Case report: Secondary immune-mediated anemia and thrombocytopenia with small intestinal intussusception in a Chihuahua

Abstract

An 11-year-old female Chihuahua mix presented with acute melena, lethargy, anorexia, and mild coughing.  Laboratory testing revealed rapidly progressive severe anemia (PCV decreasing from 17% to 13% within 24 hours) and acute thrombocytopenia.  Multiplex PCR testing for hemoparasites, and screening for canine parvovirus and canine coronavirus were negative. Abdominal ultrasonography identified a small intestinal intussusception. A direct antiglobulin test (DAT) performed by flow cytometry was positive, supporting the diagnosis of immune mediated destruction of both erythrocytes and platelets. The patient received two urgent blood transfusions totaling 500 mL, followed by exploratory laparotomy and resection anastomosis of a 7-cm segment of intussuscepted intestine. Histopathological examination of a tissue biopsy specimen confirmed severe necrotizing and hemorrhagic enteritis. Postoperatively, clinical signs and hematologic parameters improved without the need for immunosuppressive therapy, which is commonly required in cases of immune-mediated hemolytic anemia (IMHA) and immune-mediated thrombocytopenia (IMT). The final diagnosis was small intestinal intussusception leading to necrotizing enteritis, which triggered secondary Evans syndrome. Concurrent myxomatous mitral valve disease (stage B1) was also diagnosed.