Haematology Flashcards
give 3 causes of microcytic anaemia
TICS
Thalassaemia
Iron-deficiency
Chronic disease (20% will be microcytic)
Sideroblastic anaemia.
give 3 causes of normocytic anaemia
- bleeding
- anaemia of chronic disease (80% is normocytic)
- bone marrow failure; - renal failure (decreased erythropoietin)
- hypothyroidism
- haemolytic anaemia
- pregnancy
give 3 general symptoms of anaemia
classic = fatigue, dyspnoea, faintness
+ palpitations, headache, tinnitus, anorexia
give 3 general signs of anaemia
classic = conjunctival pallor
pallor, tachycardia
give a physiological cause of anaemia
Pregnancy
give some causes of iron-deficiency anaemia
- inadequate intake: poor diet, poverty
- poor absorption: poor acid production, gastric surgery, coeliac
- excessive loss: GI bleeding, peptic ulcers (NSAID use), diverticulosis, neoplasm, menorrhagia
- increase requirement: infancy, pregnancy, hookworm
possible presenting features of iron deficiency anaemia?
koilonychias (spoon nails)
mouth changes - angular stomatitis, atrophic glossitis
fatigue, pallor, faintness, dyspnoea
pica (classic = ice craving)
In iron deficiency anaemia, what will happen to the iron, ferritin and total iron binding capacity (TIBC) (aka iron studies)?
iron and ferritin are decreased.
TIBC is increased.
transferrin saturation = low.
NB - ferritin is acute phase protein so may be raised in inflammation/infection/malignancy
how would you treat iron deficiency anaemia? how long would this treatment be given?
oral ferrous sulphate - given until anaemia resolved + further 3-6/12
consider transfusion if symptomatic at rest w/ dyspnoea and chest pain.
what are some side effects of ferrous sulphate?
nausea, abdominal discomfort, diarrhoea/constipation, black stools
what causes pernicious anaemia?
autoimmune atrophic gastritis - autoantibodies against intrinsic factor (and parietal cells), so these are destroyed leading to achlorydia and B12 malabsorption.
associated with other AI disease - thyroid, vitiligo, DM.
risk of gastric cancer.
how does B12/folate deficiency lead to anaemia?
B12 and folate needed for DNA synthesis - developing red cells can’t divide, they are stuck as large immature cells (megaloblastic) which then become macrocytic RBCs
what signs characterise pernicious anaemia?
mild jaundice due to haemolysis - pallor + jaundice = “lemon tinged skin” is classic.
headache is hallmark of megaloblastic anaemia.
what specific tests would you perform if you suspected pernicious anaemia?
BC, blood film etc and:
- intrinsic factor antibody
- antiparietal cell antibody (90% sensitive, but not specific as elevated in atrophic gastritis)
give some causes of folate deficiency
- poor diet.
- increased demand - pregnancy or increased cell turnover.
- malabsorption (coeliac)
- drugs, alcohol, methotrexate (inhibits folic acid synth)
how would you investigate and treat folate-deficiency anaemia?
blood film shows macrocytic RBCs, hypersegmented neutrophils.
do other anaemia bloods.
oral folic acid (1-5mg) + B12 for 4 months min. treat cause.
give some hereditary causes of haemolytic anaemia
- Enzyme defects - G6PD deficiency, pyruvate kinase deficiency
- Membrane defects - hereditary spherocytosis, elliptocytosis
- Abnormal Hb production - sickle cell disease, thalassaemia
what is aplastic anaemia?
anaemia due to bone marrow failure
triad = pancytopenia with hypoplastic marrow and no abnormal cells
marrow stops making all cells
what is sickle cell anaemia?
autosomal recessive disorder causing production of abnormal beta globin chains.
HbSS instead of HbA
sickle shaped cells disrupt the blood cell, haemolyse earlier and causes varying degrees of anaemia.
obstruction of small blood capillaries leads to painful crises, organ damage and increased vulnerability to infection
being a carrier of sickle cell protects you against what disease?
p. falciparum malaria
what is the pathogenesis of sickle cell anaemia?
HbS causes RBCs to sickle - rigid, fragile cells that occlude small vessels and have short lifespan (haemolyse).
describe the clinical features of vaso-occlusive crises seen in sickle-cell anaemia
- severe pain due to effect on marrow of microvascular occlusio
- acutely painful hands and feet
- dactylitis
- visual floaters
- chest/abdo pain (mesenteric ischaemia)
- chronic renal failure.
- avascular necrosis femoral head/bone infarcts.
general symps/signs - parent with sickle cell anaemia/trait. symps of anaemia + haemolysis = jaundice, pallor, lethargy, tachycardia.
what is splenic sequestration?
a type of sickle-cell crisis:
vaso-occlusion produces acute painful enlargement of spleen.
pooling of RBCs in spleen = hypovolaemia = circulatory collapse and death.
immediate transfusion needed.
give 3 long-term complications of sickle-cell disease
poor growth, bone problems, infections, leg ulcers, neurological complication, gallstones, retinal disease, lung fibrosis, pulmonary hypertension
what tests would you perform in a case of sickle cell disease? what would you see?
FBC. - low Hb.
blood film - sickle cells and target cells (pale centre). Howell-Jolly bodies.
sickle solubility test - HbSS/HbAS instead of HbA
Hb electrophoresis - distinguishes HbSS and HbAS.
how would you treat sickle cell disease?
Hydroxyurea - increases HbF production
Blood transfusions