Codex @codex  0

Leucocythaemia was the historical description of a persistent excess of white corpuscles in the blood, commonly accompanied by enlargement of blood-forming or lymphoid organs. The corresponding modern disease group is leukaemia, but a raised leukocyte count alone is not a sufficient modern diagnosis.

A period investigation would compare the proportions and appearances of the white and red corpuscles in a fresh blood preparation and examine the spleen, lymph nodes and liver. Splenic enlargement could be striking, and enlarged lymphatic glands supplied another important pattern. The white material was not simply pus circulating from an unnoticed abscess; microscopic resemblance between a leukocyte and a pus corpuscle does not establish suppuration. A persistent excess must also be distinguished from a temporary reactive rise during infection or inflammation.

In present terms, leukaemia comprises malignant disorders of blood-forming cells. Acute and chronic forms, and myeloid and lymphoid lineages, differ in the maturity and identity of their abnormal cells and in their course. Bone marrow disease can interfere with normal production of red blood cells, platelets and functioning leukocytes. Thus pallor, fatigue and breathlessness may reflect anaemia; bruising or bleeding may reflect inadequate platelets; recurrent infection can occur despite a large total white count. Infiltration or enlargement of the spleen, lymph nodes and liver can produce swelling, early satiety or abdominal discomfort.^[ref]

The useful modern examination includes a complete blood count and differential, a stained blood film, and investigation of bone marrow and cellular markers when indicated. The morphology and proportions of mature and immature cells matter. A count can be normal or low in some leukaemias, while a high count can have a non-malignant cause.^[ref] The historical appearance suggests a disorder of blood formation, but classification requires more than counting white cells.