signs of acute compartment syndrome; the new sensory loss, weak pulse, and pale, cool hand show that perfusion is already failing. Rising pressure inside a closed fascial compartment collapses capillary flow, and muscle and nerve necrosis become irreversible within roughly 4–6 hours. Removing casts, splints, and circumferential dressings is the correct first move in suspected compartment syndrome, but here that has been done and the syndrome is established on clinical grounds. The only limb-saving treatment is emergent surgical fasciotomy of every compartment of the segment, and it must not wait for imaging, pressure measurement, or observation.

Incorrect answer explanations

• Continue close observation with serial examinations – appropriate only when the diagnosis is unclear; with a tense compartment and neurovascular deficits, every hour of watching adds necrosis.

• Elevate the extremity above heart level – reduces arterial inflow and worsens ischemia; the limb is kept at heart level.

• Obtain computed tomography angiography of the extremity – arterial occlusion produces a pulseless, cold limb with a soft compartment; imaging here only delays decompression.

• Start intravenous heparin – treats thrombosis, not compartment pressure, and increases bleeding at fasciotomy.

Clinical Pearls

• The 6 Ps — pain, paresthesia, pallor, pulselessness, poikilothermia, paralysis. Pain on passive stretch is the earliest sign; pulselessness and paralysis are late, so never wait for them.

• When the examination is equivocal or the patient is obtunded, measure compartment pressure: an absolute pressure above 30 mm Hg or a delta pressure (diastolic blood pressure minus compartment pressure) below 30 mm Hg supports fasciotomy.

• The forearm has volar, dorsal, and mobile-wad compartments; the leg has four. Fasciotomy must release all of them.

• After decompression, check creatine kinase and watch for rhabdomyolysis, myoglobinuria, and hyperkalemia; give fluids to protect the kidneys.

• Untreated forearm compartment syndrome leaves a Volkmann ischemic contracture, a fixed flexion claw deformity of the wrist and fingers.

Blueprint Comparisons — Compartment syndrome and its mimics

Extra Challenge

• What is the most reliable early physical finding for suspecting acute compartment syndrome?

Answer: Pain with passive stretch of the muscles in the affected compartment — the earliest and most sensitive sign, present well before pulses are lost.

• A trauma patient with a tibial fracture is intubated and cannot report pain. What objective measurement supports proceeding to fasciotomy?

Answer: An absolute compartment pressure above 30 mm Hg, or a delta pressure (diastolic blood pressure minus compartment pressure) below 30 mm Hg.

Intussusception is the telescoping of a segment of the proximal bowel into a distal portion, most commonly affecting children younger than 2 years old. It presents with intermittent, severe, colicky abdominal pain, vomiting, and currant jelly stools (blood and mucus). A palpable sausage-shaped abdominal mass, typically in the right upper or mid-abdomen, is highly characteristic. Ultrasound is the preferred imaging study and shows a target sign. Treatment involves non-surgical reduction with an air or contrast enema. Surgical intervention is reserved for cases where enema reduction fails or perforation is suspected.

Incorrect answer explanations:

• Duodenal atresia: Presents within the first 24–48 hours of life with bilious vomiting and double-bubble sign on imaging; no bloody stools.

• Hirschsprung’s disease: Presents with failure to pass meconium, chronic constipation, and abdominal distention, not intermittent severe abdominal pain and bloody stools.

• Pyloric stenosis: Presents at 2–8 weeks of life with projectile non-bilious vomiting and an olive-shaped mass in the epigastrium, not bloody stools.

• Meckel’s diverticulum: May present with painless rectal bleeding, but not the intermittent severe pain or palpable abdominal mass typical of intussusception.

Key Points:

• Definition and pathophysiology: Intussusception involves bowel telescoping that causes obstruction, venous congestion, and ischemia.

• Epidemiology and risk factors: Most common in infants 6 months to 2 years old; sometimes associated with viral illnesses or Meckel’s diverticulum.

• Classic presentation and symptoms: Sudden onset intermittent crampy abdominal pain, currant jelly stools, vomiting, and sausage-shaped mass.

• Diagnostic approach: Ultrasound (first-line) shows a target or donut sign; air or contrast enema can diagnose and treat.

• Treatment guidelines: Attempt non-surgical reduction first; surgery if unsuccessful or signs of bowel perforation.

• Complications and prognosis: Delayed diagnosis can lead to bowel necrosis, perforation, sepsis, and death.

Differential Diagnosis:

• Meckel’s diverticulum: Painless bleeding, no abdominal mass or cramping episodes.

• Pyloric stenosis: Projectile vomiting without bloody stools; palpable olive mass.

• Malrotation with volvulus: Bilious vomiting and abdominal pain, more acutely toxic appearance.

• Necrotizing enterocolitis: Seen in premature infants; presents with feeding intolerance, abdominal distension, and bloody stools.

• Gastroenteritis: Diffuse diarrhea and vomiting, typically without localized abdominal mass or currant jelly stool.

Extra Challenge:

• What is the therapeutic and diagnostic procedure of choice for a stable patient with suspected intussusception?

Answer to Extra Challenge: An air or contrast enema is the therapeutic and diagnostic procedure of choice, as it can both confirm the diagnosis and potentially reduce the intussusception non-surgically.

Palpitations, tremor, weight loss, lid lag, a diffusely enlarged nontender goiter, suppressed thyroid-stimulating hormone (TSH), and high free thyroxine (T4) define thyrotoxicosis, here most likely from Graves disease, and the excess thyroid hormone has triggered atrial fibrillation. The fastest way to control the adrenergic symptoms and the ventricular rate is a beta blocker, started as soon as hyperthyroidism is recognized: atenolol (once-daily, beta-1 selective) or propranolol (nonselective; at higher doses it also modestly reduces peripheral T4-to-triiodothyronine [T3] conversion). A thionamide (methimazole) is begun at the same visit to shut down hormone synthesis, but it takes weeks to work, so the beta blocker is the drug that treats the patient now. Definitive therapy (radioactive iodine or thyroidectomy) follows once she is euthyroid.

Incorrect answer explanations

• Amiodarone – 37% iodine by weight; it can cause both hypothyroidism and thyrotoxicosis and is avoided in thyroid-driven atrial fibrillation.

• Flecainide – a class IC rhythm-control drug; it does not treat the adrenergic symptoms, and rhythm control is not attempted until the thyroid state is corrected.

• Methimazole – essential and started concurrently, but its effect on hormone levels takes 2 to 6 weeks, so it cannot be the immediate symptom controller.

• Radioactive iodine ablation – definitive, not immediate; it is deferred until symptoms are controlled and is contraindicated in pregnancy and active Graves ophthalmopathy.

Clinical Pearls

• If a beta blocker is contraindicated (asthma, decompensated heart failure), use a nondihydropyridine calcium channel blocker (diltiazem) for rate control.

• Propylthiouracil (PTU) replaces methimazole only in the first trimester of pregnancy and in thyroid storm; it carries a boxed warning for hepatic failure.

• Both thionamides can cause agranulocytosis: any fever or sore throat on therapy means stop the drug and check a white blood cell count.

• Thyrotoxic atrial fibrillation often converts spontaneously once the patient is euthyroid; anticoagulation decisions follow the usual CHA2DS2-VASc approach.

• Do not confuse with thyroid storm: fever, delirium, and hemodynamic instability call for the full package of PTU, beta blocker, iodine given an hour after the thionamide, and glucocorticoids.

Blueprint Comparisons — Thyroid Disorders

Extra Challenge

• A thyrotoxic patient with a tender, painful thyroid gland and a low radioiodine uptake asks whether she needs methimazole. What is the answer and why?

Answer: No. Low uptake means the gland is leaking stored hormone (thyroiditis), not synthesizing more, so thionamides do nothing; treat with a beta blocker and NSAIDs or glucocorticoids.

• Why is propylthiouracil, not methimazole, chosen in the first trimester of pregnancy?

Answer: Methimazole is associated with first-trimester embryopathy (aplasia cutis, choanal and esophageal atresia); switch back to methimazole after the first trimester because of propylthiouracil hepatotoxicity.

Central retinal artery occlusion (CRAO) is a blockage of the artery that feeds the inner retina, usually by an embolus from the carotid artery or the heart, or less often by thrombosis or giant cell arteritis. Without blood flow, the inner retina quickly swells and turns pale and opaque. The fovea is the one spot where the retina is too thin to block the view, so the healthy blood supply of the choroid underneath still shows through as a cherry-red spot. The arteries look thin and may appear nearly bloodless. This man's untreated atrial fibrillation is a ready embolic source, and his sudden, painless, severe monocular loss with an afferent pupillary defect fits an arterial blockage, not a venous one.

Board-Level Insight: Central retinal artery occlusion (CRAO)—an ocular emergency most commonly due to atheroembolism (carotid plaque / Hollenhorst plaque) or cardiogenic embolism—presents with sudden, painless, severe monocular vision loss; funduscopic examination reveals diffuse ischemic retinal whitening (edema) with a prominent, classic "cherry-red spot" at the fovea.

Classic Board Trap: Contrast CRAO with central retinal vein occlusion (CRVO): CRVO is caused by thrombosis of the central retinal vein, producing a funduscopic appearance of diffuse, dramatic retinal hemorrhages across all four quadrants with dilated tortuous veins ("blood and thunder" fundus), rather than retinal pallor.

Incorrect answer explanations

• Dilated and tortuous retinal veins – venous engorgement from blocked outflow in central retinal vein occlusion (CRVO).

• Diffuse retinal hemorrhages in all four quadrants – the "blood and thunder" fundus of CRVO, not arterial occlusion.

• Macular edema with optic disc swelling – leakage from backed-up venous flow in CRVO.

• Neovascularization of the optic disc – a late response to weeks of retinal ischemia, not a finding in the first hour.

Clinical Pearls

• Treat CRAO as a stroke of the eye: look for the embolic source with carotid Doppler ultrasound and echocardiography.

• In an older patient, always ask about headache, jaw claudication, and scalp tenderness, and check erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and platelets; giant cell arteritis needs high-dose glucocorticoids right away to protect the other eye.

• A bright yellow cholesterol embolus in a retinal artery is a Hollenhorst plaque, a clue to carotid atherosclerosis.

• Branch retinal artery occlusion causes a partial field cut and a better visual outcome; central occlusion usually leaves profound permanent loss.

Blueprint Comparisons — Eye disorders (sudden vision loss)

Extra Challenge

• A 74-year-old woman with CRAO also reports new headaches and jaw pain when chewing. Which blood test should be sent immediately?

Answer: Erythrocyte sedimentation rate (with C-reactive protein), to screen for giant cell arteritis.

• Why does the fovea appear red in central retinal artery occlusion?

Answer: The fovea has no inner retinal layers to turn white, so the intact choroidal circulation beneath it still shows through.

An unsensitized Rh-negative woman (negative antibody screen) who has a second-trimester pregnancy loss has just had a potentially sensitizing fetomaternal hemorrhage, and because fetal blood type is unknown the fetus is assumed to be Rh-positive. The most appropriate step is to administer Rho(D) immune globulin within 72 hours to prevent Rh isoimmunization. The immune globulin is passive anti-D antibody that binds and clears any fetal Rh-positive red cells in the maternal circulation before her immune system can mount its own antibody response, protecting future Rh-positive fetuses from hemolytic disease. Per the American College of Obstetricians and Gynecologists (ACOG), prophylaxis is indicated after spontaneous or induced abortion at 12 weeks of gestation or later, ectopic pregnancy, second- or third-trimester bleeding or fetal death, abdominal trauma, invasive procedures, external cephalic version, routinely at 28 weeks, and within 72 hours of delivering an Rh-positive infant.

Incorrect answer explanations

• Obtain a Kleihauer-Betke test to decide whether prophylaxis is needed – the Kleihauer-Betke (acid elution) test quantifies fetal cells in maternal blood after a suspected large fetomaternal hemorrhage (trauma, abruption, delivery) so that additional doses can be calculated; it is never used to decide whether an unsensitized Rh-negative woman receives prophylaxis at all.

• Perform Rh typing of the products of conception before deciding on prophylaxis – fetal typing is rarely obtainable after a loss and would only delay treatment past the 72-hour window; the fetus is assumed Rh-positive.

• Repeat the maternal antibody screen in 6 weeks – a positive screen later would mean sensitization has already occurred, at which point immune globulin no longer helps; prophylaxis must precede antibody formation.

• Withhold prophylaxis because she received it after her previous delivery – the passive antibody wanes over about 12 weeks and confers no lasting protection; each sensitizing event in each pregnancy requires a fresh dose.

Clinical Pearls

• Who never needs it: Rh-positive mothers (they already carry the D antigen), Rh-negative mothers whose infant is confirmed Rh-negative, and Rh-negative mothers who are already sensitized (positive antibody screen) — those patients need antibody titers and, above the critical titer, serial middle cerebral artery Doppler for fetal anemia rather than immune globulin.

• Under 12 weeks: per ACOG, routine Rh testing and immune globulin are no longer recommended for spontaneous or induced abortion before 12 weeks because the alloimmunization risk is negligible; it may still be offered through shared decision-making. Older sources and some institutions still give a microdose — expect the board to test the clear indications (12 weeks and beyond, ectopic, delivery, 28 weeks) rather than this gray zone.

• A standard dose covers about 30 mL of fetal whole blood (15 mL of fetal red cells); a large hemorrhage on Kleihauer-Betke or flow cytometry means extra doses.

• ABO incompatibility (group O mother, group A or B infant) causes only mild neonatal jaundice and is not prevented by immune globulin; Kell alloimmunization ("Kell kills") causes severe fetal anemia and is also not preventable with it.

Blueprint Comparisons — Complicated Pregnancy

Extra Challenge

• A standard dose of Rho(D) immune globulin protects against approximately how much fetomaternal hemorrhage?

Answer: About 30 mL of fetal whole blood (15 mL of fetal red blood cells).

• What test is performed when a massive fetomaternal hemorrhage is suspected, and why does the result matter?

Answer: The Kleihauer-Betke test (or flow cytometry) quantifies fetal hemoglobin in the maternal circulation so that additional doses of immune globulin can be calculated to cover the full volume of fetal blood.

The dividing line between hypomania and mania is drawn by severity, not just the calendar. A hypomanic episode is at least 4 days of persistently elevated or irritable mood with increased energy plus three or more of decreased need for sleep, grandiosity, pressured speech, flight of ideas, distractibility, increased goal-directed activity, or risky behavior, and, critically, no marked functional impairment, no psychotic features, and no need for hospitalization. This patient's 6-day episode fits that description exactly; he is still going to class and working. Two months earlier he had a full major depressive episode: 3 weeks (2 weeks are required) of depressed mood and anhedonia with fatigue, hypersomnia, weight gain, and worthlessness, meeting the five-symptom threshold. At least one hypomanic episode plus at least one major depressive episode, with no lifetime manic episode, defines bipolar II disorder. Should a future episode bring psychosis, marked impairment, or hospitalization, the diagnosis is reclassified as bipolar I.

Incorrect answer explanations

• Bipolar I disorder – requires at least one manic episode, defined by marked impairment, psychosis, or hospitalization (or symptoms lasting at least 7 days); a depressive episode is common but not required for the diagnosis.

• Cyclothymic disorder – at least 2 years (1 year in children) of numerous hypomanic and depressive symptoms that never satisfy full criteria for a hypomanic, manic, or major depressive episode.

• Major depressive disorder – requires that the patient has never had a hypomanic or manic episode; documenting one changes the diagnosis and the treatment.

• Schizoaffective disorder – requires delusions or hallucinations for at least 2 weeks in the absence of a major mood episode; this patient has no psychotic symptoms.

Clinical Pearls

Bipolar II patients spend far more time depressed than hypomanic and often present asking for an antidepressant, so always screen every depressed patient for past hypomania before prescribing. Antidepressant monotherapy can flip the patient into hypomania or mania and is avoided; quetiapine, lamotrigine, or lithium are the preferred agents for the depressive pole. Lithium has the best evidence for reducing suicide risk but needs monitoring of renal and thyroid function and levels. Rule out a substance or medication cause (stimulants, corticosteroids) and hyperthyroidism before labeling a first episode. A first hypomanic episode after age 50 warrants a medical and neurologic workup.

Blueprint Comparisons — Bipolar and related disorders

Extra Challenge

• Which maintenance medication has the strongest evidence for reducing suicide risk in bipolar disorder, and what must be monitored?

Answer: Lithium; monitor serum levels, renal function, thyroid function, and calcium, and avoid dehydration, nonsteroidal anti-inflammatory drugs, and thiazides, which raise levels.

• A woman with bipolar II disorder who is planning pregnancy asks about valproate. What is the concern?

Answer: Valproate is teratogenic (neural tube defects and lower cognitive outcomes) and is avoided in women of childbearing potential; lamotrigine is a safer alternative for the depressive pole.

Persistent hypotension with cool mottled extremities, oliguria, and a rising lactate despite adequate filling after a large anterior infarction is cardiogenic shock: end-organ hypoperfusion from pump failure, with a low cardiac index, high filling pressures, and high systemic vascular resistance. When the patient is frankly hypotensive, the first pharmacologic priority is to restore perfusion pressure, and norepinephrine is the first-line vasopressor per the American College of Cardiology/American Heart Association (ACC/AHA) and the Society for Cardiovascular Angiography and Interventions. Its predominant alpha-1 vasoconstriction raises mean arterial pressure and therefore coronary perfusion pressure, with modest beta-1 inotropy and less tachyarrhythmia than dopamine, which increases arrhythmias and mortality in cardiogenic shock, or epinephrine, which produces more refractory shock and lactic acidosis. An inotrope such as dobutamine is layered on after perfusion pressure is restored when cardiac output remains inadequate; dobutamine alone is the first agent only in the normotensive low-output patient, because its beta-2 vasodilation can deepen hypotension. Pressors are a bridge: definitive therapy is emergent revascularization of the culprit artery, with mechanical circulatory support for refractory shock.

Incorrect answer explanations

• Intravenous dobutamine – a beta-1 inotrope that raises cardiac output but also causes beta-2 vasodilation; with a systolic pressure of 78 mm Hg it can worsen hypotension, so it is added only after norepinephrine restores perfusion pressure.

• Intravenous furosemide – relieves pulmonary congestion once perfusion is restored, but diuresing a hypotensive, hypoperfused patient lowers preload further and aggravates renal and end-organ injury.

• Intravenous nitroglycerin – reduces preload and afterload and relieves ischemic pain, all harmful in a patient whose problem is inadequate perfusion pressure; nitrates are contraindicated in hypotensive shock.

• Oral metoprolol – beta-blockade reduces contractility and heart rate, exactly the wrong physiology in pump failure; it is contraindicated in acute cardiogenic shock and started only after the patient is stable off inotropic support.

Clinical Pearls

• Hemodynamic signature of cardiogenic shock: cardiac index below 2.2 L/min/m², pulmonary capillary wedge pressure above 15 mm Hg, and elevated systemic vascular resistance (cold and wet).

• Right ventricular infarction (inferior ST-elevation myocardial infarction, hypotension, clear lungs, elevated jugular venous pressure) is preload-dependent: give fluids and strictly avoid nitrates and diuretics.

• Routine intra-aortic balloon counterpulsation does not reduce mortality in infarct-related cardiogenic shock; mechanical support is reserved for selected refractory cases.

• In infarct-related shock with multivessel disease, revascularize the culprit lesion only at the index procedure; immediate multivessel intervention increases mortality.

• Always exclude a mechanical complication (papillary muscle rupture, ventricular septal rupture, free-wall rupture) with echocardiography, since these need emergent surgery rather than pressors.

Blueprint Comparisons — Shock

Extra Challenge

• The same patient is started on norepinephrine and his blood pressure rises to 102/64 mm Hg, but his lactate stays at 4.5 mmol/L, his extremities remain cool, and his cardiac index is 1.8 L/min/m². What is the next step?

Answer: Add dobutamine; perfusion pressure has been restored but cardiac output has not, which is exactly when an inotrope is layered onto the vasopressor, while emergent revascularization proceeds in parallel.

• A patient with an inferior ST-elevation myocardial infarction becomes hypotensive after one sublingual nitroglycerin tablet; his lungs are clear and his jugular venous pressure is elevated. What happened, and what is the treatment?

Answer: Right ventricular infarction from proximal right coronary artery occlusion; the preload-dependent right ventricle collapsed with venodilation. Give an intravenous fluid bolus, withhold nitrates and diuretics, and proceed to reperfusion.

Cystic fibrosis is an autosomal recessive disease of the CFTR chloride channel that produces thick, dehydrated secretions in the airways, pancreas, intestine, and reproductive tract. It is confirmed by an elevated sweat chloride concentration (≥60 mmol/L) on quantitative pilocarpine iontophoresis, or by identification of two disease-causing CFTR mutations. The sweat chloride test remains the gold standard: a value of ≥60 mmol/L is diagnostic, 30–59 mmol/L is intermediate and requires repeat testing plus CFTR genetic analysis, and ≤29 mmol/L makes cystic fibrosis unlikely. Clinical features (failure to thrive, chronic cough, steatorrhea, meconium ileus) or a positive newborn screen raise suspicion, but none of them confirms the diagnosis on its own.

Incorrect answer explanations

• Elevated immunoreactive trypsinogen level: IRT is the newborn screening test, not a confirmatory test. It has many false positives, and every elevated IRT must be followed by a sweat chloride test and usually CFTR genetic testing.

• Positive family history: Family history raises suspicion for this autosomal recessive disease but cannot establish the diagnosis; most affected infants are born to asymptomatic carrier parents with no known history.

• Recurrent respiratory infections: A hallmark clinical feature, but nonspecific. The diagnosis relies on laboratory confirmation with sweat chloride or CFTR genotyping.

• Low fecal elastase: Documents pancreatic insufficiency and guides enzyme dosing, but it is not specific to cystic fibrosis and is not part of the diagnostic criteria.

Clinical Pearls

• Cystic fibrosis is autosomal recessive; the most common mutation is F508del on chromosome 7, affecting the CFTR chloride channel.

• Sweat chloride cutoffs: ≥60 mmol/L diagnostic, 30–59 intermediate, ≤29 unlikely. Test infants after 2 weeks of age and ≥2 kg when adequate sweat can be collected.

• Meconium ileus in a newborn is cystic fibrosis until proven otherwise. Other clues: nasal polyps in a child, rectal prolapse, salty-tasting skin, infertility from congenital absence of the vas deferens.

• Airway pathogens shift with age: Staphylococcus aureus and Haemophilus influenzae early, then Pseudomonas aeruginosa; Burkholderia cepacia carries a poor prognosis.

• CFTR modulators (elexacaftor/tezacaftor/ivacaftor) have transformed outcomes for patients with at least one eligible mutation.

• Immunoreactive trypsinogen screens, sweat chloride confirms, CFTR genotyping defines modulator eligibility, and fecal elastase measures pancreatic insufficiency; keep the four tests straight.

Blueprint Comparisons — Obstructive Pulmonary Disease

Extra Challenge

• An infant with a positive newborn screen has a sweat chloride of 45 mmol/L. What is the next step?

Answer: This is an intermediate result; repeat the sweat test and obtain CFTR genetic analysis, because a value of 30–59 mmol/L neither confirms nor excludes cystic fibrosis.

• Why does a newborn with cystic fibrosis develop meconium ileus?

Answer: Defective CFTR chloride secretion produces thick, dehydrated intestinal secretions and pancreatic enzyme deficiency, so the meconium becomes viscous and obstructs the terminal ileum.

Recurrent severe, throbbing, unilateral headaches with nausea, photophobia, and phonophobia, no aura, and a normal examination and imaging define migraine without aura. The decision here is acute (abortive) versus preventive (prophylactic) therapy. Abortive drugs stop an attack in progress; preventive drugs lower attack frequency and are indicated when migraines are frequent (about 4 or more headache days per month), disabling despite acute treatment, or when acute medications are being overused. With 5 to 6 attacks per month and lost work days, this patient meets that threshold, and propranolol, a nonselective beta-blocker, is an established first-line preventive alongside metoprolol, topiramate, amitriptyline, and valproate. Every other option listed is an acute-attack drug.

Incorrect answer explanations

• Acetaminophen-aspirin-caffeine – an over-the-counter abortive combination for mild to moderate attacks; it has no effect on attack frequency and, overused, causes rebound headache.

• Hydrocodone – opioids are a last-resort rescue medication in migraine; they do not prevent attacks and are the strongest drivers of medication-overuse headache and dependence.

• Ibuprofen – a nonsteroidal anti-inflammatory drug (NSAID) is first-line acute therapy, which she already uses; it does not reduce frequency.

• Sumatriptan – the triptan is first-line acute therapy for moderate to severe attacks, but it treats only the attack in progress.

Clinical Pearls

• Choose the preventive by comorbidity: topiramate if overweight (weight loss, kidney stones, paresthesias), amitriptyline if depressed or insomniac, beta-blocker if hypertensive; avoid valproate and topiramate in pregnancy and beta-blockers in asthma.

• Calcitonin gene-related peptide (CGRP) antagonists — monoclonal antibodies (erenumab, fremanezumab, galcanezumab) and gepants (atogepant, rimegepant) — are preventives for patients who fail or cannot tolerate first-line agents; onabotulinumtoxinA is for chronic migraine (15 or more headache days per month).

• Keep acute medication use under about 10 days per month for triptans, opioids, and combination analgesics (15 for simple analgesics) to avoid medication-overuse headache.

• Give any preventive a 2 to 3 month trial at an adequate dose before calling it a failure.

• Triptans and ergotamines are contraindicated in coronary artery disease, uncontrolled hypertension, prior stroke, and hemiplegic or basilar migraine.

Blueprint Comparisons — Headaches

Extra Challenge

• A patient with migraine and uncontrolled asthma needs prevention. Why avoid propranolol, and what is a reasonable alternative?

Answer: Nonselective beta-blockers can provoke bronchospasm; choose another first-line preventive such as topiramate or amitriptyline.

• A migraine patient uses sumatriptan more than 10 days per month and now has daily headache. What is the likely diagnosis and management?

Answer: Medication-overuse (rebound) headache — withdraw the overused acute drug and start an appropriate preventive.

Frostbite is a freezing cold injury in which ice crystals form within tissue, producing pale, waxy, firm, insensate skin with absent capillary refill. The depth declares itself after rewarming: clear (serous) blisters with returning sensation indicate superficial frostbite and a favorable prognosis, while hemorrhagic blisters, persistent anesthesia, and hard nonblanching tissue mark deep frostbite extending into muscle and bone. Returning sensation plus clear blisters therefore places this injury at the superficial end of the spectrum.

Incorrect answer explanations

• Immersion foot: follows prolonged wet exposure at above-freezing temperatures; the tissue is macerated, pale, and painful but never frozen firm, and clear blisters after rapid water-bath rewarming are not the pattern.

• Pernio: chilblains are delayed pruritic, painful red-purple papules and plaques appearing hours after damp nonfreezing cold, without ice crystal formation or insensate waxy tissue.

• Raynaud phenomenon: episodic, reversible digital vasospasm with white-blue-red color changes triggered by cold or stress; tissue does not freeze or blister.

• Cellulitis: a bacterial dermal and subcutaneous infection producing warm, erythematous, tender, spreading skin with fever — the opposite of cold, pale, firm, insensate tissue.

Clinical Pearls

• Clear blisters = superficial; hemorrhagic blisters = deep — the highest-yield frostbite discriminator, and it is assessed only after rewarming.

• Rapid rewarming in circulating water at 98.6–102.2°F (37–39°C) with generous parenteral analgesia; rewarming is intensely painful.

• Never rub the tissue, never use dry radiant heat, and never rewarm in the field if refreezing is possible — freeze-thaw-refreeze cycles multiply tissue destruction.

• Update tetanus status, elevate and splint the part, drain tense clear blisters selectively, and leave hemorrhagic blisters intact; ibuprofen is a reasonable antiprostaglandin adjunct.

• Severe frostbite with absent perfusion after rewarming → consider thrombolysis (tPA) within 24 hours at a center with expertise; iloprost is an alternative where available.

• Delay surgical decisions — demarcation of nonviable tissue takes weeks to months ("frostbite in January, amputate in July").

Blueprint Comparisons — Skin Integrity

Extra Challenge

Q: After rewarming, a climber's toes develop tense hemorrhagic blisters and remain insensate. What does this indicate?

A: Deep frostbite involving the dermis and deeper structures, with a much worse prognosis — assess perfusion and consider thrombolysis if within 24 hours of thawing.

Q: Why is field rewarming discouraged during a prolonged wilderness evacuation?

A: Because refreezing after thawing causes far greater tissue destruction than delayed rewarming — keep the part frozen and protected until definitive rewarming can be maintained.

References

• Cold Injuries (Frostbite) — Smarty PANCE

• Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Frostbite (2024 update)

• NCCPA PANCE Blueprint — Dermatologic System: Skin Integrity

A microcytic, hypochromic anemia with an elevated red cell distribution width, reactive thrombocytosis, and a ferritin of 6 ng/mL in a woman with menorrhagia is iron deficiency anemia, the most common anemia worldwide. Ferritin is the single most useful confirmatory test: a value below 30 ng/mL indicates iron deficiency, and a value this low is diagnostic. Serum iron and transferrin saturation are low while total iron-binding capacity (TIBC) is high. Because she is a menstruating woman with an obvious source of loss, no further search for bleeding is needed. First-line treatment is oral iron replacement with ferrous sulfate, taken on an empty stomach with vitamin C and away from calcium, antacids, and proton pump inhibitors. Expect reticulocytosis within about a week and a hemoglobin rise of roughly 1 g/dL every 2 weeks, and continue iron for several months after the hemoglobin normalizes to refill stores.

Incorrect answer explanations

• Cyanocobalamin – vitamin B12 deficiency causes a macrocytic anemia (MCV above 100 fL) with hypersegmented neutrophils and neurologic findings such as paresthesias and posterior column signs.

• Epoetin alfa – erythropoiesis-stimulating agents treat anemia of chronic kidney disease or chemotherapy and are ineffective in an iron-deficient patient until iron is repleted.

• Folic acid – folate deficiency is also macrocytic (alcohol use, pregnancy, methotrexate) and has nothing to do with microcytosis and a low ferritin.

• Prednisone – treats warm autoimmune hemolytic anemia, which is normocytic with reticulocytosis, high lactate dehydrogenase and indirect bilirubin, low haptoglobin, and a positive direct antiglobulin (Coombs) test.

Clinical Pearls

• Alternate-day dosing of oral iron is now preferred: each dose raises hepcidin for about 24 hours and blocks absorption of the next, so every-other-day dosing absorbs more with fewer gastrointestinal side effects.

• Intravenous iron is reserved for intolerance of oral iron, malabsorption (celiac disease, bariatric surgery, inflammatory bowel disease), chronic kidney disease, ongoing losses that outpace oral replacement, or the need for rapid repletion before surgery.

• Iron deficiency in a man or postmenopausal woman is gastrointestinal blood loss until proven otherwise — order colonoscopy and upper endoscopy.

• Failure to respond within 2–4 weeks means nonadherence, malabsorption, ongoing bleeding, or the wrong diagnosis; recheck the ferritin and think about celiac disease and Helicobacter pylori.

• Buzzwords: pica (ice craving, pagophagia), koilonychia (spoon nails), angular cheilitis, restless legs, and Plummer-Vinson syndrome (esophageal web with dysphagia).

Blueprint Comparisons — Cytopenias (Anemias)

Extra Challenge

• Her 62-year-old father has the same laboratory picture. How does the workup differ?

Answer: Iron deficiency in a man (or a postmenopausal woman) requires evaluation for gastrointestinal blood loss with colonoscopy and upper endoscopy, because colorectal cancer must be excluded.

• A patient with an MCV of 62 fL and a hemoglobin of 11.5 g/dL has a normal ferritin and a normal red cell distribution width. What is the likely diagnosis, and what should you avoid?

Answer: Thalassemia trait (microcytosis out of proportion to a mild anemia); confirm with hemoglobin electrophoresis and do not prescribe iron, which causes iron overload.

As nephrons are destroyed, the surviving tubules dilate and hypertrophy, so casts formed in them are unusually wide, and prolonged stasis degenerates the cast matrix into a glassy, sharply outlined cylinder with squared-off ends and cracks. These broad waxy casts are the sediment finding most specific for chronic kidney disease, defined as kidney damage or an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73 m2 persisting for at least 3 months and staged by GFR category (G1–G5) and albuminuria category (A1–A3). Hematuria and proteinuria are extremely common in chronic kidney disease but occur across acute and chronic disease and many nonrenal conditions, and hyaline casts are a normal finding. This man's 4-year decline in eGFR and small, echogenic kidneys confirm a chronic process.

Incorrect answer explanations

• Hematuria – nonspecific; dysmorphic red cells and red cell casts point to glomerulonephritis, while isomorphic red cells suggest stones, infection, or urothelial malignancy. It does not distinguish chronic from acute injury.

• Hyaline casts – composed of Tamm-Horsfall mucoprotein, colorless and low-refractile; they appear in normal concentrated urine, after strenuous exercise, with volume depletion, and with loop diuretics, and carry no specificity for disease.

• Muddy brown granular casts – the signature of acute tubular necrosis: sloughed tubular epithelial cells and debris after ischemia or a nephrotoxin, indicating an acute, potentially reversible process rather than chronic scarring.

• Proteinuria – albuminuria is a staging criterion and the strongest predictor of progression, but it is also present in acute glomerulonephritis, nephrotic syndrome, preeclampsia, fever, and orthostatic states.

Clinical Pearls

• Cast cheat sheet: broad waxy = chronic kidney disease; muddy brown granular = acute tubular necrosis; red cell = glomerulonephritis; white cell = pyelonephritis or interstitial nephritis; fatty with Maltese cross = nephrotic syndrome; hyaline = normal.

• Confirm chronicity with two measurements at least 3 months apart; when duration is unknown, small echogenic kidneys with cortical thinning on ultrasound indicate chronic disease.

• Four pillars of therapy per KDIGO: an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) for albuminuria, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, blood pressure control (systolic target under 120 mm Hg when tolerated), and finerenone in diabetic kidney disease.

• Monitor and treat complications: anemia (iron, then an erythropoiesis-stimulating agent with a hemoglobin target of 10–11.5 g/dL), metabolic acidosis, hyperkalemia, and secondary hyperparathyroidism with hyperphosphatemia.

• Refer to nephrology when eGFR falls below 30 mL/min/1.73 m2, and plan dialysis access or transplantation before stage 5.

Blueprint Comparisons — Renal Diseases

Extra Challenge

• A patient with a creatinine of 3.0 mg/dL and no prior labs has muddy brown granular casts on microscopy. How does the sediment change the assessment?

Answer: It points to acute tubular necrosis, an acute and often reversible injury, so the priority becomes restoring renal perfusion and removing nephrotoxins rather than staging and treating chronic kidney disease.

• Why are the casts of advanced chronic kidney disease described as "broad"?

Answer: Nephron loss forces the surviving tubules to dilate and hypertrophy, so casts formed in their lumens are two to six times normal width, the morphologic footprint of reduced nephron mass.

Acute otitis externa (swimmer's ear) is a bacterial infection of the skin lining the ear canal, most often Pseudomonas aeruginosa or Staphylococcus aureus. Water softens the canal skin and washes away protective earwax, so bacteria get in. The canal swells, so pulling on the tragus hurts and pus drains. Treatment is topical: clean the canal, place a wick if it is swollen shut, and give antibiotic drops. The drop choice depends on the eardrum. If the tympanic membrane cannot be seen, assume it may be perforated — an aminoglycoside drop such as neomycin could then reach the inner ear and cause permanent hearing loss. A fluoroquinolone drop (ofloxacin or ciprofloxacin) is not ototoxic and is safe either way. This swimmer's drum is hidden behind a swollen canal and she is already failing a neomycin drop, so she should switch to ofloxacin through the wick.

Board-Level Insight: In acute otitis externa when the tympanic membrane (TM) is perforated, has a patent tympanostomy tube, or cannot be fully visualized due to severe canal edema, topical fluoroquinolone otic drops (ofloxacin or ciprofloxacin-dexamethasone) are the only safe first-line choice because they are non-ototoxic.

Classic Board Trap: Aminoglycoside-containing otic preparations (neomycin-polymyxin B-hydrocortisone, gentamicin) are strictly contraindicated whenever the tympanic membrane is non-intact or non-visualized! Aminoglycosides crossing into the middle and inner ear cause permanent sensorineural hearing loss and vestibular toxicity.

Incorrect answer explanations

• Clotrimazole otic solution – an antifungal for otomycosis, which causes intense itching with fluffy white or black debris; this is purulent bacterial otitis externa.

• Continued neomycin-polymyxin B-hydrocortisone drops – neomycin is ototoxic when the drum may be open and is a frequent cause of contact allergy that can look like treatment failure.

• Oral amoxicillin – the treatment for acute otitis media; it does not cover Pseudomonas and oral drugs add little for a canal infection.

• Oral ciprofloxacin – systemic therapy is for severe infection with cellulitis beyond the canal or necrotizing otitis externa, not an uncomplicated case in a healthy teen.

Clinical Pearls

• Tympanostomy tubes count as a hole in the drum — same rule: fluoroquinolone drops only.

• Tragal tenderness points to otitis externa; in acute otitis media the canal is not tender and the drum bulges.

• Suspect necrotizing (malignant) otitis externa in an older adult with diabetes or immunosuppression who has severe deep night pain, granulation tissue on the canal floor, or a facial nerve palsy — this is a Pseudomonas skull-base osteomyelitis that needs imaging and systemic antibiotics.

• Prevention for swimmers: dry the ears after swimming, avoid cotton swabs, and use acidifying drops only when the drum is known to be intact.

Blueprint Comparisons — Ear Disorders

Extra Challenge

• A 6-year-old with tympanostomy tubes develops purulent ear drainage. Which class of topical antibiotic should be used?

Answer: A fluoroquinolone (ofloxacin or ciprofloxacin) otic drop — aminoglycoside drops are avoided because the tubes open a path to the middle ear.

• A 72-year-old man with poorly controlled diabetes has weeks of severe ear pain, granulation tissue on the canal floor, and new facial weakness. What is the most likely diagnosis?

Answer: Necrotizing (malignant) otitis externa.

Osgood-Schlatter disease (tibial tubercle apophysitis) is an overuse traction injury of the immature tibial tuberosity caused by repetitive quadriceps contraction transmitted through the patellar tendon during an adolescent growth spurt. It classically affects physically active boys aged 10 to 15 years (and girls aged 8 to 13 years) involved in jumping and sprinting sports (basketball, soccer, volleyball, gymnastics). Physical examination is diagnostic and reveals localized swelling, warmth, and a firm, tender bony prominence directly over the tibial tuberosity, with pain reproduced by resisted knee extension or squatting.

Board-Level Insight: Osgood-Schlatter disease is a clinical diagnosis that does not require routine radiographs unless atypical red flags (night pain, systemic symptoms, acute trauma) are present; when lateral knee radiographs are obtained, they show fragmentation/irregularity of the tibial tubercle apophysis with overlying soft-tissue swelling.

Classic Board Trap: Watch the exact anatomic landmark in adolescent anterior knee pain: point tenderness at the tibial tuberosity is Osgood-Schlatter disease, whereas point tenderness at the inferior pole of the patella in a slightly younger child (10–12 years) is Sinding-Larsen-Johansson syndrome (and calcaneal heel pain in an 8–12-year-old is Sever disease).

Incorrect answer explanations:

• Chondromalacia patella — Softening of the articular cartilage on the undersurface of the patella (patellofemoral pain syndrome); causes vague retropatellar pain worse when walking down stairs or sitting with flexed knees for prolonged periods ("moviegoer's sign").

• Discoid meniscus — Congenital malformation (usually of the lateral meniscus) presenting with lateral joint-line popping, clicking, and incomplete extension in children.

• Osteochondritis dissecans — Focal osteonecrosis and separation of a subchondral bone/cartilage fragment (most commonly on the lateral aspect of the medial femoral condyle), causing joint effusion and mechanical locking.

• Sinding-Larsen-Johansson syndrome — Traction apophysitis at the proximal origin of the patellar tendon on the inferior pole of the patella rather than the tibial tubercle.

Clinical Pearls:

• Management of Osgood-Schlatter disease is strictly conservative and self-limiting: activity as tolerated (complete sports cessation is unnecessary unless pain is severe), ice after exercise, NSAIDs, infrapatellar strap, and quadriceps/hamstring stretching.

• Symptoms resolve spontaneously once the proximal tibial growth plate closes (around age 14 in girls and age 16 in boys), though a painless residual bony bump at the tibial tubercle often persists into adulthood.

Blueprint Comparisons (Adolescent Anterior Knee Pain & Apophysitis):

Extra Challenge:

• What is the pediatric traction apophysitis that affects the Achilles tendon insertion on the calcaneus and is the most common cause of heel pain in young athletes aged 8 to 12 years?

Answer: Sever disease (calcaneal apophysitis).

• Why are intra-articular or peritendinous corticosteroid injections contraindicated in Osgood-Schlatter disease?

Answer: Corticosteroid injections weaken the patellar tendon, predisposing to patellar tendon rupture and subcutaneous fat atrophy without accelerating resolution of this benign, self-limited condition.

Varenicline is the most effective first-line agent for smoking cessation and is recommended over nicotine replacement therapy (NRT) and bupropion — even in patients with cardiovascular or psychiatric comorbidity. As an α4β2 nicotinic partial agonist, it eases cravings and withdrawal while blunting the reward of smoking. Because he has already failed nicotine-patch monotherapy, escalating to the most effective agent is the logical next step.

Why not tailor to bupropion for his concerns? Bupropion does limit weight gain and can treat depression — but he denies active psychiatric symptoms, so there is no mood disorder to co-treat, and bupropion has lower quit rates with no proven benefit after acute coronary syndrome. His weight worry and CAD do not contraindicate varenicline: the EAGLES trial showed no increase in neuropsychiatric events, and later data confirmed cardiovascular safety in stable disease (he is 8 months post-MI). Bupropion becomes the better choice mainly when varenicline is contraindicated or when active depression itself requires treatment.

Incorrect answer explanations:

• Bupropion SR: Helps with weight gain and depression, but there is no active depression to treat here; lower efficacy than varenicline and no post-ACS benefit.

• Cytisine: A partial nicotinic agonist used abroad; not FDA-approved in the U.S. and with limited CV safety data.

• Nicotine patch monotherapy: He already failed patch therapy, and single-agent NRT is the least effective option.

• Combination NRT (patch + gum): Better than single-agent NRT and useful if varenicline were contraindicated, but varenicline has higher quit rates and he already failed the patch.

Clinical Pearls

• Varenicline is the most effective single agent for cessation and is first-line per ATS 2020 guidelines — over NRT and bupropion.

• EAGLES trial: varenicline is safe in stable CVD and in psychiatric patients, with no increase in major cardiovascular or neuropsychiatric events.

• Bupropion is favored mainly when there is active depression to co-treat, a strong weight-gain concern, or when varenicline is contraindicated. Avoid it in seizure or eating disorders.

• Nausea is varenicline’s most common side effect — minimized by gradual titration and taking with food and water.

Blueprint Comparisons — smoking-cessation efficacy (approx. 6-month abstinence)

Extra Challenge

• How do you minimize varenicline’s most common side effect?

Answer: Its main side effect is nausea; reduce it with gradual dose titration (0.5 mg daily → 0.5 mg BID → 1 mg BID) and taking it with food and water.

• Why do guidelines favor varenicline over bupropion in patients with cardiovascular disease?

Answer: Varenicline has higher quit rates and no increased cardiovascular risk in large trials, whereas bupropion is less effective and showed no benefit in post-ACS patients.

Suspected nephrolithiasis (renal colic) in a nonpregnant adult calls for a study that confirms the stone, sizes and localizes it, detects obstruction (hydronephrosis), and excludes dangerous mimics of flank pain. Noncontrast helical computed tomography (CT) of the abdomen and pelvis does all of this with the highest sensitivity and specificity of any modality, needs no iodinated contrast, is fast, detects stones of essentially every composition (including radiolucent uric acid stones that plain films miss), and reveals alternative diagnoses. A low-dose CT protocol is preferred when body habitus allows, and CT is the study to choose when the question asks for the most accurate or confirmatory test.

Incorrect answer explanations

• Intravenous pyelogram – largely obsolete; slower and less sensitive than CT, and it requires iodinated contrast that is unsafe in renal insufficiency or contrast allergy.

• Magnetic resonance imaging (MRI) – visualizes calcified stones poorly; reserved for pregnancy when ultrasound is inconclusive.

• Plain radiographs – a kidney-ureter-bladder (KUB) film may show large radiopaque stones but misses radiolucent uric acid stones and cannot assess obstruction.

• Ultrasound – the first-line study in pregnancy and when limiting radiation, but it is less sensitive than CT for ureteral stones and for defining stone size and location.

Clinical Pearls

• Stone size predicts passage: stones ≤5 mm usually pass spontaneously; stones >10 mm rarely pass without intervention, and any stone not passed in 6–8 weeks typically needs removal.

• Pain control: nonsteroidal anti-inflammatory drugs (NSAIDs, e.g., ketorolac) are first-line; add tamsulosin (medical expulsive therapy) for distal ureteral stones 5–10 mm. Forcing fluids does not speed passage.

• Obstructing stone plus infection (fever, pyuria, sepsis) is a urologic emergency requiring urgent decompression with a ureteral stent or percutaneous nephrostomy, not antibiotics alone.

• An ultrasound-first strategy is acceptable in the emergency department to limit radiation, but a negative or equivocal ultrasound with persistent suspicion still needs CT.

Blueprint Comparisons — Acute Flank Pain

Extra Challenge

• A 30-year-old man with a history of nephrolithiasis presents with flank pain and microscopic hematuria. His body mass index is 34 kg/m². Which CT protocol should be used?

Answer: Standard-dose noncontrast CT — low-dose protocols lose accuracy in patients with a body mass index above 30 kg/m².

• A 26-year-old woman who is 22 weeks pregnant presents with right flank pain and microscopic hematuria. What is the most appropriate initial imaging study?

Answer: Renal and pelvic ultrasound — it avoids ionizing radiation; if inconclusive with persistent suspicion, magnetic resonance urography (without gadolinium) is the next step, reserving CT for when it is essential.

Hypotension, distended neck veins, a hyperresonant hemithorax with absent breath sounds, and tracheal deviation away from the affected side in a trauma patient are the bedside diagnosis of tension pneumothorax: air enters the pleural space through a one-way leak, intrapleural pressure rises until the mediastinum shifts, the venae cavae kink, venous return fails, and obstructive shock follows. Because it kills within minutes, treatment precedes imaging. The immediate step is needle decompression with a large-bore (14-gauge), 8 cm or longer catheter at the 4th or 5th intercostal space in the anterior-to-mid axillary line (thinner chest wall; preferred in adults) or the 2nd intercostal space in the midclavicular line, inserted directly over the top of the rib to avoid the intercostal neurovascular bundle. Finger thoracostomy is an equally acceptable alternative, particularly in intubated patients. Decompression converts tension into a simple pneumothorax, so tube thoracostomy follows immediately as definitive management.

Incorrect answer explanations

• CT scan of the chest – requires moving an unstable patient out of the resuscitation bay; tension physiology progresses to cardiac arrest in that window. CT is for the stable patient with occult or complex thoracic injury.

• Portable chest radiograph – even a bedside film costs time this patient does not have, and a positive film adds nothing to a diagnosis already made clinically. Radiography is for suspected simple pneumothorax without tension physiology.

• Supplemental oxygen and observation – he is already on a non-rebreather at 84%; the problem is mechanical compression of the mediastinum, and observation guarantees arrest.

• Tube thoracostomy after radiographic confirmation – a chest tube is the correct definitive treatment, but making it contingent on a film adds fatal delay. Decompress first, then place the tube.

Clinical Pearls

• Tracheal deviation and distended neck veins are late and often absent findings; do not require them before decompressing a hypotensive trauma patient with unilateral absent breath sounds. Neck veins may also be flat if the patient is hypovolemic.

• A standard 5 cm catheter fails to reach the pleura in many adults at the 2nd intercostal space, especially women and patients with obesity; use a catheter of at least 8 cm.

• Positive-pressure ventilation converts a simple pneumothorax into a tension pneumothorax: suspect it in any intubated trauma patient who suddenly becomes hypotensive with rising peak airway pressures.

• Cardiac tamponade is the mimic: Beck triad (hypotension, distended neck veins, muffled heart sounds) but with equal breath sounds, no tracheal deviation, pulsus paradoxus, and low-voltage QRS or electrical alternans. Bedside extended focused assessment with sonography for trauma (eFAST) separates the two in seconds.

• Persistent large air leak with failure of the lung to re-expand after a chest tube suggests tracheobronchial injury; obtain bronchoscopy and thoracic surgery consultation.

Blueprint Comparisons — Pleural Diseases

Extra Challenge

• What bedside finding distinguishes massive hemothorax from tension pneumothorax when both present with shock and absent unilateral breath sounds?

Answer: Dullness to percussion with flat neck veins in hemothorax, versus hyperresonance with distended neck veins in tension pneumothorax.

• An intubated trauma patient suddenly becomes hypotensive while peak airway pressures climb. What is the diagnosis and the next step?

Answer: Positive-pressure ventilation has converted a simple pneumothorax into a tension pneumothorax; perform immediate needle or finger decompression on the side with absent breath sounds, then place a chest tube.

Cushing syndrome refers to the clinical manifestations of chronic glucocorticoid (cortisol) excess from any source—most commonly iatrogenic exogenous corticosteroid therapy overall, and most commonly an ACTH-secreting pituitary adenoma (Cushing disease) among endogenous causes.

Chronic hypercortisolism redistributes adipose tissue from the limbs to the trunk and face—producing central (truncal) obesity, a rounded plethoric face ("moon facies"), and a dorsocervical and supraclavicular fat pad ("buffalo hump")—while simultaneously driving peripheral protein catabolism. Protein breakdown in skeletal muscle and dermis leads to wasted, thin extremities with proximal muscle weakness (difficulty rising from a chair or climbing stairs), skin fragility with easy bruising, and wide (>1 cm) reddish-purple (violaceous) abdominal striae. Excess cortisol and adrenal androgens also cause hypertension, hyperglycemia (insulin resistance), osteoporosis, neuropsychiatric mood changes, hirsutism, and menstrual irregularities (oligomenorrhea or amenorrhea).

Board-Level Insight: The most specific clinical signs that distinguish true Cushing syndrome from simple obesity are catabolic protein-wasting features: proximal muscle weakness with thin extremities, wide (>1 cm) violaceous striae, and easy bruising / dermal atrophy.

Classic Board Trap: Do not confuse Cushing syndrome (the broad umbrella term for hypercortisolism from any cause, most commonly exogenous prednisone) with Cushing disease (specifically an ACTH-producing anterior pituitary adenoma). Also remember the 3 first-line screening tests to confirm hypercortisolism before ordering ACTH levels or imaging: late-night salivary cortisol, 24-hour urinary free cortisol, and the overnight 1-mg low-dose dexamethasone suppression test.

• Addison disease: Primary adrenal insufficiency presents with the exact opposite picture: weight loss, anorexia, orthostatic hypotension, hyponatremia, hyperkalemia, and ACTH-driven hyperpigmentation of skin creases and oral mucosa.

• Hypothyroidism: Causes fatigue, cold intolerance, dry skin, delayed deep tendon reflex relaxation, bradycardia, and typically menorrhagia (heavy menses) rather than catabolic extremity wasting and violaceous striae.

• Pituitary insufficiency: Causes deficiency of anterior pituitary hormones (ACTH, TSH, LH/FSH, GH), resulting in hypotension, hypoglycemia, and weight loss rather than hypercortisolism.

• Primary hyperaldosteronism: Autonomous aldosterone secretion (Conn syndrome) causes hypertension and hypokalemia without Cushingoid body habitus, moon facies, or violaceous striae.

Clinical Pearls:

• Stepwise Diagnostic Workup: Step 1: Confirm hypercortisolism with at least two of the three screening tests (overnight 1-mg dexamethasone suppression test, 24-hour urinary free cortisol, or late-night salivary cortisol). Step 2: Measure plasma ACTH to separate ACTH-dependent (pituitary Cushing disease or ectopic ACTH from small cell lung cancer) from ACTH-independent (adrenal adenoma/carcinoma) causes. Step 3: Use the high-dose (8-mg) dexamethasone suppression test—pituitary Cushing disease suppresses cortisol (>50% reduction), whereas ectopic ACTH does not suppress.

• Metabolic & Hematologic Effects: Cortisol excess causes hyperglycemia, hypokalemic metabolic alkalosis (via mineralocorticoid receptor cross-reactivity at high cortisol levels), and neutrophilic leukocytosis (via demargination of neutrophils) with decreased eosinophils and lymphocytes.

Blueprint Comparisons (Diseases of the Adrenal Glands):

Extra Challenge:

• What is the most common overall cause of Cushing syndrome in clinical practice, and what is the most common endogenous cause?

Answer: The most common overall cause is iatrogenic (exogenous) glucocorticoid administration (e.g., chronic prednisone therapy); the most common endogenous cause is Cushing disease (an ACTH-secreting anterior pituitary adenoma).

• How does the high-dose (8-mg) dexamethasone suppression test differentiate pituitary Cushing disease from an ectopic ACTH-producing tumor (such as small cell lung carcinoma)?

Answer: Pituitary corticotroph adenomas (Cushing disease) retain partial negative-feedback sensitivity and suppress serum cortisol by >50% after high-dose (8-mg) dexamethasone, whereas ectopic ACTH-secreting tumors are autonomous and fail to suppress.

Tearing pain with defecation, bright red blood on the tissue, and a posterior midline tear of the anoderm without chronic features (sentinel tag, hypertrophied papilla, exposed sphincter fibers) define an acute anal fissure. The fissure persists because internal anal sphincter hypertonicity reduces blood flow to the already poorly perfused posterior midline, so the goal of pharmacologic therapy is to relax the sphincter and restore perfusion. Once fiber, stool softeners, and sitz baths are in place, the first-line agent is a topical sphincter relaxant: nitroglycerin ointment donates nitric oxide, which relaxes internal sphincter smooth muscle and increases anodermal blood flow, healing most acute fissures within weeks. Topical nifedipine (a calcium channel blocker) is an equally effective first-line alternative with fewer headaches and is often preferred where it can be compounded; topical diltiazem is another option. Injected botulinum toxin and lateral internal sphincterotomy are reserved for chronic fissures that fail topical therapy.

Incorrect answer explanations

• Botulinum toxin A injection into the internal anal sphincter – temporarily paralyzes the sphincter for chronic fissures that have failed topical nitroglycerin or calcium channel blockers; it is a second-line, procedural option, not initial therapy.

• Lateral internal sphincterotomy – the definitive surgical treatment with the highest healing rate for chronic, refractory fissures, but it carries a small permanent risk of fecal incontinence and is inappropriate for a 3-week-old acute fissure.

• Oral docusate sodium – a stool softener that reduces trauma from hard stool and is part of the conservative measures already started; it does nothing to relieve sphincter spasm or ischemia.

• Topical hydrocortisone cream – corticosteroids do not lower sphincter pressure and prolonged use thins the anoderm, impairing healing; they have no role in fissure treatment.

Clinical Pearls

• A fissure that is off the midline, multiple, painless, or non-healing is atypical; evaluate for Crohn disease, human immunodeficiency virus (HIV), syphilis, tuberculosis, or anal carcinoma.

• Headache is the dose-limiting side effect of topical nitroglycerin; switching to topical diltiazem or nifedipine usually solves it. Avoid nitroglycerin in patients taking phosphodiesterase-5 inhibitors.

• A fissure is chronic after 8 weeks or when a sentinel pile, hypertrophied anal papilla, or visible sphincter fibers are present; chronic fissures rarely heal with conservative care alone.

• Do not force a digital rectal examination or anoscopy through a painful acute fissure; inspection alone makes the diagnosis, and the examination can be completed once pain settles.

Blueprint Comparisons — Colorectal Disorders (Anorectal)

Extra Challenge

• A patient has used topical nitroglycerin for 8 weeks with fiber and sitz baths, but the fissure persists and she cannot tolerate the headaches. What is the most appropriate next step?

Answer: A fissure persisting beyond about 8 weeks warrants endoscopy to exclude Crohn disease. Then offer lateral internal sphincterotomy (most effective if there are no incontinence risk factors), or botulinum toxin injection if there are incontinence risk factors or she declines surgery; a trial of a topical calcium channel blocker is reasonable if she wants to keep trying medication.

• A 40-year-old man has three painless lateral anal fissures with perianal skin tags and intermittent diarrhea. What underlying condition must be excluded?

Answer: Crohn disease; atypical (lateral, multiple, painless) fissures warrant evaluation for inflammatory bowel disease, infection, or malignancy rather than sphincterotomy.

Weakness that worsens with use and recovers with rest, beginning in the ocular and bulbar muscles, with normal reflexes, sensation, and pupils, localizes the problem to the neuromuscular junction. Myasthenia gravis is an autoimmune disorder in which antibodies against the postsynaptic acetylcholine receptor (80–90% of generalized cases) or muscle-specific kinase (MuSK) impair neuromuscular transmission. This explains the jaw that gives out mid-meal, the nasal speech by evening, and the overnight recovery. Sustained upgaze provoking ptosis and progressive weakness with repeated exertion demonstrate fatigability, and a positive ice pack test (ptosis improves after 2 minutes of cooling because low temperature slows acetylcholinesterase) supports the diagnosis. Onset is bimodal: women in their 20s to 30s and men over 60.

Confirm with acetylcholine receptor antibody testing (then MuSK antibodies if negative) and electrodiagnostic studies showing a decremental response on repetitive nerve stimulation or increased jitter on single-fiber electromyography. Every new patient needs a chest computed tomography (CT) to look for thymoma. First-line symptomatic treatment is pyridostigmine, with glucocorticoids and steroid-sparing immunosuppressants for inadequate control; thymectomy is required for thymoma and benefits many patients under 65 with generalized acetylcholine receptor antibody–positive disease.

Incorrect answer explanations

• Botulism – a rapidly progressive descending paralysis from preformed toxin with fixed, dilated pupils and anticholinergic features; the 6-week fluctuating course and reactive pupils exclude it.

• Guillain-Barré syndrome – acute ascending weakness with areflexia after a recent infection, evolving over days; normal reflexes and a fatigable, bulbar-predominant pattern argue against it.

• Lambert-Eaton myasthenic syndrome – presynaptic voltage-gated calcium channel antibodies cause proximal leg weakness that transiently improves with repeated effort, hyporeflexia, and autonomic dysfunction, usually in an older smoker with small cell lung cancer; prominent ocular and bulbar weakness with normal reflexes favors myasthenia gravis.

• Multiple sclerosis – a central demyelinating disease with deficits separated in time and space, sensory symptoms, optic neuritis, and upper motor neuron signs; fatigable weakness that reverses with rest or cooling is not a feature.

Clinical Pearls

• Bedside clues: fatigable ptosis on sustained upgaze, positive ice pack test, weak neck flexion, nasal speech, and a "myasthenic snarl" on smiling.

• Myasthenic crisis is respiratory failure from diaphragmatic weakness: monitor forced vital capacity and negative inspiratory force, and treat with intravenous immunoglobulin (IVIG) or plasmapheresis plus airway support. Triggers are infection, surgery, pregnancy, and medications. A cholinergic crisis from excess pyridostigmine looks similar but adds fasciculations, salivation, and diarrhea.

• Drugs that can precipitate or worsen weakness: aminoglycosides, fluoroquinolones, macrolides, beta-blockers, magnesium, procainamide, and immune checkpoint inhibitors.

• Over half of patients transiently worsen when high-dose glucocorticoids are started, so steroids are begun in the hospital or titrated slowly.

• Edrophonium (Tensilon) testing is historical and no longer available in the United States; antibody testing and repetitive nerve stimulation have replaced it.

Blueprint Comparisons — Neuromuscular Disorders

Extra Challenge

• This patient's acetylcholine receptor antibody test returns negative. What is the next test, and what treatment nuance does a positive result carry?

Answer: Muscle-specific kinase (MuSK) antibodies; MuSK-positive patients respond poorly to pyridostigmine and thymectomy, need earlier aggressive immunotherapy, and respond well to rituximab and plasmapheresis.

• Two days after starting an antibiotic for a urinary tract infection, she develops worsening dysphagia, a weak cough, and a forced vital capacity of 14 mL/kg. What is happening and what is the management?

Answer: Impending myasthenic crisis, precipitated by infection and possibly the antibiotic (avoid fluoroquinolones and aminoglycosides). Admit to the intensive care unit, monitor forced vital capacity and negative inspiratory force closely, intubate if forced vital capacity falls below 15 mL/kg or is trending down, and start IVIG or plasmapheresis.

Effort-induced chest tightness that resolves with rest in a patient with objective reversible ischemia is chronic stable angina, a supply-demand mismatch across a fixed atherosclerotic stenosis. Per the American College of Cardiology/American Heart Association (ACC/AHA), a beta-blocker is the first-line agent to prevent episodes when there is no contraindication (symptomatic bradycardia, high-grade atrioventricular (AV) block, decompensated heart failure, or active bronchospasm). Beta-blockers cut myocardial oxygen demand by lowering heart rate, contractility, and blood pressure, and the slower rate prolongs diastole, when the coronary arteries fill, so oxygen supply also improves. The dose is titrated to a resting heart rate of about 55 to 60 beats per minute. With a resting rate of 78, clear lungs, no edema, and no history of asthma or heart block, this patient is an ideal candidate for a cardioselective agent such as metoprolol succinate.

Incorrect answer explanations

• Isosorbide mononitrate – long-acting nitrates relieve angina by venodilation (lower preload) but are add-on or alternative therapy when a beta-blocker is contraindicated or insufficient; a daily nitrate-free interval is required to prevent tolerance.

• Nifedipine – immediate-release dihydropyridine calcium channel blockers drop blood pressure abruptly and trigger reflex tachycardia, raising oxygen demand and potentially worsening ischemia; a long-acting dihydropyridine such as amlodipine is the acceptable add-on.

• Ranolazine – inhibits the late inward sodium current, easing diastolic calcium overload without changing heart rate or blood pressure; it is reserved for angina that persists despite optimal first-line therapy.

• Sublingual nitroglycerin – the drug for acute relief of an episode (onset within 1.5 to 3 minutes); every patient should carry it, but its short action makes it useless for prevention.

Clinical Pearls

• If a beta-blocker cannot be used, a nondihydropyridine calcium channel blocker (diltiazem or verapamil) is the preferred substitute; if a beta-blocker is not enough, add a long-acting dihydropyridine or a long-acting nitrate.

• Never combine a nondihydropyridine calcium channel blocker with a beta-blocker in a patient with bradycardia or conduction disease; the two together can cause heart block.

• Antianginal drugs improve symptoms; mortality benefit in chronic coronary disease comes from aspirin, high-intensity statin, blood pressure control, and smoking cessation.

• Nitrates are contraindicated within 24 hours of sildenafil or vardenafil and 48 hours of tadalafil because of profound hypotension.

• In vasospastic (variant) angina, nonselective beta-blockers can worsen spasm through unopposed alpha activity; a calcium channel blocker is first-line.

Blueprint Comparisons — Coronary Artery Disease

Extra Challenge

• A patient with stable angina takes tadalafil for erectile dysfunction. Which antianginal class must he avoid for 48 hours after a dose, and why?

Answer: Nitrates (nitroglycerin, isosorbide); combined with a phosphodiesterase-5 inhibitor they cause profound, potentially fatal hypotension.

• What is the mechanism by which aspirin lowers the risk of myocardial infarction in chronic coronary disease?

Answer: Irreversible inhibition of platelet cyclooxygenase-1, blocking thromboxane A2 production and platelet aggregation for the life of the platelet.

Abruptio placentae (placental abruption) is the premature separation of a normally implanted placenta from the uterine wall after the first trimester, most often when damaged maternal vessels (as in chronic hypertension) bleed into the space behind the placenta. That trapped blood irritates the myometrium and strips the placenta away from its blood supply, which is why the patient has sudden painful vaginal bleeding, a firm, tender uterus, and fetal distress. The diagnosis is clinical: fetal heart rate monitoring, a complete blood count (CBC), coagulation studies, and pelvic ultrasound are part of the evaluation, but a normal ultrasound does not rule out abruption. In this hypertensive patient with dark bleeding, a tender uterus, and recurrent late decelerations, ultrasound did its real job — it excluded placenta previa by showing a fundal placenta — while the missing retroplacental clot changes nothing.

Board-Level Insight: Placental abruption (abruptio placentae)—premature detachment of the placenta from the uterine wall before delivery—classically presents in the third trimester with painful, dark vaginal bleeding accompanied by continuous severe abdominal/back pain, uterine hypertonicity/rigidity, and uterine tenderness, with chronic hypertension being the most common risk factor.

Classic Board Trap: Contrast placental abruption with placenta previa: placenta previa presents with painless, bright red vaginal bleeding and a completely soft, non-tender, relaxed uterus! Performing a digital cervical examination is strictly contraindicated in third-trimester bleeding until placenta previa is ruled out by ultrasound.

Incorrect answer explanations

• Chorioamnionitis – intra-amniotic infection with fever, maternal and fetal tachycardia, and uterine tenderness; it is a risk factor for abruption, but it does not cause sudden heavy bleeding in an afebrile patient.

• Placenta previa – painless, bright red bleeding from a placenta over or near the cervical os; ultrasound here shows a fundal placenta.

• Uterine rupture – abrupt pain, loss of fetal station, and fetal bradycardia, usually during labor in a woman with a prior uterine scar.

• Vasa previa – painless bleeding when the membranes rupture, from unprotected fetal vessels crossing the os, with rapid fetal compromise.

Clinical Pearls

• Blood can stay concealed behind the placenta, so pain and uterine tenderness may be out of proportion to the visible bleeding.

• Know the risk factors: hypertension, cocaine or tobacco use, abdominal trauma, prior abruption, older maternal age, and prelabor rupture of membranes.

• Watch for hemorrhagic shock and disseminated intravascular coagulation (DIC). Chronic abruption presents as intermittent dark brown spotting.

• If mother and fetus are stable before 34 weeks, hospitalize and give corticosteroids for fetal lung maturity.

Blueprint Comparisons — Pregnancy (third-trimester bleeding)

Extra Challenge

• In a patient with third-trimester vaginal bleeding, what must be excluded by ultrasound before any digital cervical examination?

Answer: Placenta previa — a digital exam can provoke catastrophic hemorrhage if the placenta covers the os.

• A patient with suspected abruption becomes hypotensive and the fetal tracing worsens. What is the definitive management?

Answer: Prompt cesarean delivery, with maternal resuscitation.