Hypokalemia and hypertensive urgency in a 10-year-old boy: Questions

Abstract

A 10-year-old boy applied to the pediatric outpatient clinic with the complaints of fatigue lasting more than 2 months, and abdominal pain. Since the routine laboratory evaluation revealed severe hypokalemia (serum potassium 2.1 mmol/L), the patient was referred to the pediatric nephrology department. We detailed the medical history of the patient and we learned that he never had polyuria or polydipsia and did not complain about muscle cramps or contractions. He had never experienced dehydration attacks, and his growth was normal. Physical examination revealed high blood pressure (190/ 130 mmhg). The weight and height percentiles were both between 25 and 50 p. The patient had diffuse and vague tenderness on abdomen. The patient had hypokalemia (serum potassium 2.1 mmol/L) and hypochloremia (serum choride 78 mmol/L) accompanying metabolic alkalosis with a blood pH of 7.5, and a serum bicarbonate level of 32 mmol/L. Serum creatinine and serum sodium were normal, 0.7 mg/dL and 138 mmol/L, respectively. The patient was hospitalized for hypertensive urgency and further evaluation. Fractional excretion of sodium was 0.01%, and fractional excretion of potassium was 30%. Tubular phosphorus reabsorbtion was 92%. Renin activity was 1.22 ng/mL/h, aldosterone level was reported as < 3.7 ng/dL, both of which were at the lowest ranges of their references (Table 1). Serum cortisol to exclude congenital adrenal hyperplasia and urine catecholamines to exclude pheochromocytoma were within normal ranges. Kidney ultrasound revealed medullary nephrocalcinosis (Fig. 1); renal arteries were observed to be normal in Doppler ultrasonographic evaluation. Left ventricular hypertrophy was demonstrated in echocardiographic evaluation, and ophthalmologic examination showed hypertensive retinopathy, both of which denote a chronic hypertensive process. We learned that the patient’s mother and grandmother were hypertensive, and the patient’s mother had chronic kidney disease with an eGFR of 25 mL/dk/1.73 m.