Paediatric Haem-Onc

Question 1

Name the most common cancer in children.

Answer 1

Acute lymphoblastic leukaemia

Question 2

Describe the pathophysiology of ALL.

Answer 2

Malignant proliferation of immature blast cells, usually B cell precursors, which infiltrate bone marrow and other organs of reticuloendothelial system.

Question 3

Describe the symptoms/signs in ALL and explain why these occur.

Answer 3

Usually presents insidiously over several weeks but may present very rapidly.

1. General
   - malaise
   - anorexia
2. BM infiltration
   - anaemia: fatigue, pallor
   - neutropenia: infections
   - thrombocytopaenia: bruising, petechiae, nose bleeds
   - bone pain (25%)
3. reticulo-endothelial infiltration
   - hepatosplenomegaly
   - lymphadenopathy

Question 4

Name 2 risk factors for the development of ALL.

Answer 4

1. age: 2-6 years

2. Down syndrome

Question 5

Which investigations would you perform on a child with suspected ALL to confirm Dx?

Answer 5

1. Bloods
   - FBC: anaemia, thrombocytopaenia, neutropenia
   - peripheral blood smear: blast cells +/- RBC abnormalities
   - clotting screen: 10% have DIC at time of diagnosis
2. BMAT (diagnostic)
   - >25% malignant blast cells
   - for morphology, immunophenotyping + cytogenetics

Question 6

Which Ix would you perform on a child with suspected/confirmed ALL to assess for disease spread?

Answer 6

1. CXR: to identify mediastinal mass characteristic of T cell disease
2. abdo. USS: may show renal enlargement from leukaemic infiltration or uric acid nephropathy as well as intra-abdo. adenopathy
3. LP: to ID CSF disease

Question 7

Which supportive treatments are required in a cild being managed for ALL?

Answer 7

1. correction of any cytopaenias e.g. RBC or platelet transfusions
2. additional hydration + allopurinol (to protect renal function against effects of rapid cell lysis)
3. co-trimoxazole on 2-3 consecutive days each week (prophylaxis against Pneumocystis jirovecii pneumonia)

Question 8

What is the definitive treatment for ALL?

Answer 8

Combination chemotherapy:
1. induction (4 wks): steroids + chemo (+ intrathecal chemo if CNS +ve)

2. consolidation: continued systemic chemo + intrathecal chemo (+ CNS radiotherapy if CNS +ve)
3. maintenance (2-3 yrs): continued systemic chemo +/- intrathecal chemo.

Question 9

what is the prognosis for ALL in children? what are high risk factors?

Answer 9

80% survival with treatment.

Poor prognostic features:

• age <1 yr or >10 yrs
• WCC >50
• some tumour cytogenetic/molecular abnormalities
• slow response to initial chemo
• detectable minimal residual disease after induction therapy

Question 10

a 5 year old girl presents with a 7 day history of frequent bruising and nose bleeds. O/E she has a purpuric rash. She had a viral URTI 2 weeks ago. What is the diagnosis and what is the pathophysiology of this? How would you manage her?

Answer 10

IMMUNE THROMBOCYTOPAENIC PURPURA

• most commonly occurs following a viral infection
• production of autoimmune IgG against platelet cell membrane antigen causing platelet destruction

Management:

• advice (e.g. avoid contact sport) and observational monitoring
• avoid aspirin and NSAIDs

Question 11

How would you treat a child presenting with severe ITP (i.e. significant bleeding)?

Answer 11

1st line: prednisolone, IV immunoglobulin

2nd line: rituximab, high dose dexamethasone

Question 12

what is the prognosis for childhood ITP?

Answer 12

Up to 80% completely recover within 6 months.
Some will develop chronic thrombocytopaenia, but most will require no Tx.
<0.5% develop intracranial haemorrhage.

Question 13

what is your differential diagnosis for a child who presents with a petechial/purpuric rash?

Answer 13

Thrombocytopaenic causes:

1. ITP
2. leukaemia
3. DIC

Non-thrombocytopaenic causes:

4. Henoch-Schonlein purpura
5. sepsis (meningococcal/viral)
6. trauma