Haemolysis 2

Question 1

What are the mechanical causes of haemolytic anaemia and what type of haemolysis do they result in ?

Answer 1

• Leaking/defective heart valve
• Infections e.g. Malaria
• Microangiopathic haemolytic anaemia (MAHA) - this is loss of RBC’s through destruction caused by diseases such as haemolytic uremic syndrome, DIC, thrombotic thrombocytopenic purpura, and malignant hypertension, eclampsia and vasculitis. They result in damage to the endothelial layer of small vessels fibrin deposition and platelet aggregation. As red blood cells travel through these damaged vessels, they are fragmented (schistocytes) and in turn haemolysis
• Burns related haemolysis

Result in extravascular haemolysis

Question 2

What type of RBC is seen and what condition is this indicative of ?

Answer 2

Schistocytes (fragmented RBC’s) indicates mechanical extravascular haemolysis

Question 3

What type of cells are typically seen in burns related haemolysis ?

Answer 3

Microspherocytes

Question 4

What are the causes of red cell membrane defects which can arise and result in haemolysis ?

Answer 4

• Liver Disease (Zieve’s Syndrome)
• Vitamin E deficiency – never came across it
• Paroxysmal Nocturnal Haemoglobinuria

Question 5

Describe the characteristic features of zieves syndrome that you should be aware of

Answer 5

• Hemolytic anemia (with spur cells/acanthocytes)
• Hyperlipoproteinaemia (excessive blood lipoprotein
• Jaundice (elevation of unconjugated bilirubin)
• Abdominal pain.

Caused by alcoholic liver disease

Question 6

What are the characterisitcs of paroxysmal nocturnal haemagolbinuria (remember the presence of this in urine can cause black urine when it sits)

Answer 6

Causes intravascular haemolysis - so the accompanying features

Characterisitically causes dark/black urine at night and in the morning

Question 7

What is the main congenital/inherited cause of red cell abnormalities and how does it result in haemolysis

Answer 7

Hereditary spherocytosis (so not only autimmune haemolytic anaemia which causes spherocytes)

1. Reduced membrane deformability - as need biconcave shape to withstand pressure of arteries and to squeeze through capiliaries
2. Increased transit time through spleen - this promotes its destruction
3. Oxidant environment in spleen causes extravascular red cell destruction

It results in extravascular haemolysis

Question 8

Descirbe the characterisitc features of hereditary spherocytosis and what is the treatment of it ?

Answer 8

May present with jaundice at bith or jaundice may be delayed for many years

Patient may eventually develop anaemia, splenomegaly and ulcers on the legs, gallstones can often develop due to the chronic nature of this haemolysis (as its inherited and ongoing from birth pretty much)

Treatment is with splenectomy to relieve symptoms due to anaemia or splenomegaly, reverse growth failure and prevent gallstones

If gallbladder affected then treat with cholestectomy

Question 9

What is the main abormality in red cell metabolism causing haemolysis that you need to know about ?

Answer 9

Glucose-6-phosphate dehydrogenase deficiency (G6PD)

Question 10

What is the inheritance of hereditary spherocytosis

Answer 10

Autosomal dominant

Question 11

What is the defect in G6PD and what does it result in ?

Answer 11

glucose-6-phosphate dehydrogenase is an enzyme which plays a vital role in the hexose monphosphate shunt as it oxidises glucose-6-phosphate to 6-phosphoglycerate with the reduction of NADP to NADPH,

Enzyme is important in ATP production

This is the only source of NADPH whcih is used to reduce glutathione to protect RBC from oxidative stress

==> its deficiency means the cell isnt portected from oxidiative stress

Question 12

What does G6PD result in ?

Answer 12

• Intravascular haemolysis
• As the cell fails to cope with oxidant stress (G6PD deficiency) and fails to generate ATP: metabolic processes fail

Question 13

What type of cell abnormality seen on blood film is suggestive of G6PD ?

Answer 13

Heinz bodies - Red cell inclusions comprised of denatured Hb normally removed by spleen

Or Keratocytes (bite cells) - occurs when macrophages in the spleen remove the heinz bodies

Question 14

Can normal cells (with normal metabolic pathways) undergo oxidiative damage like in G6PD if sufficiently stressed?

Answer 14

Yes if stressed by drugs dapsone or salazopyrin

Can result in haemolysis and keratocytes and haemolysis

Question 15

What are the 2 main conditions resulting in abnormal haemoglobin production and subsequent extravascualar haemolysis ?

Answer 15

1. Sickle cell
2. Thalassaemia

Question 16

What test is used to look at the haemoglobin present which aids diagnosis of haemoglobinopathies?

Answer 16

Hb electrophoresis

Question 17

What are the characterisitic features of G6PD ?

Answer 17

Mainly affects males in the mediterranean, africa, middle/far east

Most people are asymptomatic but may present with intravascular haemolysis precipitated by:

• Drugs e.g. aspirin, sulfonamides, primaquine
• Fava beans
• Illness

In attacks there is rapid anaemia and jaundice along with the other signs of intravascular haemolysis

Treatment includes avoiding precipitants and transfusion if severe

Question 18

What characterisitc appearance on blood film is seen in HbH ?

Answer 18

HbH(β4) containing golf balls(blue)

Question 19

Use the end of the lecture saved on desktop as it has slight cases etc