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Haematology 1

oelomar's version from 2018-11-03 19:56


Question Answer
What are the symptoms of general anaemia?All are non-specific, and include fatigue, headaches, faintness, breathlessness, angina, intermittent claudication, and palpitations.
What are the signs of general anaemia?Pallor, tachycardia, systolic flow murmur, cardiac failure.
What is mean corpuscular volume (MCV)?The average volume of red cells.
What is the normal range for MCV?80-100fL.
What is the normal haematocrit?45% for men and 40% for women.


Question Answer
What is microcytic anaemia?A type of anaemia characterised by small red cells. The MCV is <80fL.
Name some causes of microcytic anaemia.Iron-deficiency anaemia, ACD (anaemia of chronic disease – may first present as normocytic anaemia and then progress to microcytic), thalassaemia, lead poisoning, sideroblastic anaemia. - LITS
What is normocytic anaemia?A normocytic anaemia is defined as an anaemia with a mean corpuscular volume (MCV) of 80-100 which is the normal range. However, the haematocrit and haemoglobin is decreased.
What is haemolytic anaemia?A form of anaemia due to haemolysis (abnormal breakdown of red cells). It is a type of normocytic anaemia. Symptoms are similar to other forms of anaemia but also include jaundice.
With regards to haemolytic anaemia, what is meant by “intravascular” and extravascular”?Intravascular haemolysis refers to red cells lysing in the blood vessels. Extravascular haemolysis refers to red cells lysing outside the blood vessels e.g. by macrophages in the liver or spleen.
Name some causes of normocytic, non-haemolytic anaemia.ACD (anaemia of chronic disease), aplastic anaemia, kidney disease. - AKA
What aplastic anaemia?A disease in which the bone marrow, and the blood stem cells which reside there, are damaged. As a result, the stem cells are unable to generate mature blood cells, and therefore, pancytopenia occurs (deficiency of all three blood cell types i.e. anaemia, leukopenia, and thrombocytopenia).
What is sickle cell anaemia?A severe hereditary form of anaemia in which a mutated form of haemoglobin – the oxygen carrying protein – distorts the red blood cells into a crescent shape at low oxygen levels.
What is macrocytic anaemia?Anaemia with an MCV >100fL. There is an insufficient number of red cells and often also insufficient haemoglobin content per cell.
What is megaloblastic anaemia?An anaemia of macrocytic classification that results from inhibition of DNA synthesis during red blood cell production. When the DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis stage. This leads to continuing cell growth without division.
Name some causes of megaloblastic anaemia.Vitamin B12 deficiency leading to folate deficiency.
Name some causes of macrocytic, non-megaloblastic anaemia.Liver disease, alcoholism, pregnancy, reticulocytosis (increase in reticulocytes), drugs.
What tests should be done following a finding of a raised MCV?Thyroid function tests, LFTs, reticulocytes, and vitamin B12/folate levels.


Question Answer
What is the most common anaemia?Iron-deficiency anaemia.
What are the clinical features of iron-deficiency anaemia?“FeKAP” – Fatigue, decreased Exercise tolerance, Koilonychia (spoon nails), Angular cheilitis/stomatitis (inflammatory condition affecting corners of the mouth or oral commissures), Pica (craving and compulsive eating of non-food substances), Pallor.
What investigations are carried out to diagnose iron-deficiency anaemia?Iron-deficiency anaemia is microcytic and hypochromic. The serum iron falls and the total iron-binding capacity (TIBC) rises. A low serum ferritin confirms the diagnosis. Note however that ferritin is an acute-phase reactant, and levels increase in the presence of inflammatory or malignant diseases.
How is iron-deficiency anaemia managed?The correct management is to find and treat the underlying cause, and to give iron to correct the anaemia. Iron deficiency anaemia without an obvious source mandates a GI check-up. The best preparation is oral ferrous sulphate.
What are the side-effects of oral ferrous sulphate used to treat iron-deficiency anaemia?Black stools, nausea, abdominal discomfort, diarrhoea/constipation.
What is Plummer-Vinson syndrome?A rare disease characterised by a triad of iron-deficiency anaemia, oesophageal web (dysphagia for solids but not liquids), and atrophic glossitis.


Question Answer
What is thalassaemia?Thalassaemia is an inherited autosomal recessive blood disorder characterised by abnormal formation of haemoglobin – more specifically, it is the defective synthesis of globin chains, resulting in ineffective erythropoiesis.
In whom are thalassaemia particularly prevalent (particularly the β form)?Mediterranean people.
What is β-thalassaemia and how is it categorised?Thalassaemia caused by a decrease in β-globin chain synthesis. It is categorised into 3 different forms depending on severity: thalassaemia major, intermedia, and minor.
What will electrophoresis show in β-thalassaemia patients?Increased HbA2 (haemoglobin A2) and increased HbF (foetal haemoglobin).
What is β-thalassaemia minor and what are its symptoms?A mild type of β-thalassaemia. It is normally asymptomatic, but is otherwise characterised by a mild hypochromic, microcytic anaemia.
What is β-thalassaemia intermedia and what are its symptoms?This describes an intermediate state with moderate anaemia but not requiring transfusions, although patients may require episodic blood transfusions. Patients may have splenomegaly and bone deformities. It should be noted that these patients may be iron overloaded despite a lack of regular blood transfusions. This is caused by excessive iron absorption.
What is β-thalassaemia major?The most severe form of β-thalassaemia in which no β-chains are formed leading to severe haemolytic anaemia, meaning an increase in unconjugated bilirubin. Extramedullary haematopoiesis also occurs. Life-long blood transfusions are required.
What is the danger associated with life-long blood transfusions?Iron overload (which can be fatal).
What are the signs/symptoms of β-thalassaemia major?Presents in the 1st year with failure to thrive and recurrent bacterial infections; severe anaemia from 3 to 6 months when the switch from γ- to β-chain production should occur; extramedullary haematopoiesis that soon leads to hepatosplenomegaly and bone expansion, giving rise to the classical thalassaemic facies. Skull X-rays in these children show the characteristic ‘hair on end’ appearance of bony trabeculation as a result of expansion of the bone marrow into cortical bone. The expansion of the bone marrow is also shown in an X-ray of the hand.
How is β-thalassaemia major managed?Long-term folic acid supplements are required. Regular transfusions should be given. MRI is useful for monitoring iron overload in thalassaemia, both the heart and the liver can be monitored. Marrow transplant can be curative. Iron chelation is with parenterally administered desferrioxamine. Ascorbic acid 200 mg daily is given, as it increases the urinary excretion of iron in response to desferrioxamine.
How is β-thalassaemia major diagnosed?The film shows hypochromic, microcytic cells. HbA2 and HbF are also increased.
Desferrioxamine is used as iron chelation therapy in the management of β-thalassaemia major. What are its side-effects?Deafness, cataracts, retinal damage, and increased susceptibility to Yersinia (gram-negative rod-shaped species of bacteria).


Question Answer
What is α-thalassaemia?A defect in the α-globin gene leading to decreased α-globin synthesis.
Deletion of 4 genes in α-thalassaemia is incompatible with life. True or false?True. This is because α-thalassaemia patients form haemoglobin Barts which causes hydrops fetalis.
What is haemoglobin Barts and what are its implications?A haemoglobin that consists of 4 gamma chains. It has an extremely high affinity for oxygen, resulting in almost no oxygen delivery to the tissues. It is produced in the disease α-thalassaemia and in the most severe of cases, it is the only form of haemoglobin in circulation. In this situation, a foetus will develop hydrops fetalis and normally die before or shortly after birth, unless intrauterine blood transfusion is performed.
What is hydrops fetalis?Hydrops fetalis is a serious condition in the foetus characterised by an accumulation of fluid, or oedema, in at least two foetal compartments. Hydrops fetalis usually stems from foetal anaemia, when the heart needs to pump a much greater volume of blood to deliver the same amount of oxygen.
Deletion of 3 genes in α-thalassaemia results in HbH (haemoglobin H) disease. True or false?True.
Deletion of 1-2 genes in α-thalassaemia is associated with mild anaemia. True or false?False. Deletion of 1-2 genes is not associated with anaemia.
What is HbH (haemoglobin H) disease and what are its clinical features?A moderate to severe form of α-thalassemia characterised by pronounced microcytic hypochromic haemolytic anaemia which is caused by excessive inclusion of β-globin chains. Typical features include hepatosplenomegaly, leg ulcers, and jaundice.
What will electrophoresis show in HbH disease?Increased HbH (β4 tetramers).


Question Answer
What is anaemia of chronic disease?Also known as anaemia of chronic inflammation (preferred term since not all chronic disease are associated with this form of anaemia), this is a form of anaemia seen in chronic infection, chronic immune activation, and malignancy. These conditions all produce massive elevation of IL-6 which stimulates hepcidin production and release from the liver, which in turn reduces the iron carrier protein ferroportin so that access of iron to the circulation is reduced.
Is anaemia of chronic disease a microcytic or a normocytic anaemia?Both. It may first present as a normocytic anaemia and then progress to a microcytic anaemia.
Are the serum iron levels and TIBC (total-iron binding capacity) in anaemia of chronic disease low or high? What about levels of serum ferritin?Serum iron levels and TIBC are both low. Serum ferritin is normal or raised because of the inflammatory process.
How is anaemia of chronic disease treated?Patients do not respond to iron therapy, and in general treatment is that of the underlying disorder (i.e. treatment of the chronic disease).
What is sideroblastic anaemia?A form of anaemia in which the bone marrow produces ringed sideroblasts as opposed to healthy RBCs.
How is sideroblastic anaemia treated?Withdrawal of drugs and alcohol (if they are the causative agents). Occasionally, there is response to pyridoxine (a form of vitamin B6). Treatment with folic acid may be required to treat accompanying folate deficiency.
When microcytic anaemia is not responding to iron, what should one think?Sideroblastic anaemia.
What is the link between lead poisoning and anaemia?Lead poisoning can lead to microcytic anaemia.
How can macrocytic anaemias be classified?As either megaloblastic or normoblastic.
There are two types of erythroblast, one of which is a normoblast. What is a normoblast?The immediate precursor of a normal erythrocyte.
There are two types of erythroblast, one of which is a megaloblast. What is a megaloblast?An unusually large erythroblast.
What is megaloblastic anaemia?Megaloblastic anaemia is an anaemia characterised by the presence of erythroblasts in the bone marrow with delayed nuclear maturation because of defective DNA synthesis – i.e. megaloblasts.


Question Answer
What is the link between a pure vegan diet and vitamin B12?A pure vegan diet can develop B12 deficiency, so prophylactic B12 should be given.
What is pernicious anaemia?A type of megaloblastic anaemia which is an autoimmune disorder in which there is atrophic gastritis with loss of parietal cells in the gastric mucosa with consequent failure of intrinsic factor production and vitamin B12 malabsorption (vitamin B12 plays a role in the formation of red blood cells).
Not including the neurological features, what are the clinical features of pernicious anaemia?The onset of PA is insidious, with progressively increasing symptoms of anaemia. Patients are sometimes said to have a lemon-yellow colour owing to a combination of pallor and mild jaundice caused by excess breakdown of haemoglobin. Glossitis and angular stomatitis are sometimes present.
What are the neurological features associated with pernicious anaemia?The classical neurological features are those of a polyneuropathy progressively involving the peripheral nerves and the posterior and eventually the lateral columns of the spinal cord. Patients present with symmetrical paraesthesiae in the fingers and toes, early loss of vibration sense and proprioception, and progressive weakness and ataxia. Paraplegia may result. Dementia, psychiatric problems, hallucinations, delusions, and optic atrophy may occur.
What investigations can be carried out in pernicious anaemia?Bone marrow shows the typical features of megaloblastic erythropoiesis. Serum bilirubin may be raised as a result of ineffective erythropoiesis. Serum methylmalonic acid (MMA) and homocysteine (HC) are raised in B12 deficiency. They are only useful in cases where the B12 and folate levels are not conclusive with only HC raised in folate deficiency. Serum vitamin B12 is low. Serum folate level is normal or high, and the red cell folate is normal or reduced owing to inhibition of normal folate synthesis. The Schilling test can be used to determine if the B12 deficiency is due to pernicious anaemia.
What is the Schilling test?A medical investigation used for patients with vitamin B12 deficiency, the purpose of which is to determine if the patient has pernicious anaemia. There are multiple stages to this test (that I don’t care enough about to bother going into detail).
How is vitamin B12 deficiency treated, and what should one look out for?Hydroxocobalamin can be given intramuscularly. Watch for hypokalaemia as treatment becomes established.

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