Primary immune-mediated thrombocytopenia in 30 dogs (1997-2003).

During a 6-year period, primary (idiopathic) immune-mediated thrombocytopenia was retrospectively evaluated in 30 dogs. Ages of the dogs ranged from 3 months to 10 years (median 4 years); female dogs were markedly overrepresented with 73%. Clinical examination revealed hemorrhages in 70% of the dogs. Platelet counts ranged from 0 to 111,000/microL (median 8000/microL); 77% of the dogs had platelet counts <30,000/microL. Seventeen dogs were anemic (hematocrit 9% to 36%; median 31%). Immunosuppressive therapy was performed in all but one dog. The recurrence rate of 19 dogs that were followed over an extended period (112 to 1684 days; median 340 days) was 26%. Twenty-nine (97%) dogs survived 14 days after initial presentation, and 27 (93%) dogs survived at least the following 15 to 1684 days (median 220 days).