Primary abdominal actinomycosis

Our patient was a 69-year-old caucasian woman, who was employed as a part-time accounts controller. She presented to the gynaecology service in December 1984 with a 2 weeks history of pain and hyperaesthesia in the right iliac fossa. Two months before she had fallen and sustained a closed fracture of the lateral malleolus of the right ankle. Gynaecological examination revealed a large abdominal swelling which suggested an ovarian cyst. Laparotomy was recommended. At operation the right rectus sheath contained purulent material, and the abdominal wall was infiltrated by apparent malignancy. A biopsy was taken from the right rectus sheath and the abdomen closed without any further operative procedure. Histological examination revealed micro-abscesses, fibrosis and typical Actinomyces organisms. There was no evidence of malignancy. The patient was transferred to the Regional Infectious Diseases Unit for further management. Reassessment confirmed the extensive infiltration of the anterior abdominal wall: there was no clinical evidence of actinomycosis elsewhere. Benzylpenicillin (600 mg, 6 hourly IV) and metronidazole (500 mg, 8 hourly IV) were administered for 8 days. Thereafter treatment was given by mouth using phenethicillin 500 mg, 6 hourly and probenecid 500 mg, 12 hourly, with metronidazole 400 mg, 8 hourly for the first 2 weeks of oral therapy. Phenethicillin and probenecid were continued for 3 months: this regime produced post-dose serum penicillin concentrations of 3.5 mg/l. Recovery was rapid and complete, the induration of the abdominal wall regressed, and regular review of the patient was discontinued 15 weeks after presentation. She was seen again in November 1992 after her general practitioner had referred her to the medical clinic with essential hypertension: there were no clinical sequelae of her actinomycosis.