Exam 3 - Companion Animal Anemia: Mechanisms & Work-Up Flashcards by Madeleine Swindell

what is anemia?

decrease in the amount of total RBC mass (O2 carrying)

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what is the consequence of anemia?

decreased O2 carrying capacity

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what does calculated hematocrit depend on?

MCV (mean corpuscular volume), agglutination, & machine accuracy

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what are the species differences & things relative to the patient between dogs & cats when it comes to parameters of anemia?

dogs are anemic at a higher hematocrit than cats

young animals have a lower hematocrit

greyhounds have a higher hematocrit

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what are the 2 classifications of anemia based off of mechanism?

regenerative & non-regenerative

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what is the exception to regenerative anemia when it comes to loss & lysis?

early hemolysis/lysis

too soon to see a regenerative response - look at 3-5 days for one

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what are the 2 mechanisms listed as causes for regenerative anemia?

loss
lysis

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what are the 2 mechanisms listed as causes for non-regenerative anemia?

systemic/inflammatory response - decreased production
primary bone marrow disorder - decreased production

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how do you differentiate between loss & lysis in regenerative anemia using total solids/total proteins?

in loss - decreased total solids, total solids from PCV/TS, total protein from the CBC, & albumin on chemistry panel

in lysis - total solids often within normal limits or may even be increased from dehydration (primary process)

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what is the exception for a decreased TS in a regenerative anemia due to loss?

very acute bleeding!!!

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what are some clin path abnormalities seen on a patient with non-regenerative anemia caused by a systemic/inflammatory response?

isosthenuria or azotemia

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what are some causes of non-regenerative anemia attributed to a systemic/inflammatory response?

chronic inflammatory disease

hypothyroidism

chronic kidney disease - decreased responsiveness to EPO & decreased iron transport

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what are some causes of non-regenerative anemia attributed to a primary bone marrow disorder?

toxicity

neoplasia - myelophthesis

immune mediated

infectious diseases - fungal or viral

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what is an important clue seen on a CBC that lends support to a primary bone marrow disorder causing a non-regenerative anemia?

bicytopenia or pancytopenia

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what is an important clue seen on a CBC that lends support to a primary bone marrow disorder causing a non-regenerative anemia?

bicytopenia or pancytopenia

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what are some causes of non-regenerative anemia attributed to a pre-regenerative anemia?

acute hemorrhage or hemolysis

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if investigating pre-regenerative anemia as a differential for a non-regenerative anemia, what should you do?

establishing chronicity is very important!!!

recheck serial lab work

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what are some external causes of hemorrhage?

trauma

mucosal surfaces - GI, urinary, & nasal

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what are some internal causes of hemorrhage where the RBCs are reabsorbed?

-body cavity (peritoneum, thorax, & pericardium)
-intraorgan (CNS, skin, +/- lungs)
-skin, often petechiae & ecchymoses

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what is involved in extravascular hemolysis destroying RBC?

immune-mediated process involving the reticuloendothelial system

destruction within the spleen

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what is involved in intravascular hemolysis destroying RBC?

-immune-mediated
-toxicity (drugs, zinc toxicity, metabolic)
-infectious: look for organisms in the RBC or a secondary immune-mediated process

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what dog breeds have an associated cause of hemolysis?

springer spaniels & basenji dogs

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what is the breed-associated cause of hemolysis in springer spaniels?

phosphofructokinase deficiency - lack of enzyme necessary for the stabilization of RBC

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what is the breed-associated cause of hemolysis in basenjis?

pyruvate kinase deficiency - lack of enzyme necessary for the stabilization of RBC

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what cat breeds are associated with osmotic fragility syndrome causing hemolysis?

oriental cat breeds, abyssinians, & somalis

what color can be seen on mucus membranes that could be concerning for hemolysis?

yellow/icteric

what are the categorizations of severity of anemia?

mild: > 28% moderate: 18-28% severe: <18%

what is the difference of microcytosis & macrocytosis when it comes to interpreting a CBC for an anemic patient?

microcytosis - small RBC - Fe deficiency anemia or abnormal Fe metabolism - breed specific (toy poodles, akitas) macrocytosis - large RBC - most likely regenerative - also seen in FeLV disease

what measures the density of RBC?

MCHC - hemoglobin content

if an animal has an Fe deficiency anemia, what would you expect the MCHC to be?

hypochromic

what is the gold standard for reticulocyte counts?

actual or absolute count

what is the formula for the actual/absolute reticulocyte count?

total RBC count * reticulocyte %

what is the cut-off value for a non-regenerative anemia when looking at reticulocyte counts for dogs & cats?

dogs: <60,000 cats: <50,000

when looking at feline reticulocytes, what is the difference between aggregate & punctate types?

aggregate - younger reticulocytes punctate - older/more mature

when looking at a CBC of an anemic patient, what do you think of with a low total solids? what if it's normal or high?

if low - consider hemorrhage if high - inflammatory disease or chronic hemorrhage

when looking at a CBC of an anemic patient, why may a thrombocytopenia be important?

hemorrhage - consumption might be the cause of bleeding if severe (IMTP leading to blood loss)

T/F: you can have platelets that are WNL with certain rickettsial diseases

true

if albumin, globulins, & cholesterol are all low on an anemic patient, what should you consider?

gi bleeding

if albumin is low on an anemic patient, what differentials should you consider?

- gi bleed - PLN - hepatic disease

if an anemic patient has hyperglobulinemia, what differentials should you consider?

- infectious disease - inflammatory process - neoplastic process

if an anemic patient has hyperbilirubinemia, what differentials should you consider?

potential pre-hepatic hemolysis

why is it important to visually inspect the serum of an anemic patient?

tells you if there is discoloration present

what does it mean if the serum of an anemic patient is yellow or orange in color?

bilirubin - hemolysis

what does it mean if the serum of an anemic patient is red in color?

hemoglobin is present - intravascular hemolysis

what does it mean if the serum of an anemic patient is lipemic?

maybe endocrinopathy

what is the most common cause of hemolytic anemia in cats?

mycoplasma & cytauxzoon felis

if you suspect babesia causing anemia in your patients, where should you sample for a blood smear?

ear tips or nail beds

what is the most common abnormality seen on a blood smear of an anemic patient?

thrombocytopenia

what dog breeds are known to be associated with babesia causing anemia?

greyhounds & staffordshire terriers

why are blood smears helpful in using for an anemic patient that you suspect has an infectious cause?

helpful for detecting infectious organisms in the RBC - babesia!!!

what do spherocytes indicate on a blood smear?

lack of central pallor & microcytic - indicates macrophage destruction of cell & essentially always indicates immune-mediated destruction/extravascular hemolysis

what do schistocytes indicate on a blood smear?

broken fragmented cells - HW disease, DIC, & splenic disease

what do heinz bodies on a blood smear indicate? what are the agents that cause these in dogs & cats?

oxidative damage to RBC dogs - onions cats - acetaminophin

what do echinocytes on a blood smear of an anemic patient indicate?

snake bite envenomation

what does basophilic stippling on a blood smear of an anemic patient indicate?

lead toxicity

what do nucleated RBCs on a blood smear of an anemic patient indicate?

regeneration, primary bone marrow disease, or splenic disease

if positive, a saline agglutination test on an anemic patient is diagnostic for what disease?

immune-mediated hemolysis (IMHA)

how do you perform a macroscopic agglutination test?

no microscope required - mix saline & blood on a slide and gently rock look for clumping

how do you perform a microscopic agglutination test? what disease process must you differentiate from agglutination in this test?

use a microscope! mix saline & blood & look for clumps rouleaux

spherocytes in a blood smear of an anemic patient is almost entirely pathognomonic for what disease?

IMHA

microcytic, hypochromic anemia is almost entirely pathognomonic for what disease?

iron deficiency anemia - chronic external blood loss microcytosis without anemia is not the same

what 3 components of the urinalysis of the anemic patient are the most important to evaluate?

1. pigmenturia 2. urine specific gravity 3. proteinuria

what 3 kinds of pigmenturia can be seen in the anemic patient? what do they indicate?

1. bilirubinemia - extravascular hemolysis 2. hematuria - decreased platelets, thrombocytopathia (dysfunction) 3. hemoglobinuria - intravascular hemolysis *must differentiate from myoglobinuria - spin down urine to see if RBC will pellet*

if there is proteinuria present on the urinalysis of an anemic patient, what may this indicate?

infection or inflammation

what may be seen on USG of an anemic patient?

inadequate concentration/isosthenuria - consistent with chronic kidney disease

when you suspect a GI bleed, why do a fecal?

whipworms, hookworms - big culprits

what are the pros & cons of VCE in a patient with a suspected GI bleed?

less invasive & may be able to see lesions in jejunum/ileum weight cut off - can't do in small dogs, & expensive

what 3 tests should you run if you suspect there is an immune-mediated disease, such as IMHA or IMTP, leading to hemorrhage?

coombs' test - looks for antigen-antibody complexes flow cytometry for RBC or platelet surface antibodies infectious disease testing - 4DX, babesia

why would an abdominal ultrasound be helpful in working up an anemic patient?

better look at architecture - look for ulcers, masses, & intestinal wall thickening

when would you consider an upper/lower gi endoscopy in an anemic patient?

bleeding ulcer - to confirm ulcer, biopsy, & neoplasia or zinc penny ingestion

when are bone marrow exams indicated in anemic patients?

- severe anemia not explained by chronic disease & non regenerative - >5 days anemia & still non-regenerative - concurrent cytopenias with a non-regenerative anemia

why does heart rate increase when O2 content is going down?

cardiac output = HR * stroke volume cardiac output contains O2 content of RBCS, so the more that O2 drops, cardiac output increases to try & get oxygen to the body

what are the transfusion guidelines for severe anemia of <18%?

often requires blood - can be case dependent as chronic severe anemias often are adjusted to their low RBC

what are the transfusion guidelines for Hct or PCV <12%?

definitely requires transfusion - need to consider if the animal has been transfused before need to also consider mechanism of deficiency

what blood product is best for treating VWF?

cryoprecipitate

what blood product should be used for hemorrhage or potentially clotting factor problems?

- whole blood or plasma is the most appropriate with fresh whole blood being associated with better survival

what blood product should be used for hemolysis or decreased production?

- packed red blood cells are the most appropriate, less volume required & less immunogenic

if a dog has been transfused before, you must what?

cross match!!!

why is it important to blood type & cross match cats that need a blood transfusion?

type b has a strong reaction to type a causing a hemolytic anemia

for every 1 ml/kg of pRBC, PCV will increase by how much?

if your pet is at 15%, using pRBC to raise PCV by 8-10% for a 10kg dog would be what?

80-100 mls of pRBC

what is the difference between using pRBC & whole blood for a transfusion?

whole blood takes 2x the amount than pRBC - so for every 2 ml/kg of product, PCV raises by 1%

if your pet is at 15%, using whole blood to raise PCV by 8-10% for a 10kg dog would be what?

180-200 mls whole blood needed

what are some contraindications to pursuing a blood transfusion?

not cross matching to any units severe heart disease - although, sometimes life & death, so go very very slow

what is the 'standard transfusion' reaction? what should you do? what are some other complications?

increased temp - slow down the fluid rate transfusion related acute lung injury & transfusion associated circulatory overload

for a normovolemic patient, what is the transfusion rate?

10 ml/hr

for a hypovolemic patient, what is the transfusion rate?

30 ml/hr

for a patient at a high risk of overload (cardiac disease), what is the transfusion rate?

ideally no more than 5 ml/hr

what is the recommended start in regards to rate for all transfusion patients?

can always start at 1/2 the recommended rate for the first 1/2 hour then increase

what monitoring should be used for transfusion patients?

monitor HR & temperature every 5 minutes for the first 30 minutes & then span out to every 15 minutes for the remainder of the transfusion