Correspondence
Low Normal Potassium Levels in Acute Renal
Failure: Evidence of Leptospirosis
It has been suggested that renal involvement in leptospirosis appears to be a special form of acute renal failure characterized by a higher frequency of polyuria and the presence of hypokalemia with an elevated urinary fractional excretion of potassium [1]. The high frequency of hypokalemia is thought to be caused by a proximal or thick
ascending limb of Henle tubular dysfunction [2, 3]. It has
been proposed that leptospirosis should be included in the
differential diagnosis in febrile patients with acute renal
failure and hypokalemia [3]. However, even the presence
of low normal levels of potassium in patients with acute renal failure should be an alarming sign for the diagnosis of
leptospirosis. In fact, we were recently faced with a patient
who presented with fever of 10 days’ duration, acute renal
failure (serum creatinine 1,060 µmol/l) and marked hyperbilirubinemia (total bilirubin 560 µmol/l) with moderate increases in serum liver and muscle enzymes (CK 930 IU/l
[normal values 30–220 IU/l], SGOT 219 IU/l [normal values 5–40 IU/l], SGPT 230 IU/l [normal values 5–40 IU/l]).
Despite the profound deterioration of renal function and
the oliguria noticed during the last few hours prior to admission, as well as the rhabdomyolysis-induced increased
potassium movement from the cells into the extracellular
fluid, serum potassium concentration was at low normal
levels (3.8 mmol/l) with urine potassium levels 30 mmol/l.
Leptospirosis was diagnosed by laboratory tests, while all
other microbiological or serological tests were negative.
Penicillin was given after the diagnosis. However, oliguria
persisted, while the patient developed disseminated intravascular coagulation with diffuse hemorrhages and deep
vein thrombosis of the lower extremities and was admitted
to the emergency room. During the prolonged hospitalization urine volume was restored to about 2–3 l/day with a
parallel improvement of renal function after careful rehydration. At that time, serum potassium levels ranged between 3.3 and 4.5 mmol/l. Thus, even the low normal potassium levels in febrile patients with acute renal failure should
be considered further evidence indicating leptospirosis.
K. Nakou, G. Liamis,
M.S. Elisaf, K.C. Siamopoulos
Infection 2000;28:196
References
1.
2.
3.
Seguro AC, Lomar AV, Rocha AS: Acute renal failure of leptospirosis: nonoliguric and hypokalemic forms. Nephron 1990; 55:
146–151.
Magaldi AJ, Yasuda PN, Kudo LH, Seguro AC, Rocha AS: Renal
involvement in leptospirosis: a pathophysiologic study.
Nephron 1992; 62: 332–339.
Lin CL, Wu MS, Yng CW, Huang CC: Leptospirosis associated with
hypokalaemia and thick ascending limb dysfunction. Nephrol
Dial Transplant 1999; 14: 193–195.
K. Nakou, G. Liamis, M.S. Elisaf (corresponding author), K.C. Siamopoulos
Dept. of Internal Medicine, University of Ioannina, Medical School,
GR-45110 Ioannina, Greece; Phone: +30-651-97500, Fax: +30-651-45944
Received: August 20, 1999 • Accepted: February 22, 2000
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Infection 28 · 2000 · No. 3 © URBAN & VOGEL