Urinary excretion patterns in renal failure due to malaria: the effects of phenoxybenzamine in two cases.

Abstract

Summary: Urinary solute excretion was studied in 4 patients with renal failure due to falciparum malaria with heavy parasitaemia. Two patterns of excretion were observed. The first pattern, noted in two patients, was characterised by a urine sodium below 10 mEq/L and a high osmotic urine and plasma ratio. The second pattern, observed in the other 2 patients, showed the urine sodium above 40 mEq/L and iso-osmotic urine. The creatinine clearance was much lower in the patients with the second urinary pattern. In all cases there was no evidence of dehydration or sodium depletion. Following phenoxybenzamine injection there was a significant increase in urine flow, creatinine and osmolar clearances and sodium excretion in the patients with the i first urinary pattern. The other 2 patients with the second urinary pattern showed no significant changes in urine flow, clearances and solute excretion. Renal failure in the first 2 patients is believed to be prerenal, being due to the temporary decrease in blood flow of the outer cortical nephrons secondary to vasoconstriction mediated by norepinephrine discharge from the sympathetic nervous system, which could be corrected by phenoxybenzamine. In the second group the urinary pattern was suggestive of acute tubular necrosis.