PANCE (Physician Assistant National Certifying Exam) — All Questions

A 32-year-old woman has weight loss, heat intolerance and palpitations. She has a diffusely enlarged, nontender thyroid, bilateral proptosis, and thickened skin over the shins. TSH is suppressed and free T4 is elevated. Which diagnosis is most likely?

• a.Subacute granulomatous thyroiditis
• b.Graves disease✓
• c.Hashimoto thyroiditis
• d.Toxic multinodular goiter

Hyperthyroidism with a diffuse goiter, exophthalmos and infiltrative dermopathy is specific for Graves disease, which is caused by antibodies that stimulate the TSH receptor. Toxic multinodular goiter produces a nodular gland without eye disease or dermopathy. Subacute thyroiditis causes a painful, tender thyroid, and Hashimoto thyroiditis usually leads to hypothyroidism.

A 74-year-old man with known coronary artery disease is diagnosed with primary hypothyroidism (TSH 38 mIU/L, low free T4). How should levothyroxine be started?

• a.At a low dose, titrated gradually✓
• b.At a high loading dose given IV
• c.Only after a trial of liothyronine (T3)
• d.At the full weight-based dose on day one

In older patients and those with coronary disease, levothyroxine is started at a low dose (for example 25 mcg daily) and increased gradually, about every 6 weeks, because rapid replacement raises myocardial oxygen demand and can provoke angina or arrhythmia. Full-dose initiation is reasonable in younger healthy patients but not here. T3 is not a standard first step, and IV loading is reserved for myxedema coma.

A 36-year-old woman has fatigue, weight loss, salt craving and darkening of her palmar creases and gums. Labs show sodium 128 mEq/L and potassium 5.9 mEq/L. Which test is most useful to confirm the suspected diagnosis?

• a.Plasma free metanephrines
• b.Overnight dexamethasone suppression test
• c.Serum aldosterone-to-renin ratio
• d.ACTH (cosyntropin) stimulation test✓

Hyperpigmentation, hyponatremia and hyperkalemia suggest primary adrenal insufficiency, confirmed by a low cortisol response to ACTH (cosyntropin) stimulation together with an elevated plasma ACTH. The dexamethasone suppression test screens for cortisol excess, metanephrines screen for pheochromocytoma, and the aldosterone-to-renin ratio screens for primary hyperaldosteronism, which causes hypokalemia rather than hyperkalemia.

A 45-year-old woman has central obesity, wide purple abdominal striae, proximal muscle weakness, easy bruising and new hypertension. She takes no glucocorticoids. Which is an appropriate initial screening test?

• a.Random morning serum ACTH
• b.Fasting serum insulin level
• c.Late-night salivary cortisol✓
• d.Serum TSH and free T4

Suspected endogenous Cushing syndrome is screened with a test of cortisol excess: late-night salivary cortisol, 24-hour urinary free cortisol, or a low-dose dexamethasone suppression test. ACTH is measured after hypercortisolism is confirmed, to separate ACTH-dependent from independent causes. Thyroid tests and insulin levels do not establish cortisol excess.

A 38-year-old man has episodes of pounding headache, sweating and palpitations with blood pressure up to 230/120 mm Hg. Plasma free metanephrines are markedly elevated and CT shows a 4-cm adrenal mass. Before surgery, how should his blood pressure be managed?

• a.Alpha-blockade first, then a beta-blocker✓
• b.A beta-blocker first, then alpha-blockade
• c.A beta-blocker alone
• d.A thiazide diuretic alone

In pheochromocytoma, alpha-adrenergic blockade (for example phenoxybenzamine or doxazosin) is started first, and a beta-blocker is added only afterward to control tachycardia. Starting a beta-blocker first leaves alpha-mediated vasoconstriction unopposed and can precipitate a hypertensive crisis. Diuretics worsen the volume contraction these patients already have.

A 19-year-old with type 1 diabetes presents with diabetic ketoacidosis. Glucose is 540 mg/dL, pH 7.12, and serum potassium 3.0 mEq/L. IV 0.9% saline has been started. What is the next step before starting an insulin infusion?

• a.Give IV sodium bicarbonate
• b.Give IV dextrose 50%
• c.Replace potassium to at least 3.3 mEq/L✓
• d.Start insulin immediately at a high rate

Insulin drives potassium into cells, so in DKA insulin is held until serum potassium is at least 3.3 mEq/L to avoid life-threatening hypokalemia and arrhythmia. Bicarbonate is considered only for very severe acidosis (pH below about 7.0). Starting insulin with a potassium of 3.0 is dangerous, and dextrose is added later when glucose falls, not before insulin.

A 28-year-old woman has amenorrhea and galactorrhea. Prolactin is markedly elevated, pregnancy test is negative, TSH is normal, and MRI shows a 7-mm pituitary adenoma. What is the usual first-line treatment?

• a.External-beam pituitary radiation
• b.Octreotide
• c.Cabergoline✓
• d.Transsphenoidal surgery

A prolactin-secreting microadenoma is usually treated first with a dopamine agonist, and cabergoline is preferred over bromocriptine because it is better tolerated. Octreotide is a somatostatin analog used for acromegaly. Surgery is an option in selected patients or when medication fails or is not tolerated, and radiation is reserved for refractory tumors.