| Lower abdomen | Localization | Clinical features | Comments |
| Appendicitis | Generally right lower quadrant | Periumbilical pain initially that radiates to the right lower quadrant. Associated with anorexia, nausea, and vomiting. | Occasional patients present with epigastric or generalized abdominal pain. |
| Diverticulitis | Generally left lower quadrant; right lower quadrant more common in Asian patients | Pain usually constant and present for several days prior to presentation. May have associated nausea and vomiting. | Clinical presentation depends on severity of underlying inflammatory process and whether or not complications are present. |
| Nephrolithiasis | Either | Pain most common symptom, varies from mild to severe. Generally flank pain, but may have back or abdominal pain. | Cause symptoms as stone passes from renal pelvis to ureter. |
| Pyelonephritis | Either | Associated with dysuria, frequency, urgency, hematuria, fever, chills, flank pain, and costovertebral angle tenderness. | |
| Acute urinary retention | Suprapubic | Present with lower abdominal pain and discomfort; inability to urinate. | |
| Cystitis | Suprapubic | Associated with dysuria, frequency, urgency, and hematuria. | |
| Infectious colitis | Either | Diarrhea as the predominant symptom, but may also have associated abdominal pain, which may be severe. | Patients with Clostridioides difficile infection can present with an acute abdomen and peritoneal signs in the setting of perforation and fulminant colitis. |
