Background: Leptospirosis is one of the leading global zoonotic causes of morbidity and mortality. It is induced by a pathogenic spirochete of the genus Leptospira. The icteric form of leptospirosis is characterized by pronounced hyperbilirubinemia and associated with significantly increased mortality. Conventional static liver function tests insufficiently assess hepatic damage and have limited prognostic value. Dynamic tests, such as indocyanine green plasma (ICG) clearance, more adequately reflect hepatic functional status. In this case report we describe the ICG plasma disappearance rates (ICG-PDR) in a patient with leptospirosis and massive hyperbilirubinemia, expanding our knowledge of liver dysfunction in icteric leptospirosis.
Case presentation: A 21-year-old Caucasian man presented with acute-onset jaundice, myalgia, fever and headaches. Laboratory tests upon admission revealed, most notably, acute kidney failure and hyperbilirubinemia of 17 mg/dl with mild elevation of aminotransferases. In the course of the following 4 days, total serum bilirubin increased to 54 mg/dl. The clinical outcome was favorable with intravenous ceftriaxone and doxycycline. Presumptive diagnosis of leptospirosis was later confirmed by PCR-based amplification of leptospiral DNA in the blood. ICG-PDR values, bilirubin as well as aminotransferases were recorded throughout hospitalization and a 3-month follow-up period. Initially dramatically reduced ICG-PDR (2.0%/min, normal range: 18-25%/min) rapidly normalized within 10 days, while bilirubin remained elevated up to week 7. Mild elevation of serum alanine aminotransferase was at its peak of 124 U/l by day 12 and reached close to normal levels by week 7 upon admission.
Conclusions: Markedly diminished ICG-PDR values presented in this case report suggest severe liver function impairment in the acute phase of icteric leptospirosis. Prolonged elevation of serum bilirubin may not adequately reflect recovery of liver injury in this disease. ICG clearance appears to be a promising marker for the detection of hepatic dysfunction and recovery in icteric leptospirosis in addition to the static tests.
Keywords: Bilirubin; Indocyanine green; Leptospirosis; Liver failure; Liver function tests; Plasma disappearance rate.