PANCE Blueprint Endocrinology (6%)

Hyperthyroidism (ReelDx)

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16-year-old with ADHD presents with chest pain and exophthalmos (watch video)

Patient will present with → Exophthalmos and pretibial myxedema are usually present with Graves’ disease whereas these two symptoms are not seen with regular hyperthyroidism. Along with those symptoms, patients may complain of irritability and nervousness, heat intolerance with increased sweating, and weight loss with an increase in appetite.   Patients may be tachycardic and hypertensive and atrial fibrillation is not uncommon, especially in elderly patients. Hyperreflexia may be present and patients may have a fine tremor. Alopecia may occur, or the hair may be finer in texture. A goiter may be evident

Weight Loss, anxiety, tachycardia, EKG changes such as PVCs.

  •  Fine, thin, moist skin, prominent eyes with lid retraction (proptosis, or exophthalmos) and a startled expression

Hyperthyroidism871px-Thyroid_system.svg

  • Patient will be complaining of heat intolerance, palpitations, weight loss, tachycardia, and anxiety
  • PE will show hyperreflexia
  • Labs will show low TSH and high free T4
  • Most commonly caused by Graves disease (autoimmune against TSH receptor)
  • Treatment is methimazole or PTU
  • Comments: Propylthiouracil (PTU) P for pregnant

Thyroid storm

Thyroid storm is an acute form of hyperthyroidism that results from untreated or inadequately treated severe hyperthyroidism. It is rare, occurring in patients with Graves disease or toxic multinodular goiter (a solitary toxic nodule is a less common cause and generally causes less severe manifestations). It may be precipitated by infection, trauma, surgery, embolism, diabetic ketoacidosis, or preeclampsia. Thyroid storm causes abrupt florid symptoms of hyperthyroidism with one or more of the following: fever, marked weakness and muscle wasting, extreme restlessness with wide emotional swings, confusion, psychosis, coma, nausea, vomiting, diarrhea, and hepatomegaly with mild jaundice. The patient may present with cardiovascular collapse and shock. Thyroid storm is a life-threatening emergency requiring prompt treatment.

Diagnosis: Low TSH, with high T3 and T4 confirms hyperthyroidism, but with Graves’ disease usually, only the T3 is elevated

  • ↓ TSH
  • ↑ Free T4, plus either free T3 or total T3
  • Sometimes radioactive iodine uptake

Antibodies:

  • Graves: Anti-thyrotropin antibodies

The cardiac symptoms of Graves’ disease can be treated with β-Blockers

  • Most often atenolol 25-50 mg PO QD is the starting dose, and it can be increased up to 200 mg PO QD if the blood pressure tolerates.

To treat Graves disease antithyroid drugs (methimazole or PTU), radioactive iodine and surgery (thyroidectomy) are all used depending on the patient.

  • Methimazole may be given; starting dose for mild hyperthyroidism is 10 mg PO QD.
  • Propylthiouracil (PTU) P for pregnant

Complications: dysrhythmias, osteoporosis, thyroid storm, CHF, pregnancy issues including miscarriage

Graves Opthalmopathy

IM_NUR_Hyperthyroidism_V1.6_ Hyperthyroidism is a metabolic imbalance that results from overproduction of the thyroid hormones T4 and T3. Graves’ disease, which is an autoimmune disorder, is considered the most common form; however, toxic nodular goiter, thyroiditis, excess iodine intake, pituitary and thyroid tumors have symptoms of elevated thyroid hormone. Overall symptoms of hyperthyroidism relate to increased metabolism.

Hyperthyroidism Assessment Picmonic

The focus of care for patients with hyperthyroidism is to block the adverse effects of too much thyroid hormone, suppress oversecretion of thyroid hormone, and prevent complications. Treatment may include antithyroid medications, radioactive iodine therapy, and surgical intervention.

Hyperthyroidism Interventions Picmonic

IM_MED_GravesCharacteristics_v1.6_ Graves' disease is an autoimmune disease of the thyroid, which leads to hyperthyroidism. Classic findings include pretibial myxedema and exophthalmos. Patients display hyperthyroid symptoms (goiter, heat intolerance, weight loss, insomnia, hyperactivity and palpitations) due to IgG antibodies which activate TSH receptors, leading to release of thyroid hormones. Typical lab values in patients with Graves' disease include decreased TSH, increased thyroid hormones (T3, T4), and increased radioactive iodine uptake when tested. Treatment includes beta blockers for immediate symptomatic relief, with methimazole, or eventually radioiodine ablation to prevent excess thyroid hormone production.

thyroid-storm_5964_1490412267 Thyroid storm is a life-threatening, hypermetabolic physiologic state that results as a complication of hyperthyroidism. While the exact pathophysiology is unknown, it is thought to be caused by a combination of decrease in thyroid-binding proteins, rapid increase in free hormone, and decrease in ability to physiologically compensate. It presents with altered mental status, fevers above 103 degrees, diarrhea, and tachycardia that may lead to fatal tachyarrhythmias. Treatment involves propranolol to control heart rate and cooling blankets and acetaminophen for hyperpyrexia. Thionamides such as PTU are given to block new hormone synthesis, and iodine is given at least one hour after PTU administration to block the release of preformed hormone

Question 1
A 38-year-old woman comes to your office with a 3-month history of sweating, palpitations, weight loss, nervousness, irritability, insomnia, hand tremors, and diarrhea. She has no significant past illness. One of her sisters has rheumatoid arthritis. The patient, a stockbroker, is finding it increasingly difficult to perform her job because of profound fatigue and inability to concentrate. On examination, her blood pressure is 140/ 70 mm Hg. Her pulse is 120 beats/ minute and regular. She demonstrates mild proptosis. You feel a smooth, diffusely enlarged, and nontender thyroid gland. Cardiovascular examination reveals a loud S1 and a loud S2 with a systolic ejection murmur heard loudest along the left sternal border. The murmur does not radiate. No other abnormalities are noted. What is the most likely diagnosis in this patient?
A
toxic multinodular goiter
B
Graves disease
C
Hashimoto thyroiditis
D
pheochromocytoma
E
panic disorder
Question 1 Explanation: 
This patient has Graves disease, which is the most common cause of hyperthyroidism in the United States. It is an autoimmune-mediated stimulation of the thyroid. It usually is manifested with symptoms of sweating, palpitations, nervousness, irritability, tremor, diarrhea, heat intolerance, and weight loss. Physical signs of Graves disease include a diffusely enlarged, nontender thyroid gland; tachycardia; loud heart sounds; and a cardiac murmur. A bruit may be heard over the thyroid. Proptosis is often seen. On occasion, patients present with severe exophthalmos accompanied by ophthalmoplegia, follicular conjunctivitis, chemosis, and even loss of vision. Toxic multinodular goiter and toxic adenoma are other causes of hyperthyroidism. Their presentation, however, is distinguished on physical examination by the presence of a nodule or several nodules, whereas the thyroid examination in Graves disease shows a diffusely enlarged gland. Hashimoto thyroiditis is a cause of hypothyroidism rather than hyperthyroidism. Its presentation is usually that of hypothyroid symptoms, but it can less commonly be manifested with a short-lived hyperthyroid phase. It is also of an autoimmune origin. Pheochromocytoma and panic disorder are not serious considerations with this presentation history.
Question 2
What is the best initial test to diagnose hyperthyroidism?  
A
radioactive iodine uptake test
B
thyroid ultrasound study
C
free serum thyroxine (T4)
D
serum thyroid-stimulating hormone (TSH)
E
thyroid antibodies
Question 2 Explanation: 
The serum TSH level is used to measure and to detect hyperthyroidism and hypothyroidism. The sine qua non of hyperthyroidism is a low serum TSH level, and it is the screening test that should be used. The serum free T4 should be measured after hyperthyroidism is confirmed by TSH. If the free T4 is normal, then a serum T3 should be ordered; 10% of the cases of hyperthyroidism are actually the result of a T3 toxicosis rather than a T4 problem. Radioactive iodine uptake will show hyperthyroidism in this case, but it is not the most appropriate initial test. Its use will be discussed later in the chapter. Thyroid antibodies will be present in Graves disease and can help confirm your suspicions, but they are not used to diagnose hyperthyroidism.
Question 3
Your diagnosis of hyperthyroidism is confirmed with the appropriate test from question 2. Which test is the next most appropriate to determine the underlying etiology?
A
radioactive iodine uptake
B
fine-needle aspiration (FNA) of thyroid
C
free T4
D
ultrasound study
E
TSH receptor antibodies
Question 3 Explanation: 
Radioactive iodine uptake testing is a valuable tool to narrow the differential diagnosis of hyperthyroidism. A homogeneous, diffuse uptake is consistent with Graves disease. Different patterns are associated with other causes, such as multinodular heterogeneous uptake in toxic multinodular goiter, a “hot” nodule in a hyperfunctioning thyroid adenoma, and diffusely decreased uptake in thyroiditis. TSH receptor antibodies are helpful in the diagnosis of Graves disease when present, but when absent, they are not helpful in differentiating the cause of hyperthyroidism. Ultrasound study may be useful in identifying nodules and goiter that may not be readily apparent, but it is not the best test to determine the cause of hyperthyroidism. FNA has a role in the investigation of thyroid nodules. Free T4 will be elevated in hyperthyroidism but does not provide diagnosis.
Question 4
What treatment will be most effective to acutely alleviate the patient’s symptoms?
A
methimazole
B
radioactive iodine
C
propylthiouracil (PTU)
D
atenolol
Question 4 Explanation: 
Patients with hyperthyroidism display symptoms of increased adrenergic tone causing tachycardia, palpitations, anxiety, and other symptoms. Beta-adrenergic blocking agents, such as atenolol, are effective in alleviating many of these symptoms in the acute setting. Use of methimazole or PTU will decrease excessive production of thyroid hormone, but they take time to work and have no effect on thyroid hormone already in circulation. Diltiazem is a calcium channel blocker that may help control tachycardia, but it is not effective at blocking increased adrenergic tone. Radioactive iodine ablation may be an appropriate definitive treatment for certain forms of hyperthyroidism, but it does not have a role in the acute setting.
Question 5
Which of the following medications provides effective long-term control of the disease presented in this problem?  
A
methimazole
B
propranolol
C
levothyroxine
D
prednisone
Question 5 Explanation: 
Antithyroid drugs: Advantage: These drugs provide the opportunity for the patient to experience a spontaneous remission and to avoid lifelong medication (e.g., levothyroxine). Disadvantages: Remissions are attained in less than 50%, rare but potentially fatal risk for agranulocytosis.
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