Haematology Flashcards
- What is the source of Bilirubin?
- Where does the body get its Iron from?
- From the destruction of Haemoglobin
- 90% of the bodies Iron is recycled from Haemoglobin, only 10% is from the diet
- What is Haemoglobinemia?
- What is Haemoglobinuria?
- Presence of excessive haemoglobin in the blood plasma
- Abnormally high concentrations of free haemoglobin in urine
What is Thrombocytopenia?
A decreased number of circulating platelets
- Explain Thrombopoiesis
- What hormone kicks off Thrombopoiesis and where is it made?
- What stimulates Thrombocoiesis?
- When is this increased and what is the risk?
- Production of Platlets
- Thrombopoietin (TPO) - made in Renal tubular epithelial, hepatocytes
- IL6
- IL6 is released uring inflammatory conditions which increases the risk of thrombosis
What is the cell life span for RBC?
Where does aged RBC go?
What happens to them here?
- Average 2-3 months
- Goes to the Spleen where it is phagocytosed by Macrophages
Explain how Neutrophils Neutralize bacteria?
What are the consequences of Acute Blood Loss Anaemia?
- Hypovolemic shock and death - Rapid loss of more then 20-30% of Blood Volume
- Rapid loss of up to 20% of the blood volume
- Immediately after - hypovolemia without anaemia, thrombocytopenia and hypoproteinmia (balanced loss of erythrocytes and plasma)
- After several hours - Normovolumia (due to compensatory systems) pre-regenerative, normocytic, normaochromic anaemia, thrombocytosis, hypoproteinemia.
- After 3-4days = regenerative, macrocytic, hypochromic anaemia
What is the functions of Monocytes?
What is the half-life of monocytes?
- Phagocytosis (Including erythrophagocytosis)
- Antigen presentation to T lymphocytes
- Immunomodulation
- Half-life
- IN the Blood 0.5days - 3days (Species dependent)
- Migrated to tissues - Macrophages upto 3months
Explain Iron metabolism
- only 3% of our iron comes from Gastro-Intesinal absorbtion
- The rest is recycled within the spleen predomantly by Macrophages phagocytosing old RBC’s (120days old)
- Iron as Ferritin (and hemosiderin) is stored within macrophages inside the macrophages
- This Iron then is coupled with Transferrin (plasma protien) which then transfers the iron to the BM for use in Erthopoiesis
Anaemia
- Regenerative Anaemia means what is happening?
- What could be causing this to happen?
- Non-Regenerative Anaemia means what?
- What can be a cause of this?
- Regenerative Anaemia - Reticulocytes are in the peripherial blood
- Caused by Haemoloysis or Haemorrage
- Non-Regenerative Anaemia - the RBC are not being replaced
- This is a problem with production, either with the bone marrow or with EPO production in the kidney
What is Polycythemia vera?
- Hypervolemia due to a neoplastic condition causing an increase in RBC
What is the main functions of Neutrophils?
- Defence against invading microorganisms, primary Bacteria :
- Recognize inflammatory signals
- Leave the blood (via Diapedies)
- Migrate through tissue to a site where bacteria are present and phagocytose them
If we gave an animal too much estrogen and caused an exodogenous Estrogen Toxicity what would we expect to see and how long would it take?
- Thrombocytopenia and Neutrophilia 10-20days after administration
- Mild but progressive non regenerative anaemia in the first 3 weeks leading to pancytopenia with BM aplasia between 3 and 4 weeks
If we have Macrocytic, Hypochromic Anaemia what could be some differentials?
- Regenerative Anaemia
- This is because the Cells are bigger (Macrocytic) and the same haemoglobin content but spread over more cytoplasm would make them lighter in colour.
What could cause a chronic Iron Deficiency?
- Gastrointestinal ulcers
- Blood-sucking parasites
- Fleas
- Ticks
What does Aplasia mean?
What does Hypoplasia mean?
- Aplasia = Completly lacking of eg no bone marrow
- Hypoplasia = Reduced quantity of.
If you have Microcytic, hypochromic anaemia what would your differentials be?
- Iron Deficiency (low iron = decreased haemoglobin = decreased size and colour of RBC) (99% of Microcytic,Hypochromic Anaemic cases)
- Anaemia of inflammatory disease (Can only be mild anaemia)
- Normal for Akita or Shiba dogs.
Classify the Anaemia of Inflammatory Disease using the Wintrobes erythrocyte indicies
- Mild to Moderate
- Non regenerative
- Normocytic (rarely microcytic)
- Normochromic
- Anaemia after 3-10 days
- and inflammatory leukocytosis
What are some differential diagnosis for thrombocytosis
- Physiologic
- Splenic contraction
- Epinephrine
- Drug-Induced
- Epinephrine
- Vincristine
- Reactive
- Inflammation
- Infection
- Neoplasia
- Trauma
- Rebound from Thrombocytopenia
- Iron Deficiency-related
- Essential Thrombocytemia
If we have a Moderate non-regenerative anaemia, normocytic, normochromic with neutropenia and thrombocytopenia
What kind of Anaemia would it likely be?
Chronic Aplastic Anaemia
According to the cell based model what are the main phases of the secondary haemostasis?
- Initiation
- Extrinsic pathway
- Tissue factor
- Cell surface : Fibroblasts
- Amplication
- Intrinsic pathway
- Thrombin
- Cekk surface : Platelets
What is the order proliferation of Red Blood Cells?
(Erythropoiesis)
What is Leukaemia?
Neoplasitic diseases characterized by the clonal proliferation of malignant hematopoietic progenitor cells in the bone marrow. This creates more leukocytes that are not fully developed. (Myeloid or Lymphoid cells)
Explain the pathogenisis for DIC
- DIC is always secondary to an underlying disease :-
- Severe inflammation
- Sepsis
- Heat Stroke
- Pancreatitis
- Viral Infection
- IMHA
- Neoplasia
- Other
- Snake Venom
- Severe inflammation
- Initiation via Tissue Factor
- Widespread/severe endothelial injury: exposes TF
- Severe organ injury : releases TF or cytokine storm
- Inflammatory Cytokines : Induce TF expression on monocytes +/- endothelial cells (no endothelial injury)
- Cancer: Aberrant TF expression
- Amplication: Intrinsic Pathway
- Thrombin activating factors XI, VIII and V, Thrombin inhibiting fibrinolysis
- DIC contained or compensatedby inhibitors = non-overt DIC
- Antithrombin ATIII - prevent fibrinogen converting to fibrin
- Protein C (PC) - vitamin K dependant anticoagulant and pro-fibrinolytic protein activated by thrombin -> inactivates factors Va and VIIIa
- Dissemination
- DIC dysregulated or uncompensated = overt DIC
What % of cases of IMHA are Intravascular compared to Extravascular?
- Intravascular - 20%
- Extravascular - 80%
What can be secondary to Haemoglobinuria?
Kidney damage
What changes in the blood would we see with Mild or Chronic inflammation?
- Neutrophilia - increased peripheral demand for neutorphils is met by release of marginal pool
What are some clinical signs of IMHA?
What would be the first test you would do if you have these clinical signs?
- Weakness
- Lethargy, Exercise intolerance
- Pallor mucous membrane
- Icterus –> pre hepatic hyperbilirubinemia
- Tachypnoea, Tachycardia –> Hypoxia secondary to severe anaemia
- Hepatosplenomegaly –> increased erythrophagocytosis
- Check for Auto-Aggulation - positive in ~60% of IMHA. If Autoaggulation present = IMHA
What are the pathogenesis for Primary and Secondary Aplastic Anaemia?
- Primary
- Idiopathic
- Secondary
- Infectious agents
- Chemical/Physical Agents
- Drugs
- Toxins
- Immune-Mediated
- What are some consequences of Chronic Blood Loss Anaemia
- What is the pathogenesis of Chronic Blood Loss Anaemia
- Main cause of Iron deficiency anaemia
- Pathogenesis
- Parasites (eg Hookworms, Flease etc)
- Gastrointestinal Ulcers (eg administration of NSAID and glucocorticoids, mast cell tumors)
- Neoplasia (eg. bleeding into body cavities and tissues
What is the Marginating pool : Circulating Pool of Neutrophils in Dogs and Cats
- Dogs - 1:1
- Cats - 3:1
- When looking at CBC what does MCV stand for?
- What does an increased number tell you?
- Mean Corpuscular Volume - the size of the erythrocytes
- The average size of the RBC are bigger meaning that they are Macrocytic.
What is the pathogenesis of Haemolytic Anaemia
- Hemolytic anaemias occur as a result of increased erythrocyte destruction in the following ways :-
- Intravascular Haemolysis - Haemoglobinemia and haemoglobinuria
- Extravascular Haemolysis - phagocytosis by cells of the mononuclear phagocyte system (**Common). Increased total bilirubin and icterus
If we have Infections (++Bacteria), tissue injury or a immune mediated disorder what kind of leukogram would we expect?
Leukocytosis with Neutrophilia with Acute inflammation with regenerative left shift.
= The peripheral demand for neutrophils is greater than the storage and marginal pools, therefore bone marrow release young neutrophils as well.
Regenerative left shift = mature neutrophils are more numerous than band nuetrophils
When leukocytosis is marked (>50000/uL) is called Leukemoid reaction because it resembles the blood pattern seen in chronic myeloid leukaemia
What are some causes of Haemolytic Anaemia? (Differential Diagnosis)
- Immune-Mediated erythrocyte destruction
- Primary
- Neonatal isoerythrolysis
- Incompatable Blood Transfusion
- Drug Induced
- Erythrocyte Parasite (may have an immune mediated component)
- Other infecginos agents (may have an immune mediated component)
- Oxidant compounds of other chemicals and plants compounds
- Fragmentation (mechanical process)
- Hereditary erythrocyte defects
What is the difference between Regenerative left shift and a Degenerative left shift?
- Regenerative left shift = More mature neutrophils than Bands
- Degenerative left shift = More Bands than mature neutrophils
How long after blood loss would we see signs of regeneration?
eg how long till we would see reticulocytes in the peripheral blood?
3-4days
What is Thrombocytopenia
Condition where there is low blood platelet count.
What are the 2 reasons we could have abnormalities in Heme synthesis?
- Iron and/or Copper deficiency
- Lead Toxicity
With Extravascular IMHA what happens in the spleen?
The Macrophages can either
- Erythrophagocytose the RBC or
- They can take a bite out of the cytoplasm of the RBC, leaving Spherocytes (Smaller RBC with more concentrated haemoglobin content.) Which can go back into the peripheral blood.
- As soon as you see Spherocytes you dont need further tests you can straight away start on Immunosuppressive drugs.
If we had a mild to moderate, non-regenerative, normocytic, normochromic anaemia with basophilic stippling and nucleated RBC’s what would be the cause of this?
An abnormality in the Heme synthesis either due to :-
- Iron and Copper deficiency
- Lead Toxicity (Basophilic stippling)
What is happening if we have a non-regenerative anaemia without an accompanying leukopenia or thrombocytopenia in the blood?
This means we have a reduced erythropoiesis and it may be secondary to
- EPO deficiency
- Anaemia of inflammatory disease
- immune-mediated anaemia
- Pure Red Cell Aplasia (PRCA)
- Abnormalities in heme synthesis
- Disorders of nucleic acid synthesis
This is the most common cause of non-regenerative anaemia in all species
- On a CBC what does MCHC indicate?
- What is it called when the numbers are above reference range?
- What is it called when the numbers are below reference range?
- The colour of the RBC
- How long does it take for a Myeloblast to become a Neutrophil?
- What is the half life of a Neutrophil?
- 6-9 days
- 5-10 hours
How can we tell a reticulocyte from a erythrocyte?
- You can see small fragments of RNA in the cell. (with special stain)
- Or with a normal H&E stain you can see slightly larger and more basophilic cell as in this picture
What is anaemia?
Before deciding that your patient is anaemic what else must you check?
- Decreased Erythrocyte mass within the body
- You must check hydration status of the patient before deciding if your animal is Anaemic.
- Remember Anaemia is a condition not a diagnosis.
How do we classify Anaemia? (3 steps)
- Assess the Severity
- Assess the Regenerativity
- Classify using erythrocyte indices
Differentiate the clinical pathological changes associated with intra and extravascular haemolysis
- Intravascular IMHA - RBC destroyed within the blood vessels with contents being released into the blood stream. Haemoglobin will then be seen in the plasma in a clasic red colour
- Extravascular IMHA - This is where in the spleen macrophages take bites out of the RBC creating Spherocytes, which then return to the peripheral blood
How long ia an Erythrocyte’s cell lifespan for a
- Dog
- Cat
- Horse
What are the Vitamin K dependant Coagulation Factors?
Factors II, VII, IX, X
How long does it take for a Rubriblast to change to a Metarubricyte?
4-5 days
What does Porphyrias mean?
Accumulation of porphyrin compounds in cells, tissues, and body fluids
Rank in order of size, Erythrocytes, Leukocytes and Platlets
- Smallest to Largest
- Platlets
- Erythrocytes
- Leukocytes
If we have a Leukopenia - with a Neutropenia what would be the cause of this?
The demand on the Neutrophils is too large and all compensatory abilities have been exhaused including the increased myelopoiesis.
Causes of this are:-
Acute Necrisis
Septicaemia