Disorders of the Thyroid

Question 1

What is thyroid storm? How do we deal with it?

Answer 1

A life threatening form of thyrotoxicosis characterized by high fever, tachyarrhythmia, psychosis, confusion, diarrhea, and liver dysfunction.

Needs antithyroid medications and B-adrenergic blockers

Question 2

What does hyperthyroidism lead to and what causes it?

Answer 2

Hyperhyroidism causes thyrotoxicosis, elevated thyroid hormones in the blood. Graves Disease causes the majority of cases.

Question 3

What is the etiology behind hyperthyroidism caused by Graves Disease?

Answer 3

Thyroid stimulating immunoglobulin (TSI) binds TSH receptor on the thyroid gland, leading to an increase in T3/T4. This is a type II hypersensitivity.

Can also be associated with other autoimmune conditions

Question 4

How does hyperthyroidism secondary to Graves Disease present?

Answer 4

Diffuse, nontender Goiter with or without bruit.

Infiltrative opthalmopathy (exopthalmos, extraocular muscle dysfunction)

Pretibial myxedema

Question 5

What is the etiology behind hyperthyroidism caused by Plummer disease? How does it present?

Answer 5

Also known as Toxic Multinodular goiter, this is where you get hyperfunctioning areas of the thyroid that dish out a lot more T3/T4 (shows a patchy uptake on thyroid scan, vs a diffuse one as we see with Graves).

This is all due to a TSH receptor mutation, and is most commonly seen in the elderly. It presents similarly as Graves, but not as severe.

Question 6

What is the etiology of hyperthyroidism caused by subacute thyroiditis?

Answer 6

Also called de Quervain thyroiditis, this is an inflammation of he thyroid gland, leading to a spilling of preformed thyroid hormones, which leads to transient hyperthyroidism. Pituitary inhibition causes transient hypothyroidism before returning to a normal thyroid state.

High yield, this is usually preceeded by an upper respiratory infection.

Question 7

Clinical manifestation of Subacute thyroiditis?

Answer 7

Thyroid gland firm and tender, fever, increased ESR with pain radiating to ears, neck, and arm

Question 8

What is struma ovarii?

Answer 8

This is a very rare condition in which ectopic thyroid tissue develops as part of an ovarian tumor, causing hyperthyroidism.

Question 9

What is the general presentation of someone with hyperthyroidism?

Answer 9

General Symptoms: Tremor, weight loss with a robust appetite, irritable, restless, sweaty, increased bowel movements, tachycardia.

Classic: Warm and moist skin due to peripheral vasodilation and excessive sweating

Question 10

Hyperthyroidism can cause an increased risk for:

Answer 10

Atrial fibrillation, isolated systolic hypertension, high-output cardiac failure

Question 11

How do we diagnose hyperthyroidism?

Answer 11

• Increase levels of T3 and T4 (big leap here, I know)
• Decreased TSH (except with TSH secreting tumors)
• Anti-TSH receptor antibodies for Graves Disease
• Radioactive iodine uptake scan (diffuse for Graves, localized for toxic adenoma and multinodular thyroid and no uptake for thyroiditis and struma ovarii)

Question 12

What are our treatment options for hyperthyroidism?

Answer 12

Propylthiouracil (PTU) and methimazole - Inhibit thyroid hormone synthesis by inhibiting the organification of iodine. Also inhibits the peripheral conversion of T4 to T3

Radioactive iodine ablation - Destroy thyroid follicular cells. Radioiodine is contraindicated for treatment of hyperthyroidism during pregnancy because it can cross the placenta and destroy the infants thyroid

B-blockers - Like propanolol; Control of adrenergic symptoms like sweating, tachycardia, tremor

Question 13

What is primary hypothyroidism?

Answer 13

Failure of the thyroid gland itself, leading to hypothyroidism

Question 14

What is Hashimoto Thyroiditis?

Answer 14

Autoimmune (HLA-DR5) condition of the thyroid.

Question 15

How do we confirm Hashimoto Thyroiditis?

Answer 15

Histo - Lymphocytic infiltrate with germinal centers AND Hurthle cells ( a Hurthle cell is a kind of thyroid cell that has a distinctive look: Under the microscope it is bigger than a follicular cell and has pink-staining cellular material)

Labs - Antithyroid peroxidase antibodies confirm the diagnosis.

Question 16

What is subacute (de Quervain) thyroiditis?

Answer 16

Self-limited hypothyroidism following a flu-like illness with hyperthyroid symptoms seen early on.

Question 17

How do we confirm subacute (de Quervain) thyroidits?

Answer 17

Histology - Granulomatous inflammation

Labs - Elevated ESR

PE - Tender thyroid and jaw

Question 18

Most common cause of hypothyroidism?

Answer 18

Iodine deficiency. We can also see it with lithium toxicity

Question 19

What is Riedel thyroiditis?

Answer 19

Rare disease in which the thyroid is chronically replaced by fibrosis. We see rock hard, fixed, but painless goiter.

Question 20

Sheehan Syndrome? How do we recognize it?

Answer 20

This is a secondary cause of hypothyroidism. This is postpartum pituitary necrosis secondary to postpartum hemorrhage. We see low levels of TSH

Question 21

What is a goiter? What is the most common cause?

Answer 21

An enlarged thyroid gland due to any cause such as inflammation, tumor, or autoimmune disease. Endemic goiter, caused by iodine deficiency, is the most common cause of goiter worldwide.

Question 22

What is the general presentation of goiter?

Answer 22

Lethargy, fatigue, muscle weakness, cold intolerance (remember, heat intolerance for hyperthyroidism), weight gain, slow mentation

Question 23

What is myxedema coma?

Answer 23

A symptom of hypothyroidism, we see stupor, a coma, and hypoventilation coupled with hypothermia, bradycardia, and hypotension

Question 24

How do we diagnose hypothyroidism?

Answer 24

Chemistries: Mild normocytic anemia, hyponatremia, and hypoglycemia

Immunology: Antithyroid peroxidase antibody test for hashimoto thyroiditis

Question 25

Risk factors for thyroid neoplasms?

Answer 25

Childhood head and neck radiation exposure, male gender, young age, and a positive family history

Question 26

Hypothyroidism in newborns causes what condition? Describe it.

Answer 26

Cretinism - Mental retardation, short stature, coarse features, umbilical hernia.

Question 27

What is the typical presentation for a thyroid neoplasm?

Answer 27

Typically presents as a solitary nodule. Dyspnea, coughing/choking spells. dysphagia and hoarseness due to compression of the trachea and esophagus.

Question 28

How do we diagnose the different neoplasms of the thyroid?

Answer 28

Fine needle aspiration - Provides diagnostics for four different types of the neoplasms

Question 29

How do we treat thyroid neoplasms?

Answer 29

Thyroidectomy unless its an anaplastic carcinoma

Question 30

What are MEN?

Answer 30

Just think Don Rees

Question 31

What are multiple endocrine neoplasias (MEN)? How do we categorize them?

Answer 31

Autosomal Dominant inherited syndromes divided into three categories:

MEN 1 (Wermer Syndrome) - Tumors of the 3 P’s (Pancreas, Pituitary, Parathyroid). May present with kidney stones secondary to hyperparathyroidism and GI ulcers secondary to gastrin-producing pancreatic adenomas which cause Zollinger-Ellison Syndrome

MEN 2A (Sipple Syndrome) - Medullary thyroid carcinoma, pheochromocytoma and parathyroid adenoma

MEN 2B - Medullary thyroid carcinoma, pheochromocytoma, and oral/GI ganglioneuromatosis (associated with marfanoid habitus)

Question 32

Mutations that cause the MEN

Answer 32

MEN 1 arises from mutations in the self-named men1 oncogene. MEN 2A and 2B stem from mutations in the ret oncogene.