Malignant Haematology Flashcards
Mechanisms of low platelets
- decreased production (problem with bone marrow) - increased destruction/consumption - over-storage (pooled in spleen rather than circulation)
Aetiology of thrombocytopenia
- laboratory artefact
- consumptive (sepsis, hypersplenism, DIC, TTP)
- immune (viral inc. HIV, hep B and C, meds, autoimmune, heparin induced)
- underproduction (B12/folate deficiency, alcohol, myelodysplasia/aplastic anaemia, marrow infiltration (leukemia), inherited syndrome, drugs (chemo, anti-epileptics, psych, rheumatological))
- dilutional (massive transfusion, pregnancy)
Thrombocytopenia: common things to consider
- low platelets as a result of clumping? - check B12 and folate as can cause all types of cytopenias - LFTs, U&Es, clotting (does anything suggest alcohol use, alcohol is directly toxic to bone marrow), (also clotting to rule out DIC) HIV, Hep - can be presenting illness - medications? - are they acutely unwell? (1% of inpatients have low platelets)
Thrombocytopenia: serious things to consider
- TTP - acute leukemia - DIC - Heparin-induced thrombocytopenia ITP
Thrombocytopenia - when to contact haematology
- acute and platelets <50X109 without cause - chronic and platelets between 50-100 - bleeding - abnormal blood film - concerned about HIT or TTP
Thrombocytopenia - other things to consider in context of low platelets
- is there bleeding (may need transfusion) - procedure planned? - pregnancy? very common in pregnancy - remember to do a pregnancy test
What would indicate a myeloproliferative neoplasm? (in broad terms)
high platelets, high Hb, high white count
Thrombocytosis - causes
- post-surgery - infection/inflammation (acute or chronic) - bleeding - iron deficiency - malignancy - rebound post-chemotherapy - hyposplenism (rare) - haematological malignancy (rare)
First line investigations for thrombocytopenia
- inflammatory markers - ferritin - if acute and clear cause repeat once stimulus is over - check blood film if persistent
When would you further investigate thrombocytopenia?
- persistent - no secondary cause - splenomegaly - unprovoked thrombosis
Primary haematological causes of increased platelets
- Myeloproliferative neoplasms (ET, PV, PMF, CML) - any malignancy
What gene mutation causes essential thrombocythaemia?
JAK2, MPL and CALR - remember around 15% are ‘triple negative”
What is essential thrombocythaemia?
Clonal bone marrow disorder - type of cancer - that normally affects over 50s (rarely children)
What investigations would you do for essential thrombocythaemia?
- normally picked up incidentally on FBC checking for other reasons - check no other secondary cause - bone marrow biopsy to confirm
Management of essential thrombocythaemia
- aspirin for all (75mg) - reduces cardiovascular risk (main priority) - review all other cardiovascular risk factors (BP, lipids) - if high risk –> cytoreduction (1st line hydroxycarbamide) Prognosis is good - small risk that it transforms to more aggressive neoplasm (MF/acute leukemia)
What makes a patient with essential thrombocythaemia high risk?
- over 60 years - platelets over 1500x109/L - previous thrombotic event - other cardiovascular risk factors
Basic definition of polycythaemia
high haemoglobin and high haematocrit
define pseudo/relative polycythaemia
caused by a reduction in plasma volume (e.g. dehydration, alcohol, diuretics) NOT increased red cell mass just appears increased
What is true/absolute polycythaemia?
Red cell mass increased
Causes of true polycythaemia
Most cases are due secondary to other medical problems: - hypoxia due to resp disease (hypoxic resp failure, OSA, smoking) - cyanotic cardiac disease - abnormal epo production or high altitude (abnormal epo production can be caused by renal carcinomas) - endocrine - testosterone, anabolic steroid, doping)
When would you investigate polycythaemia?
When HCT is over 0.52 in men and 0.48 in women
Primary polycythaemia
High red cells Classical picture = no secondary cause identified, epo low, JAK2 mutation identified
Pathophysiology of JAK2 V617F mutation
Mutation results in activation of JAK/STAT signalling pathway –> autonomous erythropoiesis not reliant on erythropoietin growth factor (also often have high PLT and WCC)
Primary polycythaemia can present with:
- arterial and venous thrombosis - headaches/migraines/blurred vision - aquagenic pruritus - plethora - splenomegaly - haemorrhage - fatigue mainly over 50s
Management of primary polycythaemia
- aspirin for all - review other cardiovascular risk factors - venesect HCT to <0.45 (gets rid of excess RBC and decreases amount of iron available for erythropoiesis) - avoid iron supplementation - if high risk then cytoreduct rather than venesect (hydroxycarbamide) - prognosis good as long as blood counts are controlled
What is the pathophysiology of myelofibrosis?
- blood picture variable but film changes and splenomegaly - clonal stem cell disease: proliferation of multiple cell lineages and progressive marrow fibrosis - around 85% have mutation in JAK2, CALR, MPL - more aggressive compared with ET & PV
Clinical picture of myelofibrosis
- weight loss, night sweats, itch and possible massive splenomegaly (that can cause abdo pain and other symptoms) - higher risk of transformation to acute leukemia - patients usually anaemic - can have low or high platelets and low or high WCC depending on stage of disease - leukoerythroblastic bold film with tear drop red cells - myelocytes seen on blood film
Management of myelofibrosis
- supportive care - epo injections/transfusion for anaemia - ruxolitinib (JAK2 inhibitor) - improves spleen size and quality of life: use if splenomegaly and systemic Sx) - hydroxycarbamide for high platelets/WCC - allogeneic haematopoietic stem cell transplant if fit (bone marrow) particularly if high risk MF
Name reactive causes of neutrophilia:
- infection/inflammation - malignancy - steroids (not normally >20) - smoking (results in mixed leukocytosis) - hyposplenism/asplenia - rebound post chemo ALWAYS CHECK FOR SPLENOMEGALY
First line investigations in neutrophilia
- inflammatory markers - blood film if persistent with no cause - if acute and clear cause then repeat once stimulus is over
When to investigate neutrophilia further
- persistent - no secondary cause - splenomegaly Contact haematology if persistent with no secondary cause and if basophilia, splenomegaly or abnormal blood film
possible haematological causes of neutrophilia
- Myeloproliferative neoplasms: PV, PMF, CML, CNL
- ET does not usually cause neutrophilia
Clinical picture of chronic myeloid leukemia
- results in very high WCC (500-600) - if you see basophilia think CML - often asymptomatic but can have splenomegaly and present with vague generally symptoms - prognosis excellent for most
What is the genetic abnormality that causes CML
translocation between chromosomes 9 and 22 resulting in Philadelphia chromosome and the BCR-ABL1 fusion gene