Hypertrophic osteopathy associated with equine multinodular pulmonary fibrosis in a gelding

Abstract

A 5 year old Thoroughbred-Warmblood gelding was presented with a six month history of weight loss, as well as a two week history of symmetrical limb swellings and intermittent fever. Physical exam revealed symmetrical, hard swellings present over both distal radii, the proximal left metacarpus, as well as both distal tibias and proximal metatarsi. Radiographs revealed moderate, smooth to palisading, diaphyseal new bone formation, confirming a diagnosis of hypertrophic osteopathy (HO). Imaging of the thorax was performed to determine an underlying cause. Ultrasonography of the thorax revealed multiple hypoechoic lung nodules in the cranioventral lung fields, along with pleural fluid. Biopsy revealed pulmonary fibrosis, whereas cytology, cultures, and EHV-5 PCR failed to identify infectious agents. A presumptive diagnosis of Equine Multinodular Pulmonary Fibrosis (EMPF) was made, in association with hypertrophic osteopathy. This is the first report of HO in association with presumptive EMPF.