The Erythron Flashcards
1
Q
What are the ways of testing for oygen-carrying capacity in blood?
A
Hb, Hct, RBC count
2
Q
What are the 3 methods of determining the size of RBC’s? Why?
A
Hct, Hb, RBC count
- confirm degree of anaemias by looking at changes in the same direction and proportion
- determine the avg sie and colour
- unequal changes in 1 of 3 tests compared to the other 2 - determine if it is diagnostic
3
Q
On rbc indics, how and what effects the MCV, MCHC, and MCH?
A
- Agglutination: increase MCV
- Storage: increase MCV, decrease MCHC
- Turbidity: increase MCH, increase MCHC
4
Q
What are the parameters used to evaluate reticulocytes?
A
Number
Age
MCH
Reticulocyte Production Index (RPI)
5
Q
What are the main features of an erythrocyte?
A
Anucleated & full of hemoglobin to carry oxygen
6
Q
What regulations does an erythrocyte partake in?
A
Acid-base balance
Ion regulation
Managing oxidative stress
7
Q
What are the 4 main characteristics of an erythrocyte membrane?
A
- ion transporters
- cytoskeleton
- surface glycoprotein antigens
- deformability & antigenicity
8
Q
What pathways/pumps are part of the metabolism of an erythrocyte?
A
- Glycolysis
- Hexose-monophosphate pathway
- Methemoglobin reductase pathway
- NaK ATPase
9
Q
When is a mitochondria present w/i an erythrocyte?
A
As a reticulocyte or earlier stages
10
Q
What is the mitochondria used for in a reticulocyte?
A
- heme synthesis
- biosynthesis
- replication
11
Q
What are the genetic and nutritional deficiencies in RBC metabolism?
A
- PFK
- PK?
- Methb Reductase
- Se-GPx
- Phosphate
- DPG
12
Q
What mnemonic is used for the oxygen Hb dissociation curve and DPG? What does it stand for and what does it mean?
A
C O2
A cid
D PG
E xercise
T emperature
- shift right, deliver more oxygen to the tissues
- shift left, pick up more (aka holding onto more) oxygen
13
Q
What is the Luebering-Rapoport Pathway?
A
A metabolic pathway in mature erythrocytes involving the formation of DPG
14
Q
What does DPG do?
A
Regulates oxygen release from hemoglobin and its delivery to tissues
15
Q
DPG is low in what species?
A
Cats, ruminants
16
Q
DPG is high in what species?
A
Dog, horse, human, pig
17
Q
What causes increases in DPG?
A
T3
PK Deficiency
PH increase
Hibernation
Anaemia
Hypoxia
18
Q
Why don’t ruminants use DPG?
A
They have structurally distint HbF w/ high oxygen affinity that favors oxygen pickup from maternal circulation
19
Q
Hct is mildly correlated to what?
A
Metabolic rate
20
Q
What are the 2 ways that RBC’s die?
A
- Become senescent as membranes and enzymes fail w/ age –> cleared by splenic macrophages
- Rupture to release Hb so the Fe & globin are recycled & bilirubin is excreted
21
Q
What are the 4 types of Plasma appearance?
A
Colourless
Icteric
Hemolysis
Lipemia
22
Q
Fibrinogen is what factor in the coagulation cascade?
A
Factor I
23
Q
Fibrinogen is increased in what processes?
A
Acute inflammation
Necrosis
24
Q
What is the calculation to determine the concentration of fibrinogen?
A
[Prot (unheated)] - [Prot (heated)] = [fibrinogen]]
25
Why is lipemia less than ideal?
- interferes w/ spectrophotometric tests, refractometer TP, flame photometric measurements of electrolytes
- may cause haemolysis
26
What may cause liipaemia in a blood sample?
-recent meal
-pathology
27
What occurs during hemolysis?
Contents of RBC's is released (ASTT, LDH, +/- K+, inorganic phosphate)
28
What does hemolysis interfere w/?
Photometric tests
Refractometer & enzyme measurements
29
What is bilirubin?
The breakdown product of heme from hemoglobin from senescent or damaged RBCs?
30
What organ does bilirubin travel to? How??
Bilirubin is transported to the liver, bound to albumin
31
How is bilirubin handled onceit reaches the liver?
It is conjugated w/ glucuronic acid in the liver for bile excretion b/c it is highly insoluble
32
What parameters are affected by bilirubin? How?
Increases [ ] of albumin, cholesterol, glucose, TP
Decreases [ ] of creatinine
33
Increases in Hct and TP =
Haemoconcentration (increase rbc in blood, decrease in plasma)
34
Increase Hct w/ normal TP =
Erythrocytosis (polycythemia) - high concentration of RBC in blood (thick blood!)
35
Decrease hct and TP =
Haemorrhagic anaemia - anaemia due to excessive bleeding when loss of RBC exceeds production
36
Decrease Hct, normal TP =
Haemolysis or bone marrow dz
37
What does an RBC count tell you?
Measures oxygen carrying capacity
Number of erythrocytes per L of blood
38
Using a neubauer haemocytometer, how do you do a RBC count?
- Count WBC in 4 primary corner squares and multiply by 50 to get cells/ microliter
- count RBC in 5 secondary squares of central primary square and multiply by 10,000 to get cells/microliter
39
Impedence counters rely on which principle?
Coulter principle
40
What do Laser flow cytometers do?
Detect & count individual cells in microdroplets as they pass thru a laser beam. The cells scatter light based on size, nucleus, and cytoplasmic contents
41
What is CHCM used for?
To flag lipemia & hemolysis by comparing against total hemoglobin and comparing size and color
42
What are red cell indices? What are they used for?
RBC count, PCV, [Hb], or direct measure by flow cytometry
Used in anaemic animals (except the horse) to classify anaemia as regenerative or non-regenerative
43
What metrics are used in red cell indices?
MCV, MCHC, MCH
44
What is MCV? What does it tell you?
- volume of avg RBC in femtolitres
- Microcytosis, normocytosis, macrocytosis
45
What does microcytosis suggest?
Copper & Iron deficiencies
46
What does macrocytosis suggest?
Regenerative anaemia
Non-regenerative anaemia
Myeloproliferative disorders
Folate deficiency
Poodles
Hereditary stomatocytosis
Hyperthyroidism in cats
Foetals/neonates
47
What causes spurious macrocytosis?
Augoagglutination of erythrocyte
Persistent hypernatremia
Prolonged blood storage prior to assay
Heparin treatment
48
What occurs in horses that receive heparin treatment for acute laminitis, thrombophlebitis, DIC?
Induces agglutination resulting in an increase in apparent MCV, decrease in RBC numbers
49
Microcytosis can be seen in what conditions?
Nutritional: Fe, Cu, B6 Def
PSS
Anaemia of inflammatory disease
Storage depletion of Fe from increased erythropoiesis
Hepatic lipidosis in some cats
Inhibitors of heme synthesis
SIADH
Genetic defects --> Thalassemia, Band 4.1 deficiency, Japanese/korean dogs w/o anaemia, familial dyserythropoiesis in English springer spaniels, hereditary elliptocytosis in dogs
50
When would you see spurious microcytosis?
severely anaemic patients
Persistent hyponatremia in dogs
51
What do erythrocyte volume histograms do?
Reveal increased numbers of microcytes or macrocytes even when MCV is normal
52
What additional info can be obtained from an erythrocyte histogram?
Hb concentration with individual cells --> identifying individual hypochromic cells
Cytogram of volume vs [Hb} of individual cells
53
How do you determine Red Cell Distribution Width (RDW)?
(STD of erythrocyte volumes/mean cell vol) x 100
54
What is the RDW?
Coefficient of variation of erythrocyte volume and an electric measurement of anisocytosis
55
Increased RDW demonstrates what possible conditions?
- Regenerative anaemias with increased numbers of large reticulocytes
- Fe deficiency anaemia with increased numbers of microcytes
- Erythrocyte fragmentation
- after blood transfusions w/ different sized cells
- Dyserythropoiesis
56
When is RDW spuriously increased?
- Erythrocyte agglutination
- Platelets counted in erythrocyte histogram of severely anaemic patients
57
What is MCHC?
Avg concentration of Hb in an RBC in g/L
58
How do you calcuulate MCHC?
[Hb] (g/L) / PCV (L/L)
59
MCHC is normally...
Hypochromic or normochromic
60
If MCHC is high, what might this indicate?
- artefact, poor calculations
- eccentrocytes
- intravascular hemolysis
- in vitro hemolysis
- heinz bodies w/i erythrocytes
- lipemia
- erythrocyte agglutination in electronic cell counter
61
What does low MCHC values possibly indicate?
- regenerative anaemias
- chronic Fe deficiency anaemias
- hereditary stomatocytosis
62
When does spurious low MCHC values occur?
- aged samples
- persistent hypernatremia
63
What is MCH?
mean cell hemoglobin concentration
The mass of Hb in an avg RBC
64
What is MCH?
mean cell hemoglobin concentration
The mass of Hb in an avg RBC
65
How is MCH determined?
[Hb]/number RBC
66
CHr is a reliable indicator of...
Fe status
67
Reticulocytes come from...
The bone marrow, spleen, liver
68
What characteristics are specific to a reticulocyte?
Reticulum of aggregates of mRNA, ribosomal protein, mitochondria
69
How can you identify a reticulocyte on a blood smear?
'Big & Blue'
Larger than RBC, basophilic
70
How long does anisocytosis & polychromasia last in reticulocytes?
Anisocytosis 7-10d
Polychromasia 1d
71
How do reticulocyte counts differ in species?
Cats have aggregate & punctate reticulocytes
Horses have a reduced reticulocyte response
72
The degree of anaemia affects...
Reticulocyte %
73
The degree of anaemia shows...
-the release of the bone marrow pool
- erythropoietin concentration
74
Reticulocyte counts show...
Species
Degree of anaemia
Duration of anaemia
Cause of anaemia
75
In dogs, how long are reticulocytes in the bone marrow?
2-3 days
76
If reticulocytes are released after 2-3 d from the bone marrow, what does this indicate?
Anaemia
77
In the first 2-3 days following reticulocyte release from BM, haemorrhage or hemolysis appears...
Non-regenerating
78
Reticulocytes max out at days _______ from onsset of anaemia
5-7 d
79
Reticulocytes are higher in ...
Younger animals
80
What is RPI?
Corrected retiulocyte count / reticulocyte maturation time
81
What are the parameters for RPI?
>2 = a response
About 1 = normal
>3 = marked response, especially hemolysis
82
What is the RPI for?
Used for release rate && pattern & since intravascular time may change during response to anaemia
83
What are the maturation times for reticulocytes inn dogs and cats?
1.5 d in doggo
3 d in kitties
84
Why do we do blood smears?
- check morphology
- compare smears vs analyser results
- check for cellular inclusions and parasites
- differential white ccell counts
85
Why is rapid air dry essential for blood smears?
To stop osmosis & cell shrinkage
86
What occurs during cell shrinkage?
The fluid concentrates & sucks water out of cells by osmois
87
Where is the monolayer on a smear?
Just in from the feather tip whhere half of all cells touch
88
What are common colour changes in RBC morphology?
Hypochromasia - increase in central pallor
Polychromasia
89
What size changes can be seen in RBC's?
Anisocytosis (increased RDW)
Macrocytosis
Microcytosis
90
What are some different shapes of RBC that can be seen on a blood smear?
Poikilocytosis, echnnocytosis, spherocytosis, acanthocytosis, schistocytosis, elliptocytosis, dacryocytosis, etc
91
What inclusions can be found in RBC's?
Howell-Jolly bodies
Nuclei
Heinz bodies
Basophilic stippling
Infectious organisms
92
What is poikilocytosis in RBC?
Abnormal shapes of Rbc
93
What species is it typical to see poikilocytosis?
Goats, young cattle
94
Poikilocytosis inclutes what types ofRBC?
Echinocytes, spherocytes, acanthocytes, schistocytes, elliptocytes, dacryocytes
95
When does crenation of echinocytes occur?
Reversible RBC dehydrationn, ATP depletion, increased pH, increased RBC Ca
96
What non-specific disorders can cause crenation of echinocytes?
Snake bites, uremia, post-transfusion, PK deficiency in dogs, neoplasia in dogs, gloerulonephritis, cation depletion (horses)
97
What are some causes of IHA?
Idiopathic, neoplasia, infection, toxicity
98
What are some clinical signs of IHA in dogs?
Lethargy, inappetance, +/- pigmenturia, tachycardia, pale MM, fever
99
How do you Dx IHA in dogs?
Hct <25-30%
Hemolysis (Hbemia, Hburia, bilirubinemia)
RBC antibodies (agglutination, spherocytosis, Coomb's positive)
100
What is the rate of survival for dogs w/ IHA?
28-70% dies in 1st 2 wks
73% live 0.5 year
51% live 1 yr
101
What are predictors of mortality in IHA in dogs?
Azotemia, icterus, thrombocytopaenia, petechiae
102
What are some predilections of IHA in dogs?
Breeds: maltese, Viszla, airedale, spinger, Irish terrier, Irish setter, cocker, poodle, rough collies, mini schnauzer
Age: middle-aged females
103
What is spherocytosis?
Smaller, darker, rounder rbc w/ no central pallor that are spherical in shape and osmotically fragile
104
What are some characteristics specifito spherocytes?
Decreased surface area to vol ratio
Increased Hb conc
No central pallor
Increased osmotic fragility
Decreased deformability
105
What condition might you commonly see spherocytes?
Immune-mediated hemolytic anaemia
106
Is IHA usually intravascular or extravascular?
Extravascular
107
What do the macrophages do in extravascular IHA? Where do they come from?
Job: phagocytose RBCs coated w/ IgG
From: liver, spleen, bone marrow
108
Partial phagocytosis in extravascular spherocytes results in...
Spherocytes w/ increased erythrocyte osmotic fragility
109
Intravascular hemolysis in IHA is instigated by ... & leads to...
From: IgG coating & complement activation
Leads to: Hbemia, Hburia, ghost cells (lysed rbc)
110
Is IHA always intravascular or extravascular?
No, can be both
111
What causes autoagglutination?
Increased amounts of IgG and IgM coated on RBC & spherocyte surface cross link
112
What test can autoagglutination interfere with?
Coomb's test
113
IMHA often results in
Agglutination of rbcs
114
What is the Coomb's test?
Autoglobulin test for IHA
115
Explain the Coomb's test
RBCs w/ immunoglobulin or complement have an antiglobulin reagent added to if agglutination occurs
116
What are acanthocytes?
Thorn or spur shaped RBCs
117
When are acanthocytes most common?
Liver dz, hemangiosarcoma, DIC, glomerulonephritis
118
What is a unique characteristic of acanthocytes?
Increased membrane cholesterol
119
What are schistocytes?
Split cells (aka rbc fragments)
120
What diseasses would have schistocytes present?
DIC, PSS, Fe deficiency anaemia, glomerulonephritis, vasculitis
121
What family of animals normally has elliptocytes?
Camelidae
122
If elliptocytes are present in a cat, what diseases are you suspicious of?
Bone marrow abnormalities
Hepatic lipidosis
PSS
Doxorubicin toxicity
123
If elliptocytes are present in a dog, what diseases might be on your differential list?
Myelofibrosis
Myelodysplastic syndrome (MDS)
Glomerulonephritis
RBC band 4.1 deficiency
124
What are dacrocytes?
Tear-drop cells
125
When might dacrocytes be present?
MPD in dogs/cats
Glomerulonephritis in dogs
Hypersplenism in dogs
Fe deficient ruminants
Myeloid metaplasia/metastatic neoplasms to the Bone marrow
TB
126
What are Howell-Jolly Bodies
Micronuclei
127
What species have low numbers of HJBs normally?
Horses, cats
128
HJB's increase during what type of anaemia?
Regenerative anaemia
129
What are 3 other times the HJBs might occur?
Splenectomy, glucocorticoids, vincristine therapy in regenerative anaemia
130
How do HJB's form?
When a chromosome is lost or breaks during final mitosis of a rubriblast to an erythrocyte
131
Nucleated erythrocytes are typically what stages of erythrocyte development?
Metarubricytes and rubricytes
132
When might nucleated erythrocytes be present?
Regenerative anaemia
Pb toxicity
Bone marrow injury/disease
Cardiovascular dz, trauma, hyperadrenocorticism in dogs
Splenic disfunction
Hereditary dyserythropoiesis (dogs/cattle)
133
Aside from anaemia, when else might bone marrow injury occur?
Septicaemia, endotoxic shock, drugs
134
What are some marrow diseases that may occur with non-regenerative anaemia?
Myelodysplasia, hematopoietic neoplasms, infiltrative disorders
135
When do you see Heinz body anaemia?
Onion poisoning
136
Heinz body anaemia is present when there is ... on thhe rbcs
Oxidized hb
137
When are heinz bodies present in small animals?
Some feline diseases - diabetes, lymphoma, hyperthyroidism
Splenectomy (dogs)
Onion ingestion
Propylene glycol in soft-moist cat foods (less common)
Zn toxicity (dogs)
Acetaminophen, methylene blue, methionine, phenazopyridine, menadione (Vit K3) ingestion
138
When are heinz bodies present in large animals?
Wild & domestic onion ingestion - livestock
Kale & other Brassica sp. Ingestion - ruminants
Lush winter ryegrass ingestion - FL cattle
Se-Def cattle on St. Augustine Grass
Post-parturient NZ cattle on pyrennial ryegrass
Red maple leaf consumption - horses
Cu toxicity - sheep/goats
Phenothiazine - horses
139
When would eccentrocytes be present on a blood smear?
Onion, garlic poisoning
T-cell lymphoma
Ketoacidosis
Severe infection
140
When might ghost cells occur in vivo?
Immune-mediated
Oxidant-induced
Enzymatic
Osmotic
141
What other ways might lysed erythrocytes appear on a smear?
In vitro hemolysis
Smudged cells
142
What is basophilic stippling?
Diffuse pattern of aggregates of ribosomes & polyribosomes
143
When would basophilic stippling occur?
Pb toxicity
Regenerative anaemia in ruminants
144
What are some common infectious protozoal organisms of rbcs?
Babesia
Theileria
Cytauxzoan sp
145
What rickettsial organisms invade rbcs?
Anaplasma spp
146
What mycoplasmal organisms invade rbcs?
Haemobartonella spp, eperythrozoon sp
147
What bacterial organism invades rbcs?
Bartonella spp
148
What viral organism invades rbcs?
Distemper
149
What infectious agents invade blood but not rbc's?
Trypanosoma spp
Clostridium haemolyticum
Leptospira spp
