Erythrocytes

Question 1

Order of erythropoeisis

Answer 1

1. Rubriblast
2. Prorubricyte
3. Rubricyte
4. Metarubricyte
5. Polychromatophil
6. Erythrocyte

Question 2

Acanthocytes

Answer 2

Projections of variable length, unevenly spaced on surface of the RBC.

Question 3

Keratocytes

Answer 3

Crescent shaped. Formed by mechanical shearing. The fragment that comes off is a schiztocyte.

Question 4

Leptocyte

Answer 4

thin macrocytic RBC with membrane surface area > Hgb. Tend to wrinkle, fold, or twist into figure-8 cells. Sometimes seen with hepatic disease.

Question 5

Codocyte

Answer 5

Target cells. Darck central area of Hgb surrounded by pale zone and darker rim. Up to 50% in dogs. May be present with hepatic disease.

Question 6

Dacrocytes

Answer 6

Tear drop shaped. 1. Artifactual - all point same direction. 2. 2’ to membrane distortions as cells pass through narrow sinusoids (myelofibrosis, bone marrow dz, splenic dz)

Question 7

Eccentrocyte

Answer 7

Eccentric Hgb distribution. Indicate oxidative damage to the RBC membrane.

Question 8

Echinocytes

Answer 8

Either due to RBC dehydration, or expansion of outer leaflet of the RBC membrane.

Question 9

Echinocyte I

Answer 9

RBC with angular shape; short, blunt projections. Often due to artifact (sample aging, excess EDTA)

Question 10

Echinocytes III

Answer 10

Spherical RBCs with sharp projections of equal length evenly spaced on the surface. Artifact, renal dz, elect. changes, crenation/dehydration.

Question 11

Echinoelliptocytes

Answer 11

Oval to cigar shaped RBCs w/ projections of equal length evenly spaced on surface of the RBC. Cats with hepatobiliary dz.

Question 12

Elliptocytes

Answer 12

oval to cigar shaped RBCs. Normal in camelids. Reported in other species with hereditary RBC disorders.

Question 13

Heinz bodies

Answer 13

Eccentrically located refractile bodies or blebs on the periphery of the RBC.

Best seen with Romanowsky stains.

Indicate oxidative damage to RBCs. The denatured globin portion of the Hgb precipitates to form the visible body.

Cats are more susceptible d/t:

1. nonsinusoidal spleen does not efficiently remove the HzBs from RBCs
2. Increased content of sulfhydryl groups in the Hgb of cats is more susceptible to exogenous oxidizing agents.

Question 14

Shizocytes

Answer 14

RBC fragments attributed to mechanical red cell injury/shearing

Question 15

Spherocyte formation

Answer 15

Formed by removal of altered RBC membrane without concurrent loss of Hgb.

Question 16

Poikilocytes

Answer 16

This is the term used when RBC shape defies description. Can be abundant in normal calves, deer, goats, and pigs. May be in vitro artifact.

Question 17

RBC skeletal proteins

Answer 17

Spectrin, ankyrin, actin.

These link to the lipid bilayer via

1. spectrin-ankyrin band 3 (aka AE1)
2. spectrin-actin band (aka 4.1)

Question 18

Embden Meyerhof pathway

Answer 18

Anaerobic metabolism of glucose to lactate provides energy for RBCs

Question 19

Rapoport-Luebering pathway

Answer 19

Production of 2,3 diphosphoglycerate

Question 20

Methemoglobin reduction pathway

Answer 20

Returns methemoglobin (oxidized form) to the reduced state (ferrous/Fe2+) which is capable of carrying oxygen.

Question 21

Hexose monophosphabe shunt

Answer 21

Maintains glutathione in the reduced state.

Question 22

Glutathione

Answer 22

Intracellular buffer that protects RBCs from oxidant injury, esp. by H2O2 and superoxide, and helps stabilize reactive sulfhydryl groups of Hgb.

Question 23

RPI

Answer 23

Reticulocyte Production Index

a calculation designed to correct the retic. count for severity of anemia and longer maturation period for early-released reticulocytes

Question 24

Hematocrit

Answer 24

= MCV x RBC count

gives the volume of RBC per liter whole blood

Question 25

MCH

Answer 25

Mean Cell Hemoglobin average amount of Hgb per RBC = Hgb/ RBC count in picograms (pg)

Question 26

MCHC

Answer 26

Mean Cell Hemoglobin Concentration average conc. Hgb per _erythrocyte_ = Hgb/ Hct in g/L

Question 27

RDW

Answer 27

Red Cell Distribution describes the coefficient of variation of the RBC sizes = std dev. of MCV / MCV in principle, correlates with degree of RBC anisocytosis

Question 28

Absolute reticulocyte count

Answer 28

= % of reticulocytes x RBC count gives the absolute # reticulocytes in a volume of blood

Question 29

Grading anemia in common domestic species.

Answer 29

Question 30

nRBCs without anemia

Answer 30

DDX: * hypoxia * necrosis * lead * acute RBC neoplasia * non-hemopoietic neoplasia with metastasis to the marrow

Question 31

Tests for iron deficiency

Answer 31

1. Serum iron 2. Total iron binding capacity (TIBC) - measures transferrin 3. Serum ferritin \*\*\* 4. Visual exam of bone marrow iron stores \*\*\*

Question 32

Anemia of Iron Deficiency vs. Inflammatory Disease

Answer 32

Question 33

Microcytosis with normal body iron

Answer 33

* Copper deficiency * PSS * Japanese breeds * Calves

Question 34

Intra vs Extravascular Hemolysis

Answer 34

Intravascular: MAC directly on RBC surface. Hemoglobinemia, hemoglobinuria. Autoagglutination. Ghost cells. Extravascular: Mononuc. phagocytic system. Hyperbilirubinemia, hyperbilirubinuria. Spherocytes.

Question 35

Oxidative Damage

Answer 35

* Heinz Bodies * Lipid peroxidation - eccentrocytes, ghost cells * Methemoglobinemia * Agents * zinc * copper * onions * garlic * acetaminophen * red maple * benzocaine * napthalene * skunk spray * propylene glycol * Brassica plants (kale, rape, turnips - Cattle)

Question 36

Nonregenerative anemia

Answer 36

1. Neoplasia 2. Renal disease 3. Inflammatory disease 4. Endocrine * Hypothyroid * Hypoadrenocorticism

Question 37

Anemia of Inflammatory Disease

Answer 37

AID Most common nonregen. anemia in veterinary medicine. 2/2 cytokines, especially: IL-1, TNF, TGF-ß, and IFN-gamma Factors: * reduced availabilty of iron * decreased RBC life span * decreased response of erythroid lineage to presence of erythropoeitin

Question 38

Primary bone marrow disease DDX for non-regenerative anemia

Answer 38

* erythroid hypoplasia or aplasia * drugs, toxins * hormones, chemicals * irradiation * etiology often unidentified * dyserythropoiesis resulting in defective maturation * marrow necrosis * neoplastic infiltrate * fibroblastic infiltrate * viral (FelV, FIV) * immune mediated destruction of erythroid precursors (IMHA @ marrow)

Question 39

Erythrocytosis

Answer 39

1. Relative * dehydration (increased TP) * splenic contraction/ epinephrine response (normal TP) 2. Absolute * Primary * neoplasia in the erythroid precursor line. * rare. normal to low circulating EPO conc. * Secondary 1. Physiologic: chronic hypoxia causes increased EPO * cardiac * pulmonary * high altitude * increased EPO 2/2 physiologic need because of chronic hypoxia 2. Non-physiologic: inappropriate EPO synthesis from neoplasias (esp. renal tumors) = "inappropriate erythrocytosis"