Lymphocytic/plasmacytic colitis in cats: 14 cases (1985-1990).

Lymphocytic/plasmacytic colitis was diagnosed in 14 cats during a 5-year period. Purebred cats were affected significantly (P < 0.001) more often than were nonpurebred cats. Six cats were male and 8 were female. Mean age at onset of clinical signs was 5.1 years (range, 0.5 to 9 years). Hematochezia, observed in 13 cats, was the most commonly reported sign; diarrhea was reported in 11 cats. Mildly high serum alanine transaminase activity and hypokalemia were frequent biochemical abnormalities. Campylobacter sp was cultured from the feces of 1 cat. On endoscopic examination, petechia and hyperemia of the colonic mucosa were detected in 7 of 8 cats. Cats were initially treated with dietary management alone or with a combination of dietary and pharmacologic management. Clinical signs in 7 of 11 treated cats completely resolved, whereas signs in 3 cats were considered improved. One cat was euthanatized when an inadequate response to treatment was observed. Most cats were eventually maintained on dietary management alone.