Severe hyperkalemia in nephrotic syndrome.

With the exception of dilutional hyponatremia,electrolyte abnormalities are uncommon in childrenwith nephrotic syndrome (NS)(1). With profoundhypoalbuminemia leading to intravascular volumedepletion, there is upregulation of the renin-angiotensin-aldosterone axis leading to avidproximal tubular sodium reabsorption(2) andstimulation of antidiuretic hormone. Abnormalitiesin serum potassium are not reported to occur ifglomerular filtration (GFR) is preserved. Werecently encountered a 4-year old Caucasian girlwith new onset of NS. Her serum creatinine atdiagnosis was normal (0.4 mg/dL) and so were herelectrolytes; screening tests for secondary causes ofNS were also normal (normal complement C3 andC4, and negative hepatitis B and C serologies), withthe exception of a positive anti-nuclear antibodyscreen. The child had been started on steroid therapybefore the test results were back. She returned aweek later with worsening edema and a weight gainof 1.3 kg. Blood tests were obtained to rule outsystemic lupus erythematosus; at the same time, anelectrolyte panel was repeated. This showed that thepatient was hyponatremic (sodium 127 mEq/L) andhad significant hyperkalemia (potassium 7.2 mEq/L). Her serum creatinine was elevated at 0.7 mg/dL,corresponding to a calculated GFR of 83 mL/min/1.73 m