IMHA Flashcards
(18 cards)
What is the primary basis for diagnosing Immune-Mediated Hemolytic Anemia (IMHA)?
Detection of haemolytic anaemia and confirmation of immune targeting
Immune targeting can be confirmed by spherocytosis, auto agglutination, or a positive Coombs’ test.
What is the significance of the saline agglutination test in diagnosing IMHA?
It is non-specific and may be positive in various conditions
True autoagglutination should be assessed by washing RBCs in saline.
What dilution of blood with saline is suggested for assessing agglutination in IMHA diagnosis?
1:4 dilution
This is sufficient in most cases unless there is hyperglobulinaemia or significant rouleaux formation.
What is the reported accuracy of Coombs’ testing for IMHA diagnosis?
Highly variable with some assays being insensitive and others non-specific
Some Coombs’ tests have over 90% accuracy but are not widely used in the UK.
What are the key considerations for diagnosing non-regenerative IMHA?
Thorough exclusion of other processes and identification of erythroid lineage arrest
Pure red cell aplasia (PRCA) is an extreme example where erythroid lineage is not identified.
What can cause secondary IMHA?
Recent drugs, vaccination, infections, neoplasias, or other inflammatory foci
Examples include Anaplasma, Babesia, and Ehrlichia infections.
What is the mainstay treatment for IMHA?
Immunosuppression with steroids
Prednisolone (2mg/kg/day) or dexamethasone (0.2mg/kg/day) are commonly used.
What is the typical treatment regimen for steroids in IMHA?
High initial doses for approximately 1 month, then gradually tapered over 6 months
If steroids are used alone, significant side effects may occur in large breed dogs.
What are the common second immunosuppressive drugs used in IMHA treatment?
Cyclosporine, azathioprine, or mycophenolate
These drugs are not licensed for this purpose in the UK but can be used under the cascade.
What is the reported survival rate for dogs with IMHA?
60-80%
Common causes of death include anaemia and thromboembolism.
What is the association between IMHA and thromboembolism?
IMHA is recognized as a hypercoagulable state
Thromboembolism is identified in the majority of patients undergoing thorough evaluation.
What is the recommended initial dose of aspirin for treating thromboembolism in IMHA?
0.5mg/kg/day
More recent studies suggest doses around 2mg/kg/day for a consistent effect.
True or False: Clopidogrel has shown to be more effective than aspirin in treating IMHA-related thromboembolism.
False
Clopidogrel has not been shown to be more effective but has fewer systemic side effects.
What is the concern regarding gastroprotectants in dogs treated for IMHA?
High doses of steroids may induce gastric ulceration
There is no evidence that gastroprotectants mitigate this risk unless ulceration is suspected.
What is a unique consideration for diagnosing IMHA in cats?
Cats’ RBCs are smaller and lack central pallor, making spherocyte identification challenging
Coombs’ testing in cats is sensitive but non-specific.
What is the typical first-line steroid dose for cats with IMHA?
2mg/kg BID
Higher doses of steroids are typically used in cats compared to dogs.
What complications are less common in feline IMHA compared to canine IMHA?
Thromboembolic complications
Feline IMHA is often associated with retroviral infections.
What should be done if a cat with IMHA tests positive for FeLV antigen?
Confirm with a second method, such as PCR
False positives may occur in cats with IMHA.
