Liver disease associated with leptospirosis in a mare

Abstract

A nine-year-old Trakehner mare was presented as an emergency due to colic, and with a history of intermittent fever and poor performance. A questionable titre for Leptospira interrogans serovars Bratislava (L. Bratislava) and Pomona and a negative titre for Babesia caballi were documented. Clinical examination revealed tachycardia, pyrexia, delayed capillary refilling time, reduced gastrointestinal borborygmi, copious reflux upon nasogastric intubation, and no abnormalities upon per-redum abdominal palpation. Trans-abdominal ultrasonography revealed congestion of the biliary tree with thickening of the ductal walls, and distention and amotility of the duodenum. Severe neutrophilic leucocytosis, liver enzyme elevation, increased bile acids, hypertriglyceridaemia, total hyperbillirubinaemia, hyperproteinaemia and hyperglycemia were present. A positive titre for L. Bratislava and Australis, and a negative titre for L. Pomona were identified. Intravenous fluid therapy was initiated and the volume of nasogastric reflux gradually declined overnight; no further colic signs were observed. A liver biopsy was obtained and histological findings included severe hepatic fibrosis with bile duct proliferation and cholestasis, multifocal mild neutrophilic hepatitis, and hepatosis with glycogen storage. Aerobic and anaerobic bacterial cultures were negative. Repeated blood analysis after one week demonstrated an increase in antibody titres against L. Bratislava and further increase in gamma-glutamyltranferase (GGT) and alkaline phosphatase. A presumptive diagnosis of liver disease associated with leptospirosis was made and therapy with procaine penicillin initiated. The mare remained clinically stable and was discharged with instructions to continue therapy for an additional 2 weeks. Six weeks after discharge the mare had remained clinically stable and all but one liver parameter had normalised. The antibody titre against L. Bratislava had declined to undetectable levels. Six months after discharge a complete recovery with return to previous performance levels was reported. Though extensively described in various other animal species, as well as in humans, the association between liver disease and leptospirosis in horses is poorly characterised. Despite the lack of a strong association between liver damage with Leptospira spp. infection in horses, leptospirosis due to acute infection or potential recrudescence of leptospiraemia should be considered a differential diagnosis in cases with clinical signs and laboratory abnormalities compatible with hepatopathy, as well as in horses with chronic, recurrent, mild fever. This case report describes the history, clinical presentation, diagnostic test results and response to treatment that support a diagnosis of Leptospira-induced hepatopathy in a mare.