There are a number of diagnostic score charts to improve diagnosis of TB in children.These score charts have rarely been evaluated.The basis of a score system is the careful and systematic collection of diagnostic information. A score system is, in fact, not diagnostic but is rather a useful screening test that helps guide your clinical judgement. A score above a certain threshold indicates a high likelihood of TB. Examples can be found in Clinical tuberculosis (Crofton, Horne & Miller) or in the article by van Beekhuizen in Tropical doctor (see "Suggestions for further reading" at the end of the chapter).
Characteristic clinical features (e.g. spinal deformity, scrofula or painless ascites) supported by simple investigations often point to the diagnosis of various forms of extrapulmonary TB. These permit a confident diagnosis of TB, even if rarely confirmed microbiologically. However, the commonest type is PTB and this is the most difficult to diagnose. Score charts are least useful for PTB because they are so nonspecific in regions where malnutrition and HIV are common. Features suggestive ofTB (and commonly used in score charts) include:
° duration of illness greater than 4 weeks, particularly if the illness has not responded to other treatments, e.g. broad-spectrum antibiotics for persistent cough;
° evidence of wasting (i.e. under 60% of median weight-for-age), especially if there is a lack of weight gain in response to intensive nutritional support; ° family history of sputum-positive PTB (this is very important information); ° significant or "positive" tuberculin test.
Some score charts use response to TB treatment as a factor supporting a diagnosis of TB.This does not mean that a TB treatment trial should be used for diagnostic purposes!
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