A 69-year-old man with small cell lung cancer has confusion. Sodium is 121 mEq/L, serum osmolality is low, urine osmolality is high, urine sodium is

Question

A 69-year-old man with small cell lung cancer has confusion. Sodium is 121 mEq/L, serum osmolality is low, urine osmolality is high, urine sodium is 58 mEq/L, and he appears euvolemic. Which of the following is the most likely diagnosis?

Accepted Answer

Syndrome of inappropriate antidiuretic hormone secretion

Answer

Nephrotic syndrome

Answer

Primary adrenal insufficiency

Answer

Diabetes insipidus

Answer

Hyperosmolar hyperglycemic state

SIADH — USMLE Step 3 MCQ

A 69-year-old man with small cell lung cancer has confusion. Sodium is 121 mEq/L, serum osmolality is low, urine osmolality is high, urine sodium is 58 mEq/L, and he appears euvolemic. Which of the following is the most likely diagnosis?