What is the most likely condition for a patient with LLQ abdominal pain, constipation, severe pain, nausea/vomiting, an elevated ESR of 45, and leukocytosis?

The presentation of left lower quadrant (LLQ) abdominal pain, combined with symptoms such as constipation, severe pain, nausea and vomiting, an elevated erythrocyte sedimentation rate (ESR) of 45, and leukocytosis strongly suggests diverticulitis as the most likely condition.

Diverticulitis occurs when diverticula, which are small pouches that can form in the walls of the colon, become inflamed or infected. The LLQ pain is indicative of involvement in the sigmoid colon, where diverticula are most commonly located. Alongside inflammation and infection, individuals may present with constipation and significant abdominal pain, due to the irritation and possible obstruction that can accompany diverticulitis.

The elevated ESR indicates an inflammatory process is occurring in the body, which correlates with the presence of diverticulitis. Additionally, leukocytosis—an increase in white blood cell count—also points to an infectious or inflammatory condition, supporting the diagnosis of diverticulitis over other gastrointestinal disorders.

In contrast, conditions such as irritable bowel syndrome typically present with more variable symptoms and do not usually manifest with high levels of inflammation like elevated ESR and leukocytosis. Bowel obstruction may require additional symptoms such as severe distension or change