Erythrocytes Flashcards
Erythron
All erythroid cells in an animal
Erythropoiesis
Part of hematopoiesis
EPO
Produced by fetal liver and adult kidney
- renal peritubular interstitial cells in response to hypoxia
Hypoxia
- anemia
- poor oxygenation of the blood
- decreased renal perfusion
Hypoxia increases ______
EPO
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
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
Hemoglobin
Tetramer of 4 globin molecules and bound to an internal heme
- heme has ferrous iron
- if ferric is attached, it cannot transport O2
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
Porphyria
Increased concentration of porphyrins in erythrocytes, plasma or urine
- can be acquired (lead toxicity), or congenital
Iron
- 50-70% erythrocytes, 25-40% storage, and rest in other molecules
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)
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)
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)
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
Polychromasia
Increased numbers of basophilic erythrocytes in the blood smear (Romanowsky)
- correspond to reticulocyte counts (dogs and cattle) and aggregate reticulocytes in cats
Erythrogram
Morphologic evaluation
- hematocrit or PCV
- [Hgb] always from erythrocytes, unless hemolysis or Hgb-O2 carriers
- erythrocytes count
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]
How is CHCM measured?
Cell counters using laser and is not sensitive to hemolysis
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
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
Discocytes
Mature normal erythrocytes
Rouleaux
Normal in some species (horses and cats)
- caused by charges interactions
- hyperglobinemia or hyperfibrinogenemia
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
Rubricytosis
Increased numbers of nRBCs in the blood
- appropriate: response to EPO with reticulocytosis
- inappropriate: loss of control of nRBC release from BM
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
Central pallor
Central area of an erythrocyte that is more clear because it is thinner
- increase: hypochromasia
- decreased: abnormal shape (including spherocytosis)
Ghost cell
- complement mediated intravascular hemolysis
- artifact
Hypochromic erythrocyte
Hypochromasia
- increased numbers of hypochromic erythrocytes
- decreased MCHC and CHCM
- decreased RBC [Hgb]
- Fe deficiency
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
Anaplasma marginale
- 5 um small coccus in the internal margin of the erythrocyte
- usually one, but possible multiple per cell
- causes hemolysis (immune mediated)
Reticulocyte concentration
Concentration of reticulocytes in the blood expressed in # of reticulocytes/uL
- is the preferred method for evaluating marrow response to anemia!!
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]
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
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
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
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
Mycoplasma spp of cattle
Rings, rods or cocci on erythrocytes surface
- 0.3 to 3 um
- immune hemolysis
Mycoplasma hemocanis
Thin chain or cocci
- immune hemolysis
Mycoplasma haemofelis
Thin chain of cocci, small rings, pale blue to purple
- less than 0.1 um
- immune hemolysis
Candidatus mycoplasma haemominutum
Cocci 0.1 to 0.2 um, individual or short chains
- immune hemolysis
Theileria
Pleomorphic piroplasma: cocci, rings rods, pears, and maltese crosses
- anemia: immune, protease, decreased cell pliability, and oxidative damage
Basophilic stippling
Regenerative anemia: persistence of ribosomal RNA
Plumbism: inhibition of pyrimidine 5’ nucleotidase
Heinz body
Exposure to oxidants
- oxidized hemoglobin precipitates
Howell-Jolly body
Increased erythropoiesis, decreased splenic function
- nuclear remnant free in the cytoplasm
Siderotic granules
Excess Fe in body, plumbism in dogs, myeloproliferative disease
- Fe accumulates in damaged mitochondria or in autophagocytic vacuoles
Acanthocyte (spur cell, burr cell)
Hemangiosarcoma, splenic, hepatic and renal disorders
- possible changes in membrane lipids or erythrocyte fragmentation
Codocyte (mexican hat cell)
Regenerative anemias, hepatic, renal, and lipid disorders
- excess membrane relative to Hgb content, possibly membrane lipid changes
Dacrocyte (teardrop shaped)
Marrow diseases (myelofibrosis, neoplasia)
- unknown formation
- artifact: stretching during film prep
Eccentrocyte (bite cell, cross bonded cells, hemighost)
Exposure to oxidants, G6PD or FAD deficiencies
- fusion of damaged membranes
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
Crenated erythrocytes
Always an artifact
- features of types 1-3
- all echynocytes should be considered artifact until proven otherwise
Keratocyte (helmet cell)
Vasculitis, intravascular coagulation, hemangiosarcoma, caval syndrome, endocarditis
- trauma, oxidative injury, vesiculation have been proposed
Ovalocyte (elliptocyte)
Protein band 4:1 deficiency in dogs, myelofibrosis, idiopathic in cats, iron deficiency
- abnormal membrane proteins in hereditary forms
Pyknocytes
Exposure to oxidants
- likely formed from eccentrocytes
Schistocyte
Intravascular coagulation, vasculitis, hemangiosarcoma, caval syndrome, endocarditis
- trauma
Sperhocytes
Immune hemolysis, fragmentation hemolysis, envenomation, clostridial infections
- membrane loss due to macrophages partial phagocytosis, trauma
Stomatocyte
Young erythrocytes, hereditary stomatocytosis of dogs
- folding of excess membrane
Torocyte
Do not confuse with hypochromia!
- artifact
Anemia
Decreased Hct, [Hgb], [RBC]
- pathological, not a disease
- caused by loss, destruction, lack of production
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
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
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
Anemia morphologic classification based on MCV
- normocytic: maturation is not defective
- macrocytic: presence of reticulocytes or defective cells
- microcytic: extra mitosis (Fe deficiency), fragments
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)
Normocytic normochromic
Blood smear: uniform erythrocytes
- most anemias begin as normocytic normochromic
- most anemias in the horse are normocytic normochromic
Macrocytic hypochromic
Blood smear: anisocytosis and polychromasia
- anemia probably due to blood loss or hemolysis
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)
Microcytic hypochromic
Blood smear: microcytosis, codocytosis, hypochromasia, anisocytosis
- defective Hgb synthesis: Fe deficiency, copper deficiency, Vit B6 deficiency
Microcytic normochromic
- hepatic failure: hepatic dz, portosystemic shunt –> may see hypochromic state!
- foals and kittens: lower MCV (also with Akitas and Shibas)
- hereditary dz
Normocytic hypochromic
Uncommon
- inaccurate data, inadequate RI
- possible w/ Fe deficiency
Macrocytic hyperchromic
Falsely increased MCHC
- compare to CHCM
Normocytic hyperchromic
Falsely increased MCHC
- compare to CHCM
Microcytic hyperchromic
Hypoosmolar plasma (cell shrinkage) - if MCHC is falsely increased, think of other causes for microcytic anemia
Increased MCHC/CHCM
Not physiologically possible! –> Hgb production stops when optimal [Hgb] is reached
- falsely increased
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
If MCHC and CHCM are affected ________
Heinz bodies and hypoosmolar states
When is an increased MCHC or CHCM true?
- eccentrocytosis
- pyknocytosis
- spherocytosis
What is the most common cause of nonregenerative anemia?
- decreased RBC production
- defective erythropoiesis
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
Does nonregenerative anemia stop RBC production completely?
No, animals are frequently anemic for several weeks before diagnosis
Severity of nonregenerative anemia
- duration of disease
- degree of erythropoiesis decrease
- presence/absence of processes that shorten RBC life span
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)
AID pathogenesis
- shortened RBC survival
- impaired Fe mobilization or utilization
- impaired RBC production
AID laboratory findings
- normocytic normochromic
- hyperproteinemia (y-globulins or positive acute phase)
- BM: normal to mildly decreased erythropoiesis
- hypoferremia
Chronic renal disease
Nonregenerative anemia
- mild to moderate
- inadequate EPO production
- decreased RBC life span
- decreased BM response to EPO
- possible hemorrhage, nutritional status
CRD - lab findings
Normocytic normochromic nonregenerative anemia
- azotemia
- isostenuria
- electrolyte disturbances
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
_____ and ____ are often idiopathic
Hypoplasia and aplasia
Infectious agents causing bone marrow hypoplasia/aplasia
- direct cell damage (myelitis)
- suppression with bacterial septicemias
- erlichiosis (disseminated micosis)
- viral agents
- protozoal infections
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)
Toxicosis
Chemotherapeutic agents
- estrogen
- phenylbutazone
- bracken fern
- nonregenerative anemia
Irradiation
Nonregenerative anemia
Myelophtisis
Marrow replacement
- myeloproliferative dz
- lymphoproliferative dz
- metastatic neoplasia: lymphoproliferative neoplasia, mast cell, carcinomas, nonhemic sarcomas
- nonregenerative anemias
_______ and ______ are nonneoplastic disorders that cause nonregenerative anemias
- myelofibrosis
- osteopetrosis
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)
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
Iron deficiencies
Chronic external blood loss or inadequate dietary Fe intake
- microcytic hypochromic, possibly microcytic normochromic
- nonregenerative anemia
Copper deficiency
Uncommon, reported in pigs and dogs
- nonregenerative anemia
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
Pyridoxine (Vit B6)
Reported dietary deficiency in kittens causing anemia
Hypothyroidism
Dogs
- decreased metabolic rate –> decreased oxygen need –> decrease EPO –> anemia
- normocytic normochromic nonregenerative anemia
- evidence of thyroid dysfunction
Hypoadrenocorticism
Dogs
- normocytic normochromic nonregenerative anemia
- unknown
- evidence of adrenal dysfunction (hyponatremia, hyperkalemia, hypocortisolemia, lymphocytosis, eosinophilia)
Hyperestrogenism
Excessive production (neoplasms: Sertoli cell tumor, granulosa cell tumor), or iatrogenic - nonregenerative anemia (pancytopenia), especially in dogs and ferrets
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
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
Blood loss anemia - causes
- hemorrhage: blood vessel damage by trauma, acquired/congenital hemostatic impairment
- parasitism
- donating for blood transfusions
Classification based on _______
Duration and location
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)
Blood loss in hemothorax or hemoperitoneum
- 65% resorption in 2 days and 80% in 1-2 weeks
- no Fe depletion
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)
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
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)
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
Increased rate of erythrocyte destruction
Hemolytic anemia
- intravascular: occurs in heart, blood vessels –> hemoglobulinemia and hemoglobinuria
- extravascular: occurs outside vessels, erythrocytes are phagocytized
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
What 3 things are caused by hemolytic anemia?
- icterus
- bilirubinuria
- urobilinogenuria
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
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
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
Drug induced hemolytic anemia
- penicillin: horses
- propylthiouracil: cats
- cephalosporins: supraphamacological doses in dogs
- TMS: horses
- levamisole: dogs
- pirimicarb: dogs
Vaccine-induced hemolytic anemia occurs mostly in _______
Dogs
Alloimmune hemolysis
Neonatal isoerythrolysis
- colostral Ig –> intestinal absorption –> bind to RBCs paternally inherited antigens
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
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
Canine hemic mycoplasma spp
M. haemocanis: splenectomized or immunologically compromised dogs
- may detach from RBCs
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
Anaplasma spp
Immune mediated
- moderate-severe anemia
- reticulocytosis/polychromasia
- mild-marked hyperbilirubinemia/hyperbilirubinuria
Does Leptospira interrogans infect RBCs?
No
- vasiculitis, infection of liver and kidneys –> hemolytic state
Leptospira - lab findings
- moderate-severe anemia
- hemoglobinemia/hemoglobinuria
- hyperbilirubinemia/uria
- neutrophilia
- leptospiral in urine
- IgM cold agglutinins
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
Clostridium
Type A
- yellow lamb disease
- alpha-toxin with phosphlipase C activity
- acute severe: anemia, hemoglobinemia/uria
- less severe: anemia, polychromasia, reticulocytosis, rubricytosis, leukocytosis
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)
EIA lab findings
- acute: intravascular hemolysis, hemoglobinemia
- chronic: extravascular hemolysis
- macrocytosis
- thrombocytopenia
- neutropenia/neutrophilia
- positive Coomb’s test
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
Theileria buffeli
Organisms in RBCs
- macrocytosis
- polychromasia
- basophilic stippling
- lymphocytosis
- hyperbilirubinemia/bilirubinuria
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
Heinz body hemolytic anemia - lab findings
- mild-severe anemia
- reticulocytosis/polychromasia
- eccentrocytosis
- hyperbilirubinemia/uria
- hemoglobinemia/uria
- methemoglobinemia
Feline Heinz bodies
- spleen with closed circulation
- feline Hgb is prone to form oxidized forms
- feline erythrocytes have lower reductive ability
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
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
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
Trauma
Presence of rigid structures
- erythrocyte trauma –> poikilocytes or lysis
- mild to moderate anemia
- possible reticuloytes/polychromasia
- schistocytes
- keratocytes
- acanthocytes
- thrombocytopenia
Hemoconcentration due to dehydration
Most common cause of erythrocytosis in mammals
- hyperproteinemia
- hyperalbuminemia
- hypernatremia and hypercholremia
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
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
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
Secondary appropriate erythrocytosis - pathogenesis
Hypoxemia –> sustained renal tissue hypoxia –> increased EPO production –> increased reythropoiesis –> erythrocytosis
Secondary inappropriate erythrocytosis
Inappropriate increased EPO production due to:
- renal cysts
- renal neoplasms
- benign neoplasms (not renal)
Primary erythrocytosis
Autonomous eryhtropoiesis (not dependent on EPO) - mild to marked erythrocytosis --> increased viscosity of blood --> poor tissue perfusion --> secondary increased EPO production
Primary erythrocytosis
Neoplastic or non-neoplastic dz that leads to increased RBC production independent of EPO
Polycythemia vera
Neoplastic dz of erythroid, myeloid and megakaryocytic cell lines
