NECROTIZING ENTEROCOLITIS IN HORSES - A RETROSPECTIVE STUDY

The clinical and clinicopathologic characteristics of fatal necrotizin g enterocolitis were examined in 16 horses (age 4 months to 12 years). At initial presentation, 8 of 16 horses were pyrexic (median temperat ure, 38.4 degrees C; range, 33.8 to 40.6 degrees C); all 16 were tachy cardic (median heart rate, 93 bpm, range, 66 to 138 bpm); 13 of 16 wer e tachypneic (median heart rate, 36 bpm, range, 16 to 80 bpm), dehydra ted, and had discolored mucous membranes. All horses that were pyrexic were also tachycardic and tachypneic. PCV was high (>45%) in 14 horse s. Six horses were leukopenic (<5,000 cells/mu L); 12 were neutropenic (<2,300 cells/mu L), and 14 had >100 band neutrophils/mu L. Twelve ho rses were acidemic (pH <7.37; range, 6.88 to 7.33) and the venous bica rbonate concentration was low (<23 mEq/L) in 14 horses. Median anion g ap in 16 horses was 31.5 mEq/L (>15 mEq/L in 15 horses). Eleven of 16 horses were hyponatremic (<137 mEq/L), 1 horse was hypernatremic (>143 mEq/L), 3 were hypokalemic (<3.2 mEq/L), 6 were hyperkalemic (>4.5 mE q/L), and 14 were hypochloremic (<98 mEq/L). Serum creatinine concentr ations were high (>1.4 mg/dL) in 15 horses. Abdominal fluid was examin ed in 12 horses: 4 had total protein concentrations >2.5 g/dL and 6 ha d nucleated cell counts >5,000/ mu L and <10,000/mu L; none had >10,00 0/mu L. Eight of 12 samples revealed a nondegenerate neutrophilia (>50 %). Abdominal fluid collected from 4 horses immediately before death w as normal in 2 horses and indicative of suppurative inflammation in 2. All 8 horses tested had low or nonexistent serum immunofluorescent an tibody titers to Ehrlichia risticii. Four of 16 horses had Salmonella spp isolated from feces or tissues. All 16 horses either died (5 of 16 ; 31%) or were euthanized because of a grave prognosis. Median time to death was 45.5 hours (range, 7 to 113 hours) from the time of admissi on. Death was preceded by severe abdominal pain in 14 horses. Fatal ne crotizing enterocolitis of horses is characterized by a brief course, profound dehydration, electrolyte derangements, acid-base abnormalitie s, and terminally, severe abdominal pain. Abdominal fluid analysis was frequently not indicative of the severity of disease. Copyright (C) 1 996 by the American College of Veterinary Internal Medicine.