Hyponatremic-hypertensive syndrome with extensive and reversible renal defects

Abstract

Two young children with renal artery stenosis and severe hypertension who presented with the so-called hyponatremic-hypertensive syndrome (HHS), with marked urine and solute loss during the acute phase, are described. Both children also presented with severe high molecular proteinuria, glycosuria, and hypercalciuria, only the first symptom having prompt remission after normalization of blood pressure. In children with renal artery stenosis, HHS is associated with severe proteinuria due to hyperfiltration and more extensive tubular functional alterations. Hyponatremia and acute tubulopathy may mask the presenting clinical picture of renal artery stenosis.

Hyponatremic hypertensive syndrome in pediatric patients: is it really so rare?

“…Laboratory findings in patients with HHS include hyponatremia, hypokalemia, hypochloremic alkalosis, and proteinuria, sometimes in the nephrotic range [2,8]. This was true in our patients as well.…”

“…Although initially considered a rare condition, HHS has been identified in approximately 16% of adults with unilateral renal artery stenosis [4,10]. Data on the pediatric population are still sparse [5][6][7][8][9][10][11]. In an editorial commentary, Nicholls [2] suggested that HHS may be underdiagnosed in children and probably more common than previously thought.…”

“…Activation of the reninangiotensin system (RAS) causes secondary hyperfiltration, pressure diuresis, and sodium loss from the contralateral, nonstenotic kidney. Renal handling of other solutes is also affected by this hyperfiltration state, as reflected by findings of hypokalemia, alkalosis, hypercalciuria, glycosuria, and proteinuria, sometimes within the nephrotic range [2,4,8,10]. Several authors reported reversible cortical hyperechogenicity of the nonstenotic kidney, probably a consequence of hyperfiltration and tubulointerstitial damage [10,14].…”

“…All presented with severe hypertension, thirst, polyuria, weight loss, confusion, and hyponatremia. HHS has been described in children as well [5][6][7][8][9][10][11][12][13], starting with the report of Blanc et al [5] in 1991. Laboratory findings of elevated plasma levels of renin in most cases suggest that the stimulation of renin release from the ischemic kidney plays an important pathophysiologic role.…”

Two cases of hyponatremic-hypertensive syndrome in childhood with renovascular hypertension

“…We hypothesized that the symptoms of HHS would develop in children only when the stenosis in the affected artery became so severe that revascularization by PTRA was impossible. In the literature, only seven case reports of pediatric HHS with renovascular hypertension were found [2,5,6,9,10,16]. Of the nine reported cases, including the present two, PTRA was technically successful in only one case [10].…”