[Polyarthritis in childhood]. 
As for chronic polyarthritis in childhood the polyarthritis due to JCA is the most frequently diagnosed one.  Today pathogenesis and pathophysiology are still gloomy.  But the characteristic clinical aspects of the disease at onset together with laboratory (serological) investigations enables us to identify the different types of polyarticular JCA.  This is very important for course and outcome of the disease, especially for choosing the best therapeutic regime.  This review will discuss the clinics, differential diagnosis, laboratory investigations, subtyping and course of the disease including therapy and prognosis.