CHAPTER 2

The child with abdominal pain

Abdominal pain is common in school-aged children and is rarely organic.

History

• Duration and location [right upper quadrant pain in hepatitis, Gilbert's syndrome and non-alcoholic steatohepatitis (NASH)]
• Associated symptoms: vomiting, dyspepsia, diarrhoea, fever, groin pain, urinary symptoms
• Blood in stool
• Vaginal discharge
• Foreign travel
• Gynaecological and sexual history
• Family history: inflammatory bowel disease, coeliac disease, migraine, irritable bowel syndrome, gallstones, pancreatitis

Investigations

• Urinalysis: haematuria in renal stones, pyuria in urinary tract infection
• Urine microscopy, culture, sensitivities
• Blood tests: blood glucose, FBC, renal function, liver function, inflammatory markers, amylase, cholesterol, triglycerides
• 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, e.g. if looking for obstruction
  • Chest X-ray, e.g. for pneumonia or air under the diaphragm
  • Ultrasound scan of the abdomen, kidneys, pelvis (females) and testes (males)
  • CT scan may also be appropriate, especially if there is a mass, trauma, jaundice or pancreatitis
• Endoscopy: will depend upon preliminary findings and history; in the absence of any abnormality on blood screen and imaging, negative endoscopy is very likely

Causes

Well child

• Functional bowel disease: recurrent abdominal pain of childhood, abdominal migraine
• Lactose intolerance: worse with dairy products (ice cream and chocolate are high lactose)
• Gastro-oesophageal reflux ± oesophagitis: dyspepsia, epigastric pain, regurgitation
• Constipation: hard, infrequent stools, soiling
• Renal pelvic/ureteric obstruction: intermittent colicky loin pain
• Coeliac disease: variable association with iron deficiency, diarrhoea, oral ampthous ulceration
• Food allergy (see Chapter 12)
• NASH: associated with obesity and metabolic syndrome

Febrile child

• Gastroenteritis (bacterial or viral)
• Mesenteric adenitis
• Urinary tract infection (lower abdominal pain, loin pain – suggests pyleonephritis)
• Pneumonia
• Inflammatory bowel disease
• Liver abscess

The ill child

• Diabetic ketoacidosis: check urine for glucose, blood gases
• Mesenteric lymphadenitis: fever, often with associated tonsillitis or pharyngitis
• Peptic ulcer disease: sharp epigastric pain after meals
• Hepatitis: raised liver transaminases ± jaundice; see Chapter 21
• Pancreatitis: high amylase, bilirubin and transaminases may be raised
• Ultrasound: biliary dilatation may be seen in acute pancreatitis
• DNA: PRSS1 mutations in familial pancreatitis, raised serum amylase and lipase
• Sickle cell anaemia/crisis: blood film shows sickle cells
• Henoch–Schönlein purpura: characteristic vasculitic rash, haematuria or proteinuria
• Acute adrenal failure: hyponatraemia ± hyperkalaemia, check for inappropriate urinary sodium losses

Surgical causes

• Appendicitis: low-grade fever, central then right iliac fossa pain, unable to stand (psoas irritation), beware of atypical symptoms
• Bowel obstruction, e.g. intussusception, volvulus: bilious vomiting, abdominal distension, tenderness
• Trauma, e.g. haematoma, pancreatitis, liver trauma: may present several days after the event. Low haemoglobin, CT scan will identify liver laceration/pancreatic transection or liver abscesses
• Incarcerated hernia: groin or scrotal swelling/discolouration/pain
• Peritonitis: rigid abdomen or distension with tenderness
• Liver abscess: ultrasound – abscess(es) in liver, raised white cell count, blood culture or aspirate from the abscess may grow pathogen (most commonly Streptococcus or Klebsiella)
• Gallstones/cholecystitis: sickle cell on blood film, raised bilirubin if obstruction, abnormal transaminases, high amylase if the ampulla of Vater is affected, cholesterol or triglycerides may be high, ultrasound – acoustic shadow (Figure 2.1), biliary dilatation if the gallstone is causing obstruction
• Testicular torsion: scrotal swelling, tenderness, discolouration
• Ureteric calculi: colicky pain, macro- or micro-scopic haematuria

Figure 2.1 Ultrasound scan appearance of gallstones with acoustic shadows. The gallbladder wall (marked with crosses) is irregular and thick, consistent with chronic cholecystitis.

Gynaecological causes

• Dysmenorrhoea or endometriosis: prior and/or during menstrual bleed
• Mittelschmerz: mid-cycle colicky pain
• Pelvic inflammatory disease: fever variable

Obstetric causes

• Ectopic pregnancy: sudden onset with shock or peritonism
• Ovarian cyst rupture/torsion
• Miscarriage/abortion/retained foetal products

Drugs/toxins

• Paracetamol overdose
• Iron overdose
• Venoms: spider bite, scorpion sting
• Soap ingestion
• Erythromycin

Referred pain

• Usually musculoskeletal: examine for scoliosis, joint tenderness

Rare causes

• Angioneurotic oedema: episodic, rash or facial/lip swelling – allergy/immunology referral
• Familial Mediterranean fever or systemic lupus erythematosis: episodic fever and raised inflammatory markers with extra-intestinal symptoms – rheumatology referral
• Acute intermittent porphyria: episodic, send urine for porphyrins during an attack
• Peptic ulcer disease – often associated with Helicobacter pylori infection

• No evidence of an inflammatory, anatomical, metabolic or neoplastic process
• Symptoms: at least once a week for at least 2 months before diagnosis

• Persistent or recurrent pain or discomfort above the umbilicus
• Not relieved by defecation or associated with the onset of a change in stool frequency or stool form

Abdominal discomfort or pain associated with two or more of the following at least 25% of the time:

• Improved with defecation
• Onset associated with a change in frequency of stool
• Onset associated with a change in form (appearance) of stool

• Episodic or continuous abdominal pain
• Insufficient criteria for other functional gastrointestinal disorders

• Must include: functional abdominal pain at least 25% of the time and either some loss of daily functioning or additional somatic symptoms such as headache, limb pain or difficulty in sleeping

Criteria:

• Two or more times in the preceding 12 months
• Paroxysmal episodes of intense peri-umbilical pain lasting >1 hour
• Intervening periods of usual health lasting weeks to months
• Pain interferes with normal activities
• Pain is associated with two or more of the following:
  • Anorexia
  • Nausea
  • Vomiting
  • Headache
  • Photophobia
  • Pallor

• Unintentional weight loss
• Growth failure or slowing
• Unexplained fever
• Chronic severe diarrhoea or significant vomiting
• Gastrointestinal bleeding
• Family history of inflammatory bowel disease
• Persistent chronic right iliac fossa or right upper quadrant pain
• Recurrent pancreatitis: consider hereditary pancreatitis or lipidaemia

Associated with:

• Haemolysis
• Prematurity
• Cystic fibrosis
• Down's syndrome
• Bone marrow and cardiac transplantation
• Childhood cancer
• Spinal surgery/injury
• Hepatobiliary trauma
• Selective IgA deficiency
• Dystrophia myotonica
• Chronic intestinal pseudo-obstruction
• Cholestatic liver disease (especially progressive familial intrahepatic cholestasis)
• Congenital anomalies

There is a bimodal incidence with initial peaks in infancy and adolescence; more common in females.

• In infancy: poor feeding, vomiting and jaundice
• In older children: right upper quadrant or epigastric pain, nausea, vomiting and obstructive jaundice

• Stones cast acoustic shadow on ultrasound and a thick-walled gallbladder (see Figure 2.1)

• Infants: gallstones may resolve
• Older children: resolution is unlikely
• Surgery is only required if symptomatic or there is bile duct dilatation
• Laparoscopic...