An 8-year-old girl has headache, vomiting, and hypertension. She appears adequately hydrated. Laboratory values are: serum sodium concentration 110 mEq/L (normal 135-145 mEq/L); blood urea nitrogen 10 mg/dL (normal 7-22 mg/dL); serum creatinine, 0.4 mg/dL (normal 0.3-0.7 mg/dL). The sodium concentration of a random sample of urine is 100 mEq/L (normal 130-260 mEq/24 h). An increase in which of the following hormones is the most likely cause of these findings?

Question

Quizplus · Accepted Answer

The symptoms and laboratory values suggest the patient is suffering from the syndrome of inappropriate antidiuretic hormone secretion (SIADH), where there is an excessive release of antidiuretic hormone (ADH). This leads to water retention, dilutional hyponatremia (low serum sodium), and relatively concentrated urine despite the presence of low serum sodium. The presence of headache, vomiting, and hypertension, along with hyponatremia and the urine sodium concentration, supports this diagnosis.

An 8-Year-Old Girl Has Headache, Vomiting, and Hypertension