Haematology Flashcards
Four factors that natural haemostasis relies on?
Vascular endothelium
Platelets
Coagulation factors
Fibrinolysis
What platelets formed from, what protein stimulates that?
Formed from megakaryocytes. Stimulated by thrombopoietin.
What organ mostly produces thrombopoeitin?
The Liver
Lifecycle of a platelet?
Circulate for 6-8days and are then destroyed in the spleen.
What will a blood film and a blood count tell you about platelets?
Number and shape of platelets
Can reveal different disorders such as leukaemia
Examples of coagulation tests?
PT (prothrombin time)
APTT (Activated Partial Thromboplastin Time)
PTTK
Thrombin Time
Prothrombin time is elongated in what disorders?
- Abnormal factor II, V, VII, X
- Liver disease
- Warfarin
- Vit K deficiency
- DIC (disseminated intravascular coagulation)
What is Disseminated intravascular coagulation? (DIC)
Pathological condition in which there is abnormal activation of the clotting cascade and blood clots form in small vessels around the body.
What is INR?
Special Prothrombin time - used for monitoring warfarin.
Activated Partial Thromboplastin Time (APTT) is prolonged in what?
- Deficiency/ inhibition of II, V, VIII, IX, X, XI, XII (not VII) – NB XII deficiency can be asymptomatic
- Unfractionated heparin therapy (not LMW heparins)
- Liver disease
- Vit K deficiency
- DIC
How does a correction test work?
Adds normal plasma to patients plasma and if that corrects the clotting time there is a deficiency. If not it is likely there is an inhibitor present.
Different types of purpura?
Senile - associated with old age and small trauma (benign)
Henoch-schonlein - associated with children following infection, mostly harmless, can lead to CKD
Steroid induced
Infection associated purpura
Thrombotic thrombocytopenic purpura
What is purpura?
A rash of purple spots on the skin caused by internal bleeding from small blood vessels.
Causes of thrombocytopenia?
Drugs, chemicals and viral infections - lead to megakaryocyte depression
Leukaemia, lymphoma, aplastic anaemia. HIV - bone marrow failure
DIC, Thrombotic thrombocytopenic purpura (TTP), Heparin - increased platelet production leads to splenomegaly.
Congenital causes of platelet disorders?
Bernard-soulier
Glazmanns
Acquired causes of platelet disorders?
NSAIDs
Renal Failure
Cardiopulmonary bypass (the pump in surgery)
Myeloproliferative disorders
Examples of coagulation disorders?
Congenital:
- Haemophilia (A and B)
- Von-willibrand disease (deficiency in von-willibrand factor)
- Factor XI deficiency
Acquired:
- Vit K deficiency
- Liver disease
- DIC
- Anticoagulant drugs
What is the diagnosis?
- 4 year old boy with increased bleeding tendency
- No FHx
- Prolonged APTT, other clotting times are normal
Corrects with normal plasma - Factor VIII assay is low
Haemophilia A
Types of Haemophilia, what are they lacking in each?
A - lacking factor VIII (8)
B - lacking factor IX (9)
Management of haemophilia?
Refer to a haemophilia centre - screen mother and siblings
Mild haemophilia treated with tranexamic acid and desmopressin
Severe will require factor VIII replacement
Avoid use of NSAIDS and injections if at all possible
Symptoms of anaemia?
Lethargy
SOB
Angina
headache
Causes of anaemia?
Bleeding
Iron, B12, Folate deficiency
Malabsorption
Systemic illness
Haemolysis
Inherited RBC disorders
Bone marrow failure
Causes of microcytic anaemia?
iron deficiency, haemoglobinopathies (including thalassaemias)
Causes of normocytic anaemia
Anaemia of chronic disease
causes of macrocytic anaemia
B12/Folate deficiency
Features of B12 deficiency anaemias?
Hypersegmented neutrophils
Macrocytic and oval red cells
Mild Jaundice
Peripheral neuropathy
What is pancytopaenia?
deficiency of white cells red cells and platelets in the blood
Causes of pancytopaenia?
- Bone marrow failure/infiltration (leukaemia, lymphoma, carcinomas, myelofibrosis)
- Septicaemia
- Splenomegaly
- Immune-mediated destruction
Types of leukaemia?
Acute - myeloid (AML) or lymphoblastic (ALL)
Chronic - myeloid (CML) or lymphocytic (CLL)
What is acute leukaemia defined as?
> 20% of nucleated bone marrow cells are blasts
Causes of leukaemia?
- Ionising radiation
- Viruses
- Chemicals
- Congenital factors
- Acquired haematological disorders
Most common type of cancer in pts below 15 yrs
ALL
Most common type of cancer in pts above 50 yrs
AML
Clinical features of leukaemia (ALL and AML)?
Anaemia
Neutropenia
Thrombocytopenia
Clinical features of CML?
- Fatigue
- Malaise
- Anorexia
- Abdominal discomfort (splenomegaly/ splenic infarction)
- Excessive sweating from hypermetabolism
- Pallor
- XS WBC breakdown = gout
- Priapism (painful persistent erection from hypercoagulation)
Most common type of leukaemia overall?
CLL
Triphasic course of CML?
1) Chronic
2) Accelerated course
Features of CLL?
- Insidious onset
- Proliferation and accumulation of immune incompetent B-lymphocytes
- Associated with infiltration of lymph nodes, spleen and liver
- Infection is common due to neutropenia, hypogammaglobulinaemia, impaired immunity
- Can lead to diffuse lymphoma/Richter’s syndrome or PLL
Role of von willibrands factor?
Helps Platelets stick to the endothelium
Basic coagulation cascade?
Prothrombin — Thrombin
Fibrinogen — fibrin
Fibrin goes on to form a fibrin polymer and then with factor XIIIa forms stable fibrin.
The anti coagulation cascade basic steps?
Plasminogen — plasmin
Plasmin converts fibrin to soluble products
What is idiopathic acquired aplastic anaemia?
Intrinsic stem cell defect, where your bone marrow no longer produces cells, due to:
- Failure of stromal microenvironment
- Growth factor defect or deficiency
- Immune suppression of the marrow
Symptoms of idiopathic acquired aplastic anaemia?
Fatigue
Bleeding
Infections
Lab investigations for anaemia?
Blood count and film
Haematinics
B12, folate, ferritin
Inflammatory indices
Reticulocytes
Special tests:
- Bone marrow biopsy
- Special tests for haemolysis
Lab features of iron deficiency?
Low haemoglobin
Low ferritin (low iron stores)
Blood film appearances:
- Hypochromic, microcytic cells,
- Pencil shaped cells
- Target cells
- Increased variation in red cell shape
Lab features of folate deficiency?
Hypersegmented neutrophils (same as b12)
Macrocytic and oval red cells (same as b12)
Low serum folate
Low red cell folate
Lab findings for anaemia of chronic disease?
Most are normal
Lab findings in haemolytic anaemia?
Decreased Hb
Raised reticulocyte (immature red cell without a nucleus) count
Red cells show altered red cell shape and colour
(depending on underlying cause of haemolysis)
Serum bilirubin raised
Serum haptoglobins low or absent
Tests to diagnose leukaemia?
Examination of blood and bone marrow
Cell morphology
Flow cytometry to detect antigens and cell surface molecules
Cytogenetic studies
Lab findings for idiopathic acquired aplastic anaemia?
Pancytopenia
Low reticulocyte count; red cells may be macrocytic
Marrow markedly low in cells
Neutrophil count low
No abnormal cells in the peripheral blood
Normal cytogenetics
