Symptoms of CML

CML (chronic myeloid leukaemia) progresses through three distinct clinical phases:

 

  • chronic phase
  • accelerated phase
  • blast crisis (also called blast phase or blastic phase)

 

At the time of initial diagnosis, most CML patients (85% to 90%) are in the chronic phase of CML.

 

There has been a trend toward the earlier detection of the disease in recent years, with a greater percentage of patients, up to 50% in some series, having no symptoms when their disease is first detected.

 

In these patients, the diagnosis is suggested by an incidental laboratory detection of an increased WBC count (leukocytosis). When they are present, symptoms in CML patients generally relate to a hypermetabolic state, excessive leukocyte count, or splenic enlargement, and include:

 

  • Fatigue
  • Night sweats
  • Weight loss
  • Abdominal fullness

 

The most characteristic laboratory feature of CML in the chronic phase is an increase in WBC count, with all stages of maturation present. The peripheral blood smear in a chronic phase CML patient often resembles a bone marrow aspiration.

 

Accompanying the leukocytosis may be an increased platelet count (thrombocytosis) and an increase in the number of basophils (basophilia) and eosinophils (eosinophilia) in the peripheral blood, as well as in the bone marrow.




Figure 1. Peripheral blood smear of a patient with chronic phase CML. The low-power view (left) and the cell count show evidence of a marked increase in the number of WBCs. The high-power view (right) shows that the cells are at all stages of maturity. Compare this with Figure 2.



Figure 2. Sample sections of normal peripheral smear. These sections from a normal peripheral smear show areas with no WBCs (left). There are occasional platelets seen. Where WBCs are visible (right), they are predominantly mature netrophils (shown) or lymphocytes (not shown). There are no immature WBCs present except 5%-10% band forms.

Specific Indicators

  • Basophilia is considered characteristic of CML and carries a poor prognosis. The reasons for this are unclear.
  • Thrombocytosis is observed in 30% to 50% of patients, occasionally at levels higher than 1,000 x 109/L.
  • Anaemia may be present in up to 20% of patients at diagnosis.
  • WBC levels in excess of 100 x 109/L occur in 50% to 70% of patients.
  • Cyclic variations in the WBC count occur in 10% to 20% of patients, which in chronic phase patients may be due to a low level of preserved regulatory control.
  • The bone marrow aspirate in CML shows a large number of granulocytic cells, with a preponderance of early forms. On biopsy, the marrow is markedly hypercellular, with a high ratio of myeloid (i.e., WBC) to erythroid precursors (increased M:E ratio)
  • Blood chemistry abnormalities, such as elevated lactate dehydrogenase (LDH) or uric acid levels, may be seen. These findings reflect the high turnover of blood cells.

 

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