Necrotizing fasciitis of the retroperitoneum: an unusual presentation of group A Streptococcus infection.

A 14-year-old girl presented with symptoms resembling acute appendicitis. Five days after appendectomy and continued fever and severe abdominal pain, blood cultures were found positive for Streptococcus pyogenes. Two days later a diagnosis of group A streptococcal peritonitis with necrotizing retroperitoneal fasciitis was confirmed by retroperitoneal cultures obtained at laparotomy. Although multiple organ systems showed impaired functioning, including hepatic, renal and respiratory changes, she did not meet the criteria for streptococcal toxic shock syndrome. She was treated with a combination of high-dose parenteral penicillin and clindamycin, followed by prolonged treatment with clindamycin orally. Recovery was complicated by persistent hydronephrosis, which was slow to resolve.