Peritonitis in horses: 67 cases (1985-1990).

Peritonitis was diagnosed in 67 horses between 1985 and 1990: 14 horses developed septic peritonitis after intestinal rupture, 25 horses developed peritonitis after abdominal surgery, and 28 horses had peritonitis not associated with intestinal rupture or abdominal surgery. Forty of 67 horses (59.7%) did not survive. Nonsurvivors had higher heart rates (P = 0.01), RBC count (P = 0.039), serum creatinine concentration (P = 0.036), PCV (P = 0.007), and anion gap (P = 0.005); lower venous blood pH (P = 0.002); and a greater number of bacterial species cultured from peritoneal fluid samples (P = 0.054), compared with those from survivors. Nonsurvivors were more likely to have signs of abdominal pain (P < 0.000), circulatory shock (P = 0.009), and bacteria in peritoneal fluid samples (P = 0.042). Physical examination and peritoneal fluid analysis were the most valuable diagnostic aids for intestinal rupture. Peritonitis after abdominal surgery resulted in high mortality (56%); peritonitis not associated with intestinal rupture or abdominal surgery had lower mortality (42.9%). Clinical and laboratory indices can be of value in determining the prognosis for horses with peritonitis.