Haemolysis

Question 1

what is compensated haemolysis?

Answer 1

Increased red cell destruction compensated by increased red cell production

Question 2

what are the consequences of haemolysis?

Answer 2

Erythroid hyperplasia (increased bone marrow red cell production)
Excess red cell breakdown products eg billirubin (clinical features differ by aetiology and site of red cell breakdown)

Question 3

what are the signs of extravascular haemolysis?

Answer 3

Hyperplasia at site of destruction (splenomegaly +/- hepatomegaly)
Release of protoporphyrin
Unconjugated bilrubinaemia
  Jaundice
  Gall stones
Urobilinogenuria
Normal products in excess

Question 4

What are the signs in intravascular haemolysis?

Answer 4

Haemoglobinaemia (free Hb in circulation)
Methaemalbuminaemia
Haemoglobinuria: pink urine, turns black on standing
Haemosiderinuria
Abnormal products

Question 5

list causes of intervascular haemolysis

Answer 5

ABO incompatible blood transfusion
G6PD deficiency
Severe falciparum malaria (Blackwater Fever)

Question 6

what investigations would be done for haemolysis?

Answer 6

FBC (+ BLOOD FILM)
Reticulocyte count
Serum unconjugated bilirubin
Serum haptoglobins
Urinary urobilinogen

Question 7

what are the two categories of autoimmune haemolysis?

Answer 7

Warm (IgG)	Idiopathic (commonest)
				Autoimmune disorders (SLE)					Lymphoproliferative disorders (CLL)			Drugs	(penicillins, etc)					Infections							
 Cold  (IgM)	Idiopathic
				Infections (EBV, mycoplasma)
				Lymphoproliferative disorders

Question 8

what does combs test do?

Answer 8

Identifies antibody (and complement) bound to own red cells

Question 9

list mechanical causes of red cell destruction

Answer 9

Disseminated intravascular coagulation
Haemolytic uraemic syndrome (eg E. coli O157)
TTP
Leaking heart valve
Infections e.g. Malaria

Question 10

Explain G6PD is essential for producing antioxidants and ATP witin the RBC

Answer 10

G6PD is an enzyme involved in glycolysis and produces NAPDH which subsequently reduces glutathione (which is an antioxidant)

Question 11

what drugs cause oxidative damage?

Answer 11

dapsone

Question 12

what’s a Heinz Body?

Answer 12

Red cell inclusions comprised of denatured Hb normally removed by spleen (seen in G6PD def and unstable HB’s eg HbH)

Question 13

what type of haemolysis is involved in hereditary spherocytosis? How is it inherited

Answer 13

extra vascular

autosomal dominant