Erythrocytes Flashcards Preview

Clinical Pathology > Erythrocytes > Flashcards

Flashcards in Erythrocytes Deck (152):
1

Erythron

All erythroid cells in an animal

2

Erythropoiesis

Part of hematopoiesis

3

EPO

Produced by fetal liver and adult kidney
- renal peritubular interstitial cells in response to hypoxia

4

Hypoxia

- anemia
- poor oxygenation of the blood
- decreased renal perfusion

5

Hypoxia increases ______

EPO

6

Increasing _______ signals cells to stop dividing

Hemoglobin concentration
- RNA produced for protein synthesis including Hgb
- maturation leads to nucleus extrusion in mammals
- reticulocyte is a erythrocyte without nucleus but with high concentration of RNA

7

Erythroid destruction in health

Old erythrocytes loose metabolic ability to keep deformability
- expose hidden antigens in the membrane
- naturally occurring antibodies bind to these antigens and mediate erythrocyte destruction

8

Hemoglobin

Tetramer of 4 globin molecules and bound to an internal heme
- heme has ferrous iron
- if ferric is attached, it cannot transport O2

9

CO2 from tissues

About 20% bind to Hgb
- rest reacts with H2O to form H and HCO3
- reaction is reversed in the lungs and CO2 is excreted

10

Porphyria

Increased concentration of porphyrins in erythrocytes, plasma or urine
- can be acquired (lead toxicity), or congenital

11

Iron

- 50-70% erythrocytes, 25-40% storage, and rest in other molecules

12

Absorption of iron is regulated by ________

Hepcidin
- produced by hepatocytes
- decreases Fe absorption
- hypoxia decreases hepcidin production (increases Fe absorption in the intestine)
- inflammation increases hepcidin production (help to decrease Fe concentration)

13

Reticulocytes

Immature erythrocyte with stainable RNA
- New methylene blue stains RNA and mitochondria --> reticulated or punctuated structure look in erythrocytes cytoplasm
- Romanowisky will stain RNA on polychromatophilic erythrocytes (polychromatophils) blue (basophilic)

14

What are the 2 types of reticulocytes?

Most species all RNA rich erythrocytes will be called reticulocytes
- cats: punctuate (2-6 granules), aggregate (large aggregates)

15

Species differences with erythropoiesis

- cattle and dogs: starts 3-4 days and peak 7-14 days (blood loss)
- cats: aggregate (start at 2, peak at 4), punctate (peak 7-14 day)
- horses: rarely have circulating reticulocytes

16

Polychromasia

Increased numbers of basophilic erythrocytes in the blood smear (Romanowsky)
- correspond to reticulocyte counts (dogs and cattle) and aggregate reticulocytes in cats

17

Erythrogram

Morphologic evaluation
- hematocrit or PCV
- [Hgb] always from erythrocytes, unless hemolysis or Hgb-O2 carriers
- erythrocytes count

18

Wintrobe's erythrocytes indices

MCHC (CHCM): average of 100 mL of erythrocytes
- MCV: average erythrocytic volume
- MCH: average [Hgb] per average sized erythrocytes
- RDW: coefficient of variation of erythrocyte volume
- HDW: coefficient of variation of erythrocytes [Hgb]

19

How is CHCM measured?

Cell counters using laser and is not sensitive to hemolysis

20

Nucleated erythrocytes

Counted per 100 leukocytes
- if present, is necessary to correct leukocytes count
- reported as #/100 WBC
- so, if nRBC = 50/100WBC it could be a lot or few
- if WBC = 500/uL, nRBC would be 250/uL
- if WBC = 50,000/uL, nRBC would be 25,000/uL

21

Reticulocytes

Reticulocyte concentration: #/uL or #/L
- reticulocyte percentage or reticulocyte count: # of reticulocytes per 100 erythrocytes
- corrected reticulocyte percentage: calculated number of RP if naimal was not anemic

22

Discocytes

Mature normal erythrocytes

23

Rouleaux

Normal in some species (horses and cats)
- caused by charges interactions
- hyperglobinemia or hyperfibrinogenemia

24

Agglutination

Immune hemolytic anemia, different from rouleaux
- will not form stacks of cells
- saline dispersion test (1 part saline to 1 part of blood will disperse rouleaux, but not agglutination)
- heparin in equine erythrocytes
- RBCs may be counted as large cells

25

Rubricytosis

Increased numbers of nRBCs in the blood
- appropriate: response to EPO with reticulocytosis
- inappropriate: loss of control of nRBC release from BM

26

Inappropriate causes of rubricytosis

- bone marrow damage (necrosis, inflammaiton, endotoxemia, neoplasia, hypoxia)
- extramedulary hematopoiesis
- splenic contraction
- splenectomy
- lead poisoning in dogs
- bone marrow dyscrasia in poodles with macrocytosis

27

Central pallor

Central area of an erythrocyte that is more clear because it is thinner
- increase: hypochromasia
- decreased: abnormal shape (including spherocytosis)

28

Ghost cell

- complement mediated intravascular hemolysis
- artifact

29

Hypochromic erythrocyte

Hypochromasia
- increased numbers of hypochromic erythrocytes
- decreased MCHC and CHCM
- decreased RBC [Hgb]
- Fe deficiency

30

Polychromatophil/reticulocyte

Polychromatophil is an erythrocyte with enough RNA to stain basophilic with Wright stain
- reticulocyte is an erythrocyte with enough RNA to form aggregates of RNA when stained with NMB
- polychromasia and reticulocytosis reflect accelerated erythropoiesis

31

Anaplasma marginale

0.5 um small coccus in the internal margin of the erythrocyte
- usually one, but possible multiple per cell
- causes hemolysis (immune mediated)

32

Reticulocyte concentration

Concentration of reticulocytes in the blood expressed in # of reticulocytes/uL
- is the preferred method for evaluating marrow response to anemia!!

33

Reticulocyte percentage

Percentage of erythrocytes that are reticulocytes in the blood
- so, if there are reticulocytes for every 1,000 erythrocytes, the RP is 1%
- RC = RP x [RBC]

34

Corrected reticulocyte percentage

Calculated percentage that represents the RP if the animal was not anemic but had the same RC
- CRP = RP x (pateint's Htc/average Hct for species)
- average Hct for species

35

Babesia spp

Intracellular, oval to teardrop throphozoites
- variable sizes (depend on species)
- pale blue, with darker outer membrane and a purple eccentric nucleus
- hemolysis: immune mediated, protease activity, decreased cell pliablity, oxidative damage

36

Cytauxzoon felix

Intracellular, oval, 0.1 to 2 um, with outer thin rim and eccentric nucleus
- one to several/cell
- anemia: inflammation, marrow damage, hemolysis

37

Distemper in dogs

Round to variably shaped, pale blue to pink, homogenous inclusions
- 0.3 to 3 um
- diff-quick is better to see than wright stain
- active distemper infection

38

Mycoplasma spp of cattle

Rings, rods or cocci on erythrocytes surface
- 0.3 to 3 um
- immune hemolysis

39

Mycoplasma hemocanis

Thin chain or cocci
- immune hemolysis

40

Mycoplasma haemofelis

Thin chain of cocci, small rings, pale blue to purple
- less than 0.1 um
- immune hemolysis

41

Candidatus mycoplasma haemominutum

Cocci 0.1 to 0.2 um, individual or short chains
- immune hemolysis

42

Theileria

Pleomorphic piroplasma: cocci, rings rods, pears, and maltese crosses
- anemia: immune, protease, decreased cell pliability, and oxidative damage

43

Basophilic stippling

Regenerative anemia: persistence of ribosomal RNA
Plumbism: inhibition of pyrimidine 5' nucleotidase

44

Heinz body

Exposure to oxidants
- oxidized hemoglobin precipitates

45

Howell-Jolly body

Increased erythropoiesis, decreased splenic function
- nuclear remnant free in the cytoplasm

46

Siderotic granules

Excess Fe in body, plumbism in dogs, myeloproliferative disease
- Fe accumulates in damaged mitochondria or in autophagocytic vacuoles

47

Acanthocyte (spur cell, burr cell)

Hemangiosarcoma, splenic, hepatic and renal disorders
- possible changes in membrane lipids or erythrocyte fragmentation

48

Codocyte (mexican hat cell)

Regenerative anemias, hepatic, renal, and lipid disorders
- excess membrane relative to Hgb content, possibly membrane lipid changes

49

Dacrocyte (teardrop shaped)

Marrow diseases (myelofibrosis, neoplasia)
- unknown formation
- artifact: stretching during film prep

50

Eccentrocyte (bite cell, cross bonded cells, hemighost)

Exposure to oxidants, G6PD or FAD deficiencies
- fusion of damaged membranes

51

Echinocyte (Burr cell)

- type 1: irregularly shaped
- type 2: regularly spaced blunt projections
- type 3: regularly spaced pointed projections
- erythrocyte dehydration, strenuous exercise, doxorubicin toxicosis, PK deficiency in dogs, snake venom

52

Crenated erythrocytes

Always an artifact
- features of types 1-3
- all echynocytes should be considered artifact until proven otherwise

53

Keratocyte (helmet cell)

Vasculitis, intravascular coagulation, hemangiosarcoma, caval syndrome, endocarditis
- trauma, oxidative injury, vesiculation have been proposed

54

Ovalocyte (elliptocyte)

Protein band 4:1 deficiency in dogs, myelofibrosis, idiopathic in cats, iron deficiency
- abnormal membrane proteins in hereditary forms

55

Pyknocytes

Exposure to oxidants
- likely formed from eccentrocytes

56

Schistocyte

Intravascular coagulation, vasculitis, hemangiosarcoma, caval syndrome, endocarditis
- trauma

57

Sperhocytes

Immune hemolysis, fragmentation hemolysis, envenomation, clostridial infections
- membrane loss due to macrophages partial phagocytosis, trauma

58

Stomatocyte

Young erythrocytes, hereditary stomatocytosis of dogs
- folding of excess membrane

59

Torocyte

Do not confuse with hypochromia!
- artifact

60

Anemia

Decreased Hct, [Hgb], [RBC]
- pathological, not a disease
- caused by loss, destruction, lack of production

61

Regenerative anemia

With reticulocytosis (increased numbers of reticulocytes)
- following blood loss or erythrocyte destruction (hemolysis), erythroid neoplasia in cats, resolution of nonregenerative anemia
- active erythropoiesis
- blunted by other conditions

62

Nonregenerative anemia

Without reticulocytosis (normal or decreased numbers of reticulocytes)
- defective or reduced erythrocyte production
- BM is not able to produce cells
- severe associated to damage to early precursosrs
- usually normocytic normochromic

63

Reticulocytosis

3-4 days after EPO sitmulus (not in horses)
- peak at 7-10 days
- dog produces a lot of reticulocytes, cats moderate, cattle low, equine will not release

64

Anemia morphologic classification based on MCV

- normocytic: maturation is not defective
- macrocytic: presence of reticulocytes or defective cells
- microcytic: extra mitosis (Fe deficiency), fragments

65

Anemia morphologic classification based by MCHC/CHCM

- normochromic: Hgb synthesis is complete
- hypochromic: Hgb synthesis is incomplete (young cells or defective synthesis)
- hyperchromic: RBCs were not produced hyperchromic (either lost volume in vitro or artifact)

66

Normocytic normochromic

Blood smear: uniform erythrocytes
- most anemias begin as normocytic normochromic
- most anemias in the horse are normocytic normochromic

67

Macrocytic hypochromic

Blood smear: anisocytosis and polychromasia
- anemia probably due to blood loss or hemolysis

68

Macrocytic normochromic

Blood smear: anisocytosis and possible polychromasia
- seen in blood loss and hemolysis
- occasionally defective erythropoiesis (FeLV, folic acid and cobalamin, erythroleukemia)
- artifact (erythrocyte agglutination, cell swelling w/ storage, in vivo hyperosmolar state, too little blood)

69

Microcytic hypochromic

Blood smear: microcytosis, codocytosis, hypochromasia, anisocytosis
- defective Hgb synthesis: Fe deficiency, copper deficiency, Vit B6 deficiency

70

Microcytic normochromic

- hepatic failure: hepatic dz, portosystemic shunt --> may see hypochromic state!
- foals and kittens: lower MCV (also with Akitas and Shibas)
- hereditary dz

71

Normocytic hypochromic

Uncommon
- inaccurate data, inadequate RI
- possible w/ Fe deficiency

72

Macrocytic hyperchromic

Falsely increased MCHC
- compare to CHCM

73

Normocytic hyperchromic

Falsely increased MCHC
- compare to CHCM

74

Microcytic hyperchromic

Hypoosmolar plasma (cell shrinkage)
- if MCHC is falsely increased, think of other causes for microcytic anemia

75

Increased MCHC/CHCM

Not physiologically possible! --> Hgb production stops when optimal [Hgb] is reached
- falsely increased

76

If CHCM is not affected ________

- hemolysis (pathological or in vitro)
- oxyglobin
- interferences on Hgb tests: lipid droplets in lipemic sample, markedly icteric sample, extreme leukocytosis, precipitated IgA

77

If MCHC and CHCM are affected ________

Heinz bodies and hypoosmolar states

78

When is an increased MCHC or CHCM true?

- eccentrocytosis
- pyknocytosis
- spherocytosis

79

What is the most common cause of nonregenerative anemia?

- decreased RBC production
- defective erythropoiesis

80

Erythrocyte life span

2-5 months
- dog: 100 days (25 days to go from 40% Hct to 30% Hct)
- cat: 70 days
- cattle/horses: 150 days

81

Does nonregenerative anemia stop RBC production completely?

No, animals are frequently anemic for several weeks before diagnosis

82

Severity of nonregenerative anemia

- duration of disease
- degree of erythropoiesis decrease
- presence/absence of processes that shorten RBC life span

83

Nonregenerative anemia - inflammatory disease

AID: anemia of inflammatory disease
- most common cause in mammals
- mild to moderate
- normocytic normochromic
- any chronic disorder with inflammation will start the process (infectious/noninfectious)

84

AID pathogenesis

- shortened RBC survival
- impaired Fe mobilization or utilization
- impaired RBC production

85

AID laboratory findings

- normocytic normochromic
- hyperproteinemia (y-globulins or positive acute phase)
- BM: normal to mildly decreased erythropoiesis
- hypoferremia

86

Chronic renal disease

Nonregenerative anemia
- mild to moderate
- inadequate EPO production
- decreased RBC life span
- decreased BM response to EPO
- possible hemorrhage, nutritional status

87

CRD - lab findings

Normocytic normochromic nonregenerative anemia
- azotemia
- isostenuria
- electrolyte disturbances

88

Diseases causing _____________ lead to nonregenerative anemias

Marrow hypoplasia or aplasia of cell lineages
- one or more BM components affected: blood vessels, reticular adventitial cells, marrow stroma, hematopoietic stem cells
- nonreversible or reversible

89

_____ and ____ are often idiopathic

Hypoplasia and aplasia

90

Infectious agents causing bone marrow hypoplasia/aplasia

- direct cell damage (myelitis)
- suppression with bacterial septicemias
- erlichiosis (disseminated micosis)
- viral agents
- protozoal infections

91

Cytauxzoonosis

Pirpolasms in RBCs and schizonts in macrophages
- rapid progression --> fatal
- anemia: mild to severe
- normocytic normochromic
- non regenerative
- AID and damage to BM, spleen and liver
- post hepatic hyperbilirubinemia, bilirubinuria
- thrombocytopenia, leukopenia (occasionally toxic changes)

92

Toxicosis

Chemotherapeutic agents
- estrogen
- phenylbutazone
- bracken fern
- nonregenerative anemia

93

Irradiation

Nonregenerative anemia

94

Myelophtisis

Marrow replacement
- myeloproliferative dz
- lymphoproliferative dz
- metastatic neoplasia: lymphoproliferative neoplasia, mast cell, carcinomas, nonhemic sarcomas
- nonregenerative anemias

95

_______ and ______ are nonneoplastic disorders that cause nonregenerative anemias

- myelofibrosis
- osteopetrosis

96

Immune-mediated nonregenerative anemia

Similar to aplastic anemia, but BM with left shift (erythroid series) and maturation arrest, or persistent erythroid hyperplasia and non-regenerative anemia
- respond to immune suppressive treatment
- occasionally Coomb's positive
- BM: left shift with maturation arrest, or erythroid hyperplasia (other cell lines are normal)

97

FeLV

Selective damage erythroid series (hypoplasia or neoplasia)
- precursor cell damage following hypoplasia
- neoplastic transformation caused by mutations --> defective cell that will not mature properly = nonregenerative anemia
- normocytic normochromic, or macrocytic normochromic non regenerative anemia
- inappropriate rubricytosis, dysplastic RBCs

98

Iron deficiencies

Chronic external blood loss or inadequate dietary Fe intake
- microcytic hypochromic, possibly microcytic normochromic
- nonregenerative anemia

99

Copper deficiency

Uncommon, reported in pigs and dogs
- nonregenerative anemia

100

Folate and cobalmin (Vit B9 and B12)

Required for DNA synthesis so deficiencies lead to abnormal cell production
- macrocytic anemia in people, rare in animals
- macrocytic (or normocytic) normochromic, nonregenerative anemia with macrocytes

101

Pyridoxine (Vit B6)

Reported dietary deficiency in kittens causing anemia

102

Hypothyroidism

Dogs
- decreased metabolic rate --> decreased oxygen need --> decrease EPO --> anemia
- normocytic normochromic nonregenerative anemia
- evidence of thyroid dysfunction

103

Hypoadrenocorticism

Dogs
- normocytic normochromic nonregenerative anemia
- unknown
- evidence of adrenal dysfunction (hyponatremia, hyperkalemia, hypocortisolemia, lymphocytosis, eosinophilia)

104

Hyperestrogenism

Excessive production (neoplasms: Sertoli cell tumor, granulosa cell tumor), or iatrogenic
- nonregenerative anemia (pancytopenia), especially in dogs and ferrets

105

Liver disease/failure

Progressive normocytic normochromic (occasionally microcytic normochromic in dogs with hepatic insufficiency) nonregenerative anemia
- AID
- defective amino acids, protein and lipid metabolism affecting RBC membranes and life span
- dogs: not total Fe deficiency, possibly functional Fe deficiency

106

Hepatic dz - lab findings

- normocytic (or microcytic) normochromic nonregenerative anemia
- hypochromasia is rare
- elevated liver enzymes
- decreased BUN/hypoalbumenemia
- prolonged clotting times
- increased serum bile acids
- hyperammonemia

107

Blood loss anemia - causes

- hemorrhage: blood vessel damage by trauma, acquired/congenital hemostatic impairment
- parasitism
- donating for blood transfusions

108

Classification based on _______

Duration and location

109

Acute blood loss anemia

- sudden loss of blood from vessel --> hypovolemia
- shift of ECF into vessels dilutes erythrocytes --> anemia
- splenic contraction reduces severity of anemia
- few hrs after blood loss
- tissue hypoxia --> EPO prodcution --> reticulocytes in 3-4 days (horses)

110

Blood loss in hemothorax or hemoperitoneum

- 65% resorption in 2 days and 80% in 1-2 weeks
- no Fe depletion

111

Acute blood loss anemia - clinical findings

- observation of blood via gross external hemorrhage, hemothorax/peritoneum
- regenerative anemia (after 3-4 days)
- hypoproteinemia, hypoalbumenemia, hypoglobulenima (less severe if internal bleeding)

112

Chronic blood loss anemia that leads to _______

Iron deficiency
- compensatory erythropoiesis prevents anemia for weeks-months
- Fe deficiency diminishes erythropoiesis and causes mild anemia
- full blown Fe deficiency causes microcytic hypochromic anemia

113

Fe depletion

- maturation and release of RBCs are impaired
- RBCs more fragile and deformable --> decreased life span
- reticulocytosis is present, but less than expected (marrow is poorly responsive)

114

Chronic blood loss - clinical findings

- melena, hematuria, parasites
- poorly or nonregenerative anemia
- microcytic normochromic or hypochromic anemia
- BM: erythroid hyperplasia but ineffective erythropoiesis
- mild-moderate hypoproteinemia
- hypoferremia, decreased total body Fe and decreased ferritin
- young animals more prone due to small Fe store

115

Increased rate of erythrocyte destruction

Hemolytic anemia
- intravascular: occurs in heart, blood vessels --> hemoglobulinemia and hemoglobinuria
- extravascular: occurs outside vessels, erythrocytes are phagocytized

116

Why differentiate between intravascular and extravascular?

- intravascular has a poorer prognosis
- diseases may switch from one to the other, or cause both
- examine blood smear

117

What 3 things are caused by hemolytic anemia?

- icterus
- bilirubinuria
- urobilinogenuria

118

Hemolytic hemoglobinemia/hemoglobinuria

- Hgb tetramers --> Hgb dimers --> bind to haptoglobin --> hepatocytes --> unconjugated to conjugated bilirubin+Fe
- secondary: bind to hemopexin instead
- overflow: Hgb dimers --> glomerular filtration --> hemoglobinuria

119

IMHA not associated to infection

Animal produces Ig that binds to RBC surface (erythrocyte surface associated immunoglobulin)
- ESAIg could be IgM/G/A
- if Ig fix complement MAC --> hemolysis
- Coombs test to detect ESAIg or complement on RBCs

120

Idiopathic hemolytic anemia clinical findings

- regenerative anemia (mild-severe)
- icterus
- possible hemoglobinuria
- spherocytosis
- positive Coombs or flow cytometry
- acute inflammatory leukogram
- lack findings of other IMHAs

121

Drug induced hemolytic anemia

- penicillin: horses
- propylthiouracil: cats
- cephalosporins: supraphamacological doses in dogs
- TMS: horses
- levamisole: dogs
- pirimicarb: dogs

122

Vaccine-induced hemolytic anemia occurs mostly in _______

Dogs

123

Alloimmune hemolysis

Neonatal isoerythrolysis
- colostral Ig --> intestinal absorption --> bind to RBCs paternally inherited antigens

124

Incompatible drug transfusion

Donor's erythrocytes attacked by recipient's antibodies
- alloantibodies are the same of neonatal isoerythrolysis
- dogs and horses: acquired (pregnancy or transfusions)
- cats: natural

125

Feline hemic microplasma spp.

Causes feline infectious hemolytic anemia
- M. hemofelix: more pathogenic, larger
- candidatus M. haemominutum: opportunistic
- parasitemia is present during hemolysis (may disappear fast)
- may detach from RBCs, so review fresh blood smears

126

Canine hemic mycoplasma spp

M. haemocanis: splenectomized or immunologically compromised dogs
- may detach from RBCs

127

Hemothropic mycoplasma spp - lab findings

Mycoplasma on erythrocytes (surface) --> most numerous when Hct is falling
- moderate-severe anemia
- reticulocytosis/polychromasia
- hyperbilirubinemia/hyperbilirubinuria
- positive Coomb's test
- spherocytosis
- autoagglutination
- PCR positive for mycoplasma

128

Anaplasma spp

Immune mediated
- moderate-severe anemia
- reticulocytosis/polychromasia
- mild-marked hyperbilirubinemia/hyperbilirubinuria

129

Does Leptospira interrogans infect RBCs?

No
- vasiculitis, infection of liver and kidneys --> hemolytic state

130

Leptospira - lab findings

- moderate-severe anemia
- hemoglobinemia/hemoglobinuria
- hyperbilirubinemia/uria
- neutrophilia
- leptospiral in urine
- IgM cold agglutinins

131

Clostridium

Haemoliticum and C. novyii type D
- cattle and sheep: bacillary hemoglobinuria
- beta-toxin with phospholipase and lecithinase activity
- severe anemia
- hemoglobinemia/uria
- postmortem diagnosis

132

Clostridium

Type A
- yellow lamb disease
- alpha-toxin with phosphlipase C activity
- acute severe: anemia, hemoglobinemia/uria
- less severe: anemia, polychromasia, reticulocytosis, rubricytosis, leukocytosis

133

Equine infectious anemia virus

Retrovirus that infects cells from mononuclear phagocytic system in horses, mules, donkeys, ponies
- production of TNF and cytokines --> decrease RBC production
- hemolysis via immune complexes or complement on RBCs (extravascular)

134

EIA lab findings

- acute: intravascular hemolysis, hemoglobinemia
- chronic: extravascular hemolysis
- macrocytosis
- thrombocytopenia
- neutropenia/neutrophilia
- positive Coomb's test

135

Babesia

Look at capillary blood or buffy coat preparation
- nonhemolytic an dhemolytic processes
- chronic: rare organisms in RBCs, mild anemia, mild lymphocytosis
- acute: many organisms in rBCs, moderate-severe anemia, reticulocytosis, polychromasia, macrocytosis

136

Theileria buffeli

Organisms in RBCs
- macrocytosis
- polychromasia
- basophilic stippling
- lymphocytosis
- hyperbilirubinemia/bilirubinuria

137

Heinz body hemolytic anemia

Oxidant exposure overwhelms reductive pathway
- decreased RBC deformability --> trapped in spleen --> removed by macrophages
- fragile cells --> intravascular lysis
- membrane associated protein change --> autologous antibodies recognition --> extravascular hemolysis

138

Heinz body hemolytic anemia - lab findings

- mild-severe anemia
- reticulocytosis/polychromasia
- eccentrocytosis
- hyperbilirubinemia/uria
- hemoglobinemia/uria
- methemoglobinemia

139

Feline Heinz bodies

- spleen with closed circulation
- feline Hgb is prone to form oxidized forms
- feline erythrocytes have lower reductive ability

140

Eccentrocytic hemolytic anemia

Eccentrocytes are more rigid/trapped and removed by macrophages in spleen --> more fragile and prone to lysis
- acquired: oxidative insult can form eccentrocytes or Heinz bodies
- inherited

141

Hypophosphatemic hemolysis

Postparturient hemoglobinuria in cattle
- decreased phosphate mobilization from bone, increased loss via milk production --> decreased phosphorous plasma concentration --> decreases ATP in RBCs = unstable RBC membranes and lysis
- hypophosphatemia
- hemoglobinemia/uria
- moderate-marked anemia

142

Hypoosmolar hemolysis

Rapid infusion of hypoosmolar fluids IV
- water intoxication in calves
- hypoosmolar plasma --> rapid movement of water into RBCs = swelling and lysis
- anemia
- hemoglobinemia/uria

143

Trauma

Presence of rigid structures
- erythrocyte trauma --> poikilocytes or lysis
- mild to moderate anemia
- possible reticuloytes/polychromasia
- schistocytes
- keratocytes
- acanthocytes
- thrombocytopenia

144

Hemoconcentration due to dehydration

Most common cause of erythrocytosis in mammals
- hyperproteinemia
- hyperalbuminemia
- hypernatremia and hypercholremia

145

Hemoconcentration due to endotoxic shock

Shift of water from intravascular to extravascular
- enothelial cell damage --> increased permeability --> decreased oncotic pressure --> plasma migrates from intra to extravascular
- mild to moderate erythrocytosis
- inflammatory leukogram
- thrombocytopenia

146

Physiologic erythrocytosis

Splenic contraction, common in dogs and horses
- physical excitement --> epinephrine --> splenic contraction --> shift of RBCs from spleen to peripheral blood
- mild to moderate transient erythrocytosis

147

Secondary appropriate erythrocytosis

Erythropoiesis is stimulated by EPO and not autonomous
- EPO is increased due to hypoxia
- erythrocytosis caused by increased production (cardiac dz, pulmonary dz, hyperthyroidism)
- high altitudes
- prolonged training in horses

148

Secondary appropriate erythrocytosis - pathogenesis

Hypoxemia --> sustained renal tissue hypoxia --> increased EPO production --> increased reythropoiesis --> erythrocytosis

149

Secondary inappropriate erythrocytosis

Inappropriate increased EPO production due to:
- renal cysts
- renal neoplasms
- benign neoplasms (not renal)

150

Primary erythrocytosis

Autonomous eryhtropoiesis (not dependent on EPO)
- mild to marked erythrocytosis --> increased viscosity of blood --> poor tissue perfusion --> secondary increased EPO production

151

Primary erythrocytosis

Neoplastic or non-neoplastic dz that leads to increased RBC production independent of EPO

152

Polycythemia vera

Neoplastic dz of erythroid, myeloid and megakaryocytic cell lines