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).
The 12 years old boy was admitted with headache for 1 mo, increased thirst, polyuria for 15 d and obtunded sensorium for 4 d. There was a documented decrease in weight of 800 g over the last 2 wk, possibly because of the polyuria. BP was 244/166 mmHg (95th\nP = 121/79). Ophthalmological examination was consistent with hypertensive retinopathy. Investigation showed hyponatremic, hypokalemic, metabolic alkalosis and normal creatinine (Table ). USG doppler revealed “parvus- tardus” like flow in left renal artery, with enlarged hyper-echogenic right kidney. MRI brain was consistent with PRES. Digital subtraction angiography confirmed left renal artery stenosis (Figure ).\nAll three cases had high urinary sodium indicating natriuresis as the cause of the hyponatremia (Table ).\nThe patients were diagnosed to have HHS presenting as hypertensive emergency. They were initially managed with Labetalol infusion and thereafter switched to oral anti-hypertensives (combination of Nifedipine sustained release, Hydralazine and Beta Blocker). Case 1 and 2 were given 3% NaCl and all required potassium supplements. Electrolyte abnormalities gradually corrected with normalization of BP.\nCase 1 was advised PTA but was lost to follow up after 3 mo till when he was hypertensive (132/86 mmHg) despite being on Enalapril, Nifedipine and Atenolol. His electrolytes had normalized but he continued to have significant proteinuria; case 2 underwent percutaneous transluminal balloon angioplasty (PTA), which restored normal blood flow. His sodium normalized in 2 wk and urinalysis by 8 wk. At last follow up (20 mo) he remains off anti hypertensive with normal BP and renal profile; Case 3 underwent a failed balloon angioplasty of left renal artery followed by successful renal artery stenting. At 9 mo follow up, his electrolytes and urinalysis had normalized and he had normal BP (110/70 mmHg) on 1.25 mg of Enalapril. The USG changes in the contra-lateral kidney also normalized by last follow up for Case 2 and 3.