Putative uremic encephalopathy in horses: five cases (1978-1998)

Objective-To determine historical, physical examination, clinicopathologic, and postmortem findings in horses with putative uremic encephalopathy. Design-Retrospective study. Animals-5 horses with renal failure and neurologic disease not attributable to abnormalities in any other organ system. Procedure-Medical records from 1978 to 1998 were examined for horses with r enal disease and neurologic signs not attributable to primary neurologic, h epatic, or other diseases. Signalment, history, physical examination findin gs, clinicopathologic data, renal ultrasonographic findings, and postmortem data were reviewed. Results-Of 332 horses with renal disease, 5 met selection criteria. Histori cal findings, physical examination findings, clinicopathologic data, ultras onographic data, and postmortem findings were consistent with chronic renal failure. Swollen astrocytes were detected in all 4 horses examined at necr opsy. Conclusions and Clinical Relevance-A single criterion was not determined to be pathognomonic for uremic encephalopathy in horses. Uremic encephalopath y should be considered as a differential diagnosis in horses with evidence of chronic renal failure and encephalopathic neurologic sign not attributab le to other causes. Astrocyte swelling, which was common to all 4 horses ex amined at necropsy, may serve as a microscopic indicator of uremic encephal opathy in horses.