Wk. 3 - Disorders of the Thyroid & Parathyroid Flashcards

What is the pathophysiology of primary hypothyroidism?

Thyroid gland dysfunction leads to low T3/T4 and elevated TSH.

What is the most common cause of hypothyroidism in the U.S.?

Hashimoto’s thyroiditis (autoimmune).

Name two secondary causes of hypothyroidism.

Pituitary not releasing TSH; hypothalamus not releasing TRH.

What is the overall effect of low T3/T4 on metabolism?

Decreased metabolic rate.

List three common manifestations of hypothyroidism.

Fatigue, cold intolerance, weight gain, constipation, dry skin.

What severe complication is associated with hypothyroidism?

Myxedema coma (hypothermia, hypotension, hypoventilation, coma).

What is the first-line medication for hypothyroidism?

Levothyroxine (Synthroid).

Why is levothyroxine started at a low dose in older adults?

To avoid cardiac stress (palpitations, angina, MI).

What is the most common cause of hyperthyroidism?

Graves’ disease (autoimmune stimulation of TSH receptor).

Name two other causes of hyperthyroidism.

Toxic adenoma, multinodular goiter.

What is the overall effect of excess T3/T4 on metabolism?

Increased metabolic rate (hypermetabolism).

List three manifestations of hyperthyroidism.

Tachycardia, weight loss, heat intolerance, tremors, nervousness.

What eye finding is classic in Graves’ disease?

Exophthalmos.

What severe complication is associated with hyperthyroidism?

Thyroid storm (hyperthermia, HF, seizures, coma).

Name two medications used to treat hyperthyroidism.

Methimazole, Propylthiouracil (PTU).

What adjunctive therapy is used for hyperthyroid symptom control?

Beta-blockers (e.g., propranolol).

What is the pathophysiology of hyperparathyroidism?

Excess PTH → hypercalcemia, hypophosphatemia.

What is the most common cause of primary hyperparathyroidism?

Parathyroid adenoma.

What mnemonic summarizes hyperparathyroidism symptoms?

“Bones, stones, abdominal groans, psychic moans.”

What skeletal complications occur in hyperparathyroidism?

Osteoporosis, bone pain, fractures.

What is the surgical treatment for hyperparathyroidism?

Parathyroidectomy.

Name two medical management strategies for hyperparathyroidism.

Hydration, loop diuretics, bisphosphonates, calcitonin.

What is the pathophysiology of hypoparathyroidism?

Inadequate PTH secretion → hypocalcemia, hyperphosphatemia.

What is the most common cause of hypoparathyroidism?

Post-thyroid/parathyroid surgery or radiation.

What signs indicate neuromuscular irritability in hypocalcemia?

Positive Chvostek’s and Trousseau’s signs.

What are two clinical manifestations of hypoparathyroidism?

Tetany, seizures, laryngeal spasm, arrhythmias.

What is the acute treatment for hypoparathyroidism?

IV calcium gluconate with ECG monitoring.

What is the chronic treatment for hypoparathyroidism?

Oral calcium, vitamin D, magnesium, high-calcium/low-phosphorus diet.

What is the MOA of levothyroxine?

Synthetic T4; increases metabolic rate by replacing deficient thyroid hormone.

What are three side effects of levothyroxine?

Palpitations, tachycardia, insomnia, tremors, osteoporosis (long-term).

What patient teaching is essential for levothyroxine?

Take in morning on empty stomach, lifelong therapy, report chest pain.

What is the MOA of methimazole?

Blocks synthesis of thyroid hormones by inhibiting iodine binding.

What serious adverse effect is associated with methimazole?

Agranulocytosis (low WBCs).

What is the MOA of PTU?

Inhibits thyroid hormone synthesis and conversion of T4 to T3.

Why is PTU sometimes preferred over methimazole?

Safe in first trimester pregnancy and in thyroid storm.

What is the MOA of radioactive iodine (RAI) therapy?

Taken up by thyroid cells; radiation destroys thyroid tissue.

What is the most common long-term side effect of RAI?

Hypothyroidism.

What are two safety precautions after RAI therapy?

Avoid close contact with children/pregnant women, use separate toilet/utensils.

How do hypothyroidism and hyperthyroidism differ in weight changes?

Hypothyroidism → weight gain; Hyperthyroidism → weight loss despite appetite.

How do hypo- and hyperparathyroidism differ in calcium levels?

Hypoparathyroidism → hypocalcemia; Hyperparathyroidism → hypercalcemia.