Haematology Flashcards
What is the percentage of plasma in the blood?
55%
What does the other 45% consist of?
- Red blood cells
- Platelets
- White blood cells
What are 4 facts about Red blood cells?
- lifespans of 120 days
- They are biconcave and anucleated
- Produced in the bone marrow
- Eryptosis occurs in the spleen liver and bone marrow
What are the types of White blood cells?
Granulocytes
Lymphocytes
Monocytes
What are the types of granulocytes?
Neutrophils
Eosinphils
Basophils
What are neutrophils?
Phagocytic
Play a role in inflammation and myeloid leukaemia
What are eosinophils?
More common in the morning
Numbers raised in parasitic infections/ allergic reactions
What are basophils?
Associated with hypersensitivity reaction
Have a similar role to mast cells, when stimulated secrete histamine
What are the two types of lymphocytes?
T cells - mediator in cellular immunity
B cells - mediator in humeral immunity
Lymphocyte numbers increase in viral infection/ inflammation but decrease in HIV and Chemotherapy
What are the types of T helper cells?
Cytotoxic (CD8+)
T Helper (CD4+)
What are monocytes?
Immature cells that differentiate once they leave the blood stream
Go on to form macrophages
What are platelets?
Derived from megakaryocytes
Major role in clotting cascade and platelet plug
What does Factor Xa convert?
Prothrombin (II) to thrombin (IIa)
What is the function of thrombin?
Converts fibrinogen to fibrin
Activates XIII into XIIa
Positive feedback effect on further thrombin production
What does warfarin inhibit?
Inhibits vit K epoxide reductase
Factors 10, 9,7 and 2
What does Heparin do? Name a LMWH
Activates antithrombin 3 and inhibits X - dalteparin
What is the fibrinolytic system?
plasminogen converted to plasmin
Plasmin cuts fibrin into fragments
Prevents blood clots from growing and becoming problematic
What is a Full Blood Count?
Basic blood test that gives information about blood constituents
- RBC volume
-WBC volume
-Platelet volume
-Haemoglobin concentration
-Mean corpuscular volume
What is a reticulocyte count?
Enables you to see how quickly the bone marrow is producing new RBC’s
What does a low reticulocyte show?
Indicative that something is preventing RBC’s from being produced e.g haematinic deficiency
What does a high reticulocyte count show?
Indicative that RBC’s are being lost or destroyed (e.g bleeding/haemolytic anaemia) New RBC production is increased to act as a compensatory mechanism
What is Serum Ferritin?
Ferritin is the major iron storage protein of the body. Ferritin can be used to indirectly measure the iron levels in the body.
Ferritin is an acute phase protein and so its levels can become falsely raised in inflammation and malignancy.
What is a blood film?
Smears of blood are placed onto slides and then examined under a microscope
What is a thick blood film used for?
permits examination of a large amount of blood for the presence of parasites ( but not identification of species)
What is a thin blood film used for?
Allows for observation of RBC morphology, inclusions and intracellular and extracellular parasites.
What is PT/INR?
Prothrombin time - measure of the time taken for a blood clot to form via the extrinsic pathway.
INR- international normalised ratio is used for patients on anticoagulants.
They measure overall clotting factor synthesis
What disease affect PT/INR?
liver disease
DIC
Vit K deficiency
Warfarin levels
What are the normal PT/INR levels?
12-13seconds/ 0.8 - 1.2 seconds
What is APTT?
Activated partial thromboplastin time - measure of the time taken for blood clot via the intrinsic pathway
APTT indicated issues with factors VIII,IX,XI
What conditions are linked to aPTT?
Haemophilia A - VIII
Haemophilia B - IX
von willerbands disease- VII
What is the normal time for APTT?
35-45 seconds
What is bleeding time?
Assess overall platelet function and levels
Measure of how long it will stop a patient bleeding from a wound
What platelet specific disorders increase BT?
Von willerband’s disease
ITP
DIC
Thrombocytopaenia
What is the normal bleeding time?
1-6 mins
What is thrombin time?
Tests how fast fibrinogen is converted into fibrin by thrombin.
If time is prolonged it is caused by either a synthetic issue or a consumption time
What disease are linked to a prolonged Thrombin time?
DIC
Liver failure
Malnutrition
Abnormal fibinolysis
What is the normal thrombin time?
10-15 secs
What are the steps that lead to a platelet plug?
- Von Willebands factor adheres to vascular injury
2.VWF then binds to GPIb receptors on surrounding platelets
3.After binding, the ADP P2Y12 receptor on the platelet is activated leading to increased expression of GPIb/IIa
4.These newly expressed receptors then finally bind to fibrinogen which leads to further platelet aggregation
What is haemoglobin?
Protein in the red blood cells that carry and delivers oxygen to tissues. Each adult Hb molecule is comprised of 2 alpha and 2 beta chain .Each Hb chain can carry 4 x 02.
What is the definition of Anaemia?
Anaemia is a lower than normal concentration of haemoglobin due to a reduction in cell mass or increased plasma volume. Also accompanied by a fall in red cell blood count and packed cell volume.
How is anaemia classified?
Based on the mean Corpuscular volume (MCV)
What is MCV?
Measure of the average size and volume volume of red blood corpuscle
What is microcytic?
MCV<80
What is normocytic?
MCV 80-100
What is macrocytic?
MCV >100
What are the consequences of Anaemia?
- Reduced 02 transports
-Tissue hypoxia
-Compensatory changes
(increased tissue perfusion, increased 02 transfer to tissues, increased RBC production)
What is Haemolytic?
Increased breakdown of RBC
What is Aplastic?
decrease in RBC,WBC,Platelets
What are the general symptoms of anaemia?
- fatigue
-lethargy
-dyspnoea
-palpitations
-headcahe
What are the general signs of Anaemia?
Pale skin
Pale mucous membranes - nose and eyelids
Systolic flow murmur
Tachycardia - to meet demand
What are the 3 main causes of Microcytic Anaemia?
- Iron deficiency
- Thalassaemia - body makes an abnormal form or inadequate amount of HB
3.Anaemia of chronic disease
What is Iron deficiency anaemia?
Iron is absorbed in the duodenum and is necessary for the formation of haemolytic. Less iron available for haemoglobin synthesis - less haemoglobin - lack of effective RBCs - Anaemia.
- mc anaemia worldwide
What are the causes of iron deficient anaemia?
- Low iron diet -malnutrition
2.Malabsorption - coeliac disease - Blood loss - menorrhagia, Gi bleeding, Hookworm
- Pregnancy
- Breastfeeding
colon cancer in elderly - rare, red flag
What are the signs of Iron deficient anaemia?
- Brittle hair and nails
-Atrophic Glossitis - tongue inflammation with atrophy of papillae
-Koilonychia - spoon shaped nails
-Angular Stomatitis - inflammation of corners of mouth
What are the investigations for iron deficient anaemia?
-Reticulocyte count - reduced
FBC and blood film - hypo chromic microcytic anaemia
-anisocytosis - variation in size
-poikilocytosis- variation in shape
-Serum ferritin - low
-Endoscopy/ colonoscopy for possible GI bleed
What is the treatment for iron deficient anaemia?
Ferrous sulphate - oral iron
Ferrous fumarate
What are the side effects of Ferrous sulphate treatment?
Black stools
Constipation
Diarrhoea
Nausea
Epigastric abdominal pain
What are the causes of Normocytic anaemia?
- Acute blood loss/haemorrhage
- combined haematinic deficiency e.g iron and B12
- Anaemia of chronic disease
- Sickle cell disease
What is Anaemia of chronic disease?
Anaemia that is secondary to a chronic disease. Occurs in patients with a chronic inflammatory disease.
What are the causes of Chronic disease Anaemia?
- Chron’s
-RA
-TB
-Malignancy
-CKD
What is the pathology of anaemia of chronic disease?
These conditions can cause either a shortening of RBC life or reducing RBC production.
- Decreased release of iron from BM to developing erythroblasts
-Less erythropoietin produced in response to anaemia
-High levels of hepcidin expression - inhibits duodenal iron absorption and macrophage release of iron
- decreased RBC survival
What is the presentation of Anaemia of chronic disease?
Anaemia symptoms and signs
What are the investigations of anaemia of chronic disease?
-FBC and blood film - Normocytic/microcytic and hypochromic (Pale)
- Low serum iron and low total iron binding capacity
-Increased or normal serum ferritin
What is the treatment for Anaemia of chronic disease?
Treat underlying cause
Recombinant erythropoietin
What are the main causes of Macrocytic anaemia?
Megaloblastic
1. B12 deficiency (pernicious anaemia)
2.Folate deficiency
Non- megaloblastic
3. Alcohol excess
What is megaloblastic?
B12 and Folate deficiency anaemia’s can be referred to as megaloblastic anaemias. Megaloblastic means that there has been an inhibition of DNA synthesis. The RBCs cannon progress onto mitosis causing continuing growth without division.
What is Pernicious anaemia?
Pernicious anaemia is an autoimmune condition in which the parietal cells are attacked and there’s a loss of Intrinsic factor production and therefore B12 malabsorption as B12 is absorbed count to IF. B12 is required for the formation of red blood cells.
What are other causes of B12 deficiency?
- low dietary intake
-atrophic gastritis
-gastrectomy
-chron’s
-coeliac disease - malabsorption
All affect If production or absorption at the terminal ileum
What are the symptoms of pernicious anaemia?
- anaemia symptoms - fatigue, lethargy, palpitations, dyspnoea
What are the signs of pernicious anaemia?
Glossitis
Angular stomatitis+ glossitis
Jaundice - excess breakdown of Hb/ lemon below skin
Neurological symptoms - polyneuropathy - B12 def causes demyelination
What is polyneuropathy?
Caused by symmetrical damage to the peripheral nerves and posterior lateral columns of the spinal cord
What are the investigations for pernicious anaemia?
FBC and blood films - would show macrocytic RBC/ megaloblasts
-Autoantibody screening- check for IF and parietal cell antibodies -anti IF Ab’s
Serum B12 low
What are the treatments for pernicious anaemia?
Vitamin B12 (hydroxycobalamin)
NOT FOLIC ACID - causes fulminant neurological deficits
Dietary advice
What are the complications of PA?
CVD
Neuropathy
What is folate deficiency anaemia?
Folate is absorbed in the jejunum and is found in green vegetables and is essential for DNA synthesis. Without Folate RBC can’t undergo mitosis so they just grow - macrocytic
What are the causes of folate deficiency ?
-Poor folate diet - poverty, alcohol, elderly
-Malabsorption - crohns, coeliac
-Pregnancy
-Anti folate drugs - methotrexate
What is the presentation of folate deficient anaemia?
- classic anaemia symptoms - fatigue, lethargy, headache, palpitations, dyspnoea
-angular stomatitis/ glossitis - no neuropathy unlike B12
What are the investigations for folate deficient anaemia?
FBC and blood film - macrocytic / megaloblastic anaemia
low serum folate
What is the treatment for folate deficient anaemia?
Dietary advice
Folic acid supplementation -
maybe for pregnancy -prophylactic
What is Haemolytic anaemia?
Haemolytic anaemia occurs when RBCs are destroyed before 120 days
How are old RBCs removed?
removed from the circulation by macrophages present in the red pulp of the spleen
Where does haemolytic occur?
intravascular - within blood vessels
Extravascular - within reticuloendothelial system, by macrophages in spleen, liver and bone marrow
What are the causes of haemolytic anaemia?
- inherited (haemoglobinopathies, membranopathies, enzymopathies)
- acquired ( autoimmune haemolytic anaemia, infections- malaria, secondary to systemic disease)
What are the symptoms of haemolytic anaemia?
- Gallstones (from excess bilirubin)
-Jaundice ( from excess bilirubin)
What is bilirubin?
A yellowish substance made during your body’s normal process of breaking down old red blood cells.
What are the signs of haemolytic anaemia?
- leg ulcers
-splenomegaly - signs of underlying disease (malar rash)
What are the investigations of haemolytic anaemia?
FBC - reduced haemoglobin normocytic normochromic
Reticulocyte count - increased
Blood film - presence of schistocytes
High serum unconjugated billirubin
High urinary urobillinogen
High faecal stercobillinogen
What is the treatment for haemolytic anaemia?
Folate and iron supplementation
Immunosuppressives
Splenectomy
What are shistocytes?
RBC fragments
What are Haemoglobinopathies?
Group of recessively inherited genetic conditions affecting haemoglobin
What is sickle cell disease?
Autosomal recessive condition, where there is a single base mutation causing a production of abnormal beta globin chains.
What is the epidemiology of sickle cell disease?
- more common in afro- Caribbean
- 1 in 4 chance of disease
-SCA is homozygous
-SCA trait is heterozygous - protected from malaria
What is the pathology of sickle cell disease?
- mutation of the B globin gene (glutamic acid to valine/ A to T) results in a HbS variant
RBC more fragile therefore low surface area so less efficient
What does sickling of cells produce?
-Premature destruction of RBCs - intravasucalr haemolysis
-Obstruction of microcirculation (vast-occlusion) -> tissue infarction
What is the presentation of sickle cell disease?
-jaundice - due to Hb breakdown
-Anaemia symptoms
-Complications: - due to cold, hypoxia
Vaso-occlusion crisis - sickle cells polymerise and trap in long bone blood vessels
-Acute chest syndrome - vaso-occlusive crisis of pulmonary vasculature
What happens if the HB falls suddenly? Possible causes?
Splenic infarction- spleen is engorged in RBC
BM aplasia - destroys erythrocyte precursors
Further haemolysis - drugs, acute infection
Gallstones, leg ulcers. -avascular necrosis of femoral head
What are the investigations for sickle cell disease?
-Screen neonates - blood/heel prick test
-FBC - normocytic normochromic high reticulocyte count
-Blood film - sickled erythrocytes
-Hb electrophoresis - Hb SS present and absent Hb A confirms diagnosis of sickle cell disease
What is the management for sickle cell disease?
Acute attacks - IV fluid +analgesia(NSAIDs) +O2
Long term:
- avoid precipitants
-Drugs: hydroxycarbamide + folic acid supplements
-Transfusion + Fe chelation
What are the complications of sickle cell disease?
Pulmonary HTN and chronic lung disease = most common cause of death in adults with SCD
- sickle cell chest crisis
-Renal impairment
What is Thalassaemia?
Autosomal recessive condition where you have a decreased rate of production or no production of one or more globin chains in red cell precursors/ mature red cells.
Where is Thalassaemia most common?
Mediterranean, Middle East, Asia
What is the precipitation of imbalance globin chains?
- in red cell precursors causes ineffective erythropoiesis ( reduced production of RBC)
-in mature red cells causes haemolysis (premature destruction of red blood cells)
What are the two types of Thalassaemia?
Alpha thalassaemia - decreased alpha chain synthesis
Beta thalassaemia - decreased beta chain synthesis
What is Alpha thalassaemia caused by?
caused by gene deletions, the more deletions the more symptomatic the anaemia
What is the presentation of 1 deletion?
Blood picture normal
What is the presentation of 2 deletions?
Asymptomatic with possible mild microcytic anaemia
What is the presentation of 3 deletions?
Common in parts of Asia. Patients have low levels of HbA and high levels of HbH Parts. Severe haemolytic anaemia and splenomegaly. Sometimes transfusion dependent -marked anemia
What is the presentation of 4 deletions?
No a-chain synthesis, only Hb Barts. Hb Parts cannot carry oxygen and is incompatible with life. (infants stillborn; they are pale, with huge spleen and livers. - Hydrops fetalis - 100% HbH Barts
What is Beta Thalassaemia?
In homozygous B-thalassaemia there is little or no normal beta chain production therefore EXCESS alpha chain production. Alpha chains bind with whatever, beta, gamma, delta. Leading to increased production of HbA2 and HbF resulting in ineffective erythropoiesis and haemolysis
What causes beta thalassaemia?
mutations
What forms HbA?
2 alpha and 2 beta chains
What forms HbA2?
2 alpha and 2 delta chains
What forms HbF?
2 alpha and 2 gamma chains