ACVIM consensus statement on the diagnosis of immunemediated hemolytic anemia in dogs and cats

IMHA Diagnosis Consensus

What is the gold standard test for IMHA?

None exists in vet med

Diagnostic Criteria for IMHA

• Anemia

• 2+ signs of immune destruction (spherocytes-dogs, positive SAT, positive DAT or FC)

• 1+ sign of hemolysis (hyperbilirubinemia, hemoglobinemia, hemoglobinuria, erythrocyte ghosts)

Supportive of IMHA, provided another cause of anemia cannot be identified

• Anemia

• Only 1 sign of immune destruction (spherocytes-dogs, positive SAT, positive DAT or FC) AND 1+ sign of hemolysis

• OR —— 2+ signs of immune destruction, but no signs of hemolysis

Suspicious for IMHA, provided another cause of anemia cannot be identified

• Anemia

• 1 sign of immune-mediated destruction (spherocytes-dogs, positive SAT, positive DAT or FC) and NO signs of hemolysis

Diagnostics for NOT IMHA

• Anemia

• has NO signs of immune-mediated destruction (spherocytes-dogs, positive SAT, positive DAT, or FC)

DAT means?

Demonstration of anti-erythrocyte antibodies

• Direct Coombs test

• Flow cytometry

Infectious agents that can cause IMHA in dogs

• Babesia - int to high

• Anaplasma (phago and platys) - low

• Dirofilaria, Ehrlichia, Borrelia [Lyme], hemotropic Mycoplasma, Bartonella, Leishmania - low

• Neospora - low

Infectious agents that cause IMHA in cats

• Babesia felis - intermediate - treatment of the bacteria often resolves IMHA without immunosuppression

• Hemotropic Mycoplasma - HIGH

• FeLV - low

Is there evidence that cancer causes IMHA in dogs and cats?

• Dogs: causal link is lacking in literature, but cannot eliminate the possibility

• Cats: causal link is lacking in literature, however retrospective evidence suggests high prevalence of concurrent cancer in cats with IMHA

Does pancreatitis cause IMHA?

The evidence for pancreatitis causing IMHA is negligible in dogs and

negligible to low in cats. Additional studies would be required to establish

a causal relationship.

Does liver necrosis cause IMHA?

The evidence for necrosis as a cause of IMHA is negligible in dogs and

is not reported in cats.

List some anecdotal reports of other inflammatory conditions that cause IMHA

• SLE

• gastroenteritis

• dermatitis

• hepatitis

• rheumatoid arthritis

• mesenteric lymphadenitis

Can drugs cause IMHA?

Antibiotics are commonly reported - CEFAZEDONE dogs

7 cats with hyperthyroidism treated with pro-pylthiouracil

one report of warfarin

The prevalence of drug-induced IMHA in dogs and cats is either rare

or underreported. However, a lack of evidence does not preclude the

possibility of a drug or toxin triggering IMHA.

Can vaccines cause IMHA?

Uncertain

Current vaccination protocols are currently considered safe

Patients should be individually assessed for their

own risks and benefits before vaccination. Further studies are needed to

determine if and when vaccine-associated IMHA occurs in dogs and cats,

and to develop better methods for the diagnosis of vaccine-associated

disease.

Optimal minimum database for IMHA suspects

• Thorough history: Vaccines, travel, flea/tick exposure, flea/tick prevention, HWT testing, HWT prevention

• Physical exam

• CBC

• Blood film by clinical pathologist

• Chemistry

• UA

• UC&S

• Fecal float

• Imaging

• (routine testing for pancreatitis NOT recommended)

Testing for infectious agents in dogs with IMHA

• Screen for Babesia using serology and PCR

• D. immitis in endemic areas

• Endemic area screening for Anaplasma, Bartonella, Ehrlichia, and Leishmania

Testing infectious agents cause for cats with IMHA

• B. felis PCR in endemic areas or those with clinical suspicion

• M. haemofelis in all cats PCR ***

• FeLV/FIV

• (routine testing for coronavirus and non-hemotropic mycoplasma is NOT recommended)

Drug & vaccine administration in dogs and cats with IMHA

• Insufficient evidence to recommend withholding necessary medications for dogs and cats with IMHA

• All meds should be used with caution

• CEFAZEDONE and Propylthiouracil in cats - maybe stop