Acute Appendicitis — Comprehensive Overview

Etiology (Causes)

• Fecaliths (hardened stool — most common in adults) — also the most important predictor of perforation
• Lymphoid hyperplasia — the predominant cause in children, triggered by enteric infections (viral/bacterial gastroenteritis, respiratory infections)
• Vegetable/fruit seeds, barium, parasites (e.g., Enterobius vermicularis, Ascaris)
• Tumours (carcinoid, mucocele) — rare, more relevant in adults

Symptoms

Classic Presentation (Adults & Older Children)

Classic Physical Signs

• McBurney's point tenderness — 2/3 of way from umbilicus to ASIS
• Rovsing's sign — LLQ pressure causes RLQ pain (peritoneal irritation)
• Psoas sign — RLQ pain on right hip extension (retrocaecal appendix)
• Obturator sign — RLQ pain on internal rotation of right flexed hip (pelvic appendix)
• Rebound tenderness (Blumberg sign) — suggests peritoneal irritation
• Guarding and rigidity — muscular defense

Complications

Treatment

1. Non-Operative Management (Antibiotics Alone)

• Viable option for uncomplicated appendicitis (no fecalith, no perforation, no abscess)
• Broad-spectrum IV antibiotics (e.g., piperacillin-tazobactam, or ceftriaxone + metronidazole)
• Resolution in 80–90% of cases within 24–48 hours
• Drawback: recurrence rate up to 40% at medium-term follow-up → many surgeons use it as a bridge to elective interval appendectomy
• Patients with fecaliths are excluded from non-operative management

2. Operative Management (Standard of Care)

• Laparoscopic appendectomy — gold standard; preferred in adults and children alike
• Performed within 12–24 hours of diagnosis
• Open appendectomy reserved for laparoscopic conversion situations
• Preoperative: IV fluids, analgesia, IV antibiotics
• Same-day discharge possible in early uncomplicated disease

3. Complicated Appendicitis (Perforated/Abscess)

• Peritonitis + haemodynamic instability → emergency surgery
• Localised abscess/phlegmon present >5 days → non-operative approach first:
  • IV antibiotics
  • Interventional radiology (IR) drain if accessible abscess present
  • Followed by interval appendectomy at 6–8 weeks
• Antibiotic duration guided by: fever, leukocytosis, source control status, ileus

Peculiarities in Children — General

⚠️ Peculiarities in Children UNDER 3 Years — Special Emphasis

1. Rarity but High Lethality

• Appendicitis is uncommon under age 5 and rare under age 3, but when it occurs it is a diagnostic emergency
• The smaller, thinner-walled appendix and immature immune/omental response mean the progression from inflammation to perforation is extremely rapid

2. Perforation Rates >50%

"Perforation is highest among children younger than 5 years, among whom more than 50% are ruptured at the time of surgery." — Rosen's Emergency Medicine

3. Atypical and Non-Specific Presentation

• Cannot describe or localise pain — they present with irritability, crying, restlessness
• Parents report refusal to eat, unusual posturing (lying still, flexing legs), lethargy
• Vomiting and diarrhoea are prominent → frequently misdiagnosed as gastroenteritis
• Fever may be the dominant or only finding early on
• The classic periumbilical → RLQ migration of pain is rarely elicitable or described

4. Diagnostic Difficulty

• Clinical signs (McBurney's, Rovsing's, Psoas, Obturator) are not assessable or reliable
• Examination is difficult due to lack of cooperation → tenderness often only detected as crying/guarding on palpation of RLQ
• WBC and CRP are helpful but non-specific
• Paediatric scoring systems (PAS, Alvarado) are not validated in this age group
• Ultrasound is first-line imaging — but visualisation is operator-dependent and may be limited

5. High Misdiagnosis Rate

• Most common misdiagnoses: gastroenteritis, viral illness, intussusception, Meckel's diverticulitis
• Significant delays in seeking care by parents (child "too young to have appendicitis") compound the problem
• By the time diagnosis is made, the disease is often already perforated with generalised peritonitis

6. Clinical Course After Perforation

• Diffuse bacterial peritonitis rather than localised abscess (due to absent omental walling)
• Systemic sepsis develops rapidly
• Toxic appearance: high fever, abdominal distension, lethargy, dehydration
• Ileus and abdominal rigidity ("board-like abdomen") in severe cases

7. Management

• Urgent surgical intervention once diagnosis suspected — do not delay for diagnostic certainty
• Pre-operative IV fluid resuscitation, broad-spectrum antibiotics (covering gram-negatives and anaerobes)
• Laparoscopic appendectomy — standard even in small children; conversion to open is rarely necessary
• Post-operative antibiotics continued based on degree of contamination and clinical response
• Non-operative management with antibiotics generally not favoured in this age group given perforation rate

Ultrasound Image — Acute Appendicitis in a Child

Summary Table — Under 3 Years vs. Older Children

• Schwartz's Principles of Surgery, 11th ed. — Chapter: The Appendix
• Rosen's Emergency Medicine: Concepts and Clinical Practice — Appendicitis (Paediatric)
• Current Surgical Therapy, 14th ed. — Paediatric Appendicitis