IMHA

Question 1

What is IMHA?

Answer 1

Disease where antibodies are directed at antigens expressed on the surface of RBCs causing accelerated destruction and anemia

Question 2

How can patients with IMHA typically present?

Answer 2

- Icterus
- Splenomegaly / Hepatomegaly (bc of extravascular hemolysis)
- Discolored urine (hemoglobinuria)
- Less specific CS: pale MM, lethargy, weakness, tachypnea, tachycardia, fever

Question 3

What diagnostic findings are most consistent with IMHA?

Answer 3

• Low PCV / RBCs
• Regenerative anemia (reticulocytes, polychromasia)
• Spherocytes on blood smear
• RBC agglutination
• Positive Coombs test

Question 4

What tests should be performed to work up and diagnose IMHA?

Answer 4

1. PCV and TP
2. Examine blood in EDTA tube for agglutination
3. Blood smear
4. Coombs test

Question 5

Why is it important to examine the blood in an EDTA tube in a patient with suspect IMHA?

Answer 5

Evidence of RBC agglutination inside purple top tube can be suggestive of IMHA

Question 6

What can be seen on blood smear that is suggestive of IMHA?

Answer 6

Agglutination and clumping of RBCs, spherocytes

Question 7

What is the Coombs test used for?

Answer 7

• Helpful in diagnosing IMHA
• Detects antibodies attached to the surface of RBCs
• Can’t tell primary vs secondary IMHA

Question 8

What are common causes of IMHA?

Answer 8

1. Primary / Idiopathic most common
2. Secondary IMHA from infection, neoplasia (lymphoma), drugs (penicillin, TMS, cephalosporins), vaccines, blood transfusions, etc

Question 9

What are secondary causes of IMHA?

Answer 9

• 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)

Question 10

What changes on biochem can be seen with IMHA?

Answer 10

• Pre hepatic hyperbilirubinemia

(R/O hepatic and post hepatic if the rest of the liver values are relatively normal)

Question 11

What is a sequelae and common cause of death in patients with IMHA and IMTP?

Answer 11

• DIC
• Thromboembolism

Question 12

What are bacterial causes of IMHA?

Answer 12

• Ehrlichia canis
• Mycoplasma
• Leptospirosis
• Pyometra
• Discospondylitis, endocarditis

Question 13

What is an infectious cause of IMHA in cats that isn’t bacterial or parasitic?

Answer 13

Feline Leukemia Virus and mycoplasma haemofelis can cause secondary IMHA

Question 14

What are non immune mediated causes of hemolytic anemia?

Answer 14

• Zinc toxicosis (Penny ingestion) intravascular hemolysis
• Onions and garlic
• Babesia and Mycoplasma (can cause direct hemolysis or IMHA)
• Hermangiosarcoma
• DIC
• Heartworm disease

Question 15

What is the treatment protocol for IMHA?

Answer 15

• 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

Question 16

What are poor prognostic indicators associated with IMHA?

Answer 16

• T bili > 10
• Intravascular hemolysis
• Autoagglutination

Question 17

What is the prognosis of IMHA?

Answer 17

• 30-70% Mortality rate 😔

Question 18

What dog breed and signalment is most common with IMHA?

Answer 18

Cocker spaniels
females > males
middle aged

Question 19

What diagnostics can help you differentiate IMHA from a non immune mediated hemolytic anemia?

Answer 19

• Do a blood smear
• IMHA shows spherocytes
• Non immune mediated hemolytic anemia doesn’t

Question 20

What drugs are contraindicated in patients with IMHA?

Answer 20

• No Cephalosporins, TMS, or NSAIDs

Question 21

What causes shistocytes to be seen on a blood smear?

Answer 21

- Hermangiosarcoma
- DIC
- Heartworm disease

Question 22

How can thoracic radiographs help in diagnosis of IMHA?

Answer 22

• Screen for thoracic lymphoma
• Screen for thromboemboli