Evan's disease in dogs results when the animal develops two distinct blood diseases at the same time. Also know as Evan's syndrome, the disorders involved are immune-mediated hemolytic anemia and immune-mediated thrombocytopenia. Since these are immune disorders, your pet's body is attacking itself. Prompt diagnosis and treatment can save your dog's life. Be forewarned -- this is an expensive disease to treat.
In immune-mediated hemolytic anemia, the dog's body destroys his red blood cells. In immune-mediated thrombocytopenia, his body destroys platelets. Either condition on its own is potentially fatal. Put them together, as in Evan's syndrome, and the consequences can be dire. Symptoms of immune-mediated hemolytic anemia generally come on quickly, and include lethargy, appetite loss, pale mucous membranes, exercise intolerance, rapid heart rate, breathing difficulties and possibly collapse. Immune-mediated thrombocytopenia symptoms include blood in the stool, skin bruising and nosebleeds. While some dogs are genetically predisposed to the disease, other canines acquire it via infectious agents from tick bites. It's imperative to get your dog to the vet immediately.
While any dog might develop Evan's syndrome, certain breeds appear genetically disposed to the condition. These include the cocker and springer spaniels -- who were once the same breed -- the pug, miniature schnauzer, Old English sheepdog, bichon frise and clumber spaniel. Evan's syndrome occurs more often in females than male dogs, and symptoms usually appear before the dog reaches the age of 6.
Diagnosis and Treatment
Your veterinarian will perform various blood tests, along with ultrasounds and X-rays, to make a diagnosis. She'll also require a thorough history of your dog's health. Once diagnosed with Evan's syndrome, your dog requires in-patient care at a veterinary hospital, preferably a facility offering around the clock critical care. Your dog likely will receive intravenous fluid therapy and blood transfusions initially to treat Evan's syndrome. He'll also receive steroids, cyclosporine and other medications.
Evan's Syndrome Prognosis
According to the Kentucky Veterinary Medical Association, between 50 and 80 percent of dogs diagnosed with Evan's syndrome recover well enough for hospital release, so prepare yourself for the possibility that your dog might not make it. If he is released, he likely will require drug therapy for the rest of his life, and frequent veterinary visits to ensure he's receiving the right dosage. Some of these powerful medications come with substantial side effects.
- Kentucky Veterinary Medical Association: Evan’s Syndrome -- A Case Study and the Technician’s Role
- Metropolitan Veterinary Associates: Immune Mediated Hemolytic Anemia (IMHA)
- Veterinary Team Brief: Canine Immune Mediated Hemolytic Anemia
- K2 Animal Health Publishing: Evans syndrome -- Breaking Down IMHA and ITP