In spite of the opposite symptoms in typical cases, the differentiation between rheumatoid and rheumatoid arthritis due to the diversity of their variants may present significant difficulties, especially at the onset of the disease before establishing a specific streptococcal disease etiology, i.e. rheumatism (Table 9).
Currently, there is no doubt that these are two different diseases. Arthritic syndrome in rheumatism begins more rapidly and disappears quickly without residual effects, yielding an adequate dose of salicylates.
If the ESR remains persistently accelerated and after 4-6 months of treatment, involvement of new joints in the process is noted, the diagnosis of rheumatism is questioned.
In the early period of the disease, two main differential diagnostic criteria can be distinguished:
1. Various reactions of the articular syndrome to an adequate dose of salicylates.
2. Presence of signs of streptococcal infection (connection with angina or chronic tonsillitis, sowing of p-hemolytic streptococcus culture from the pharynx, detection of streptococcal antigens in the blood and in elevated titers of anti-streptococcal anti bodies – ASL – O, ASH, ASF).