Right Iliac Fossa (RIF) Pain and Appendicitis
RIF pain is a common ED presentation with a broad differential spanning gastrointestinal, gynaecological and urological causes. Emergency priorities are: (1) recognise appendicitis early, (2) identify uncomplicated versus complicated disease (perforation, abscess, intra‑abdominal sepsis), and (3) initiate appropriate investigations, resuscitation and timely surgical or interventional escalation (RCEM, NICE, Resuscitation Council UK).
Learning objectives
- Recognise typical and atypical presentations of appendicitis across age groups and pregnancy.
- Systematically differentiate appendicitis from common mimics.
- Choose appropriate imaging (POCUS/USS/CT/MRI) by clinical context and patient group.
- Start immediate ED management (analgesia, fluids, NPO, pregnancy test) and start early antibiotics when complication or sepsis is suspected.
- Identify complications and indications for urgent surgical, interventional radiology or critical care escalation.
Anatomy and pathophysiology
- The appendix is a blind‑ended tubular structure on the caecum; its variable positions (retrocaecal, pelvic, subcaecal, pre‑ or post‑ileal) influence presentation and examination findings.
- Retrocaecal: less superficial peritonism, flank/loin pain, may produce a positive psoas sign.
- Pelvic: suprapubic pain, urinary frequency, tenesmus; may mimic gynaecological pathology or UTI.
- Pain evolution reflects a visceral → somatic transition: early visceral, poorly localised periumbilical (T10) pain often migrates to a constant, focal RIF somatic pain as parietal peritoneum becomes involved.