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August 6, 2020 – Wiley was a tough, happy and mischievous beagle. She suffered from a seizure disorder, hypothyroidism and Addison’s disease, but with the help of her devoted owners Brenda and Keith, Wiley enjoyed an active, wonderful life. However, when Brenda found Wiley lying outside one night, she had no idea that Wiley was about to begin a fight neither of them could win.

Early the next morning, Brenda and Keith got Wiley immediately to her veterinarian. After a few tests, Wiley was diagnosed with immune-mediated hemolytic anemia (IMHA). Brenda and Keith had never heard of the disease before and the prognosis was grim. Despite beginning treatment, Wiley’s condition continued to deteriorate, and Brenda and Keith had to make the heart-breaking decision to say goodbye.

“It’s like someone hit you in the gut with a baseball bat,” said Brenda. “With IMHA you have to act so quickly. There’s not much information out there about the disease.”

What dog owners need to know

Immune-mediated hemolytic anemia occurs when the body suddenly perceives red blood cells as foreign invaders. The immune system attacks the red cells and destroys them much the same way as if the red blood cells were a virus or bacteria. The disease comes on quickly, with many dogs only having noticeable signs for one or two days at most. A sudden collapse like Wiley’s is a frequent finding.

Wiley and Brenda’s story is all too common for dogs with this disease. As red blood cell numbers plummet to dangerously low levels, all body systems are affected by a concurrent lack of oxygen, which is carried by red blood cells. Dogs with IMHA are prone to forming blood clots which can lodge in any organ. The combination of blood clots and low red blood cell numbers tragically can result in organ failure and death.

Dogs at risk

IMHA can strike any dog although some breeds have a higher predisposition to the disease than others. Breeds at higher risk include:

  • Beagle
  • Cocker spaniel
  • Shih tzu
  • Bichon fries
  • Old English sheepdog
  • Collie
  • Miniature schnauzer
  • Maltese
  • Labrador retriever
  • Poodle
  • Dachshund
  • English springer spaniel
  • Jack Russell terrier

IMHA typically is a disease that affects middle-aged to older dogs although it’s been reported in dogs as young as 1 year old.

Signs of IMHA
Signs of immune-mediated hemolytic anemia are secondary to low red blood cell counts and can include:
  • Pale gums
  • Panting or labored breathing
  • Yellow color to gums or whites of the eyes
  • Sudden collapse or fatigue
  • Anorexia

These signs tend to come on suddenly and are dramatic. Most owners quickly recognize that something is wrong and seek veterinary care.

Diagnosis and treatment

Diagnosis is generally straightforward. Low red blood cell counts are the hallmark feature and other red blood cell abnormalities often are present.

Treatment is aimed at stopping the immune system from destroying red blood cells. Drugs that suppress the immune system, such as steroids, are a first line of treatment. Many dogs require blood transfusions to try to raise their red blood cell counts temporarily until the medications begin to quiet the immune system.

Because dogs with IMHA are at risk for abnormal blood clot formation, anticoagulant medications, commonly known as blood thinners, are recommended.

Almost all the therapies used have serious side effects, making treatment a lot like walking a tightrope. Unfortunately, IMHA has a high mortality rate even in dogs that receive prompt treatment, with 50% to 70% of dogs dying of the disease in the first few weeks after diagnosis. In addition, there are reports that as many as 20% of dogs that recover from IMHA will relapse within the first year.

New treatments needed

More effective therapies with fewer side effects are desperately needed to improve survival and quality of life for dogs with IMHA.

A Morris Animal Foundation-funded team at Cornell University is currently enrolling dogs in a clinical trial testing a new treatment for IMHA. The team is using a targeted approach for suppressing the immune system that wouldn’t have the debilitating side effects of standard therapy. The Cornell team is focusing in on a particularly deadly subtype of IMHA known as intravascular IMHA. If successful, this treatment could be a breakthrough for dogs suffering from IMHA.

The Foundation understands that better treatment is needed for this terrible disease. That’s why in the last 20 years we’ve invested more than $1 million in 16 studies focused on novel treatments for IMHA.

Our work has helped veterinarians improve the care of dogs suffering from IMHA, but we’ve still got a long way to go.