Myelosuppression

Question 1

What causes treatment-related myelosuppression?

Answer 1

-Many cytotoxic chemo drugs are toxic to the bone marrow, causing deficiencies in peripheral blood cells
-Leukocyte and platelet count most commonly affected
-Different drugs induce different effects eg carboplatin causes more thrombocytopenia

Question 2

What are the causes of myelosuppression?

Answer 2

-Treatment-related
-Bone marrow infiltration
-Paraneoplastic syndromes
-Blood loss causing anaemia

Question 3

What are the effects of malignant bone marrow infiltration?

Answer 3

-Can produce pancytopenia
-More common in haematological malignancies and some solid cancers eg breast, lung, prostate
-Anti-tumour therapy will improve pancytopenia

Question 4

How would you investigate a patient with myelosuppression?

Answer 4

-Transient nadir (period of lowest cell count) can be observed
-Prolonged / excessive suppression requires exclusion of alternative causes
-Blood film, haematinics, bone marrow aspirate and trephine biopsy should be ordered

Question 5

How would you treat anaemia in a cancer patient?

Answer 5

-<10g/dL can impair quality of life so should consider treatment
-Blood transfusion is often beneficial
-Recombinant EPO can prevent and treat symptomatic anaemia

Question 6

How would you treat thrombocytopenia in a cancer patient?

Answer 6

-Signs of significant disease = petechial haemorrhage, spontaneous nose bleeds, corneal haemorrhage, haematuria
-Platelet count <10x10^9/L - urgent indication for platelet transfusion (risk of cerebral haemorrhage)
-Platelet count of 10-20x10^9/L often require platelet transfusion, especially in cases of other complications eg infection
-Platelet count >20x10^9/L, in the absence of spontaneous bleeding, do not normally require platelet transfusion

Question 7

What risks are associated with platelet transfusion?

Answer 7

-Development of antibodies against foreign platelets - single donor / HLA matched platelets for patients needing multiple transfusions is preferred

Question 8

How would you manage a patient with neutropenia?

Answer 8

-Neutropenic infection = emergency, IV broad-spec abx required
-Any patient presenting with fever after cytotoxic chemo requires a review within the hour
-NB patients may be septic but pyrexial - can present feeling non-specifically unwell
-WCC <1x10^9/L requires immediate IV abx

-Careful examination to look for infection sites
-DRE / vaginal exams are contra-indicated due to risk of inducing bacteraemia

-Blood/urine/throat cultures, CXR should be done
-IV abx for 5 days, switch to 2nd-line broad spec abx if no response in 48h, then consider antifungal / antivirals