PANCE Blueprint Cardiology (16%)

Acute and subacute bacterial endocarditis (ReelDx)

REEL-DX-ENHANCED

Endocardits

Patient will present as → a 45 y/o female with known history of IVDA presents with fever (39.0º C), a new mitral regurgitant murmur and blood culture reveals two out of two positive growth

Infective endocarditis is infection of the endocardium, usually with bacteria (commonly, streptococci or staphylococci) or fungi

It causes fever, heart murmurs, petechiae, anemia, embolic phenomena, and endocardial vegetations.

  • Acute bacterial endocarditis: Infection of normal valves with a virulent organism (S. aureus)
  • Subacute bacterial endocarditis: Indolent infection of abnormal valves  with less virulent organisms (S. viridans)
  • Endocarditis with intravenous drug users - Staph aureus
  • Prosthetic valve endocarditis  - Staph epidermidis
"Differentiate bacterial endocarditis from acute rheumatic fever which is a multi-system autoimmune response and may also affect the heart and valves - diagnosed by Jones criteria"

Vegetations may result in valvular incompetence or obstruction, myocardial abscess, or mycotic aneurysm.

  • Candida is a slow-growing organism. Most common source is a contaminated line. It typically causes large vegetations in endocarditis.
    • Large vegetation endocarditis in the early post–valve replacement period (2 months post-surgery) is most likely due to fungus, that is, Candida infection. Amphotericin B is recommended followed by several weeks of antifungals that carry less adverse events.
  • HACEK organisms tend to grow on native valves
  • Staphylococcus aureus causes smaller vegetations; it is more common in injection drug users
  • Streptococcus viridans is the most common cause of endocarditis. It typically occurs as late complication of valve replacement and presents as small vegetations and embolic events.
  • Endocarditis can occur at any age. Men are affected about twice as often as women. IV drug abusers and immunocompromised patients are at highest risk.
  • Most patients with new murmur or change in existing murmur; signs of heart failure (rales, edema) if valve function compromised

Peripheral stigmata of IE:

  • Splinter hemorrhages in fingernail beds
  • Osler nodes painful lesions on fleshy portions of extremities
  • Roth spots” retinal hemorrhages
  • Janeway lesions (cutaneous evidence of septic emboli)
  • Palatal or conjunctival petechiae
  • Splenomegaly
  • hematuria (due to emboli or glomerulonephritis)

Neurologic findings consistent with CVA, such as visual loss, motors weakness, and aphasia

Modified Duke Criteria for Diagnosis of Infectious Endocarditis

Definite: 2 major criteria, or 1 major and 3 minor criteria, or 5 minor criteria

Possible: 1 major and 1 minor criteria, or 3 minor criteria

  • Major clinical criteria
    • Positive blood culture: isolation of typical microorganism for IE from 2 separate blood cultures or persistently positive blood culture
    • Single positive blood culture for C. burnetii or antiphase-1 IgG antibody titer >1:800
    • Positive echocardiogram: presence of vegetation, abscess, or new partial dehiscence of prosthetic valve; must be performed rapidly if IE is suspected
    • New valvular regurgitation (change in preexisting murmur not sufficient)
  • Minor criteria
    • Predisposing heart condition or IV drug use
    • Fever ≥38.0°C (100.4°F)
    • Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhage, Janeway lesions
    • Immunologic phenomena: glomerulonephritis, Osler nodes, Roth spots, rheumatoid factor (RF) Microbiologic evidence: positive blood culture, but not a major criterion (excluding single positive cultures for coagulase-negative staphylococci and organisms that do not cause endocarditis) or serologic evidence of infection likely to cause IE

Diagnosis requires demonstration of microorganisms in blood and usually echocardiography

  • Blood cultures (before antibiotics are started) 3 sets at least 1 hour apart
  • EKG at regular intervals

Transesophageal echocardiogram is Gold Standard

LABS: CBC, ESR, RF

Management - treatment consists of prolonged antimicrobial treatment and sometimes surgery

  • IV antibiotics (based on the organism and its susceptibility)
  • Sometimes valve debridement, repair, or replacement
  • Initial therapy before organism identification (but after adequate blood cultures have been obtained) should be broad spectrum to cover all likely organisms.
    • Typically, patients with native valves and no IV drug abuse receive ampicillin 500 mg/h continuous IV infusion plus nafcillin 2 g IV q 4 h plus gentamicin 1 mg/kg IV q 8 h.
    • Patients with a prosthetic valve receive vancomycin 15 mg/kg IV q 12 h plus gentamicin 1 mg/kg q 8 h plus rifampin 300 po q 8 h.
    • IV drug abusers receive nafcillin 2 g IV q 4 h.
    • In all regimens, penicillin-allergic patients require substitution of vancomycin 15 mg/kg IV q 12 h.

Antibiotic prophylaxis to prevent recurrent endocarditis is recommended : 2 g of Amoxicillin 30-60 minutes before procedure

IM_Bacterial_Endocarditis_ASSETS_ Bacterial endocarditis is an infection of the inner surface of the heart or heart valves due to bacteria in the bloodstream, typically introduced via dental or medical procedures in the mouth, intestinal tract or urinary tract. The bacteria can grow on the edges of a heart defect or surface of an abnormal valve and continue to grow producing large particles called vegetations. These particles can then break off and embolize to the lungs, brain, kidneys, and skin. Symptoms and signs of endocarditis vary but include prolonged fever, a new or changing heart murmur and specific vascular and immunologic phenomena. Vascular phenomena include septic emboli, Janeway lesions, splinter hemorrhages and renal and splenic infarcts. Immunologic phenomena include Osler’s nodes and Roth’s spots.

View Bacterial Endocarditis Picmonic

IM_MED_Dukes_criteria_v1.2_ The Duke criteria are a set of clinical criteria set forward for the diagnosis of infective endocarditis. Fulfilling the criteria includes either having 2 major criteria, 1 major and 3 minor criteria, or 5 minor criteria. The two major criteria are positive blood cultures for infective endocarditis and evidence of endocardial involvement. The five minor criteria are having a predisposing heart condition or intravenous drug use, fever, vascular phenomena, or having microbiologic evidence or echocardiographic evidence that does not meet the major criteria.

Duke's Criteria for Infective Endocarditis Picmonic

Question 1
A 44 year-old male with a known history of rheumatic fever at age 7 and heart murmur is scheduled to undergo a routine dental cleaning. The murmur is identified as an opening snap murmur. Patient has no known drug allergies. What should this patient receive for antibiotic prophylaxis prior to the dental cleaning?
A
This patient does not require antibiotic prophylaxis for a routine dental cleaning.
B
This should receive Pen VK 250 mg p.o. QID for 10 days after the procedure.
C
This patient should receive Amoxicillin 2 grams 30-60 minutes before the procedure
D
This patient should receive Erythromycin 250 mg QID for 1 day before the procedure and then 10 days after the procedure.
Question 1 Explanation: 
These are the current recommendations from the American Heart Association if the patient is not allergic to penicillin. http://www.aapd.org/media/policies_guidelines/g_antibioticprophylaxis.pdf
Question 2
What is the most likely mechanism responsible for retinal hemorrhages and neurologic complications in a patient with infective endocarditis?
A
Metabolic acidosis
Hint:
See B for explanation.
B
Systemic arterial embolization of vegetation
C
Hypotension and tachycardia
Hint:
See B for explanation.
D
Activation of the immune system
Hint:
Glomerulonephritis and arthritis result from activation of the immune system.
Question 2 Explanation: 
The vegetations that occur during infective endocarditis can become emboli and can be dispersed throughout the arterial system.
Question 3
A 38 year-old female with history of coarctation of the aorta repair at the age of two presents with fevers for four weeks. The patient states that she has felt fatigued and achy during this time. Maximum temperature has been 102.1 degrees F. She denies cough, congestion, or other associated symptoms. Physical examination reveals a pale tired appearing female in no acute distress. Heart reveals a new grade III-IV/VI systolic ejection border at the apex, and a II/VI diastolic murmur at the right sternal border. What is the most likely diagnosis?
A
Acute myocardial infarction
Hint:
Acute MI presents with complaint of chest pain, SOB, not with fever and myalgias.
B
Bacterial endocarditis
C
Acute pericarditis
Hint:
Pericarditis does not present with systolic or diastolic murmur or vegetation, more commonly pericardial friction rub would be noted.
D
Restrictive cardiomyopathy
Hint:
Restrictive cardiomyopathy will show impaired diastolic filling on echocardiogram and is not associated with fever.
Question 3 Explanation: 
Bacterial endocarditis presents as febrile illness lasting several days to weeks, commonly with nonspecific symptoms, echocardiogram often reveals vegetations on affected valves.
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Question 1
Janeway lesions are painful lesions on the hands?
A
True
B
False
Question 1 Explanation: 
Janeway lesions are PAINLESS lesions on the hands. Osler's nodes are PAINFUL lesions on the hands. Think "O" for OUCH!
Question 2
If a patient has both a stroke and a fever you should consider endocarditis?
A
True
B
False
Question 2 Explanation: 
Stroke + Fever think endocarditis! The patient has vegetation on the aortic or mitral valve the vegetation breaks off goes up to the brain causes the stroke. They will have the fever from the endocarditis and the vegetation in brain causing the stroke.
Question 3
Roth spots are lesions on the retina?
A
Ture
B
False
Question 3 Explanation: 
Roth spots are secondary to retinal hemorrhage with a pale center. Think "R" for "Retina".
Question 4
In a non intravenous drug user, the mitral valve is most commonly infected valve of bacterial endocarditis and the most common organism is streptococcus viridans?
A
True
B
False
Question 4 Explanation: 
The mitral valve is the most commonly involved with a virulent organism (ex. S. viridans). In intravenous drug users the Tricuspid valve is the most common and the organism is S. aureus.
Question 5
Which of these patients is not in need of endocarditis prophylaxis?
A
Bicuspid aortic valve
B
Prosthetic heart valve
C
Congenital heart disease
D
History of endocarditis
Question 5 Explanation: 
The following cardiac conditions require endocarditis prophylaxis: 1. Prosthetic heart valve 2. Heart repair using prosthetic material 3. Prior history of endocarditis 5. Congenital heart disease
Question 6
Which antibiotic regimen is considered first line treatment for endocarditis prophylaxis?
A
Amoxicillin 2g 30-60 minutes before the procedure
B
Amoxicillin 1g 30-60 minutes before the procedure
C
Amoxicillin 2g three hours before the procedure
D
Clindamycin 600 mg 30-60 minutes before the procedure
Question 6 Explanation: 
Amoxicillin 2g 30-60 minutes before the procedure is first line in non-penicillin allergic patients. If Penicillin allergic give Clindamycin 600mg.
Question 7
Which of the following is not part of the minor Modified Duke Criteria for diagnosing endocarditis?
A
Fever greater than 100.4
B
Sustained bacteremia (2 + blood cultures by organism known to cause endocarditis)
C
Predisposing condition (abnormal valves, IVDA, indwelling catheters)
D
Immunologic phenomena: Osler's nodes, Roth spots
E
Vascular and Embolic phenomena: Janeway lesions, pulmonary emboli
Question 7 Explanation: 
Al of the other options are minor criteria. Clinical criteria for IE: 2 major or 1 major + 3 minor or 5 minor
Question 8
A patient is 6 weeks post–aortic valve replacement. He presents with low-grade fever and malaise for 1 week. Exam reveals a new systolic murmur. Echocardiography shows large vegetations around the inferior side of the mitral valve. What is the most likely etiology?
A
Candida albicans
B
HACEK organisms
Hint:
HACEK organisms tend to grow on native valves.
C
Staphylococcus aureus
Hint:
Staphylococcus causes smaller vegetations; it is more common in injection drug users.
D
Streptococcus viridans
Hint:
Streptococcus viridans is the most common cause of endocarditis. It typically occurs as late complication of valve replacement and presents as small vegetations and embolic events.
Question 8 Explanation: 
Candida is a slow-growing organism. Most common source is a contaminated line. It typically causes large vegetations in endocarditis.
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Brian Wallace PA-C Podcast: S2 E018 Endocarditis, Pericarditis and Tamponade (Prev Lesson)
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