Renal Artery Stenosis Precipitates Hyponatremic Hypertensive Syndrome and Posterior Reversible Leukoencephalopathy

Abstract

BackgroundHyponatremic hypertensive syndrome (HHS) is an uncommon disorder usually encountered in the adult population with unilateral renal artery stenosis and is under-recognized in the pediatric population.Case diagnosis/treatmentA 19-month-old male presented with new-onset status epilepticus associated with neurological sequelae, and hypertension to a high of 248/150 mmHg. Lab work revealed significant hyponatremia, elevated peripheral renin activity, and increase in aldosterone and ADH levels. A diagnosis of HHS was made. Initial analysis revealed a high-grade proximal renal artery stenosis by magnetic resonance imaging (MRI) and angiogram. Electroencephalogram and an MRI of the brain demonstrated characteristic abnormalities of the left temporal–parietal regions consistent with posterior reversible leukoencephalopathy syndrome (PRES). The patient responded to right renal artery balloon dilation and stent placement. Since intervention and close blood pressure control with Amlodipine, the patient has been free of seizures and is neurologically intact.ConclusionWe report a case of malignant hypertension in a 19-month-old male secondary to renal artery stenosis with associated HHS and PRES. Prognosis of PRES in children with renal disease is excellent. Prompt intervention may offer near complete resolution of physiologic and symptomatic effects of HHS and PRES due to high-grade renal artery stenosis. This report was written with parental consent for de-identified case presentation and radiographs for the educational benefit of other medical professionals.

A pediatric patient with hyponatremic hypertensive syndrome without persistent hypertension in acute phase: A case report and review of literature

“…To the best of our knowledge, there are 23 previously reported pediatric patients with HHS under the age of 15 years, excluding causes such as tumor or Takayasu disease ( Table 2 ). 2 , 4 , 8 – 20 Including our patient, the male-to-female ratio was 9:15. The average age of onset was 3 years (range: 14 days–12 years).…”

“…Urinary chloride level more than 15 mEq/L (Table 2). 2,4,[8][9][10][11][12][13][14][15][16][17][18][19][20] Including our patient, the male-tofemale ratio was 9:15. The average age of onset was 3 years The clinical course after admission just before catheter therapy: hypertension appeared at day 9, which lasted after administration of several anti-hypertension drugs.…”

Unilateral Posterior Reversible Encephalopathy Syndrome Secondary to Renal Artery Obstruction: A Case Report

“…The posterior portion of the brain is more vulnerable because autoregulation and sympathetic activity are relatively weak in the posterior area 2,8,9) . The range of cerebral perfusion pressure in which the autoregulation of cerebral blood flow functions nor mally differs individually 2) .…”

Hyponatremic Hypertensive Syndrome Complicating Unilateral Renal Artery Stenosis: A Rare Manifestation in Childhood

“…HHS is characterised biochemically by hyponatremia, hypokalemia, hypochloremia, metabolic alkalosis, hyperreninemia, hyperaldosteronemia and elevated urinary sodium and protein. [ 3 ] The central pathophysiology in HHS involves activation of the Renin-Angiotensin-Aldosterone system (RAAS) secondary to the unilateral renal ischemia. The RAS-mediated elevation in blood pressure causes pressure diuresis and natriuresis through the contralateral kidney.…”

“…Revascularisation is preferred for unilateral RAS, usually by percutaneous transluminal angioplasty and authors have reported the normalisation of blood pressure after either angioplasty or nephrectomy. [ 2 3 4 5 ] Our patient had a nonfunctional right kidney, a source of persistent hypertension, hence, right nephrectomy was done.…”