Mechanisms of Hypercoagulability in Dogs
with
Immune-Mediated Hemolytic Anemia
Suzanne Donahue, VMD; University of Pennsylvania
The
formation of excessive blood clots (thrombosis) is a major cause of mortality in a variety of diseases that affect purebred
and mixed breed dogs. A very common condition is immune-mediated hemolytic anemia
(IMHA; a disease in which the dog’s immune system destroys its own red blood cells).
Once thomboses form, specialized or invasive procedures must be used to confirm their presence and define the extent
of organ involvement. Even with definitive diagnosis, treatment is limited. This study was designed to test the ability of a specialized clotting test, Thromboelastography
(TEG), to identify increased coagulation (hypercoagulability) in dogs with IMHA. 35
dogs were included in the study: 12 dogs with IMHA, 13 sick control dogs, and
10 normal dogs. TEG confirmed the increased tendency for dogs with IMHA to form
clots (hypercoagulability). By evaluating standard coagulation studies, we have
identified multiple mechanisms that contribute to hypercoagulability, including an increase in the factors that promote clots. Through our studies of the mechanisms of hypercoagulability in IMHA, we can now design
specific treatment strategies for the prevention of the devastating syndromes of thromboembolic (inappropriate formation and
migration of clots) disease in IMHA. The ability to diagnose animals at risk
for the complications of hypercoagulable states is revolutionary and will change critical care practice and treatment of these
potentially fatal syndromes.
Some symptoms of IMHA are depression, lethargy,
pale gums or conjunctiva, and possible vomiting and abdominal pain. Death can
occur suddenly, even with appropriate treatment. The mortality rate for dogs
with Immune-mediated Hemolytic Anemia is 26-70% with the victims experiencing refractory anemia, acute renal failure, and/or
pulmonary thromboembolism.
AWS Partners’
recommended resources:
Immune-Mediated Hemolytic Anemia: Pathophysiology, Clinical Presentation,
and Diagnosis
http://www.vetmedpub.com/cp/pdf/special_reports/biopure_1.pdf
Immune-Mediated Hemolytic
Anemia (IMHA) or Autoimmune Hemolytic Anemia (AIHA)
http://www.vetinfo.com/dencyclopedia/deimha.html
Immune Mediated Hemolytic Anemia (IMHA)/Autoimmune Hemolytic Anemia
(AIHA)
http://www.petplace.com/articles/artShow.asp?artID=2195
Immune Mediated Hemolytic Anemia
http://www.upei.ca/~cidd/Diseases/immune%20disorders/autoimmune%20hemolytic%20anemia.htm
Diagnosis of Immune-mediated Hemolytic Anemia
http://www.vet.uga.edu/vpp/clerk/hiers
Research in Canine Immune-mediated Hemolytic Anemia
http://www.vet.purdue.edu/depts/vcs/research/scottmondogimmune.html
University of Pennsylvania School of Veterinary Medicine Canine Symposium
http://www.vet.upenn.edu/schoolresources/communications//publications/bellwether/49/canine_symposium.html
Treatment of Immune Mediated Hemolytic Anemia in Dogs with Cyclophosphamide
http://www.inno-vet.com/articles/2000/0900/15.html
