The differential diagnosis of rheumatic fever.

Since the efficacy of continuous daily sulphonamide or penicillin administration in the prevention of attacks of rheumatic fever has now been established, and the measure recommended not only nationally but by international committees (World Health Organization, 1957), it has become increasingly important to recognize even mild cases of rheumatic fever. At the same time it is equally essential to avoid diagnosing this erroneously, since the resulting continuous daily prophylaxis is undesirable from the point of view both of the patient and of the tax-payer. We thought therefore that an account of our observations at this National Centre for Juvenile Rheumatism over the last nine years would be useful, since over this period there has accumulated considerable experience not only of rheumatic fever, but also of many conditions which masquerade as such. Out of such prolonged experience at the House of the Good Samaritan in Boston, Duckett Jones (1944) was able to formulate a set of diagnostic criteria which have proved extremely useful in a modified form (Rheumatic Fever Committee Joint Report, 1955) for ensuring in a large therapeutic trial that cases from many different centres were of the same general type. He realized that cases of other diseases were as far as possible to be ruled out. It was realized further that many cases of genuine rheumatic fever, if first observed late in the course of the disease, or if mild, could not be fitted in and would have to be called 'probable rheumatic fever'. Furthermore, some of the criteria depend upon continuous clinical observation or laboratory tests usually possible in hospital, but only comparatively rarely made in this country in the average general practice. In this centre then, a discharge diagnosis of rheumatic fever has been made on unformulated but rather wider grounds than those of the Duckett Jones criteria, so that of 2,214 patients admitted to the unit over the nine-year period, 959 were discharged with the diagnosis of rheumatic fever. Nearly two thirds of these satisfied diagnostic criteria comparable to those of Duckett Jones, save that chorea was excluded as a major criterion and past rheumatic fever as a minor criterion. In addition, 42 cases were discharged with a diagnosis of 'possible rheumatic fever' and 202 with a diagnosis of Still's disease, the remaining 1,011 cases being various other miscellaneous disorders.