Identification of Bartonella henselae in the Liver of a Thoroughbred Foal with Severe Suppurative Cholangiohepatitis

A 3.5-month-old, 170-kg, Thoroughbred colt was referred to University of Pennsylvania’s New Bolton Center for evaluation of dullness and dermatitis of the pasterns and muzzle. The pastern dermatitis affected all 4 limbs, appeared 10 days before presentation, and was treated by the owner with an iodine solution and triple antibiotic ointment, with no improvement. Dermatitis of the muzzle appeared 2 days before presentation and was treated with dexamethasone (0.02 mg/kg IV once). The day before presentation, the colt was noted to be uncharacteristically quiet with a dull demeanor. Before these problems, the foal was reported to have been healthy and thriving. Serum biochemistry analysis (SBA) performed in the morning of presentation identified increased liver enzyme activities, which prompted referral of the foal. The foal was born in Kentucky and had been moved to its current farm in Maryland 1 month earlier. The farm was reported to have problems occasionally with Rhodoccocus equi (R. equi) pneumonia in its foals. The foal had been routinely vaccinated and dewormed. On physical examination, the colt had a body condition score of 4/9 and was dull with decreased response to environmental stimuli. Heart rate (60 beats/min) and rectal temperature (100.4F) were normal but tachypnea was present (36 breaths/min). Sclerae and oral mucous membranes were mildly icteric. No heart murmurs or arrhythmias were auscultated. Normal bronchovesicular sounds were audible on rebreathing examination, but the foal coughed several times after removal of the rebreathing bag. The submandibular lymph nodes were considered normal on palpation. No abnormalities were identified on abdominal auscultation. Despite dullness, the foal had a good appetite for hay and was observed to nurse well. Erythematous lesions with crusts were present in regions of unpigmented and pigmented skin, including all 4 pasterns (worst in the hind limbs) and the muzzle (unpigmented). Joint palpation was within normal limits and no obvious lameness was seen. Aside from its very dull demeanor, neurologic examination was normal. Clinical laboratory tests (CBC and SBA) identified the presence of mature neutrophilia (10,200/lL; reference range, 2,200–8,100/lL), hyperproteinemia (8.6 g/ dL; reference range, 4.6–6.9 g/dL), hyperfibrinogenemia (679 mg/dL; reference range, 200–400 mg/dL), increases in GGT (184 IU/L; reference range, 12–45 IU/L) and SDH (19.65 IU/L; reference range, 0.30–7.0 IU/L) activities, increased total bilirubin concentration (7.1 mg/dL; reference range, 0.1–1.9 mg/ dL), increases in serum lipids (triglycerides and cholesterol, 116 mg/dL; reference range, 11–52 mg/dL and 149 mg/dL; reference range, 51–109 mg/dL, respectively), and increased bile acid concentration (16.9 lmol/L; reference range, 1.0–8.6 lmol/L). Red blood cell indices (HCT, RBC numbers, HGB, MCV) were within normal limits. Direct bilirubin concentration was within the normal reference range. Ammonia concentration was within the normal reference range. Based on the history, physical examination and abnormal liver function test results, a hepatopathy with secondary photosensitization was suspected. Abdominal ultrasonography was performed to further characterize the hepatopathy, and identified an enlarged liver that displaced peritoneal viscera caudally. The hepatic parenchyma had diffusely increased echogenicity and no biliary distension was present. The remainder of the abdominal ultrasound examination was normal. Because the foal had signalment (age), history (endemic R. equi on the farm), physical examination (cough, tachypnea), and hematologic (inflammatory leukogram and hyperfibrinogenemia) findings that could be consistent with a respiratory tract infection, thoracic ultrasonography and radiography also were performed. From the Department of Clinical Studies (Setlakwe, Sweeney, Johnson); and the Department of Pathobiology (Engiles), University of Pennsylvania School of Veterinary Medicine, New Bolton Center, Kennett Square, PA. Corresponding author: E.L. Setlakwe, University of Pennsylvania, New Bolton Center, 382 West Street Road, Kennett Square, PA 19348; e-mail: [email protected]. Submitted February 3, 2014; Revised April 9, 2014; Accepted April 9, 2014. Copyright © 2014 by the American College of Veterinary Internal Medicine DOI: 10.1111/jvim.12372 Abbreviations: