Summary

Acute appendicitis is the most common surgical emergency worldwide, with a lifetime risk of 7-8%. It typically presents with periumbilical pain migrating to the right iliac fossa (RIF), anorexia, nausea, and low-grade fever. The classic pathophysiology involves luminal obstruction (faecolith, lymphoid hyperplasia) leading to inflammation, ischaemia, and perforation if untreated. Diagnosis is clinical, often supported by CT (adults) or ultrasound (children/young women). Laparoscopic appendicectomy within 24 hours is the gold standard treatment. Recent evidence supports antibiotics as a non-operative alternative in uncomplicated cases, though recurrence rates of 30-40% limit this approach.

Key Facts

• Lifetime Risk: 7-8%
• Peak Age: 10-30 years
• Classic Pain Pattern: Periumbilical → RIF migration (over 6-24 hours)
• Diagnosis: Clinical + CT (adults); Ultrasound (children, pregnant)
• Treatment: Laparoscopic appendicectomy (gold standard)
• Perforation Rate: 20-30% at presentation; higher at extremes of age

Clinical Pearls

"Migration of Pain is Key": The classic periumbilical to RIF migration occurs as inflammation extends from visceral peritoneum (vague, central) to parietal peritoneum (localised, sharp).

"Anorexia is Almost Universal": A patient with RIF pain who is hungry is unlikely to have appendicitis.

"Perforation at Extremes": Children <5 and elderly >65 have higher perforation rates (>50%) due to atypical presentations and delayed diagnosis.

"CT if in Doubt": CT has 98% sensitivity and specificity. Don't hesitate to image if diagnosis is uncertain - reduces negative appendicectomy rates.

Vital Signs

• Low-grade fever (higher if perforated)
• Tachycardia (especially if septic)
• May be dehydrated

Abdominal Examination

Alvarado Score (MANTRELS)

• 0-4: Low risk (discharge)
• 5-6: Intermediate (observe, image)
• 7-10: High risk (surgery)

Outcomes

• Mortality: <0.1% (uncomplicated); 1-4% (perforated, elderly)
• Return to normal activity: 1-2 weeks (laparoscopic)
• Hospital stay: 1-2 days (uncomplicated); 5-7 days (complicated)

Negative Appendicectomy

• Historically 15-25%
• Reduced to <5% with routine CT imaging
• Acceptable rate balances against missed perforation

Long-Term

• No long-term consequences of appendicectomy
• Some studies suggest minor immune/GI effects (not clinically significant)

Key Guidelines

1. WSES Jerusalem Guidelines for Appendicitis (2020)
2. NICE Clinical Knowledge Summaries
3. American College of Surgeons

Key Evidence

CODA Trial (2020)

• Antibiotics non-inferior to surgery at 30 days
• But 29% of antibiotic group required surgery within 90 days
• Faecolith = higher failure rate with antibiotics

CT Imaging

• Meta-analyses show CT reduces negative appendicectomy from 15-25% to <5%

Laparoscopic vs Open

• Cochrane: Laparoscopic reduces wound infections, pain, hospital stay
• Equivalent efficacy

What is Appendicitis?

Appendicitis is inflammation of the appendix, a small tube attached to your large intestine. It's the most common reason for emergency abdominal surgery.

What Are the Symptoms?

• Pain that starts around your belly button and moves to the lower right side
• Loss of appetite (you won't feel hungry)
• Feeling sick or vomiting
• Low fever
• Tenderness when pressing on the lower right abdomen

How is it Treated?

The standard treatment is surgery to remove the appendix (appendicectomy). This is usually done by keyhole (laparoscopic) surgery, which means smaller cuts, less pain, and faster recovery.

In some cases, antibiotics alone may be used, but there's a higher chance the problem will come back.

When to Seek Help

Go to A&E if you have:

• Severe abdominal pain (especially lower right)
• Pain that gets worse when you move, cough, or take deep breaths
• Fever with abdominal pain
• Unable to eat due to pain

After Surgery

Most people go home within 1-2 days and return to normal activities within 1-2 weeks.