A 72-year-old man with hypertension and diabetes presents with progressive memory loss, confusion, and polyuria over 6 months. Serum sodium is 118 mEq/L (normal 135-145). Urine osmolality is 285 mOsm/kg (low), and serum osmolality is 237 mOsm/kg (low). TSH and cortisol are normal. Chest X-ray shows a small lung nodule. Which of the following is the most likely diagnosis?
- A)Central diabetes insipidus from pituitary mass
- B)Syndrome of inappropriate antidiuretic hormone secretion from lung cancerGABARITO
- C)Hypothyroidism
- D)Nephrotic syndrome
- E)Primary adrenal insufficiency
Explicação
SIADH from small cell lung cancer presents with hyponatremia, inappropriately concentrated urine (osmolality >serum osmolality), and euvolemia. The lung nodule is key; SCLC is the most common malignancy causing ectopic ADH. Normal TSH and cortisol exclude endo... Ver explicação completa e trilha adaptativa →