Acute Appendicitis: Signs, Scores and Management

Acute appendicitis is inflammation of the appendix and the most common surgical emergency of the abdomen worldwide. It can happen at any age but is most common in children and young adults. Delayed diagnosis leads to perforation, peritonitis and abscess formation.

Cause

Obstruction of the appendix lumen, for example by a faecolith or lymphoid hyperplasia, leads to bacterial overgrowth, inflammation, ischaemia and, if untreated, perforation.

Clinical features

• Pain that starts around the umbilicus (visceral pain) and then moves to the right iliac fossa as the parietal peritoneum becomes inflamed.
• Loss of appetite (anorexia), nausea and vomiting.
• Low-grade fever.
• Signs:
  • tenderness at McBurney's point (one-third of the way from the anterior superior iliac spine to the umbilicus)
  • guarding
  • rebound tenderness
  • Rovsing's sign (pressing the left iliac fossa causes pain in the right)
  • psoas sign (retrocaecal appendix)
  • obturator sign (pelvic appendix)
• Atypical presentations are common in:
  • young children
  • older people
  • pregnant women (the appendix is displaced upwards)
  • retrocaecal or pelvic appendix

Differential diagnosis

• Mesenteric adenitis (in children).
• Gastroenteritis.
• Ureteric colic and urinary tract infection.
• Constipation.
• Meckel's diverticulitis.
• Crohn's disease.
• In women:
  • ectopic pregnancy
  • ovarian cyst rupture or torsion
  • pelvic inflammatory disease

Investigations

• Pregnancy test in every woman of reproductive age.
• Blood tests: full blood count (raised white cells) and CRP.
• Urinalysis: to exclude urinary causes. Mild pyuria can occur in appendicitis.
• Scoring systems: for example the Alvarado score or the Appendicitis Inflammatory Response score, to estimate risk.
• Imaging:
  • Ultrasound first in children and pregnant women.
  • CT in adults when the diagnosis is uncertain.
  • MRI in pregnancy if ultrasound is inconclusive.

Management

• Nil by mouth.
• IV fluids.
• Analgesia. Pain relief does not mask the diagnosis and should not be withheld.
• Antibiotics according to local guidelines.
• Appendicectomy, usually laparoscopic, is the standard treatment.
• Antibiotics-only treatment is an option for some adults with uncomplicated appendicitis confirmed on CT. There is a risk of recurrence, and the decision should be shared with the patient.
• Appendix mass or abscess: often initial antibiotics with percutaneous drainage, then possible interval appendicectomy.
• Perforation with generalised peritonitis: urgent surgery with peritoneal washout.

Complications

• Perforation.
• Peritonitis.
• Appendix mass or abscess.
• Sepsis.
• After surgery:
  • wound infection
  • intra-abdominal collection
  • ileus
  • adhesions

Exam pearls

• Pain moving from the umbilicus to the right iliac fossa, with anorexia, is the classic story.
• Always do a pregnancy test in women. Ectopic pregnancy must not be missed.
• Children under 5 and older adults perforate early because diagnosis is delayed.

For more, see our Surgery Companion (acute abdomen chapter) and Exam Night Notes 1.0: Gastro Surgery.

Test yourself

5 exam-style single-best-answer questions. Choose your answer, then tap “Show answer”.

1. Classic history of acute appendicitis:

   1. Suprapubic pain with dysuria only
   2. Periumbilical pain moving to the right iliac fossa with anorexia
   3. Left iliac fossa pain with diarrhoea
   4. Epigastric pain radiating to the back
   5. Loin-to-groin colicky pain
   Show answer

   Answer: B. Periumbilical pain moving to the right iliac fossa with anorexia
   Visceral periumbilical pain shifts to the RIF when the parietal peritoneum is involved.

2. Pain in the right iliac fossa when the left iliac fossa is pressed is:

   1. Murphy's sign
   2. Psoas sign
   3. Cullen's sign
   4. Kernig's sign
   5. Rovsing's sign
   Show answer

   Answer: E. Rovsing's sign
   Rovsing's sign supports appendicitis.

3. First investigation in a 24-year-old woman with right iliac fossa pain:

   1. CT abdomen
   2. Pregnancy test
   3. Barium enema
   4. Laparotomy
   5. Colonoscopy
   Show answer

   Answer: B. Pregnancy test
   Ectopic pregnancy must always be excluded in women of reproductive age.

4. First-line imaging for suspected appendicitis in children:

   1. CT
   2. Plain X-ray
   3. Ultrasound
   4. MRI
   5. Nuclear scan
   Show answer

   Answer: C. Ultrasound
   Ultrasound avoids radiation in children and pregnancy.

5. Should analgesia be withheld until a surgeon examines the patient?

   1. Yes, it masks signs
   2. Only opioids are allowed
   3. No, pain relief does not mask the diagnosis
   4. Only in children
   5. Only after CT
   Show answer

   Answer: C. No, pain relief does not mask the diagnosis
   Adequate analgesia does not reduce diagnostic accuracy.

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Disclaimer

For education and exam preparation only. This is not medical advice and must not be used to diagnose or treat patients. Always follow current clinical guidelines and the advice of qualified senior colleagues.