Childhood abdominal pain is a very common reason for parents to seek medical advice. The good news is that most childhood abdominal pain is benign and self-limiting, resolving rapidly. However, this means that we need to be especially astute at picking up the more serious cases which can life-threatening.

Pathological causes of abdominal pain¹

1. Visceral pain (splanchnic), e.g. stomach, intestine
2. Parietal pain (somatic) - from parietal peritoneum
3. Referred pain, e.g. pneumonia

Visceral pain is usually dull whilst parietal and referred pain are usually sharp and discrete.

Presentation

History

This varies according to the age of patient.

• Neonates and babies may present with crying and difficulty feeding
• Toddlers - can usually answer simple questions
• Teenagers - may be more embarrassed to talk about the pain
• Ask about duration, location, character
• Associated symptoms include vomiting, diarrhoea, fever, groin pain, urine symptoms, bloody diarrhoea, vaginal discharge
• Also enquire about recent travel history
• Gynaecological and sexual history may also be appropriate

Physical examination

• Does the child look ill?
• Babies may have abnormal facial expressions
• Haemodynamic status - pulse rate, blood pressure in older patients, mucous membranes, urine, e.g. wet nappy
• Rash, e.g. Henoch-Schönlein purpura
• Icteric
• Temperature
• Can you distract the child from the pain?
• Ask patient to suck abdomen in and blow it out.
• Get them to point at the pain with one finger
• Check the abdomen for tenderness, rebound tenderness, guarding, organomegaly, loin pain, bowel sounds
• In males check testes for torsion
• Rectal and vaginal examinations should only be performed if they will provide significant information
• Other system examination as appropriate
• Urine dipstick

Causes

Investigations

• These will depend upon the clinical findings and may not be needed, e.g. viral gastroenteritis
• Urinalysis - microscopy, culture, sensitivities, stone analysis
• Blood tests - capillary blood glucose, plasma glucose, full blood count, renal function, liver function, inflammatory markers, amylase
• Other blood tests if indicated, e.g. paracetamol levels, thyroid function tests
• Stool samples if diarrhoea - microscopy, culture, sensitivity, ova, cysts, parasites
• Abdominal imaging - abdominal X-ray (looking for obstruction), chest X-ray (looking for pneumonia and air under diaphragm), ultrasound scan of the abdomen and testes
• CT scan may also be appropriate
• More specialist investigations, e.g. barium enema will depend upon preliminary findings

Differential diagnosis

A good way to consider the differential diagnosis is according to the patient's age.

Management

This depends on the cause. Self-limiting causes, e.g. gastroenteritis may just require reassurance and simple advice to parents and carers. The advice should include continued use of the child's usual and age-appropriate diet to prevent and limit dehydration.³ Clear liquids should not be substituted for oral rehydration solutions (ORSs) or regular diets to prevent or treat dehydration.³ For other causes, more specific therapies may be required, e.g. surgery in appendicitis, treatment of diabetic ketoacidosis with insulin, fluids and potassium.

Some specific causes

Infantile colic

Synonym: gripe.

• Occurs in babies in first few months after birth month.
• Babies scream, draw up their knees and experience severe pain.
• Episodes can last up to 3 hours and occur often in a week.
• Changes in feed type and routine may help.
• Over-the-counter medicines, e.g. simethicone may help, but have not been proven to be of benefit.⁴

Mesenteric lymphadenitis

• This is associated with adenoviral infection.
• Presents similarly to appendicitis but there is no peritonism.
• The abdominal pain tends to be more diffuse.
• There may also be generalised lymphadenopathy.

Functional abdominal pain⁵

• Consider it in patients with abdominal pain on and off for three months but with otherwise normal investigations.
• There is no clear cause but enhanced sensitivity of the enteric nervous system and stress probably play a role.⁶
• H. pylori infection has not been shown to be a cause.⁷
• It can affect 15% of school age children.
• Management involves reassurance and supportive therapy, e.g. muscle relaxants, antacids.
• Crucially management involves education of patient and carers to prevent the abdominal pain taking over their lives. An example of this is not allowing the abdominal pain be a reason to take time off school.
• Other factors that may help are a good night's sleep, a healthy diet and reduced stress levels.⁸
• Cognitive behavioural therapy and family therapy are also effective.⁹
• The prognosis is good and the condition remits spontaneously.