Acquired Brown's syndrome in children with juvenile rheumatoid arthritis.

Two children with systemic juvenile rheumatoid arthritis developed the features of Brown's syndrome coincident with an increase in disease activity. While acquired Brown's syndrome is known to occur in adults with both classical adult rheumatoid arthritis and persistent polyarticular juvenile rheumatoid arthritis, this is the first report of such an occurrence in childhood. The mechanism is likely to be an inflammatory mass which restricts the passage of the superior oblique tendon through the trochlea.