Approach to Anemic Patient Flashcards
What is anemia?
-reduced oxygen carrying capacity from insufficient hemoglobin and red blood cell mass within the vasculature
-should probably be called hyponemia as it does not mean “no blood”
-not a diagnosis, this is a PROBLEM
What are the 3 broad differentials for anemia?
Loss
Destruction
Lack of Production
What are the two types of loss that occurs that can cause anemia?
Induced due to trauma or parasites
Spontaneous due to thrombocytopenia, coagulopathy or DIC
What are some causes of RBC destruction?
-infectious
-immune mediated (most common)
-drug induced
-mechanical (DIC)
What are the different problems that can result in lack of production of RBCs?
Refractory:
-anemia of chronic disease or renal failure (lack of erythropoietin)
-these can potentially be reversed or addressed
Bone marrow:
-aplastic anemia, pancytopenia, drugs, immune mediated, neoplastic, idiopathic
-often untreatable
How long do WBCs last in the bloodstream? Platelets? RBCs?
WBC: 7 hours
Platelets: 7 days
RBCs: 7 weeks
What are history findings that may indicate a patient could be anemic?
-Weakness/lethargy/collapse
-pallor/pale gums
-jaundice/icterus/yellow gums/sclera/skin
-recent trauma (especially blunt)
-melena or hematochezia
-obvious blood loss
-breathing changes: due to tissue hypoxia, hemothorax, or pulmonary contusions
-distended abdomen (could be hemoabdomen)
What are some common physical exam changes seen with anemia?
-pale pink to white mucous membranes
-tachycardia
-heart murmurs (due to changes in blood viscosity)
-bounding or weak pulses
-dullness, weakness, collapse
-icterus
-bruising/ecchymoses/petechiae
-pleural or abdominal effusion
-obvious bleeding
Explain how the clinical signs of anemia can differ based on chronicity
In more chronic cases of anemia, the animals have the opportunity to adapt
-in acute cases, clinical signs are more likely to be more severe
How do you confirm that a patient is anemic?
-measure PCV AND total solids (need both in order to characterize the anemia and reach definitive diagnosis)
-CBC- hematocrit, blood smear, reticulocyte count
T/F: you can confirm rapid blood loss with bloodwork
False
-Hct and PCV measure the percentage of RBCs in the blood -wont change with loss
-CBC cannot tell you how much total blood is in the patient
you can be anemic with a normal PCV
What is the difference between Hct and PCV?
They are essentially the same, except the Hct is calculated compared to PCV which is directly measured
After acute blood loss, when and why do the PCV drop?
PCV drops within a few hours
-number of red cells does not change but water enters vasculature through pulling from interstitium and intercellular cases
Should you give fluids to anemic patients?
Yes- should not be worried that fluids will worsen the anemia
- you are just revealing the anemia that was already there
What changes occur to the PCV/TS with anemia due to loss? Destruction? Lack of production?
Loss: PCV and TS will both drop
Destruction: PCV will go down, TS will stay the same or increase (due to dehydration or due to inflammatory reactions). Serum may be yellow
Lack of Production: Decreased PCV and normal total solids
What changes may you see on a CBC with lack of production?
Non-regenerative anemia (lack of reticulocytes, normal MCV and decreased MCHC)
-Normocytic, hypochromic
What occurs to the MCV and MCHC with regenerative anemia?
Increased MCV- When the cells are immature, as in the case of regeneration they are larger
Decreased MCHC- hemoglobin concentration is lower as the cells are larger
AKA Macrocytic, hypochromic or polychromasia
What changes may you see on a CBC with loss?
Regeneration - increased reticulocytes (macrocytic, hypochromic)
-but this takes some time (2-3 days)
-with acute loss, don’t expect to see regeneration right away
What changes may you see on a CBC with destruction?
Regeneration- increased reticulocytes (macrocytic, hypochromic)
-increased spherocytes if IMHA
-inflammatory leukogram
What types of blood loss can be either acute or chronic?
Cancer
If you suspect blood loss but you cant find blood anywhere, what is the most likely place the blood is going?
Being lost in the GI tract
Describe hemolytic anemia
Commonly this is immune mediated
-sometimes can be due to infections, oxidative damage or toxins
-rarely can be caused by microangiopathies, or inherited RBC abnormalities
-hemolysis can be intravascular or extravascular or both
How do you expect the plasma to look different when there is intravascular hemolysis vs extravascular?
Extravascular- plasma will appear icteric
Intravascular- plasma may appear redder than normal due to release of hemoglobin
Describe the main causes of hypoplastic anemia
Refractory: anemia of chronic disease/anemia of chronic inflammation, renal failure, iron deficiency
-can diagnose through bloodwork
Bone marrow diseases: aplastic anemia, pancytopenia, drug induced, cancer, immune mediated, idiopathic, infectious
-definitive diagnosis from bone marrow sampling (aspirate or biopsy)
What is a condition that can look a lot like IMHA but does not often result in spherocytes?
Zinc toxicosis
-most commonly from ingestion of pennies made after 1982
-results in vomiting, moderate to severe regenerative anemia, hyperbilirubinemia, inflammatory leukogram
-treat through foreign body surgery in most cases or endoscopy
What confirmatory test can you run to support diagnosis of IMHA?
Slide agglutination test
-perform with anticoagulated blood
-combine one drop of blood and one drop of saline and look for agglutination - supportive of diagnosis
What are some secondary causes of IMHA?
Babesia in dogs, FeLV in cats, mycoplasma in cats
-cancer: screen via radiographs, abdominal imaging
What is the mainstay of treatment for IMHA?
Prednisone for immunosuppression
- 2 mg/kg/day split into BID dosing. Usually see response in 5-7 days
- can also add on adjunctive agents such as azothiaprine in order to reduce the side effects of prednisone
Antithrombosis:
-antiplatelet drugs: clopidogrel, aspirin
-anticoagulant drugs: more effective than antiplatelet drugs but more expensive. Includes unfractionated heparin, low molecular weight heparin, oral anti-xa (rivoroxaban)
Blood transfusion as needed
What are the 2 reasons that patients die from IMHA?
-thromboembolism
-or not enough money for blood transfusions
When should blood transfusions be performed in anemic patients?
When the patients have severe clinical signs of disease
In a patient with rodenticide poisoning, what should you give the patient in terms of fluids?
Fresh frozen plasma
-clotting factors are what these patients need due to the current ones in their system not working
-LRS would be another decent option for rehydration, as well as whole blood or packed red cells (in addition to plasma)
Start with fluid bolus, then give fresh frozen plasma after thawed, then if there is still minimal to no improvement add on packed red cells
When should you give the vitamin K in rodenticide cases?
As soon as possible after stabilization with fluids/plasma
-if known exposure but no evidence of bleeding, can just give the vitamin K
What is the main cause of a microcytic, hypochromic anemia?
Iron deficiency anemia
-due to chronic external blood loss (usually lost to GI tract or due to parasitism)
