Summary

Acute Appendicitis is the inflammation of the vermiform appendix, typically caused by luminal obstruction (faecolith or lymphoid hyperplasia). It is the most common cause of the "Acute Abdomen" requiring surgery, with a lifetime risk of ~8%. The classic presentation involves migratory pain (central abdominal pain shifting to the Right Iliac Fossa), associated with anorexia, nausea, and low-grade fever. While diagnosis is clinical, CT imaging is increasingly standard in adults to reduce negative appendicectomy rates. Treatment is primarily Laparoscopic Appendicectomy, though antibiotics alone can be used in selected uncomplicated cases (with higher recurrence risk).

Key Facts

• Lifetime Risk: 7-9%.
• Peak Incidence: 10-30 years.
• Classic Triad (Murphy's): Pain -> Nausea/Vomiting -> Fever. (Pain almost always comes first).
• Sign: Tenderness at McBurney's Point (1/3 distance from ASIS to Umbilicus).
• Gold Standard Tx: Laparoscopic Appendicectomy.
• Mimics: Ectopic Pregnancy, Ovarian Cyst, Mesenteric Adenitis, Crohn's Disease.

Clinical Pearls

"The Pain Migrates": The initial pain is Visceral (T10 dermatome - Umbilicus) due to distension. As the inflammation reaches the parietal peritoneum, the pain becomes Somatic (Localised to RIF). This takes 6-24 hours.

"Don't forget the urine": A retrocaecal appendix lies on the ureter. Inflammation can cause microscopic haematuria or pyuria, mimicking a UTI. Don't be fooled by "positive dipstick".

"The hunger strike": Anorexia (loss of appetite) is a very sensitive symptom. A child who asks for a burger probably doesn't have appendicitis ("The Hamburger Sign").

"Rectal Exam?": Rarely useful or done now. Only helpful for a deep pelvic appendix causing tenderness on the right side of the rectum.

Alvarado Score (MANTRELS)

• Migratory pain (1)
• Anorexia (1)
• Nausea/Vomiting (1)
• Tenderness in RIF (2)
• Rebound tenderness (1)
• Elevated Temperature (1)
• Leukocytosis (2)
• Shift to left of neutrophils (1)

Interpretation:

• <4: Unlikely.
• 5-6: Possible (Observe/Image).
• 7-10: Probable (Surgery).

          ACUTE RIGHT ILIAC FOSSA PAIN
                     ↓
        CLINICAL ASSESS + ALVARADO SCORE
                     ↓
      ┌──────────────┼───────────────┐
    LOW RISK       EQUIVOCAL       HIGH RISK
    (<4)           (5-6)           (>7)
      ↓              ↓               ↓
  DISCHARGE      CT IMAGING      SURGERY
  (Return advice)    │           (Lap Appy)
                     │
          ┌──────────┴──────────┐
        NORMAL               INFLAMED
          ↓                     ↓
     OBSERVE / MIMIC         SURGERY

1. Antibiotics Only (Conservative)

• Indication: Uncomplicated appendicitis (No faecolith, no perforation).
• Evidence (CODA Trial):
  • 70% success rate avoiding surgery at 1 year.
  • 30% recurrence rate requiring surgery later.
  • Conclusion: Antibiotics are a safe alternative, but surgery is definitive. Most patients choose surgery to "get it over with".

2. Surgical: Appendicectomy

• Laparoscopic (Keyhole):
  • Standard of care.
  • 3 Ports (Umbilicus, Suprapubic, LIF).
  • Better diagnostic view (can check ovaries etc).
  • Fewer wound infections.
• Open (Gridiron):
  • McBurney or Lanz incision.
  • Rarely done now unless conversion needed or lack of equipment.

Steps

1. Access: Pneumoperitoneum. Ports inserted.
2. Survey: Confirm diagnosis. Check for Meckel's Diverticulum (distal ileum).
3. Dissection: The appendix is held. The Mesoappendix (containing the Appendicular Artery) is divided using Diathermy or Clips.
4. Base Division: The base of the appendix (at the caecum) is secured with Endoloops (sutures) or a Stapler.
5. Extraction: Appendix removed in a bag (to prevent wound infection).
6. Washout: Saline irrigation if pus present.

Hazards

• Stump Blowout: If the tie necrotic base is not secure.
• Bleeding: From the appendicular artery.

• Definition: Removing a normal appendix.
• Rate: Historically 20-30%. With CT, now <5-10%.
• Rule: If you go in and the appendix looks normal, look for other causes (Meckel's, Ovarian cyst, Crohn's). If no other cause found, REMOVE IT ANYWAY. (Why? Prevents future diagnostic confusion, and microscopy might show early inflammation).

Key Trials

1. CODA Trial (NEJM 2020): Antibiotics vs Appendicectomy. Confirmed safety of antibiotics but highlighted recurrence risk.
2. LISA Trial: Laparoscopic vs Open. Laparoscopic has less pain, shorter stay, faster return to work.

What is Appendicitis?

The appendix is a small, finger-sized tube attached to the large bowel. It has no essential function. If it gets blocked (by poop or swelling), it becomes infected and swollen.

Is it dangerous?

Yes. If left untreated, it can burst (perforate), spreading infection throughout the tummy (peritonitis), which is life-threatening.

What are the symptoms?

Usually a tummy ache that starts in the middle (belly button) and moves to the lower right side. You may feel sick, vomit, and have a fever. It hurts to cough or move.

How is it treated?

The best treatment is to remove it with surgery (Appendicectomy). This is usually done with "keyhole" surgery (small cuts) under general anaesthetic. You can live perfectly well without an appendix. In some mild cases, antibiotics can be used, but there is a chance it will come back.