Abstract
INTRODUCTION: Recognition of elderly-onset ulcerative colitis (UC) remains poor as the differential diagnosis in older patients with acute abdominal pain and bloody diarrhea is extensive and UC is generally not the obvious cause. A typical presentation in an elderly patient with acute severe UC can mimic surgical abdomen. PRESENTATION OF CASE: An 80-year-old female had been presented with high grade fever, abdominal pain and diarrhoea. Physical examination showed sign of peritonitis and severe hypotension. A provisional diagnosis of perforated sigmoid diverticulitis was made. However, at the theater, there was only turbid yellowish ascites at cal-de-sac. Consequently, colonoscopy was performed and revealed continuous and circumferential erythematous with friable mucosa and multiple shallow ulcer along upper left side colon. Histologic examination of the colonic tissue was consistent with UC. DISCUSSION: As UC is uncommon in Thailand and clinical features of elderly-onset UC are much more non-specific; as a result, misdiagnosis at initial presentation is more common in elderly patients (60%) than that in younger population (15%). These might result in an unnecessary exploratory laparotomy; however, computed tomography scan can reduce the risk of that event. CONCLUSION: The diagnosis of severe acute UC in elderly patients with acute abdomen had been complicated by the distinctive physiology of this aged group with atypical presentation and markedly unreliable physical examination. Eventually, severe UC should always be kept in mind with a circumstance of abdominal pain in geriatric population.