A 74-year-old woman presents with 3 weeks of left lower quadrant abdominal pain, changes in bowel habits, and intermittent fever. Her temperature is 38degC (101degF), respirations are 19 per minute, and blood pressure is 130/80 mm Hg. Physical examination shows left lower quadrant tenderness. A CBC reveals neutrophilia. An abdominal-pelvic ultrasound examination is normal. Which of the following is the most likely diagnosis?

Diverticular disease refers to two entities: a condition termed diverticulosis and an inflammatory complication called diverticulitis. Diverticulosis is generally asymptomatic. Diverticulitis results from the irritation caused by retained fecal material that obstructs the lumen of a diverticulum. Clinically, the most common symptoms of diverticulitis usually follow microscopic or gross perforation of the diverticulum. Diverticula are most common in the sigmoid colon, which is affected in 95% of cases. Peritonitis and sepsis are serious complications. Appendicitis (choice A) usually presents with right lower quadrant pain. None of the other choices presents with gastrointestinal symptoms and fever.Diagnosis: Diverticulitis