COMMON PRESENTATIONS OF HAEMATOLOGICAL DISEASES

abnormal blood count or blood cell morphology does not necessarily indicate a primary haematology problem because it may reflect an underlying non-haematological condition or may be the result of therapeutic interventions. Anaemia occurs in many conditions, but a primary blood disease should be considered when a patient has splenomegaly; lymphadenopathy; a bleeding tendency or thrombosis; and/or non-specific symptoms (malaise, sweats, or weight loss). As with any clinical problem, the first steps in determining the diagnosis include obtaining a care-ful clinical and drug history and thorough physical examination. The result of these, in combination with the patient’s age, sex, ethnic origin, social and family history, and knowledge of the locally prevalent diseases, will determine subsequent laboratory investigations. INITIAL SCREENING TESTS Although the range of haematological tests avail-able to support clinical and public health services is broad, it is often the simplest investigations that are most useful in indicating the diagnosis. Even poorly resourced laboratories are usually able to provide an initial panel of tests such as haemoglobin concen-tration (Hb), white blood cell count (WBC) and platelet count (Chapter 27), and examination of a peripheral blood smear for a differential leucocyte count (Chapter 3) and cellular morphology (Chapter 5). These screening tests will often enable the under-lying pathological processes to be suspected promptly and point to a few key diagnostic tests. 23 Approach to the diagnosis and classification of blood disease