Chapter 5 - Regenerative anemia and tests Flashcards
If hemolysis is occuring in the spleen what do you expect to see on blood film
spherocytes
If hemolysis is occuring in the blood vessels what do you expect to see on blood film
ghost cells
__ undergo extravascular or intravascular hemolysis bc of their rigidity and fragility.
spherocytes
RBC coated with __ undergo extravascular hemolysis by macrophages and are conveverted to spherocytes
surface-associated Ig and/or complement protein 3
Some RBC surface IgM may bind complement which activates the complement cascade and leads to intravascular hemolysis via the __
membrane attach complex (MAC attach)
complex of complement factors 5b through 9
damaged cells are removed from circulation by
macrophages
7 lab findings for IMH
- Regenerative anemia (usually) - polychormatophils, howell jolly bodies
- macro or microagglutination
- Spherocytosis
- Neutrophilia
- pigmentemia/uria
- variable platelets
- abnormal liver enzymes
__ test is used to distinguish rouleaux from autoagglutination. It should be ran at __ temperature.
saline, Body
microagglutination looks like __ where rouleaux looks like __
grapes, stack of coins
what animals normally have rouleaux RBC
Cats, horses, pigs, bovides
how will you treat autoagglutination
steroids (do not treat rouleaux usually)
__ is the nonspecific binding of RBC due to high blood protein
rouleaux (do not treat)
__ is the specific binding of RBC by Ab seen in IMHA
agglutination (treat with steroids)
what animals are spherocytes difficult to ddx and other tests need to be preformed
cats and horses, less central palar
__ can occur due to inflammation or infection, seen with IMHA
Neutrophilia (high neutrophil count)
2 types of Primary IMHA
idiopathic auto-immune hemolytic anemia (AIMA)
neonatal isoerythrolysis
most common ddx IMHA
idiopathic AIHA
most commonly IMHA is __
secondary
__ is common in horses and can happen in cats but is rare in small animals
neonatal isoerythrolysis
First steps when suspecting p with IMHA
Get a good history, test for underlying causes
what are 4 class of infectious dz that can cause secondary IMHA
- RBC parasite (babesia, hemoplasma)
- Tick borne dz (anaplasma)
- virus (FeLV, EIA)
- bacterial infection anywhere
chemicals that can cause secondary IMHA
Drugs, vaccines, toxins
type of neoplasia that causes secondary IMHA
Lymphoma
other Immune mediated dz such as __ can cause secondary IMHA
systemic lupus erythematosus (SLE), IM thrombocytopenia, others
what are some common tests used to work-up an IMH case
- good history (vx, ticks, travel, drugs, etc)
- ddx imaging
- serology (Ab against infectious dz present)
- PCR (and infectious dz DNA present)
- cultures (test fluid/tissue samples for infectious dz)
- coomb’s test
- erythrocyte osmotic fragility (cats)
__ is done when anemic animals exhibit signs of hemolysis and there is clinical suspicion that the hemolysis may be caused by autoimmune dz
Coombs’ test (if have autoagglutination do not have to do this test)
Coombs’ test is used in cases when there is evidence of hemolysis but __ is abscent
autoagglutination
What is the purpose of a coombs’ test
detect immune system proteins on p RBCs
What are 2 tests to ddx IMHA
autoagglutination or coombs’ test
what are 4 disadvantages to the Coombs test
- doesn’t tell what’s causing the hemolysis
- doesn’t differentiate primary v secondary IMHA
- False positives
- False negative (doesn’t rule IMHA out)
positive coombs test determines what
there is an immune mediated component of hemolysis
if you get a negative coombs test can IMHA be excluded from ddx list
NO!
many things that can result in a negative test, p may still have IMHA
how is infectious dz that may be causing secondary IMHA ddx
ID of parasite in blood or ancillary testing (PCR, serology, microbiology)
occurrence of oxidative damage depends on what 2 things
- quantity and duration of exposure
2. p ability to metabolize oxidant
oxidative damage results in decreased RBC __ and/or __ of damaged cells leading to hemolysis
deformability, premature removal
5 common oxidants (cause hemolysis)
- acetaminophen (tylenol and panadol tablets)
- allium genus (onions, garlic)
- red maple leaves (horses, alpacas)
- brassica genus (kale, rapeseed - ruminants)
- propylene glycol in semi-moist foods (cats)
What oxidant is most likely to effect ruminants
brassica genus (kale)
what oxidant is most likely to effect horses and alpacas
red maple leaf
what animal is more sensitive to oxidative damage bc it has more sulfahydryl groups on it’s RBC (targets for oxidation)
cats
is skunk musk and oxidant in dogs
yes
__ portion of hgb forms heinz bodies (oxidized ppt of hgb), cats can normally have a few of these.
globin
membrane of erythrocytes form __ due to lipid membrane oxidation
eccentrocytes
iron portion of hgb becomes ___, causes chocolate syrup blood, does not cause hemolysis but decreases O2 delivery to tissue
methemoglobin
3 targets for oxidative damage
- globin of Hgb (heinz bodies)
- iron of Hgb (methemoglobin, decreased O2)
- lipid membrane (eccentrocytes)
seeing __ and __ on blood film is characteristic of oxidative damage
eccentrocyte shape and heinz body inclusions of RBCs
6 signs of hemolytic anemia caused by oxidant includes
- regenerative anemia
- history of exposure and clinical signs
- lots of heinz bodies (NMB stain)
- eccentrocyte and pyknocytes
- methemoglobinemia (spot or filter paper test)
- hgb crystals
__ is seen in puppies that have ingested pennies post 1982 which causes hemolysis
acute zinc toxicity
__ cells are seen in envenomation cases due to venom phospholipases causing hemolysis
spheroechinocytes (no central palar with spicules)
__ is a large animal issue after calving due to metabolic state/low ATP causing RBC to be fragile, normally rare
hypophosphatemia (can also be seen in small animals with diabetic ketoacidosis or lipidosis)
___ hemolysis is seen with rapid infusion of hypotonic fluid (“drown”) or with calf milk replacer that has too much water
hypo-osmolar
__ and __ are common cell changes seen with regenerative anemia
anicocytosis and polychromasia
spherocytes are seen with __ hemolysis
extravascular
microscopic autoagluttination, spherocytes, ghost cells, anicocytosis, polychromasia, macrocytosis, nRBC =
IMHA
Bilirubenemia is ddx for intra or extravascular hemolyssi
neither! it occurs in both. only hemoglobinemia/uria is ddx
High WBC count but IMHA, can you give immunosuppressants?
yes, wbc count is due to immune response to hemolysis not infection
decreased PCV with increased TS helps exclude __ from being cause of regenerative anemia
hemorrhaging
