[An ischiorectal abscess due to Actinomyces].

Actinomycosis is a chronic granulomatous inflammatory disease, with fistulization tendency, caused by Actinomyces. The clinical observation in presented of a patient with intermittent fever of three weeks duration, associated to pain and functional impotence of the right hip, observing with CT Scan an ischium-rectal abscess. After spontaneous fistulization, Actinomyces israelii was isolated in the biopsy sample by culture in anaerobic medium, confirming the diagnosis by anatomo-pathology. The patient was treated with intravenous penicillin for six weeks, followed by six months of oral treatment with which the symptoms disappeared and the radiological images normalized. Bone infection ranges between 1 and 15% of total actinomycosis.