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Right iliac fossa (RIF) pain is pain localized to the lower right quadrant of the abdomen, a frequent cause of emergency admissions. It has a broad differential diagnosis including gastrointestinal, genitourinary, and gynecological causes.
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RIF pain = “appendicitis until proven otherwise,” but a wide range of GI, GU, and gynecological causes must be considered.
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| Domain | Etiology |
|---|---|
| Gastrointestinal | • Acute appendicitis (commonest surgical cause). |
| • Cecal diverticulitis. | |
| • Mesenteric adenitis (post-viral, Yersinia). | |
| • Crohn’s disease (terminal ileitis). | |
| • Tuberculosis of ileocecal region. | |
| • Meckel’s diverticulitis. | |
| • Constipation, bowel obstruction. | |
| Genitourinary | • Ureteric colic (right distal ureter stone). |
| • Urinary tract infection/pyelonephritis. | |
| • Renal transplant complications (if graft in RIF). | |
| Gynecological (females) | • Ovarian torsion. |
| • Ruptured/hemorrhagic ovarian cyst. | |
| • Ectopic pregnancy (tubal). | |
| • Pelvic inflammatory disease (PID), tubo-ovarian abscess. | |
| • Endometriosis (ruptured endometrioma). | |
| Vascular / Other | • Iliac artery aneurysm/dissection (rare). |
| • Abdominal wall pathology (hernia, rectus sheath hematoma). |
| Cause | Key Clinical Clues | Imaging Features |
|---|---|---|
| Appendicitis | Migratory pain, anorexia, fever | Dilated appendix, fat stranding |
| Ureteric colic | Colicky pain radiating to groin, hematuria | Stone, hydronephrosis |
| Ovarian torsion | Sudden severe pain, adnexal mass | Enlarged ovary, absent flow |
| Ectopic pregnancy | Amenorrhea, vaginal bleed, shock | Adnexal mass, free fluid |
| Crohn’s disease | Chronic diarrhea, weight loss | Terminal ileal thickening, comb sign |
| Mesenteric adenitis | Recent viral illness, fever | Multiple enlarged mesenteric nodes |
| Cecal diverticulitis | RIF pain, mild fever | Inflamed cecal diverticulum |