Infectious Diseases: Diagnosis

There are various ways of reaching a diagnosis. The saying: "One recognises only what one knows" is of great importance. Knowledge of diseases and pattern recognition are the basis. Recognition of clinical presentations and reaching a diagnosis is the outcome. In the case of infectious diseases, an attempt can be made to detect the pathogenic organisms directly by microscopy (for example thick smear for malaria, Ziehl-Neelsen staining of sputum for pulmonary tuberculosis, faecal specimen for amoebae, bone marrow aspirate for visceral leishmaniasis, etc). Cultures and serological tests are usually difficult or impossible in rural areas. Radiology and ultrasound are mostly of limited availability.

Often, a definite diagnosis is not possible and a probable diagnosis must be established: the disease that is most likely in the differential diagnosis. The differential diagnosis is the list of those diseases that might explain the patient’s clinical picture. It is not advisable to make a long list by including all sorts of rare possibilities. By definition, rare diseases are always rare. It is, however, important to think of a rare disease if it is severe and treatable in the given circumstances.

Category: Medicine Notes