Physician Assistant Endocrine System Disorders 4

Question 1

An ICU patient with septic shock has low total T3, elevated reverse T3, and a low-normal TSH. What is the most likely diagnosis?

Accepted Answer

Nonthyroidal illness (euthyroid sick) syndrome

Answer

Severe illness reduces peripheral T4-to-T3 conversion and raises reverse T3 without true thyroid disease.

Question 2

A 45-year-old with resistant hypertension and spontaneous hypokalemia needs screening for the most likely secondary cause. Which test is best?

Accepted Answer

Plasma aldosterone-to-renin ratio

Answer

Primary aldosteronism is screened with an elevated plasma aldosterone concentration to plasma renin activity ratio.

Question 3

Before surgical resection of a pheochromocytoma, which medication should be started first?

Accepted Answer

Phenoxybenzamine

Answer

Alpha blockade must precede beta blockade to prevent unopposed alpha-mediated hypertensive crisis.

Question 4

A child is found to carry a germline RET proto-oncogene mutation associated with MEN 2A. Which intervention is recommended?

Accepted Answer

Prophylactic total thyroidectomy

Answer

RET carriers nearly always develop medullary thyroid carcinoma, so prophylactic thyroidectomy is advised in childhood.

Question 5

A euvolemic patient with small cell lung cancer has serum sodium 124 mEq/L. Which lab pattern supports SIADH?

Accepted Answer

Serum osm low, urine osm >100, urine Na >40

Answer

SIADH causes hypotonic hyponatremia with inappropriately concentrated urine and elevated urine sodium in a euvolemic patient.

Physician Assistant Practice Test