Suspected adult-onset Still's disease: unexpected manifestation of leprosy
A 23-year old male from Sri Lanka was admitted to hospital with symmetrical inflammatory peripheral polyarthritis, fever of 39 degrees C and poly-lymphadenopathy. At first we suspected adult onset Still's disease. The histological findings from axillary lymph node biopsy strongly suggested the diagnosis of leprosy, for which we had had little evidence thus far. Typical skin lesions were absent, skin smears were negative and neurological symptoms only became obvious much later when fever and arthritis had subsided under anti-inflammatory treatment. At this time a right ulnar palsy developed, with atrophy of the interosseous muscles and thickening of the ulnar nerves at both medial epicondyles. Fite-stains of a sural nerve biopsy confirmed the diagnosis when mycobacteria were detected. Leprosy displays a clinico-pathological spectrum caused by variations in host resistance. A widely accepted classification is the five group system of Ridley and Jopling. At one extreme of this spectrum are patients with lepromatous or low resistance leprosy with numerous bacilli, and at the other those with high resistance or tuberculous leprosy where few or no bacilli are found. The numerous bacilli in the sural nerve biopsy classified the disease as lepromatous in our case. Of the various manifestations of the lepra reaction occurring in lepromatous leprosy, one is acute arthritis, but a more common one is erythema nodosum leprosum. Our patient's clinical presentation was interpreted to be a rheumatic manifestation of a type-2 reaction. This form of immunological response in leprosy is an immune complex syndrome and may mimic different rheumatic diseases.(ABSTRACT TRUNCATED AT 250 WORDS)