Pain in the right iliac fossa

Specialty: Gastrointestinal.

• Pain in the right lower quadrant
• appendicular pain
• right iliac fossa pain

Why it occurs

• Acute appendicitis due to obstruction of the appendiceal lumen (lymphoid hyperplasia, fecalith or appendiceal neoplasia)
• Mesenteric adenitis (common in young people, often of self-limiting viral etiology)
• Ileocecal Crohn's disease with active transmural inflammation of the terminal ileum and cecum
• Cecal or right colon diverticulitis (less common but relevant anatomical variant)
• Acute gynecological pathology (ruptured ectopic pregnancy, left/right ovarian torsion, ruptured ovarian cyst or pelvic inflammatory disease).

Initial workup

CT of the abdomen and pelvis with intravenous contrast (high sensitivity and specificity for acute appendicitis and ruling out differential diagnoses) | Abdominal and inguinopelvic ultrasound (first choice in pediatrics, pregnant women or women of childbearing age to evaluate the uterus and adnexa) | Emergency analysis: complete blood count (leukocytosis with neutrophilia and shift to the left), C-reactive protein, beta subunit of human chorionic gonadotropin (beta-hCG) in urine or serum mandatory in women of childbearing age, kidney function and electrolytes | General urine examination to rule out renal colic or atypical urinary tract infection.

Standard management

• Parenteral hydration with isotonic crystalloids — 0.9% saline or Ringer's lactate
• Directed or therapeutic preoperative antibiotic therapy for complicated appendicitis — piperacillin/tazobactam 4.5 g IV every 6 hours, or combination of ceftriaxone 2 g IV every 24 hours plus metronidazole 500 mg IV every 8 hours
• Controlled intravenous analgesics — metamizole 1-2 g IV or fentanyl at low doses under medical monitoring; historically proscribed but currently accepted once the patient has been evaluated by surgery to not mask clinical signs
• Antidespasmodics (relatively contraindicated if they delay the diagnosis of an acute obstructive surgical process).