A 41-year-old man with bipolar disorder on lithium presents with a 3-month history of polyuria and nocturia. Vital signs: BP 128/82, HR 88, RR 16, Temp 37°C, SpO2 98%. Labs show serum sodium 148 mEq/L, serum osmolality 305 mOsm/kg, and urine osmolality 180 mOsm/kg after water deprivation. Urine osmolality remains low even after desmopressin administration. Thyroid function tests are normal. Which mechanism best explains his clinical presentation?
- A)Destruction of adrenal medulla chromaffin cells
- B)Autoantibodies stimulating the TSH receptor
- C)Deficiency of 21 hydroxylase
- D)Collecting duct insensitivity to ADHGABARITO
- E)Excess pituitary ACTH production
Explicação
Lithium is a classic cause of nephrogenic diabetes insipidus. The kidneys are unable to respond to ADH at the collecting duct, so water deprivation and desmopressin fail to concentrate the urine. Persistent dilute urine with hypernatremia points to renal ADH r... Ver explicação completa e trilha adaptativa →