Functional abdominal pain disorders in children

Functional abdominal pain disorders (FAPDs) in children, also called abdominal pain-related disorders of gut-brain interaction, are a group of conditions characterized by chronic or recurrent abdominal pain that cannot be attributed to an organic cause. FAPDs comprise irritable bowel syndrome (IBS), abdominal migraine, functional dyspepsia, and functional abdominal pain not otherwise specified (NOS). FAPDs are diagnosed clinically based on the Rome IV diagnostic criteria for each condition, a normal physical examination, and no concerns for an organic cause. Diagnostic studies are indicated for signs of pediatric organic abdominal pain and/or diagnostic uncertainty. Management is condition-specific and includes nonpharmacological and pharmacological interventions (e.g., antispasmodics, antiemetics). Specialist referral is recommended for severe manifestations, refractory symptoms, and/or continued diagnostic uncertainty.

• Approximately 10–15% of children are affected worldwide. ^[1][2]
• ♀ > ♂ ^[2][3]

Epidemiological data refers to the US, unless otherwise specified.

• Dysregulation of the gut–brain axis ^[1]
• Often associated with anxiety, depression, trauma, and psychological stress ^[2][3]

Features of pediatric functional abdominal pain ^[1][4]

See individual conditions (e.g., IBS in children) for specific clinical features.

• Recurrent or chronic abdominal pain, typically with the following:
  • Stable or fluctuating (nonprogressive) pattern
  • Diffuse or periumbilical localization (epigastric in functional dyspepsia)
  • Improvement with distraction
• No evidence of an organic disease
• Often associated with stressors and/or psychological conditions (e.g., anxiety, depression)

Features of pediatric organic abdominal pain ^[4][5]

Abdominal pain that is associated with red flags for acute abdominal pain in children and/or any of the following:

• Systemic features
  • Fever
  • Growth faltering
  • Delayed puberty
  • Arthritis
• Persistent or progressive symptoms
  • Diarrhea, including persisting at night
  • Vomiting
  • Abdominal distention
• Focal localization
  • Dysphagia
  • Odynophagia
  • Right upper quadrant and/or right lower quadrant pain
  • Gastrointestinal bleeding
  • Perirectal disease
  • Genitourinary symptoms or findings
  • Abdominal or retroperitoneal mass palpated on examination
• Functional impairment
  • Frequent school absences
  • Disrupts daily activities
• Positive family history of an organic GI condition, e.g.,:
  • Inflammatory bowel disease
  • Celiac disease
  • Peptic ulcer disease

Patients with multiple features of organic abdominal pain have an increased likelihood of an organic cause of pediatric abdominal pain. ^[4][5]

Recurrent or chronic organic causes of abdominal pain in children include: ^[3][5][6]

• Gastrointestinal disorders
  • GERD in children
  • Inflammatory bowel disease in children
  • Infectious gastroenteritis in children
  • Eosinophilic esophagitis
  • Erosive esophagitis
  • Hiatal hernia
  • Peptic ulcer disease
  • Food allergy
  • Chronic pancreatitis
  • Autoimmune conditions (e.g., celiac disease, polyarteritis nodosa, familial Mediterranean fever)
  • Cyclical vomiting syndrome
  • Pediatric constipation
• Urogenital disorders
  • Ureteropelvic junction obstruction
  • Pelvic inflammatory disease
  • Endometriosis
  • Dysmenorrhea
• Hematological and oncological
  • Sickle cell disease
  • Malignancy (e.g., lymphoma, spinal tumor)
• Toxin-mediated: lead poisoning

The differential diagnoses listed here are not exhaustive.

Approach ^[3][4][5][7]

• Perform a clinical evaluation for pediatric abdominal pain.
• Diagnose a functional abdominal pain disorder clinically if all of the following are met:
  • Rome IV diagnostic criteria (see individual conditions)
  • Normal or nonfocal physical examination
  • No features suggesting an organic cause
• For atypical presentation and/or signs of pediatric organic abdominal pain, consider targeted testing.
• Initiate management based on the identified cause.
• Screen for and optimize management of comorbidities (e.g., anxiety, depression).
• Address quality of life and functional impairment.
• Refer to a pediatric specialist (e.g., dietician, gastroenterology, neurology) for:
  • Dietary recommendations ^[8]
  • Diagnostic uncertainty, including suspected or confirmed organic cause
  • Severe and/or refractory symptoms

Patients may meet the criteria for more than one functional gastrointestinal disorder. ^[4]

Individuals with functional abdominal pain disorders report quality of life impairment comparable to those with inflammatory bowel disease. ^[7]

Targeted testing for suspected organic abdominal pain ^[5]

For acute abdominal pain, see "Diagnostics for acute abdominal pain in children." Obtain testing based on clinical evaluation and suspected diagnosis, e.g.:

• Anemia: CBC with differential, iron studies
• Inflammation: ESR and/or CRP
• Chronic diarrhea: fat-soluble vitamin levels, stool studies
• Risk factors for STIs and/or vaginal or urethral discharge: STI testing
• Hepatobiliary disease: liver chemistries
• Symptoms of celiac disease : diagnostics for celiac disease
• Dyspepsia: H. pylori stool antigen test
• GI bleeding: stool guaiac test and/or diagnostics for IBD in children
• Patients who can become pregnant: pregnancy test
• Imaging (e.g., ultrasound abdomen with or without pelvis, EGD, x-ray) as indicated

IBS occurs in ∼ 6% of children. ^[2]

Rome IV diagnostic criteria for IBS in children ^[3][4]

All of the following criteria must be fulfilled for diagnosis:

• Abdominal pain occuring ≥ 4 days/month for ≥ 2 months with ≥ 1 of the following: ^[3][4]
  • Association with bowel movements
  • Change in stool frequency
  • Change in stool appearance
• In children with IBS-C, abdominal pain is not relieved with the resolution of constipation.
• Symptoms cannot be attributed to another cause after appropriate evaluation.

If abdominal pain improves with the resolution of constipation, the etiology is likely functional constipation. ^[4]

IBS subtypes ^[4]

Subtypes are analogous to the IBS subtypes in adults (e.g., IBS-D, IBS-C, IBS-M, IBS-U)

Management of IBS in children ^[1]

Initial management ^[1]

• Patient education
• Brain-gut-directed psychological therapies: hypnotherapy (preferred), CBT
• Dietary supplements (e.g., soluble dietary fiber, lactobacillus rhamnosus GG probiotics)
• Subtype-specific pharmacological treatments
  • IBS-D: loperamide (off-label) or bile acid sequesterants (off-label)
  • IBS-C: laxatives (off-label), linaclotide (if ≥ 7 years of age) ^[9]
• The following may be considered: ^[1]
  • Anticholinergic antispasmodic therapy: hyoscyamine (off-label), dicyclomine (off-label)
  • Nonopioid oral analgesia in children (only for intermittent or episodic pain)

Additional interventions ^[1]

• Neuromodulation with percutaneous electrical nerve field stimulation (PENFS) ^[1]
• The following options may be suggested: ^[1]
  • Multi-strain probiotics or prebiotics
  • Enteric-coated peppermint capsules
  • Domperidone (not available in the US)
  • Cyproheptadine (off-label)
  • Amitriptyline (off-label)
• Referrals as indicated (e.g., dietician, pain management program)

Linaclotide is the only pharmacological treatment approved for IBS in children. ^[9]

Abdominal migraine affects < 5% of children and may be associated with and/or precipitated by triggers of migraine headache. ^[3][10]

Rome IV diagnostic criteria for pediatric abdominal migraine ^[4]

Diagnose abdominal migraine if all of the following have occurred ≥ 2 times over a period of ≥ 6 months: ^[4]

• Episodes of severe periumbilical, midline, or diffuse abdominal pain lasting ≥ 1 hour ^[4]
• Pain that significantly interferes with activities of daily living
• Stereotypical pattern of episodes in the affected individual
• Pain associated with ≥ 2 of the following: ^[4]
  • Anorexia
  • Nausea
  • Vomiting
  • Headache
  • Photophobia
  • Pallor
• Weeks or months between episodes
• Symptoms cannot be attributed to another cause after appropriate evaluation.

Abdominal migraine has a stereotypical symptom pattern, and abdominal pain is the most severe and distressing symptom. ^[3][10]

Management ^[10][11][12]

Pediatric abdominal migraine is uncommon, and available studies are limited; management is extrapolated from pediatric migraine guidelines. ^[1]

Acute interventions ^{[4][10][11][12]}

• Rest in a dark and quiet room.
• Initiate pharmacological treatments for acute migraine in children, e.g.:
  • Nonopioid oral analgesia in children (e.g., ibuprofen, acetaminophen)
  • Intranasal sumatriptan (off-label)
  • Antiemetics in children for nausea and/or vomiting

Preventive interventions

• Lifestyle modifications for migraine prevention: all patients ^[10][11][12]
  • Avoid or minimize migraine triggers.
  • Ensure good sleep hygiene and adequate rest.
• Pharmacological treatment: considered for patients with frequent and/or severe symptoms ^[4][10][13]
  • Consider pharmacological migraine prophylaxis in children. ^[13]
  • Other options: cyproheptadine (off-label) ^[4][10]
• Specialist management
  • Refer to a pediatric specialist (e.g., neurology, gastroenterology) for severe and/or refractory symptoms.
  • Address psychological stressors (e.g., with CBT).

Rome IV diagnostic criteria for pediatric functional dyspepsia ^[4]

• Presence of ≥ 1 symptom on ≥ 4 days of the month for ≥ 2 months ^[4]
  • Epigastric pain or burning not affected by bowel movements
  • Early satiety
  • Fullness after meals
• Symptoms cannot be attributed to another cause after appropriate evaluation.

Subtypes ^[4]

• Postprandial distress syndrome
  • Fullness after meals or early satiety that limits the completion of an age-appropriate meal
  • May have additional features (e.g., upper GI bloating, nausea, and frequent burping) after eating
• Epigastric pain syndrome is abdominal pain or burning with the following features:
  • Severe enough to interfere with daily activities
  • Localized to the epigastric region (not generalized and not localized to other areas)
  • Not improved with the passage of stool or gas per rectum
  • Often worsened or improved with eating; may also occur while fasting

Management ^[3][4][14]

There are no specific guidelines for the management of functional dyspepsia in children. The following options are typically recommended:

• Nonpharmacological interventions
  • Avoidance of NSAIDs
  • Dietary modifications
    • Small, frequent meals
    • Avoidance of triggers (e.g., carbonated beverages, caffeine, spicy and/or greasy food)
  • Management of psychological stressors
  • Referral for CBT if other interventions are not successful
• Pharmacological interventions based on symptoms, e.g.:
  • Postprandial distress syndrome
    • Cyproheptadine (off-label)
    • Prokinetics (off-label), e.g., low-dose erythromycin ethylsuccinate, metoclopramide
    • Buspirone (off-label)
  • Epigastric pain syndrome
    • Acid suppressive therapy (off-label)
    • Cyproheptadine (off-label)
  • Additional options
    • Neuromodulators, e.g., tricyclics (e.g., amitriptyline), mirtazapine
    • Antiemetics in children for nausea (short-term intermittent use)

Functional abdominal pain NOS is difficult to distinguish from IBS in children. ^[1]

Rome IV diagnostic criteria for functional abdominal pain-NOS in children ^[4]

Diagnose functional abdominal pain NOS in children with all of the following:

• Episodic or continuous abdominal pain ≥ 4 times/month for ≥ 2 months that does not solely occur during physiological events (e.g., during menses, after meals) ^[4]
• Criteria for other pediatric FAPDs are not met.
• Symptoms cannot be attributed to another cause after appropriate evaluation.

Management ^[1]

The approach is the same as the management of IBS in children.