Hyponatremia Clinical Update, August 16, 2011

The latest in clinical research on the diagnosis and treatment of hyponatremia.

A review published recently online ahead of print in Nature Reviews Nephrology discussed the issue of patients with liver cirrhosis developing progressive circulatory dysfunction.

This condition induces activation of the renin-angiotensin-aldosterone system (RAAS), activation of the sympathetic nervous system, and increased activity of antidiuretic hormone, activation that results in renal fluid retention, ascites, and dilutional hyponatremia, according to researchers in the liver unit, Hospital Clinic Barcelona, at the University of Barcelona in Spain.

“In patients with advanced cirrhosis, these processes culminate in renal vasoconstriction and type 2 hepatorenal syndrome (HRS), which is characterized by slowly progressive renal failure and refractory ascites. Type 1 HRS is characterized by acute renal failure and rapid deterioration in the function of other organs in the setting of a precipitating event,” the authors wrote in the study abstract.

“Prognosis for both types of HRS is notably poor and orthotopic liver transplantation is the only definitive treatment; however, various therapies that restore renal function can provide a bridge to transplantation. Vasoconstrictors plus albumin improve renal function in 40-60% of patients with type 1 HRS,” the authors concluded.

“Transjugular intrahepatic portosystemic shunt (TIPS) placement is also effective in type 1 HRS, but its applicability is low (as it is not suitable for all patients), and it increases the risk of encephalopathy. Albumin dialysis is a potentially effective treatment for type 1 HRS still under investigation. Patients with type 2 HRS are treated with repeated large-volume paracentesis or TIPS.”

Salt-Losing Crisis in Infants Not Always of Adrenal Origin

In a study recently published online ahead of print in the European Journal of Pediatrics, clinicians presented their experience with three infants (age 1.5, four, and seven months) who presented with vomiting, hyponatremia, and hyperkalaemia that was suggestive of a salt-losing congenital adrenal condition.

The clinicians from the Department of Endocrinology at Birmingham Children’s Hospital in the United Kingdom conducted diagnostic endocrine blood tests and started adrenal steroid therapy. “The infants were subsequently found to have raised plasma aldosterone and renin levels due to pyelonephritis and structural anomalies of the kidneys, demonstrating secondary aldosterone resistance,” the authors wrote in the study’s abstract.

The concluded that establishing the diagnosis of congenital adrenal disorders is essential in a baby who develops a salt-losing crisis in the first few weeks of life. “However, pyelonephritis should be considered and can be rapidly excluded in any infant presenting with a salt-losing crisis with hyponatremia and hyperkalaemia, in particular, outside the neonatal period. Only then should an endocrine cause for this presentation be considered and treatment commenced.”

SourcesManagement of Hepatorenal Syndrome in Patients with Cirrhosis [Nature Reviews Nephrology]Salt-Losing Crisis in Infants Not Always of Adrenal Origin [European Journal of Pediatrics]