Anaemia 2 Flashcards
What are the causes of macrocytic anaemia? (6)
B12 or folate deficiency, liver disease, alcoholism, myelodyspasia, some haemolytic anaemias, bone marrow failure, anticonvulsants, chemotherapy
What is B12, where is it found, how is it absorbed?
Water soluble vitamin. Found in meat, eggs, etc. Not destroyed by cooking. 3 years worth can be stored. Bound to IF in stomach and absorbed in ileum.
What is B9, where is it found, how is it absorbed?
Water soluble. Liver, veg, yeast. Destroyed by cooking. 4 months stored. Absorbed in duodenum/ jejunum.
B12/ folate deficiency test results?
Low Hb, MCV >120, decreased platelets and WBC.
Oval macrocytes and hypersegmented neutrophils
Increased LDH and bilirubin
What are the causes of B12 deficiency?
Diet. Gastric malabsorption- pernicious anaemia. Intestinal malabsorption- Crohn’s, ileal disease, hookworm.
What is pernicious anaemia?
Autoimmune. Autoantibodies produced against IF and gastric mucosa. Leads to gastric atrophy, decreased acid and IF. Associated w fair hair, blue eyes, blood group A.
What are the symptoms of pernicious anaemia?
Anaemia, glossitis, mild jaundice, neurological symptoms: peripheral neuropathy, spinal column damage, dementia, optic atrophy
How is pernicious anaemia treated?
IM B12 every 3 months
What are the causes of folic acid deficiency? (4)
Poor diet, alcoholism, malabsorption from coeliac or Crohn’s, excess utilisation because of pregnancy, lactation, psoriasis, haemolytic anaemia. Anticonvulsants
What are the three main categories of erythrocyte abnormalities?
Membrane, haemoglobin, enzymes
Biochemistry of extravascular haemolysis?
Increased serum unconjugated bilirubin, LDH, urinary urobilinogen
What are the causes of extravascular haemolysis? (5)
Sickle cell, thalassaemia, antibody induced haemolytic anaemia, Rhesus mismatched transfusion, hereditary spherocytosis
Where does extravascular haemolysis occur? (3)
Spleen, liver, bone marrow
What are the causes of intravascular haemolysis? (3)
ABO mismatched transfusion, snake bites, some infections
What are the signs of haemolytic anaemia? (4)
Pallor, jaundice, gallstones, splenomagaly
What is hereditary spherocytosis?
Autosomal dominant. Defect in cytoskeleton. Chronic splenic haemolytic anaemia. Spherocytes in peripheral blood.
What is G6PD deficiency?
G6P dehydrogenase reverses oxidation. Result of 400 different X linked mutations.
What are the signs of G6PD deficiency? (3)
Neonatal jaundice, acute haemolysis with oxidant drugs, triggered by some foods eg favs beans
What is sickle cell anaemia?
Point mutation; glutamine to valine. Autosomal recessive. Hb forms rods when O2 declines. Blocks microcirculation-> ischaemia, pain
What is AIHA?
Autoimmune haemolytic anaemia- self reacting IgG triggers removal by spleen.
How is AIHA tested for?
Direct Coombs test. Sample incubated with Coombs reagent- antihuman antibodies. Erythrocytes agglutinate.
What are the causes of AIHA? (4)
50% idiopathic. Drugs- penicillin, methyldopa. Connective tissue disease- SLE, RA. Blood transfusion.
