Appendicitis is treatable and, caught before the appendix bursts, carries an excellent outcome. The hard part is the diagnosis. The textbook story — central pain that shifts to the right lower abdomen, fever, and tenderness at McBurney's point — works well in older children and adolescents, but is unreliable in the under-5s, in whom the appendix often sits higher in the abdomen, the pain history is harder to take, and the inflammatory response is less localised.
Miss the diagnosis and the appendix can perforate. A perforated appendix in a child causes peritonitis, abscess formation, and a markedly more complicated recovery — typically several extra days in hospital and a meaningfully higher rate of post-operative complications. Parents who know what to watch for and when to push for an urgent assessment make the difference.
Healthbooq (healthbooq.com) covers childhood surgical conditions and emergencies.
What the Appendix Is and Why It Causes Problems
The appendix is a finger-shaped pouch attached to the caecum, where the small and large intestines meet. It has no settled essential function in humans. Appendicitis happens when the appendix becomes obstructed — usually by a faecolith (a hard piece of stool), by swollen lymph nodes from a recent gut infection, or occasionally by other material — leading to bacterial overgrowth, inflammation, and, if untreated, perforation within 48–72 hours.
The peak age is 10–14 years. Appendicitis is less common under 5 but more dangerous in this group: the omentum (the fatty apron of tissue that can wall off infection in older children) is less developed, the child can't describe symptoms well, and clinicians may anchor on viral gastroenteritis. Roughly 30–60% of children under 5 present with a perforated appendix, compared with about 10–20% of older children.
The Classic Presentation
In older children and teens, appendicitis usually starts with central or umbilical pain — visceral pain from the inflamed appendix that the gut nerves localise poorly. Over the next 12 to 24 hours, the pain migrates to the right lower quadrant as the inflammation reaches the parietal peritoneum, which is well supplied with somatic nerves and produces sharp, well-localised pain.
Other typical features:
- Low-grade fever — usually 37.5–38.5°C in early appendicitis, climbing higher with perforation
- Nausea and vomiting that come after the pain (vomiting first, then pain, points more towards gastroenteritis)
- Loss of appetite — almost universal; a child asking for food rarely has appendicitis
- Reluctance to move, jump, or cough — movement worsens peritoneal pain
- A child who walks bent forward, climbs onto the examination couch slowly, or who cannot hop on the right leg
McBurney's point is the classic site of maximal tenderness, one-third of the way along an imaginary line from the right anterior superior iliac spine (the bony hip bump) to the navel. Rebound tenderness — pain that is worse when the examiner releases pressure than when it is applied — and Rovsing's sign — pain felt in the right lower quadrant when the left lower quadrant is pressed — both indicate peritoneal irritation.
Atypical Presentations
Children under 5 frequently break the rules. Pain may be diffuse and poorly described. Fever may be higher early on. The child may simply be irritable, refusing food, and unwilling to walk. Because so many common childhood illnesses look similar in this group, you have to keep appendicitis on the list.
A child who has had central tummy pain for 24 hours and is now refusing to walk, lying still with their legs drawn up, and not interested in food should be assessed urgently — even if you can't pinpoint pain to the right lower quadrant.
Girls approaching puberty add a layer of difficulty: ovarian cysts, ovarian torsion, and Mittelschmerz can all produce right-sided pain that overlaps with appendicitis. Pelvic ultrasound usually distinguishes them.
Investigations
White cell count and C-reactive protein (CRP) are usually raised in appendicitis but are non-specific. CRP roughly tracks severity — a CRP above 100 mg/L raises the likelihood of perforation. Urinalysis is essential to exclude a urinary tract infection, which can produce right-sided abdominal pain and a mild white cell rise that mimics appendicitis.
The Paediatric Appendicitis Score (PAS), developed by Madan Samuel in 2002 (Journal of Pediatric Surgery), combines clinical and lab findings to stratify low, intermediate, and high probability — a PAS of 7 or more has high specificity for appendicitis. The Alvarado score is widely used in adults and older teenagers.
Ultrasound is first-line imaging in children; it avoids radiation and, in good hands, has sensitivity of 80–90%. It is operator-dependent, and the appendix isn't always visualised. If ultrasound is inconclusive and clinical concern remains high, MRI is preferred over CT in children to avoid ionising radiation, though CT is faster and more reliable when MRI is unavailable or the child is unstable.
Treatment
Appendectomy — surgical removal of the appendix — is the definitive treatment. Laparoscopic (keyhole) appendectomy is now the standard approach in most UK paediatric surgical centres. Recovery is shorter than open surgery (typical hospital stay 1–2 days for uncomplicated cases), and wound infection rates are lower.
Non-operative management — antibiotics alone, no surgery — is an active area of research. The APPY-1 and COMPASS trials have explored it. It avoids surgery in the short term but carries a 20–30% rate of recurrence requiring eventual appendectomy within 5 years. It isn't current standard practice in UK paediatric surgery, though it is offered in selected uncomplicated cases at some specialist centres.
A perforated appendix is managed with appendectomy plus IV antibiotics, with hospital stays typically 4–7 days. If a well-formed abscess is present, initial percutaneous drainage followed by interval appendectomy 6–8 weeks later is sometimes used.
Key Takeaways
Appendicitis is the most common surgical emergency in childhood, with a lifetime risk of around 7% and a peak incidence between 10 and 14 years. The classic story is central tummy pain that shifts to the right lower abdomen, with fever, nausea, loss of appetite, and reluctance to move. In children under 5 the presentation is often atypical and diagnosis is often delayed — perforation rates in children reach 30–40% at presentation, compared with around 20% in adults. The Paediatric Appendicitis Score (PAS) and Alvarado score are validated clinical tools. Ultrasound is first-line imaging in children; MRI is preferred over CT if ultrasound is inconclusive. Treatment is appendectomy, increasingly laparoscopic; antibiotics-alone management is used in selected uncomplicated cases at some specialist centres.
