Approach to Anemic Patient

Question 1

What is anemia?

Answer 1

-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

Question 2

What are the 3 broad differentials for anemia?

Answer 2

Loss
Destruction
Lack of Production

Question 3

What are the two types of loss that occurs that can cause anemia?

Answer 3

Induced due to trauma or parasites

Spontaneous due to thrombocytopenia, coagulopathy or DIC

Question 4

What are some causes of RBC destruction?

Answer 4

-infectious
-immune mediated (most common)
-drug induced
-mechanical (DIC)

Question 5

What are the different problems that can result in lack of production of RBCs?

Answer 5

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

Question 6

How long do WBCs last in the bloodstream? Platelets? RBCs?

Answer 6

WBC: 7 hours
Platelets: 7 days
RBCs: 7 weeks

Question 7

What are history findings that may indicate a patient could be anemic?

Answer 7

-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)

Question 8

What are some common physical exam changes seen with anemia?

Answer 8

-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

Question 9

Explain how the clinical signs of anemia can differ based on chronicity

Answer 9

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

Question 10

How do you confirm that a patient is anemic?

Answer 10

-measure PCV AND total solids (need both in order to characterize the anemia and reach definitive diagnosis)
-CBC- hematocrit, blood smear, reticulocyte count

Question 11

T/F: you can confirm rapid blood loss with bloodwork

Answer 11

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

Question 12

What is the difference between Hct and PCV?

Answer 12

They are essentially the same, except the Hct is calculated compared to PCV which is directly measured

Question 13

After acute blood loss, when and why do the PCV drop?

Answer 13

PCV drops within a few hours
-number of red cells does not change but water enters vasculature through pulling from interstitium and intercellular cases

Question 14

Should you give fluids to anemic patients?

Answer 14

Yes- should not be worried that fluids will worsen the anemia
- you are just revealing the anemia that was already there

Question 15

What changes occur to the PCV/TS with anemia due to loss? Destruction? Lack of production?

Answer 15

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

Question 16

What changes may you see on a CBC with lack of production?

Answer 16

Non-regenerative anemia (lack of reticulocytes, normal MCV and decreased MCHC)
-Normocytic, hypochromic

Question 17

What occurs to the MCV and MCHC with regenerative anemia?

Answer 17

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

Question 18

What changes may you see on a CBC with loss?

Answer 18

Regeneration - increased reticulocytes (macrocytic, hypochromic)
-but this takes some time (2-3 days)
-with acute loss, don’t expect to see regeneration right away

Question 19

What changes may you see on a CBC with destruction?

Answer 19

Regeneration- increased reticulocytes (macrocytic, hypochromic)
-increased spherocytes if IMHA
-inflammatory leukogram

Question 20

What types of blood loss can be either acute or chronic?

Answer 20

Cancer

Question 21

If you suspect blood loss but you cant find blood anywhere, what is the most likely place the blood is going?

Answer 21

Being lost in the GI tract

Question 22

Describe hemolytic anemia

Answer 22

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

Question 23

How do you expect the plasma to look different when there is intravascular hemolysis vs extravascular?

Answer 23

Extravascular- plasma will appear icteric
Intravascular- plasma may appear redder than normal due to release of hemoglobin

Question 24

Describe the main causes of hypoplastic anemia

Answer 24

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)

Question 25

What is a condition that can look a lot like IMHA but does not often result in spherocytes?

Answer 25

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

Question 26

What confirmatory test can you run to support diagnosis of IMHA?

Answer 26

Slide agglutination test
-perform with anticoagulated blood
-combine one drop of blood and one drop of saline and look for agglutination - supportive of diagnosis

Question 27

What are some secondary causes of IMHA?

Answer 27

Babesia in dogs, FeLV in cats, mycoplasma in cats
-cancer: screen via radiographs, abdominal imaging

Question 28

What is the mainstay of treatment for IMHA?

Answer 28

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

Question 29

What are the 2 reasons that patients die from IMHA?

Answer 29

-thromboembolism
-or not enough money for blood transfusions

Question 30

When should blood transfusions be performed in anemic patients?

Answer 30

When the patients have severe clinical signs of disease

Question 31

In a patient with rodenticide poisoning, what should you give the patient in terms of fluids?

Answer 31

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

Question 32

When should you give the vitamin K in rodenticide cases?

Answer 32

As soon as possible after stabilization with fluids/plasma
-if known exposure but no evidence of bleeding, can just give the vitamin K

Question 33

What is the main cause of a microcytic, hypochromic anemia?

Answer 33

Iron deficiency anemia
-due to chronic external blood loss (usually lost to GI tract or due to parasitism)