Hemolysis

Question 1

What are possible clinical clues to hemolysis

Answer 1

Icterus
- usually only apparent with severe, acute hemolysis

Discolored urine
- hemoglobinuria in case of intravascular hemolysis (rare in cats)

+/- Splenomegaly and hepatomegaly

Question 2

What are specific clues for hemolysis on blood smear

Answer 2

Erythrocyte fragments

Spherocytes
- not commonly observed in cats due to the fact that their RBCs are, by nature, small and round

Auto-agglutination
- a mild degree of agglutination is common in sick cats

Heinz bodies

RBC parasites

Erythrophagocytosis
- evidence of RBC ingestion by phagocytic cells
- rare

Question 3

Are their any other clinicopathological clues (aside clinical and blood smear clues) that you can mention

Answer 3

Positive feline specific Coomb’s test

Increased total bilirubin
- the liver has a large capacity for heme catabolism, thus significant increases in bilirubin associated with hemolytic anemia are only observed in cases where there is severe, acute hemolysis or in cases with concomitant hepatic dysfunction such as hepatic lipidosis

Question 4

What will be your differentials for hemolytic anemia in cats

Answer 4

Hemoplasmas (e.g., Mycoplasma haemofelis and other species)

Oxidative (Heinz body) anemia
- e.g., onion ingestion, paracetamol, repeated propofol administration (consecutive days)

Hereditary RBC defects
- Pyruvate kinase deficiency (Abyssinian, Somali, DSH)
- Increased erythrocyte osmotic fragility (Abyssinian, Somali)

Porphyria (Siamese, DSH)

Hypophosphatemia
- usually secondary to treatment for DKA or re-feeding syndrome

Primary immune-mediated

Secondary immune-mediated
- e.g., lymphoma, FIP

Neonatal isoerythrolysis

Acute hemolytic transfusion reactions

Microangiopathic (fragmentation injury) anemia
- e.g., DIC, hemangiosarcoma

Gram-negative sepsis

Some strains of FeLV

Other infectious agents
- Cytauxzoon felis
- Babesia

Snake envenomation
- e.g., red belly black snake, tiger snake