Acute appendicitis is caused by obstruction of the appendix lumen, which increases intraluminal pressure and leads to vascular compromise and tissue necrosis. Initial symptoms are vague abdominal pain that localizes to the right lower quadrant as inflammation spreads. A physical exam may reveal tenderness at McBurney's point. Imaging studies like CT scans can help diagnose appendicitis, especially in atypical cases. Treatment is an appendectomy along with preoperative antibiotics to prevent infection.