Oncology & Haematology

Question 1

What is Hereditary Spherocytosis?

Answer 1

Inherited defect in red cell membrane cytoskeleton resulting in sphere shaped red blood cells.

Majority inherited as autosomal dominant, recessive variety usually more severe. Some occur as de novo mutations.

Most common cause of inherited haemolytic anaemia in Northern Europeans.

Question 2

What is the pathophysiology of Hereditary Spherocytosis?

Answer 2

Sphere shaped RBCs are more fragile, have a lower surface area and have a shorter lifespan than regular RBCs.

When they pass through the spleen they are destroyed en masse.

This results in hyperbilirubinaemia from RBC breakdown, chronic anaemia and increased RBC production resulting in circulation of high numbers of reticulocytes.

Question 3

What are the complications of Hereditary Spherocytosis?

Answer 3

• Anaemia
• Splenomegaly and splenic rupture
• Gallstones
• Haemolytic crisis (during any infection)
• Aplastic crisis (during infection with parvovirus B19)

Question 4

What are the FBC and blood film features of Hereditary Spherocytosis?

Answer 4

• Increased MCHC
• Normocytic
• Raised reticulocytes
• Spherocytes on blood film

Question 5

What is the management for Hereditary Spherocytosis?

Answer 5

• Life long folate supplementation to support RBC turnover and bone marrow demand
• Splenectomy or partial splenectomy (avoided until at least age 5 and only indicated in moderate-severe disease)
• Cholecystectomy
• Blood transfusion
• EPO in patients for whom blood transfusion is contraindicated

Question 6

What are the presenting features of Hereditary Spherocytosis?

Answer 6

• Anaemia
• Pallor
• Jaundice
• Splenomegaly

Question 7

What is Idiopathic Thrombocytopenic Purpura?

Answer 7

Low platelet counts resulting in a purpuric (non-blanching) rash. Randomly occurring.

Question 8

What is the pathophysiology of ITP?

Answer 8

• Type 2 hypersensitivity response

- Leads to production of antibodies that target and destroy platelets

Question 9

What are the signs and symptoms of ITP?

Answer 9

• Bleeding
• Bruising
• Petechial or purpuric rash (petechiae are smaller than purpura)

Question 10

What is the management of ITP?

Answer 10

• Urgent FBC (other than low platelets all other readings should be normal - necessary to rule out other differentials such as leukaemia)
• Rule out other differentials such as meningitis
• Depending on platelet levels, no treatment may be needed
• If severe, treatment may include prednisolone, IV immunoglobulins, blood/platelet transfusions
• Condition usually resolves on its own within 3 months

Question 11

What is Sickle Cell Anaemia?

Answer 11

Autosomal recessive inherited blood disorder that results in sickle shaped red blood cells.

This leads to haemolysis and puts patients at risk of a sickle cell crisis

Question 12

What is the pathophysiology of Sickle Cell Anaemia?

Answer 12

Sickle cell patients have an abnormal type of haemoglobin, known as haemoglobin S (HbS) as opposed to the normal haemoglobin A (HbA).

This is due to an abnormal gene for beta globin on chromosome 11.

One copy of the gene is known as sickle cell trait, is asymptomatic and protective against Malaria.

Question 13

What are the potential complications of Sickle Cell Anaemia?

Answer 13

• Anaemia
• Increased risk of infection
• Stroke
• Avascular necrosis in large joints
• Pulmonary hypertension
• Priapism
• Chronic kidney disease
• Sickle cell crises
• Acute chest syndrome
• Complications relating to asplenism if splenectomy performed

Question 14

What is the general management of Sickle Cell Anaemia?

Answer 14

• Antibiotic prophylaxis (usually with penicillin V)
• Hydroxycarbamide (used to stimulate foetal haemoglobin production - HbF - as this does not lead to sickling and is protective against crises)
• Blood transfusion
• Bone marrow transplant (curative)
• Splenectomy (for haemolysis)
• Cholecystectomy (secondary to haemolysis)

Question 15

What is meant by Sickle Cell Crisis?

Answer 15

A term used to describe a number of acute complications arising from Sickle Cell Anaemia, including:

• Vaso-occlusive Crisis (due to sickle cells clogging capillaries) URGENT CARE NEEDED - EMERGENCY IF PRIAPISM
• Splenic Sequestration Crisis (due to sickle cells blocking blood flow through spleen; can cause splenic infarctions, severe anaemia and shock) EMERGENCY
• Aplastic Crisis (due to Parvovirus B19 infection - loss of bone marrow RBC creation) URGENT CARE NEEDED - EMERGENCY IF SEVERE ANAEMIA
• Acute Chest Syndrome (fever with respiratory symptoms + new infiltrates on xray. Can also be due to vaso-occlusion) EMERGENCY