Haematology Flashcards
Anaemia (Microcytic)
Iron deficiency
- Malabsorption
- Chronic blood loss
- Decreased dietary intake
- Increased demand
Anaemia of chronic disease
Thalassaemia
Anaemia (Normocytic)
Acute blood loss Anaemia of chronic disease Endocrine disease Malignancy Haemolytic anaemia
Anaemia (Macrocytic)
Megaloblastic
- Folate deficiency
- B12 deficiency
- Pernicious anaemia
- Crohn’s disease
- Gastrectomy, ileal resection
- Alcohol
Drugs
- Azathioprine
- hydroyurea
- Methotrexate
Non-megaloblastic anaemia
- liver disease
- alcohol
- pregnancy
- hypothyroidism
Polycythaemia primary
Hb>18g/dl males
Hb>16g/dl females
Polycythaemia secondary
Appropriate increase in erythropoietin - High altitude - cardiac disease - Pulmonary disease Smoking
Inappropriate
- Renal/hepatic cancer
- cerebellar haemangioblastoma
- renal transplant
- uretine fibroblasts
Relative
- dehydration
- burns
Neutrophilia
Acute infection
- Bacteria, fungi, spirochaetes, viruses, rickettsiae
Inflammation
- Burns, trauma, MI, gout, glomerulonephritis, collagen vascular disorders, hypersensitivity
Metabolic
- DKA
- Pre-eclampsia
- Uraemia
Thrombocytopaenia (5)
Platelet dysfunction DIC Thrombotic thrombocytopenic purpura Haemolytic uraemic syndrome Idiopathic thrombotic purpura
Platelet dysfunction
Most often due to iatrogenic causes e.g. aspirin/warfarin.
Aspirin should be stopped 14 days prior to operation
Disseminated Intravascular Coagulation
Simulataneous activation of coagulation and fibrinolytic systems in the body causing microvascular thrombosis, fibrin deposition and bleeding due to clotting factors and fibrinolysis
Thrombotic thrombocytopenic purpura
- Usually affects young adults
- Deposition of hyaline thrombi in small vessels causes microangiopathic widespread haemolysis
- Renal failure
- Neurological disturbance
Haemolytic uraemic syndrome
Usually post illness e.g. URTI and GI infections such as E.Coli
- Microangiopathic haemolysis
- Thrombocytopaenia
- Acute renal failure
Idiopathic thrombotic purpura
Autoimmune destruction of platelets secondary to IgG
- Acute: Post viral e.g. children, Henoch-Schonlein purpura
- Chronic (Adults, female predominance, treated with high dose steroids, rarely splenectomy)
Thrombocytosis (Primary)
Essential thrombocythaemia
- PCV
- Bruising, bleeding, cerebrovascular
- Splenic atrophy due to recurrent thromboses after initial hypertrophy
Thrombocytosis (Secondary)
- Haemorrhage
- Connective disorders
- Surgery
- Splenectomy
- Malignancy
- Myeloproliferative disorders
Sickle Cell Disease I
Hb is made of 2 Alpha and 2 Beta chains
Beta chain abnormalities lead to sickle cell haemoglobin creating HbS (Glutamine @ position 6 on Beta chain is replaced by Valine) as Hb AS or HbSS
Sickle Cell Disease II
Deoxygenated HbS is insoluble and polymerises causing the red blood cells to form rigid inflexible shapes. Initially responsive to oxygen therapy and reversible.
Causes:
-Haemolytic anaemia–gallstone pigmentation
-Vaso-occlusive crises
Infarction, severe ischaemic pain seen in the bones, chest , kidney, liver and penis (Priapism)
Increased susceptibility to infections such as streptococcus pneumoniae, salmonella meningitis, renal failure and blindness
Thalassaemia causes
Defective globin chain synthesis
Haemolysis, anaemia and ineffective erythropoiesis
Beta-thalassaemia major (homozygous 3-4 defective) Beta-thalassaemia minor (heterozygous 2 defective) Alpha thalassaemia (4 chains defective)
Beta thalassaemia trait
Symptomless microcytosis
Mild anaemia
Severe anaemia from approx 3 months with failure to thrive and requiring regular transfusions with the following occuring:
- Extramedullary haemopoiesis
- hepatosplenomegaly
- Frontal bossing
- Characteristic appearance
- Requires blood transfusion to keep Hb above 10g/dl
- Desferrioxamine acts as iron chelation
Anisocytosis
Poikilocytosis
A: Variation in size
P: Variation in shape
Poikilocytosis (5)
Spherocytosis (hereditary)
Elliptocytosis (Hereditary and iron deficiency)
Target cells (Liver disease, obstructive jaundice, hyposplenism)
Irregularly contracted cells (Oxidant damage)
Sickle cells
Haemolytic anaemia causes (II)
Inherited and Acquired
Haemolytic anaemia inherited
Hereditary spherocytosis
Sickle cell anaemia
Pyruvate kinase pathway
G6PD deficiency
Haemolytic anaemia acquired
Autoimmune haemolytic anaemia
Oxidant damage e.g. dapsone
Microangiopathic haemolytic anaemia
Folate deficiency
Megaloblastic anaemia
Neural tube defects (Spina bifida, anencephaly)
B12 deficiency causes
Crohn’s/Coeliac’s disease
Pernicious anaemia
Gastrectomy
B12 deficiency consequences (Absorbed in stomach via IF and then ileum)
Megaloblastic anaemia
Bilateral peripheral neuropathy
Subacute combined degeneration of the cord (Parasthesia, muscle weakness, difficulty walking, visual and cognitive impairment, Hyporeflexia and upgoing plantars)
Optic atrophy
Dementia
Schilling test
1) Replenish Vit B12 stores
2) Radiolabelled B12
3) Measure urine B12
4) If normal urinary B12 present
4b) If depletion no urinary B12
5) Repeat with intrinsic factor
6) If rectified–>pernicious anaemia
Antithrombotic factors
Prostacyclin
Thrombomodulin
Nitric oxide
Tissue plasminogen activator (tPA)
Prostacyclin
Inhibitis platelet aggregation and acts as a vasodilator
Thrombomodulin
Glycoprotein situated on endothelial cells, combines with thrombin to a activate protein C (co-factor to protein S) which degrades Factor Va and VIIIa. hence fibrin formation is reduced
Nitric oxide
Vasodilator
Inhibits platelet aggregation and adhesion
tPA
Regulates fibrinolysis
Thrombotic factors
Von Willebrand factor
Platelet activating factor
Plasminogen activator inhibitor
Von willebrand factor
Platelet aggregator
Factor VIII activator
Platelet activating factor
Platelet aggregation
Plasminogen activator inhibitor
Inhibits tPA
Platelets
- Vascular injury
- Platelets bind to collagen via vWF
- activation causes alpha and dense granules to release fibrinogen and ADP causing aggregation and thromboxane A2 causing vasoconstriction
- Platelet plug formed
- Cross linked fibrin
Haemophilia A
x-linked recessive disorder deficiency in factor VIII
Haemophilia B/Xmas disease
x-linked recessive disorder deficiency in factor IX
Von willebrand’s disease
Type 1 (most common), type 2 (moderate), type 3 (Virtually no vWF)
Congenital platelet disorders
Bernard Soulier: Platelet membrane disorder
Grey platelet syndrome (Storage granules)
COX and thromboxane synthetase deficiency
Congenital platelet disorders
Bernard Soulier: Platelet membrane disorder
Grey platelet syndrome (Storage granules)
COX and thromboxane synthetase deficiency
