Haematology Flashcards
What is key to look at in a FBC and what do they indicate?
- RBC (anaemias)
- Neutrophils (bacterial infection)
- Lymphocytes (chronic infection)
- Platelets (clotting ability)
- Eosinophils (parasitic infection)
- Monocytes (myelodysplastic syndromes)
What is a normal number of RBCs for men and women?
Men = 4.0 - 5.9 x 10^12 / litre
Women = 3.8 - 5.2 x 10^12 / litre
How is blood clotting measured (3 ways)
- Prothrombin time (PT)
- Activated partial thrombo-plastin time (APTT)
- Bleeding/ thrombin time (TT)
What is prothrombin time a measure of and how long is it?
Extrinsic pathway (10 - 13.5 seconds)
What is INR
Patient PT / standard PT time
What is activated partial thrombo-plastin time a measure of and how long is it?
Intrinsic pathway (35 - 45 seconds)
What is thrombin time a measure of?
Fibrinogen –> fibrin (12 - 14 seconds)
What does mean corpuscular volume (MCV) measure?
Average size of your RBCs
What is anaemia?
Low levels of haemoglobin in the blood
What is a low haemoglobin level in grams per litre?
Males = <130 g/l
Females = <120 g/l
What are the 3 classes of anaemia?
- Microcytic
- Normocytic
- Macrocytic
What is the normal MCV value?
Normocytic = 80-95
What are the general symptoms of anaemia (5)?
- Fatigue
- Pallor
- Tachycardia
- Raised respiratory rate
- Dysponea (exertional)
What are two types of haemolysis?
- Intravascular (contents released into BVs)
- Extravascular (@spleen mostly)
What is the most common cause of anaemia worldwide?
Iron deficiency anaemia
What are 4 causes of microcytic anaemia?
- Fe deficiency anaemia
- Thalassaemia
- Sideroblastic anaemia
- Lead poisoning
What is Fe deficiency anaemia?
Low haemoglobin levels due to non-inherrited Fe deficiency
Where is iron absorbed in the gut?
Duodenum + proximal jegunum
Iron first, bro
What causes iron deficiency (4)?
- Malnutrition
- Malabsorption (coeliacs, IBD)
- Menorrhagia (heavy periods)
- GI bleeding (cancer, ulcers)
What medications can interfere with the absorption of iron?
Medications that alter stomach pH as stomach acid is required to keep iron in a soluble form (e.g. PPIs)
What does iron circulate bound to?
Transferrin
What is iron stored bound to?
Ferritin
Why does Fe deficiency cause microcytic anaemia?
Not enough iron to fatten up RBCs
What are the specific symtpoms of Fe deficent anaemia?
- Koilonychia (spoon shaped nails)
- Angular stomatitis (ulcers at mouth corners)
- Atrophic glossitis (white texture on tounge)
How is Fe deficiency anaemia investigated (3)?
- FBC = microcytic anaemia
- Fe studies
- Blood film
What do Fe studies show in Fe deficient anaemia? (4)
- Low ferritin
- Low Fe
- High transferrin
- Low transferrin saturation/ total iron binding capacity (TIBC)
What does the blood film show in Fe defficient anaemia (3)?
- Hypochromic RBC (as low haemoglobin)
- Target cells (dark RBC due to high SA/V ratio)
- Howell jolly bodies (nucleated RBCs)
Who is given an endoscopy for Fe deficient anaemia?
Over 60s
How is Fe deficient anaemia treated?
Oral Fe (ferrous sulphate)
What is thalassaemia?
Change in the genes that code for the proteins that make up haemoglobin (2 alpha, 2 beta chains), microcytic
What are the two types of thalassaemia?
- Alpha
- Beta
Which chromosome is affected in alpha thalassaemia?
16
What are the 4 chains found in haemoglobin?
- Alpha
- Beta
- Gamma
- Delta
What is found in feta haemoglobin?
2 alpha, 2 gamma
What is HbH?
4 Beta chains
What types of thalassaemia alpha are there?
Ranging from 1 to 4 gene deletions, increasing in severity (more HbH = more severe)
What is Hb A2
2 alpha, 2 delta chains
What are the types of Beta thalassaemia?
Thalassaemia minor, intermedia and major
What is thalassaemia minor?
1 abnormal, 1 normal Beta gene OR 1 deletion, 1 normal Beta gene
What is thalassaemia intermedia?
2 defective genes OR 1 defective, 1 deletion gene
What is thalassaemia major?
2 deletion beta genes
What haemoglobin levels does thalassaemia increase?
- HbA2 (in beta)
- HbF (in beta)
- HbH (in alpha)
What are the specific signs/ symptoms of thalassaemia (2)?
- Chipmunk facies (look like chipmunk)
- Hepatosplenomegally (increased destruction of RBCs)
How is thalassaemia investigated (2)?
- FBC/ blood film
- Hb electrophoresis (diagnostic - shows Hb type proportions)
What would be abnormal on FBC and Blood film in thalassaemia (3)?
- Hypochromic RBCs
- Target cells (microcytic)
- High reticulocytes (fast RBC turnover)
How is thalassaemia treated (3)?
- Supportive
- Stem cell bone marrow transplant (definitive)
- Transfusion (+ chelation)
What supportive treatments are given for thalassaemia (4)?
- Iron chelaction (reduce iron levels)
- Transfusions
- Folate
- Splenectomy
What is Sideroblastic anaemia?
Genetic problem, mitochondria not able to synthesis Hb properly
What are iron levels like in sideroblastic anaemia?
High
What are the normocytic haemolytic anaemias?
- Sickle cell
- Hereditary spherocytosis
- G6PDH deficiency
- Malaria
- Autoimmune haemolytic
What are the normocytic non haemolytic anaemias
- CKD
- Aplastic anaemia
What is sickle cell disease?
Autosomal recessive condition that affects the beta chains of haemoglobin
What is Hb S made of?
2 Alpha chains, 2 mutated B chains
What nucleotides are different in sickle cell disease?
GAG –> GTG on 6th codon of beta globulin (glutamate –> valine)
What is the result of this mutation in sickle cell disease?
RBCs become sickle shaped under stressed conditions
What are some examples of conditions that stress RBCs in sickle cell disease (5)?
- Dehydration
- Hypoxia
- Infection
- Cold temp
- Acidosis
Specific symptoms/ signs of sickle cell disease (2)?
- Pre hepatic jaundice (lots of RBCs killed)
- Painful limbs (RBCs getting stuck)
Complications of sickle cell anaemia (3)?
- Splenic sequestration (spleen jammed up by sickle RBCs)
- Vaso-occlusive crisis (cappilaries jammed –> ischemia)
- Acute chest crisis (vaso-occlusion of pul vessels)
Investigations for Sickle cell disease (2)
- Blood film + FBC
- Hb electrophoresis (diagnostic)
What would blood film + FBC show in sickle cell disease (3)?
- High reticulocytes
- Sickle RBCs
- Howell Jolly bodies (nucleated RBCs)
How are acute sickle cell attacks treated (4)?
- Fluids
- Analgesia (NSAIDs)
- O2
- (Antibiotics)
How is sickle cell treated long term (5)?
- Hydroxycarbomide = hydroxyurea (reduce DNA synthesis)
- Folic acid supplements
- Transfusion
- Fe chelation
- BM transplant (last resort)
What drug is used for Fe chelation?
Desferrioxamine
What is G6PDH deficiency?
Glucose-6-phosphate dehydrogenase deficiency allows ROS to damage RBCs
How does G6PDH protect agains ROS
G6PDH involved with glutathione synthesis, glutathione protects against ROS by reacting with them
How is G6PDH deficiency inherrited?
X-linked recessive
What would precipitate symptoms in those with G6PDH deficiency?
Things that increase ROS e.g. smoking, fava bean consumption, certain medications
What sort of haemolysis occurs in G6PDH deficiency?
Intravascular
What is present within the blood of people with G6PDH deficiency (blood film, 2)?
- Heinz bodies (damaged/ denatures Hb by ROS)
- Bite cells (chunks taken out as denatured Hb removed by spleen)
How is G6PDH deficiency treated?
- Blood transfusions
What is hereditary spherocytosis?
Deficiency in structural membrane protein spectrin
How is hereditary spherocytosis inherrited?
Autosomal dominant
What change in shape does hereditary spherocytosis cause?
RBC become spherical + rigid
What is a result and complication of these spherical RBCs in hereditary spherocytosis?
Increased splenic recycling, RBCs get stuck in capillaries –> splenomegally, autosplenectomy
What are some specific symptoms of hereditary spherocytosis?
- Neonatal jaundice
- Splenomegally
- Gall stones
Why are gall stones common in some anaemias?
Low iron levels –> bile supersaturation, increasing the risk of gall stones
How is hereditary spherocytosis diagnosed (2)?
- Blood film = spherocytes
- Coombs -ve (therefore not AHA)
How is hereditary spherocytosis treated?
Splenectomy
What age is a splenectomy usually done after?
6 years (due to risk of sepsis)
How is neonatal jaundice treated?
Phototherapy (expose skin to UV) - helps liver break down bilirubin
What is a complication of neonatal jaundice?
Kernicterus - Collection of bilirubin in basal ganglia –> death
What is autoimmune haemolytic anaemia?
Abs bind to RBC –> haemolysis
How is autoimmune haemolytic anaemia tested for?
Direct Coombs test (tests for auto RBC Abs)
How does CKD cause anaemia?
Low production of erythropoetin
What is aplastic anaemia?
Pancytopenia (all 3 blood componenets low in levels) bone marrow fails to make haemopoeitic stem cells
What causes aplastic anaemia?
- Idiopathic
- Congenital
- Infection (maybe)
How is aplastic anaemia diagnosed?
Bone marrow biopsy (hypocellularity)
What are the types of Megaloblastic macrocytic anaemia?
- B-12 deficiency
- Folate deficiency
What are the types of non-megaloblastic macrocytic anaemia?
- Hypothyroidism
- Alcohol excess
- Liver disease
What is the difference between megaloblastic and non-megaloblastic macrocytic anaemia?
Megaloblastic is to do with deficiency/ impairment of utilisation of B12/ folate
What is B12 needed for?
RBCs DNA to mature and condense
What are 3 causes of vitamin B12 deficiency?
- Malnutrition
- Pernicious anaemia
- Absorption problems (e.g. crohns)
What cells produce intrinsic factor?
Parietal cells
What is pernicious anaemia?
Autoimmune response against parietal cells or intrinsic factor
What does B12 attach to in the saliva and protect it from the stomach acid and transports it around the blood?
Transcobalamin 1
(Cobalamin = Vit B12)
Where is B12 absorbed in the gut?
Distal ileum
What are the specific symptoms of B12 deficiency (3)?
- Yellow skin (high bilirubin)
- Angular stomatits + glossitis
- Neurological symtpoms
What causes neurological symptoms in B12 deficiency?
Low B12 –> demyelination
What sort of neurological symptoms occur with Vit B12 deficiency (2)?
- Symmetrical paraesthesia
- Muscle weekness
Lots of other stuff
How is vit B12 deficiency diagnosed (2)?
- Blood film
- Low serum B12
What would the blood film in vit B12 deficiency show (2)?
- Macrocytic RBCs
- Megaloblasts
What is a megaloblast?
Large, nucleated RBC precursor
How is pernicious anaemia diagnosed?
Anti IF/ parietal cell antibodies present
How is vitamin B12 deficiency treated (2)?
- Oral B12 supplements (cyanocobalamin)
- Pernicious anaemia = IM hydroxocobalamin (synthetic B12)