What condition is indicated by fever, left lower quadrant abdominal pain, and increased white blood cell count?

The presentation of fever, left lower quadrant abdominal pain, and an elevated white blood cell count strongly suggests diverticulitis. This condition occurs when diverticula, which are small pouches that can form in the walls of the colon, become inflamed or infected. The left lower quadrant pain is particularly characteristic given that the sigmoid colon is located in this area.

Fever and leukocytosis are common signs of inflammation or infection, which aligns with the inflammatory process seen in diverticulitis. The increased white blood cell count reflects the immune response to the infection.

In contrast, appendicitis typically presents with right lower quadrant pain due to inflammation at the appendix, which does not correspond to the left lower quadrant pain described. Pancreatitis usually causes severe abdominal pain that may radiate to the back, along with other symptoms like nausea and vomiting, but does not typically cause localized tenderness in the left lower quadrant. Gastroenteritis is characterized by diarrhea and vomiting, which are not mentioned in this case. Hence, the clinical picture points most clearly to diverticulitis as the underlying condition.