A 4-year-old boy, who had no systemic or inherited disease, presented with a 3-week history of intermittent vomiting without diarrhea or abdominal pain. In the past year, he experienced polydipsia and polyuria. Physical examination revealed body weight 17.5 kg (50th percentile), body height 100 cm (15~50th percentile), blood pressure 230/120 mmHg, heart rate 138 /min, and decreased skin turgor. There was no focal neurological deficit, blood pressure discrepancy between upper and lower extremities, palpable mass, nor any appreciation of an abdominal thrill. Laboratory studies revealed serum Na+ 124 mmol/L, K+ 2.4 mmol/L, Cl− 87 mmol/L, Ca2+ 8.5 mg/dL, HCO3− 34.5 mEq/L, creatinine 0.41 mg/dL, albumin 3.4 g/dL, IgG 247 mg/dL, and osmolality 290 mOsm/KgH2O. Urine analysis was significant for creatinine 11.2 mg/dL, Na+ 24 mEq/L, K+ 18 mEq/L, Cl− 24 mEq/L, osmolality 232 mOsm/KgH2O, RBC 168/μL, FENa 6%, and nephrotic-range proteinuria (55 mg/m2/hour). Survey for possible glomerulonephritis demonstrated the absence of anti-streptolysin O, p-ANCA, c-ANCA, ANA, and normal immunoglobulin A, C3, and C4 levels. In addition, work-up for secondary hypertension included: free T4 1.51 (normal range 0.8–2.0 ng/dL), TSH 5.7 (normal range 0.25–5.00 μIU/mL), cortisol 40.18 (normal range 4.3–25 μg/dL), ACTH 9.32 (normal range < 46 pg/mL), renin 1745 (normal range 2–15 ng/L), aldosterone 92.6 (normal range 4–25 ng/dL), and urine vanillylmandelic acid 3.8 (normal range 1.9–9.9 g/day). Renal ultrasonography revealed hyperechoic right kidney (7.6 cm in length) and small left kidney (5.3 cm in length). Due to the presence of hyperreninemic hypertension, natriuretic-hyponatremia, hypokalemia, and nephrotic range proteinuria, HHS was highly suspected. Computed tomography angiography confirmed high-grade renal artery stenosis with hypoplasia of the left kidney (Fig. ).\nIn terms of management for this case, we began with volume repletion by normal saline administration. Subsequently, his blood pressure declined from 210/120 mmHg to 180/90 mmHg. Intravenous calcium channel blocker was used to treat his hypertensive emergency, while oral captopril was prescribed for RAA axis blockage after diagnosis of unilateral renal artery stenosis. The systolic blood pressure gradually declined to 150~160 mmHg on the 3rd day. Potassium supplement was infused for his profound hypokalemia and generalized muscle weakness. Due to the severity of left renal artery stenosis, he was not a candidate for angiographic intervention, and decision was made to proceed with left nephrectomy. Overall, electrolyte abnormalities such as hyponatremia and hypokalemia were corrected within 1 week after admission, and resolution of polyuria, polydipsia, proteinuria, and hypertension were achieved 2 weeks after nephrectomy (Additional file : Table S1).
Eight years old boy presented with complain of headache for a week with increasing thirst and polyuria. He was having altered sensorium and convulsions prior to admission. He appeared hypovolemic with feeble peripheral pulses, possibly contributed by the polyuria. His BP was 184/110 mmHg (95th\nP = 114/75). There was left sided hemiparesis along with 6th and 7th nerve palsy. Ophthalmological examination was consistent for hypertensive retinopathy. Investigations revealed hyponatremic, hypokalemic, metabolic alkalosis along with normal creatinine (Table ). USG with Doppler revealed bilateral hyper-echogenic kidneys with right relatively bigger (7.5 cm) than the left (6.2 cm) and suspected decreased blood flow in the left kidney. Renin and aldosterone was elevated. Digital subtraction angiography (DSA) of kidneys confirmed 90% stenosis of the left renal artery. MRI brain was consistent for PRES (Figure ).