Surgery chapters
Abdominal pain in children of different ages
The causes of acute abdominal pain in neonates, infants, preschool children, school-age children and adolescents, how to assess them, and the pitfalls in diagnosing appendicitis in children.
- The cause of abdominal pain depends on age: neonates and infants have surgical obstruction (malrotation, intussusception, hernia, NEC); school-age children mostly have non-specific abdominal pain or appendicitis; adolescent girls add gynaecological causes.
- Persistent right iliac fossa guarding on repeated examination separates appendicitis from non-specific pain; active observation with re-examination is the key tool.
- Under-fives often present with a perforated appendix because the omentum is underdeveloped; always examine the chest, throat, testes and urine.
On this page
Overview
Abdominal pain is one of the commonest reasons children see a doctor. Most cases are self-limiting, but a few are surgical emergencies. The likely causes change with age, so always ask: how old is the child?
Young children cannot describe or localise pain well, so the history from the parents, repeated examination and a full examination of other systems (chest, throat, testes, hernial orifices, urine) are essential.
Causes by age
| Age group | Surgical causes | Medical / other causes |
|---|---|---|
| Neonate (first month) | Malrotation with volvulus, NEC, atresias, Hirschsprung disease, meconium ileus, incarcerated hernia, perinatal testicular torsion | Sepsis, feeding problems, colic |
| Infant (1–12 months) | Intussusception, malrotation with volvulus, incarcerated inguinal hernia, pyloric stenosis (vomiting), testicular torsion | Infantile colic, gastroenteritis, UTI, cow's milk protein allergy, constipation |
| Preschool (1–5 years) | Intussusception, appendicitis (often perforated), Meckel diverticulum, hernia, foreign body | Gastroenteritis, UTI, constipation, pneumonia, HSP, sickle cell crisis |
| School age (5–12 years) | Appendicitis, Meckel diverticulitis, adhesions, testicular / hydatid torsion | Non-specific abdominal pain, "mesenteric adenitis", constipation, UTI, pneumonia, HSP, DKA, abdominal migraine, worms (ascariasis), typhoid |
| Adolescent | Appendicitis, testicular torsion, ovarian torsion / cyst rupture, ectopic pregnancy, cholecystitis, pancreatitis, renal stones, IBD complications | PID, dysmenorrhoea, haematocolpos (imperforate hymen), IBD, peptic ulcer, functional pain |
In children over about 3 years admitted with acute abdominal pain, roughly a third to a half have non-specific abdominal pain, about a third have appendicitis, and most of the rest have benign problems such as constipation or UTI.
Assessment
History
- Onset, site, character, movement of the pain; vomiting (bilious?), anorexia, fever.
- Bowel habit (diarrhoea, constipation, blood), urinary symptoms.
- Recent viral illness, cough, sore throat.
- Rash, joint pain (HSP), polyuria and polydipsia (DKA).
- In girls: menstrual history; in adolescents, a sensitive sexual history in private.
- Perinatal, family and social history; consider abuse in recurrent unexplained pain.
Examination
- Watch the child first: a child with peritonitis lies still; a child with colic writhes.
- Examine a frightened toddler gently, even while asleep on the parent's lap.
- Hop test, coughing, walking bent forward suggest peritoneal irritation.
- Always check: chest (right lower lobe pneumonia), throat and neck nodes, hernial orifices, testes, skin (purpura), and urine.
- Rectal examination is rarely needed; do it only if pelvic appendicitis is suspected and only by the surgeon whose decision it will change.
Active observation
When the diagnosis is unclear, admit, rehydrate, give simple analgesia, and re-examine after a few hours (by the same surgeon if possible). This "active observation" lowers the negative appendicectomy rate (to as low as about 4% in Bailey & Love) and reduces unnecessary scans.
Analgesia does not mask appendicitis. Giving pain relief is correct and makes examination easier.
Investigations
| Test | Use |
|---|---|
| Urinalysis, microscopy, culture | UTI (but sterile pyuria occurs with pelvic appendicitis) |
| FBC, CRP | Raised in appendicitis but not specific |
| Ultrasound | Appendicitis (thick, non-compressible appendix, collection), intussusception, ovarian pathology, renal tract, intra-abdominal fluid |
| Plain abdominal X-ray | Selected cases only, e.g. a preschool child with pain and vomiting (obstruction); may show a faecolith |
| CT | Complex cases (avoid routine use because of radiation) |
| Others as indicated | Blood glucose / ketones (DKA), amylase, pregnancy test in adolescent girls, chest X-ray, stool culture, blood culture, diagnostic laparoscopy |
Non-specific abdominal pain (NSAP)
- It resembles early appendicitis, but the child cannot point to one spot, movement does not worsen the pain, and guarding is absent or comes and goes.
- The site of maximum tenderness changes between examinations.
- Usually settles within 24–48 hours.
- Causes are unclear: viral infections with reactive lymph node enlargement (the old term "mesenteric adenitis", now discouraged), transient intussusception.
Acute appendicitis in children
Classic picture
- Anorexia, a few vomits, central (periumbilical) pain moving to the right iliac fossa.
- Low-grade fever (about 37.3–38.4°C early).
- Localised RIF tenderness and guarding.
- Pain usually comes before vomiting.
The key to diagnosis is right iliac fossa guarding that is still there each time the child is re-examined. NSAP does not show persistent guarding.
Pitfalls
| Pitfall | Why it happens |
|---|---|
| Called "gastroenteritis" because of loose stools | A pelvic appendix or pelvic abscess irritates the rectum |
| Called "UTI" because of dysuria and pyuria | An inflamed appendix lying on the bladder or ureter causes sterile pyuria |
| Missed in under-fives | Poor history, rapid progression; the omentum is short and underdeveloped, so it cannot wall off the inflammation, and perforation is common |
| Confused with right lower lobe pneumonia | Pain from the diaphragmatic pleura is referred to the abdomen (T10–T12) |
| Signs reduced by prior antibiotics | Presentation is delayed and atypical |
Many under-fives with appendicitis present already perforated. This is mainly because of their anatomy and the speed of the disease, not only late diagnosis.
Management
- Resuscitation: IV fluids, analgesia, broad-spectrum antibiotics (covering coliforms and anaerobes).
- Appendicectomy, laparoscopic or open (muscle-splitting RIF incision).
- Perforated appendix: postoperative antibiotics for several days (Basis of Paediatrics quotes 5–7 days), and watch for a pelvic abscess.
- Appendix mass (without obstruction): non-operative treatment with antibiotics, then consider an interval appendicectomy about 6 weeks later.
Meckel diverticulum
In a boy with lower abdominal or groin pain, examine the testes; testicular torsion often presents as abdominal pain.
- Remnant of the vitellointestinal (omphalomesenteric) duct, on the antimesenteric border of the distal ileum.
- May contain ectopic gastric mucosa (or pancreatic tissue). Acid causes an ulcer in the adjacent ileum.
- Classic presentation: a toddler (often under 2 years) with painless, heavy rectal bleeding (maroon or dark red) and anaemia.
- Other presentations: intussusception (as a lead point), volvulus around a band to the umbilicus, diverticulitis (mimics appendicitis), perforation, Littre hernia.
- Diagnosis: technetium-99m pertechnetate scan (picks up gastric mucosa). Treatment: surgical excision.
Rule of 2s: about 2% of people, within about 2 feet of the ileocaecal valve, about 2 inches long, 2 types of ectopic tissue, symptoms usually before age 2.
Other important causes
| Condition | Clues |
|---|---|
| Constipation | Commonest; often over-diagnosed in the acutely ill child because a dehydrated child's X-ray shows faecal loading |
| UTI | Infants: fever, vomiting, poor feeding; older children: dysuria, frequency; confirm by culture, then image the renal tract |
| PUJ obstruction | Episodic loin or abdominal pain, sometimes after large fluid intake, without urinary symptoms |
| Henoch–Schönlein purpura | Purpuric rash on buttocks and legs, arthritis, colicky pain; may cause ileo-ileal intussusception |
| Gastroenteritis | Diarrhoea and vomiting; pain before diarrhoea plus lower abdominal tenderness should raise suspicion of appendicitis |
| Tropical / local causes | Ascariasis (worm bolus obstruction), typhoid (perforation of the terminal ileum), amoebiasis, abdominal TB, which are relevant in Pakistan |
| Others | Sickle cell crisis, primary peritonitis (nephrotic syndrome), pancreatitis, gallstones (haemolytic disease), DKA, lead poisoning |
Recurrent abdominal pain
- Common in school-age children; most is functional (periumbilical, no red flags, normal growth).
- Red flags suggesting an organic cause: pain away from the umbilicus, waking at night, weight loss or poor growth, vomiting, GI bleeding, fever, family history of IBD.
- Psychological stress, bullying or abuse should be considered.
Expect: likely cause of abdominal pain at a given age (intussusception in an infant, appendicitis in a school child, ovarian torsion in a teenage girl), NSAP as the commonest diagnosis, persistent RIF guarding as the key sign of appendicitis, why under-fives perforate, mimics (pneumonia, UTI, gastroenteritis, HSP, DKA), management of appendix mass, Meckel diverticulum features and the pertechnetate scan, and the need to examine the testes and chest.
Quick revision
- Neonate/infant: malrotation, intussusception, hernia, NEC.
- School age: NSAP (commonest), appendicitis (about a third), constipation, UTI.
- Adolescent: add torsion (testis or ovary), ectopic pregnancy, PID.
- Appendicitis: persistent RIF guarding; fever only low-grade early.
- Under-fives perforate early: poor omentum.
- Mimics: pneumonia, UTI, gastroenteritis, HSP, DKA, testicular torsion.
- Appendix mass: antibiotics, interval appendicectomy at about 6 weeks.
- Meckel: painless big rectal bleed in a toddler; pertechnetate scan; excise.
Written by The House Job from standard references (Bailey & Love; Basis of Paediatrics).
FAQ
What is the commonest diagnosis in children admitted with acute abdominal pain?
Non-specific abdominal pain, which settles within a day or two; appendicitis is next.
Why does appendicitis perforate more often in children under five?
Their omentum is short and underdeveloped, so it cannot wall off the inflamed appendix, and the history is harder to obtain.
Can a chest infection cause abdominal pain in a child?
Yes. Right lower lobe pneumonia can cause right-sided abdominal pain that mimics appendicitis, so always examine the chest.
How does a bleeding Meckel diverticulum present?
As painless, heavy, dark red or maroon rectal bleeding in a young child, from an ileal ulcer next to ectopic gastric mucosa.