AKT · Gastroenterology/Acute abdomen & surgical

Appendicitis

Obstruction + inflammation of the appendix (commonest surgical abdominal emergency)

Overview

Inflammation of the appendix, usually from luminal obstruction (faecolith/lymphoid hyperplasia) — the commonest cause of the acute surgical abdomen. Classic migration of central/periumbilical pain to the right iliac fossa (McBurney point) with anorexia, nausea and low-grade fever. A largely clinical diagnosis; treated by appendicectomy. Perforation → peritonitis/abscess. Beware atypical presentations (children, elderly, pregnancy, retrocaecal/pelvic appendix).

Recognise

Central/periumbilical pain MIGRATING to the right iliac fossa (McBurney point), anorexia, nausea/vomiting, low-grade fever
Signs: RIF tenderness/guarding, rebound/percussion tenderness, Rovsing sign (LIF palpation → RIF pain), psoas/obturator signs (retrocaecal/pelvic)
Raised WCC/CRP; perforation → generalised peritonitis or a localised appendix mass/abscess

Red flags

Generalised peritonitis (perforation) → emergency
Atypical/missed in young children, elderly, pregnancy (appendix displaced up) — lower threshold to image

Differentials & how to tell them apart

Mesenteric adenitischildren, post-viral, higher fever, less localised — self-limiting

Gynaecological (ectopic, ovarian torsion/cyst, PID)women — pregnancy test, pelvic exam/ultrasound mandatory

Meckel diverticulitis / terminal ileitismimics RIF appendicitis

Ureteric colic / UTIloin-to-groin pain / dysuria, urinalysis

Investigations

Clinical (± scoring e.g. Alvarado). FBC/CRP (raised), urinalysis (exclude UTI), pregnancy test. ULTRASOUND (children/women — also excludes gynae causes); CT in adults/diagnostic doubt.

Management

Appendicectomy (IV antibiotics + fluids peri-operatively)

1Resuscitate (IV fluids, analgesia, antibiotics) and refer for appendicectomy. Pregnancy test and urinalysis in everyone; ultrasound in children/women to exclude gynae/urological mimics.Gate: ALWAYS do a pregnancy test and consider gynaecological causes in a woman with RIF pain (ectopic/torsion) before labelling it appendicitis; atypical groups (children, elderly, pregnancy, retrocaecal appendix) present atypically — image with a low threshold
2Appendix mass/abscess → antibiotics ± drainage and interval appendicectomy; perforation/peritonitis → urgent surgery.

Appendicectomy (laparoscopic) — definitive treatment

IV antibiotics + analgesia + fluids — resuscitation pre-op; antibiotic-only management in selected uncomplicated cases

Key points

Migrating central→RIF pain + anorexia + low fever + McBurney tenderness = appendicitis → appendicectomy. The non-negotiables: pregnancy test + gynae causes in women, and atypical presentations in children/elderly/pregnancy.

Monitor & prognosis

Post-op recovery; complications.

Excellent with timely surgery.

Source: NICE; ACPGBI; RCS