Red cell disorders

Question 1

Anaemia

Answer 1

reduced levels of Hb

Question 2

symptoms of anaemia

Answer 2

shortness of breath
lethargy
tachycardia
weakness

Question 3

is skin colour a reliable sign for anaemia?

Answer 3

no- conjunctiva and nail beds may be pale

Question 4

severe anaemia in elderly can cause

Answer 4

angina

Question 5

signs of anaemia

Answer 5

glossitis (painful red tongue)
angular cheilitis (fissures at corner of mouth)
DPGs may be elevated in RBCs so O2 more readily given up

Question 6

iron deficiency anaemia

Answer 6

microcytic (decreased mean corpsular volume) 
input reduced (diet/ removal of stomach) or output increased (menstruation, GI bleeding ulcers, use of NSAIDs, colon cancer 

demand increased from pregnancy
when bone marrow and macrophage iron stores depleted
monitor full blood count
give iron sulfate

Question 7

Acute iron deficiency anaemia

Answer 7

rapid loss of blood- haemorrhage
bp falls
haemodilution

Question 8

chronic iron deficiency anaemia

Answer 8

long term bleeding- gastric bleeding, excessive menstruation

Question 9

acute vs chronic anaemia FBC

Answer 9

HB: decreases both 
haematocrit decrease both 
MCV: decrease in chronic 
reticulocyte: increase in chronic 
WBC: decrease in acute 
platelets: decrease in acute 
EPO: increase in both 
DBG may be elevated to try to transport more oxygen 
iron stores: normal in acute and zero in chronic

Question 10

Treatment of iron deficient anaemia

Answer 10

find and treat underlying cause
oral iron sulfate (take with food as irritates stomach)
prophylaxis in pregnancy: oral iron with folic acid before and after conception- precursor to DNA, reduces chance of neurotube defect, produces RBC
transfusion

Question 11

renal anaemia

Answer 11

complicates CRF- impaired kidney doesnt produce EPO 
normocytic anaemia (lack of stimulation to produce RBC) 
treat with iron and EPO

Question 12

pregnancy

Answer 12

dilution/ iron deficiency

normocytic- pregnancy increase MCV but iron deficiency decreases it

Question 13

Megaloblastic anaemia

Answer 13

rare form of anaemia
abnormal RBC maturation due to defective DNA synth
bone marrow contains megaloblasts (abnormal precursor cells)- nuclear maturation impaired compared to cytoplasm
if macrocytic and not anaemic- alcohol

Question 14

why is megaloblastic anaemia macrocytic?

Answer 14

vit B12 or folate deficiency (increased in alcohol abuse)
anaemia, jaundice (XS breakdown of Hb due to ineffective erthryopoiesis)
symptomless, diagnosed on blood test
larger RBC more likley to breakdown

Question 15

what is B12 essential for?

Answer 15

cofactor for (THF) purine and pyrimidine synth (cell division) 
requires Castle's intrinsic factor for absorption (absence after gastrectomy) 

• Folate (folic acid) - essential for thymidylate synthesis (a rate limiting step in DNA synth as thymidine is a pyrimidine base), use in pregnancy
Most foods (esp. liver, greens, yeast, marmite)
• Methotrexate - inhibits dihydrofolate reductase (therefore folate regeneration impaired - treat with folinic acid), immunosuppressant, impairs DNA synth
• Pernicious anaemia - lack of intrinsic factor for absorption of B12 due to autoimmune disease - treat with hydroxocobalamin i.m. (bypass absorption)
• Crohn’s Disease- malabsorption of B12, folate or iron

Question 16

haemolytic anaemia

Answer 16

increased rate of RBC destruction
• Spherocytosis - genetic - abnormal reduction in RBC membrane protein (spectrin) - cells fragile
• Acquired - haemolytic transfusion reaction, malaria, drug-induced
• causes Jaundice (?) and enlarged spleen (red cell destruction) - folate deficiency may occur due to increased erythropoiesis

Question 17

sickle cell anaemia

Answer 17

Genetic SNP: single nucleotide polymorphism
valine substituted for glutamic acid
abnormal Hb- crystals at low o2 can block microcirculation- muscle pain- can cause haemolytic anaemia

Question 18

Thalassaemia

Answer 18

Genetic- deletion of genes
Reduced rate of alpha or beta globin units production many variations e.g. deletion of both alpha-genes leads to death in uterus as Hb (gamma4) produced
one alpha deletion- reduced haematocrit and RBC volume

Question 19

Aplastic anaemia

Answer 19

insufficient production of RBC, platelets (pancytopenia) and WBC (can just be RBC pure red cell aplasia)

decreased resistance to infections, increased bleeding and tiredness

Question 20

how is aplastic anaemia acquired?

Answer 20

viral, radiation and drugs 
Cytotoxic (anticancer) agents
		Chloramphenicol- antibiotic
		Sulphonamides- antimycrobial
		Insecticides

Question 21

treatment of aplastic anaemia

Answer 21

• Immunosuppressants – prevent immune destruction of stem cells
• Colony-stimulating factors - increase WBC count
• Bone marrow transplant - with tissue match

Question 22

polycythaemia

Answer 22

Increased Hb content and haematocrit (>55 in males and >47 in females)
increased blood viscosity- poor tissue perfusion

Question 23

signs and symptoms of polycythaemia

Answer 23

Ruddy appearance
Headaches
Blurred vision
Hypertension
Cyanosis- sluggish blood flow- deoxygenation

Question 24

causes of polycythaemia

treatment

Answer 24

primary: changes in bone marrow, stem cell defect
secondary: increased EPO- altitude, smoking, renal carcinoma and COPD

treatment of primary: venesection (bleeding), radioactive phosphorous (reduce turnover stem cells), cytotoxic agents- myelosupression (target RBC)