Characteristics and risk factors for failure of horses with acute diarrhea to survive: 122 cases (1990-1996).

Objective: To characterize horses with acute diarrhea and determine risk factors for failure to survive.

Design: Retrospective study.

Animals: 122 adult horses admitted for acute diarrhea at the teaching hospital between Jan 1, 1990 and Dec 31, 1996.

Procedure: Medical records of horses with acute diarrhea were reviewed to abstract information regarding signalment, history, physical examination, clinicopathologic testing, treatment, and outcome.

Results: 91 of 122 (74.6%) horses lived and were discharged from the hospital. Horses with history of administration of antimicrobials for a problem preceding diarrhea were approximately 4.5 times less likely to survive. The following variables that had been determined at the time of admission were significantly associated with failure to survive: administration of antimicrobial drugs for another illness, serum creatinine concentration > 2.0 mg/dl, PCV > 45%, tachycardia (heart rate > 60 beats/min), and low serum total protein concentration. Prevalence of laminitis was 11.5%.

Clinical Implications: Diarrheic horses that are azotemic and have clinicopathologic findings consistent with hemoconcentration and hypoproteinemia have a poor prognosis for survival. Antimicrobial administration may induce diarrhea, and antimicrobial-associated diarrhea may have a worse prognosis than other types of acute diarrhea.