Severe shigellosis can produce toxic dilatation and perforation of the colon. In patients expressing HLA-B27, Reiter's syndrome may develop. Incidence is higher with clindamycin. May or may not be bloody stool. May have only watery, voluminous diarrhea, or may also have abdominal cramps, fever, and leukocytosis.
Toxic megacolon is a complication , but course is highly variable.
Fulminant, sometimes fatal, colitis may be precipitated by pregnancy. Transmural involvement may produce peritonitis. Liver abscess in pregnancy is unusual. Over one third of reported cases have been in pregnant women or neonates. Fever, myalgia, and gastrointestinal symptoms are reported most commonly in pregnancy.