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).
A 19-month-old African American male was transferred from an outside hospital to our pediatric unit for new-onset status epilepticus and hyponatremia (serum sodium of 126 mmol/L). He initially presented with generalized tonic–clonic seizures unresponsive to rectal Diazepam, but eventually resolved with intravenous Lorazepam after approximately 15 min. Upon admission, the patient appeared lethargic but responsive. Vital signs on admission: blood pressure 218/144, heart rate of 210, respiratory rate was 32, and temperature was 36.8°C. Lab work revealed hyponatremia, an elevated peripheral renin activity, aldosterone and ADH levels, and a normal serum creatinine (Table ). His weight was 10.6 kg (29th‰ for age) and his height was 87.3 cm (88th‰ for age). His physical exam was unremarkable. He was awake and alert, normal heart, and lung sounds. Abdomen was soft, non-tender, and non-distended with no evidence of organomegaly. Extremities were warm with normal pulses and capillary refill.\nElectrocardiogram (ECG) showed sinus tachycardia and a waveform characteristic concerning for left ventricular hypertrophy. Echocardiogram demonstrated normal biventricular size with qualitatively mild concentric left ventricular hypertrophy.\nUpon review of systems, the family revealed a 1 kg weight loss over the course of 10 days. He was seen by a pediatric gastroenterologist for daily non-bloody, non-bilious emesis, and was treated for gastroesophageal reflux disease (GERD). During this time, he also demonstrated signs of polyuria and polydipsia with water intake increasing to 8–10 bottle per day.\nShortly after admission, his blood pressure increased to 248/150 mmHg. He became lethargic and suffered a second episode of seizure activity, which was successfully treated with Lorazepam followed by a loading dose of Phenobarbital. His blood pressure was titrated with a nicardipine infusion for a target range of 120–140 mmHg systolic and 70–80 mmHg diastolic.\nA renal ultrasound revealed a smaller right kidney (length 6.4 cm) as compared to the left (length 7.6 cm). The right kidney when compared to the left had less cortical thickness and increased echogenicity suggestive of vascular insult. The vessels were not completely visualized via color Doppler.\nMRI of the brain without contrast demonstrated features consistent with PRES (Figure ). MRI of the abdomen with contrast showed a small right kidney and a high-grade proximal renal artery stenosis (Figures and A). Upper pole hypointense lesions of the right kidney consistent with long-standing ischemic insults. Diagnostic angiography later confirmed a complete occlusion of his renal artery accompanied by a 20% narrowing of the perirenal aorta. Video EEG was performed which exhibited frequent, focal spikes and sharp waves in the left temporal region. Seizure activity was thought to emanate from accrued pathological alterations in the brain regions specified.\nThe right renal artery was balloon dilated to 50% as shown in Figure B. This was complicated by renal artery re-stenosis, with a peak systolic velocity of 200 cm/s (normal <180 cm/s) on serial renal Doppler ultrasounds. Repeat angiogram showed a 30% opening. Following repeat balloon angioplasty, the patient’s renal artery progressively re-occluded over 15 min requiring a 4 × 14 Genesis stent to maintain adequate flow, as shown in Figures C,D. He was weaned off the nicardipine to amlodipine 2.5 mg in a.m. and 5 mg in p.m. to good effect. Since his hospitalization, the patient has been free of seizures and is neurologically intact.