An interesting case series was published this month in Frontiers in Veterinary Science (see reference below) detailing three dogs with hemophilia A and neurologic disease. I thought we might keep with our vascular discussion this week and chat about this article. Enjoy!
Signalment and Presenting Signs
Three young, male, dogs (4 months, 11 months and 5.5 months of age) were evaluated for signs ranging from spinal hyperpathia alone, to ambulatory paraparesis and proprioceptive ataxia in the pelvic limbs to non-ambulatory tetraparesis and cervical pain. All three dogs had spinal MRI which showed changes consistent with hemorrhage. One dog underwent decompressive surgery at which point a hematoma was confirmed.
Diagnosis
Hemophilia A is an X-linked coagulation disorder that occurs due to genetic mutation and resulting abnormal function of factor VIII. All three dogs had prolonged aPTT, and normal PT testing. Reminder: aPTT requires functional I, II, V, VIII, IX, X, XI and XII factors so it isn't highly specific when prolonged. PTT evaluates I, II, V, VII, and X. Additionally, genetic testing is now available that can measure the quantity of VIII (more like a percentage of normal) and all three dogs had reduced levels of VIII, supporting the final diagnosis of Hemophilia A in these cases.
Outcome
Two dogs underwent CSF analysis during the diagnostic process, which resulted in hematoma formation and ultimately the demise of one of the dogs. The other dog recovered, was noted to have intermittent cutaneous hemorrhage over the next 5 months at which time it sustained gastrointestinal hemorrhage which was suspected to be secondary to a foreign body and the dog was euthanized. The third dog under went surgical decompression, improved markedly after surgery, and was discharged with a normal neurologic examination two weeks after surgery. No additional follow-up was provided. In dogs requiring invasive procedures with a risk of hemorrhage, fresh frozen plasma or cryoprecipitate is recommended however there is no known cure. Gene therapy is available for humans with hemophilia A however this is not available yet for veterinary patients. A low impact life style is recommended!
Thanks for reading! I am in Michigan this week, and Chicago Vet at the end of the week speaking about super cool neurology-related topics (of course). However, I am reachable by email or telephone if you need me. I look forward to working with you next week!
Reference: Fowler KM, Bolton TA, et al. Clinical, Diagnostic, and Imaging Findings in Three Juvenile Dogs with Paraspinal Hyperestesia or Myelopathy as Consequence of Hemophilia A: A case report. Frontiers in Vet Science (2022): 9,1-9.