IMHA Flashcards
What is IMHA?
Disease where antibodies are directed at antigens expressed on the surface of RBCs causing accelerated destruction and anemia
How can patients with IMHA typically present?
- Icterus
- Splenomegaly / Hepatomegaly (bc of extravascular hemolysis)
- Discolored urine (hemoglobinuria)
- Less specific CS: pale MM, lethargy, weakness, tachypnea, tachycardia, fever
What diagnostic findings are most consistent with IMHA?
- Low PCV / RBCs
- Regenerative anemia (reticulocytes, polychromasia)
- Spherocytes on blood smear
- RBC agglutination
- Positive Coombs test
What tests should be performed to work up and diagnose IMHA?
1. PCV and TP
2. Examine blood in EDTA tube for agglutination
3. Blood smear
4. Coombs test
Why is it important to examine the blood in an EDTA tube in a patient with suspect IMHA?
Evidence of RBC agglutination inside purple top tube can be suggestive of IMHA
What can be seen on blood smear that is suggestive of IMHA?
Agglutination and clumping of RBCs, spherocytes
What is the Coombs test used for?
- Helpful in diagnosing IMHA
- Detects antibodies attached to the surface of RBCs
- Can’t tell primary vs secondary IMHA
What are common causes of IMHA?
- Primary / Idiopathic most common
- Secondary IMHA from infection, neoplasia (lymphoma), drugs (penicillin, TMS, cephalosporins), vaccines, blood transfusions, etc
What are secondary causes of IMHA?
- Drugs (TMS, Cephalosporins, Penicillin)
- Neoplasia (Large cell, lymphoblastic lymphoma)
- Infectious (Babesia canis, Mycoplasma haemofelis and FIV/FeLV in cats) … these can be either IMHA or non immune mediated
- Ricketsial diseases (RMSF, E.canis)
What changes on biochem can be seen with IMHA?
- Pre hepatic hyperbilirubinemia
(R/O hepatic and post hepatic if the rest of the liver values are relatively normal)
What is a sequelae and common cause of death in patients with IMHA and IMTP?
- DIC
- Thromboembolism
What are bacterial causes of IMHA?
- Ehrlichia canis
- Mycoplasma
- Leptospirosis
- Pyometra
- Discospondylitis, endocarditis
What is an infectious cause of IMHA in cats that isn’t bacterial or parasitic?
Feline Leukemia Virus and mycoplasma haemofelis can cause secondary IMHA
What are non immune mediated causes of hemolytic anemia?
- Zinc toxicosis (Penny ingestion) intravascular hemolysis
- Onions and garlic
- Babesia and Mycoplasma (can cause direct hemolysis or IMHA)
- Hermangiosarcoma
- DIC
- Heartworm disease
What is the treatment protocol for IMHA?
- Correct underlying cause (Infection, neoplasia, Drugs, Venom)
- Prednisone, Azathioprine, Mycofenolate drug therapy
- Clopidogrel or Heparin: IMHA can lead to DIC and Thromboembolism
- Omeprazole, Sulcrafate for GI protection
