Exam 3 - IMHA Diagnosis & Therapy Flashcards
which is worse: intravascular hemolytic anemia or extravascular hemolytic anemia?
intravascular
what is the mechanism associated with intravascular hemolytic anemia?
rupture within the blood vessel – IgM associated
can happen from toxins, not just immune
hemoglobin released in blood & urine
what is the mechanism associated with extravascular hemolytic anemia?
destruction of RBC by macrophages in spleen or liver – usually IgG
what lab abnormalities are associated with intravascular hemolytic anemia?
hemoglobinemia, hemoglobinuria, pigmenturia, & red serum
what lab abnormalities are associated with extravascular hemolytic anemia?
hyperbilirubinemia, hyperbilirubinuria, pigmenturia, & yellow serum
what are the main differences between the causes of primary & secondary hemolytic anemia?
primary – synonymous with idiopathic, underlying cause not found
secondary – identifiable underlying trigger such as: antibiotics, vaccination, infectious, parasites, must rule out toxins such as zinc & penny ingestion
what breeds are predisposed to IMHA?
cocker spaniels, poodles, & springers
what patient signalment is predisposed to IMHA?
female spayed, young to middle aged animal
what are 2 external factors that can predispose an animal to developing IMHA?
- antibiotics with a hapten group – penicillins & cephalosporins
- rickettsial or bacterial infections triggering immune system
what can be seen on physical exam on a patient with IMHA?
pale MM, may be icteric, poor pulse quality, pigmenturia, tachypnea
what lab abnormalities are commonly seen with IMHA?
severe leukocytosis with left shift, can fluctuate with MCV/MCHC, anisocytosis, macrocytosis, nRBC, +/- Heinz bodies
what are the red & yellow arrows indicating in the serum seen on PCV?
red – hemoglobin
yellow – bilirubin
what is expected of a PCV/TS in an animal with IMHA?
usually normal or high total solids
what is classic of IMHA on a blood smear?
spherocytes – dogs
agglutination – macroscopic or microscopic, but differentiate from rouleaux
what may be seen on a chemistry panel of a patient with IMHA?
variable depending on underlying problem & type of hemolysis - +/-:
increased bilirubin, hepatopathy, hyperglobulinemia, & azotemia (pre-renal or renal) often from intravascular hemolysis & subsequent AKI
why do abdominal rads in a patient with IMHA?
rule out zinc toxicity
what are some negative prognostic markers for IMHA?
- intravascular hemolysis
- presence of concurrent thrombocytopenia – evans syndrome or babesia
- persistently non-regenerative
- increasing number of blood transfusions
- degree of hyperbilirubinemia
- azotemia
only intravascular hemolysis causes what 2 lab abnormalities?
hemoglobinuria & hemoglobinemia
why is it important to rule out infectious causes for patients with intravascular hemolysis?
consider necessary immunosuppression
what are some absolute ‘triggers’ for transfusing an IMHA patient?
PCV <12% or the animal is unstable
why is it ideal to give an IMHA patient packed RBC instead of whole blood?
whole blood is more inflammatory/immunogenic
transfusions make it difficult to assess what CBC parameters of your patient?
reticulocytes, RBC parameters, & agglutination
T/F: it Is very rare for cats to have IMHA
true
prior to immunosuppressing a cat with suspected IMHA, what should you do?
treat for mycoplasma
what steroid therapy is used for IMHA patients initially?
steroids – injectable dex or dex sp at 2 mg/kg/day until patient is eating
why use clopidogrel in a patient with IMHA?
anti-platelet agent because IMHA patients are prone to thromboembolisms
dose 1-2 mg/kg/day
when should you add a secondary non-steroidal immunosuppressant for an IMHA patient?
technically every IMHA, but especially when negative prognostic factors are present such as: intravascular hemolysis, non-regenerative anemia, & multiple blood transfusions
what is the action & dosage used for cyclosporine?
inhibits normal t cell function – dose at 5 mg/kg PO twice daily
what are the pros & cons of using cyclosporine?
very good immunosuppressant that can be monitored with a pharmacodynamic assay
expensive & animal is most susceptible to fungal disease in certain parts of the country
what care must be used when you put an IMHA patient on cyclosporine?
monitor very closely for fungal disease – wipe paws with chlorohexidine wipes every time the animal goes outside, swims, or digs in dirt
ideally limit exposure to outside world while immunosuppressed
when are IMHA patients discharged?
when they are eating & drinking, taking oral meds well, PCV/TS stabilizing/holding well, & no longer requiring transfusions
what monitoring should be used for IMHA patients once they leave the hospital?
recheck PCV/TS, agglutination, spherocytes, or CBC – weekly until PCV reaches at least 30%
when do you taper steroids or secondary immunosuppressants in your IMHA patients?
normal Hct/PCV >30% for at least 2-3 weeks
taper in 25% increments every 3-4 weeks
taper steroids first then secondary agent
what should you do if you have a refractory case of IMHA?
look for missed trigger, ensure gi bleeding isn’t a confounding problem, & reassess for infectious disorders
babesia in dogs is nearly identical to what two concurrent diseases?
concurrent IMHA & IMTP – evans’ disease
what animals are predisposed to babesiosis?
splenectomized animals
pitbulls & greyhounds
how do you rule out babesia in dogs?
species specific PCR if you don’t see the organism in RBC & capillary blood test from the ear or nail bed to look for the organism
picture of babesia – what is this organism seen in this blood smear?
babesia
what infectious process in cats mimics IMHA? how do you treat this?
mycoplasma – treat all cats with doxycycline or pradofloxacin prior to starting steroids
what are some other disorders that mimic IMHA? how do they mimic it?
babesia in dogs, mycoplasma in cats, zinc, & copper toxicity
can have spherocytes & agglutination
