Chronic Myeloid Leukemia in MRCP

Chronic Myeloid Leukemia in MRCP

Chronic Myeloid Leukemia (CML) is always a popular differential diagnosis in your MRCP PACES examination if you encounter massive hepatosplenomegaly during your abdominal short case.

CML is one of the 4 disorders ( besides polycythamia rubra vera, essential thmrobocythemia and myelofibrosis) termed as myeloproliferative disorders.

The term myeloproliferative disorders describes a group of conditions characterized by clonal proliferation of one or more haemopoietic components in the bone marrow and in many cases, the liver and spleen.

OK, patients usually present the following ways,

1) abdominal pain and distention because of massive hepatoslpenomegaly
2) bleeding tendency due to platelet dysfunction
3) features of anaemia
4) gout or renal impairment due to hyperuricaemia ( because of excessive purine breakdown)
5) some rare symptoms such as priapism ( this is the only cause of priapism I can remember during my medical school time because there was no Viagra yet at that time!!)

I think if you see a case of CML during your MRCP PACES, you must know how to come to a diagnosis of CML, basically, you can do the following,

1) You always find very high total white cell count when you do full blood count. I remember when I was a house-officer, I encountered a patient who were well and had a TWC of 150,000!!
2) Neutrophil alkaline phosphatase ( NAP) score is low!! ( Remember this well because it is a popular question in MRCP. Also remember diseases that have low NAP score!)
3) Chromosomal study- Remember that you usually find Philadelphia Chromosome which is a translocation of chromosome 9 and 22. ( This is the hottest exam question in MRCP and also your final MBBS!!)
4) Bone marrow is hypercellular with granulopoitic predominance.

5) Peripheral blood film may show various stages of granuloiesis including promyelocytes, myleocytes, metamyelocytes and band and segmented neutrophils

When I was a house officer, I remember that my consultant used a lot of hydroxyurea to treat CML. However, currently imatinib ( Gleevec) which is a tyrosine kinase inhibitor has become the first line treatment for CML.