Chronic abdominal pain

Chronic abdominal pain is constant or recurring abdominal pain lasting ≥ 3 months. The most common causes are disorders of gut-brain interaction, such as irritable bowel syndrome (IBS) and functional dyspepsia, followed by organic diseases of the viscera and disorders of the abdominal wall. A targeted clinical evaluation is required to identify red flags in chronic abdominal pain (e.g., unexplained weight loss, symptom onset over 50 years of age) and to help narrow the differential diagnoses. Initial laboratory studies are based on clinical suspicion; imaging and endoscopy may be necessary. Management is based on the underlying cause. Management of persistent pain in disorders of gut-brain interaction is multimodal and can include nonpharmacological management and central neuromodulators.

For acute pain, see "Acute abdomen."

• Chronic abdominal pain: constant or recurring abdominal pain lasting ≥ 3 months ^[1]
• Disorders of gut-brain interaction ^[2]
  • A group of chronic conditions characterized by recurrent gastrointestinal symptoms (e.g., abdominal pain, bloating, altered bowel habits) without structural abnormalities
  • Likely due to dysregulated communication along the gut-brain axis involving motility disturbances, visceral hypersensitivity, altered mucosal and/or immune function, microbiota changes, and/or central pain amplification

Disorders of gut-brain interaction are the most common cause of chronic abdominal pain. ^[3]

Disorders of gut-brain interaction (nociplastic pain) ^[1][4]

• Irritable bowel syndrome (IBS)
• Functional dyspepsia
• Centrally mediated abdominal pain syndrome
• Narcotic bowel syndrome
• Functional gallbladder disorder (e.g., gallbladder dyskinesia)
• Sphincter of Oddi dysfunction

Intra-abdominal (visceral pain) ^[1][4]

Gastrointestinal

• Inflammatory
  • Inflammatory bowel disease (IBD)
  • Gastroesophageal reflux disease (GERD)
  • Peptic ulcer disease (PUD)
  • Gastritis
  • Duodenitis
  • Diverticular disease
• Malabsorptive
  • Celiac disease
  • Lactose intolerance
  • Small intestinal bacterial overgrowth
  • Small intestinal fungal overgrowth
• Mechanical and motility-related
  • Intestinal adhesions
  • Chronic constipation
  • Gastroparesis
• Vascular
  • Chronic mesenteric ischemia
  • Celiac artery compression syndrome
• Malignancy
  • Colorectal cancer
  • Gastric cancer

Non-gastrointestinal

• Hepatobiliary and pancreatic
  • Gallbladder disease (e.g., chronic cholecystitis)
  • Biliary cancer
  • Chronic pancreatitis
• Splenomegaly (due to, e.g., chronic liver disease, hematological malignancies)
• Genitourinary
  • Endometriosis
  • Pelvic inflammatory disease (PID)
  • Ovarian tumors or masses
  • Urological causes (referred pain due to, e.g., nephrolithiasis)
• Immunological
  • Mast cell activation syndrome
  • Hereditary angioedema
• Other
  • Acute intermittent porphyria
  • Ehlers-Danlos syndrome
  • Familial Mediterranean fever

Abdominal wall ^[1][4]

• Musculoskeletal (somatic pain)
  • Myofascial pain
  • Rectus sheath hematoma
  • Spigelian hernia
• Peripheral nerves (neuropathic pain)
  • Anterior cutaneous nerve entrapment syndrome
  • Herpes zoster
  • Postherpetic neuralgia
  • Slipping rib syndrome

Focused history ^[1][4]

• Pain characteristics
  • Duration
  • Location and radiation
  • Quality (e.g., dull, sharp, cramping)
  • Type (e.g., visceral pain, somatic pain, neuropathic pain)
  • Timing (e.g., constant vs. intermittent)
  • Triggers or exacerbators (e.g., physical activity, meals, menstrual cycle)
  • Severity and impact on daily activities (e.g., sleep disruption)
• Associated symptoms
  • Changes in bowel habits (e.g., diarrhea, constipation)
  • Nausea, vomiting, early satiety
  • Unintentional weight loss or gain
  • Bloating, flatulence
  • Dysmenorrhea, dyspareunia
  • Symptoms of lactose intolerance
  • Symptoms of celiac disease
  • Systemic symptoms (e.g., fever, tachycardia, clinical features of angioedema)
• Medication history
  • NSAIDs
  • Opioids
  • Antibiotics
  • PPIs
• Psychosocial factors
  • Stress
  • Symptoms of anxiety disorders, depressive disorders
  • History of trauma or abuse
• Family history
  • GI tract cancers
  • IBD
  • Celiac disease

Chronic pancreatitis, malignancy, abscess, and psychiatric conditions can cause constant chronic abdominal pain. Other causes of chronic abdominal pain typically manifest with intermittent pain. ^[1]

Focused examination ^[1][4]

• General
  • Signs of malnutrition or cachexia
  • Jaundice or scleral icterus
  • Pallor
• Abdominal examination
  • Inspection: distention, visible masses, surgical scars
  • Auscultation: bowel sounds and bruits
  • Palpation: tenderness zones, masses, organomegaly
  • Percussion: organomegaly, signs of ascites (e.g., shifting dullness, fluid wave test)
  • Assess for peritoneal signs.
  • DRE: Assess for masses, fecal impaction, tenderness, and/or blood.
  • Assess for Carnett sign.
• Pelvic examination
  • Cervical motion tenderness
  • Adnexal masses or tenderness
• Skin examination: rashes associated with gastrointestinal conditions (e.g., dermatitis herpetiformis in celiac disease, erythema nodosum in IBD)

The following features raise suspicion for structural disease and may warrant an expedited or specialized evaluation. ^[1][4]

• Age > 50 years with new-onset symptoms
• Family history of gastrointestinal malignancy
• Pain that disrupts sleep
• Associated symptoms
  • Unintentional weight loss and/or anorexia
  • Fever and/or night sweats
  • GI bleeding (e.g., rectal bleeding, hematochezia)
  • Progressive dysphagia
  • Persistent vomiting
  • Palpable abdominal mass
  • Jaundice

Approach ^[1][4]

• Perform a focused clinical evaluation.
• Refer for specialist assessment if red flags in chronic abdominal pain are present.
• Consider initial laboratory studies to evaluate for common causes of chronic abdominal pain and their complications.
• Perform additional diagnostic testing based on clinical suspicion.

Red flags in chronic abdominal pain may warrant an expedited and/or specialized evaluation. ^[1][4]

Disorders of gut-brain interaction can only be diagnosed after excluding structural disease.

Laboratory studies ^[1][4]

• Initial studies
  • CBC with differential
  • CMP
  • Serum lipase
  • ESR, CRP
  • Urinalysis
  • β-hCG in individuals who can become pregnant
• Targeted studies (based on clinical suspicion)
  • Celiac disease: tissue transglutaminase antibodies
  • IBD: fecal calprotectin
  • Acute intermittent porphyria: urine porphobilinogen
  • Mast cell activation syndrome: serum tryptase
  • Hereditary angioedema: C4 and C1 inhibitor levels

Imaging ^[1][4]

Imaging in chronic abdominal pain is obtained selectively for patients with red flags in chronic abdominal pain, abnormal examination, and/or laboratory findings.

• Ultrasound abdomen and pelvis
  • Initial imaging for gallbladder, liver, kidneys, and/or reproductive tract
  • Assess for masses, free fluid
• CT abdomen and pelvis with IV contrast
  • Evaluate for inflammatory conditions, masses, vascular pathology
  • Identify complications (e.g., abscesses, fistulas, strictures)
• MRI abdomen and pelvis
  • MRCP for evaluating biliary and pancreatic diseases
  • MR enterography for small bowel evaluation (e.g., in Crohn disease)
  • Pelvic MRI for endometriosis, adenomyosis
• CT angiography: to evaluate for chronic mesenteric ischemia

Repeat imaging is discouraged if clinical features have not changed. ^[1][4]

Additional studies ^[1][4]

Further testing under the direction of specialists is tailored to the clinical presentation, e.g.:

• EGD: persistent upper abdominal symptoms, alarm features, and/or age > 55 years
• Colonoscopy: altered bowel habits, lower abdominal pain, iron-deficiency anemia, age ≥ 45 years, and/or suspicion of IBD
• Capsule endoscopy: to assess for small bowel pathology not visible on standard endoscopy
• Diagnostic laparoscopy: suspicion for intra-abdominal pathology (e.g., endometriosis or adhesions) despite negative noninvasive studies
• Diagnostic nerve block: suspicion for neuropathic pain (e.g., anterior cutaneous nerve entrapment syndrome)

• Identify and treat the underlying disease.
• Provide symptomatic management based on the underlying cause, e.g.:
  • Antispasmodics (e.g., for IBS)
  • Non-opioid analgesics (e.g., for endometriosis or chronic pancreatitis)
• Manage triggers and/or factors that worsen symptoms (e.g., discontinue NSAIDs in patients with PUD).
• Consider additional measures for patients with persistent abdominal pain in disorders of gut-brain interaction.

General principles ^[3]

• Use a culturally sensitive and patient-centered approach.
  • Validate the patient's pain experience and align on shared goals (e.g., function, quality of life).
  • Set realistic expectations focused on symptom improvement and functional gains.
• Avoid escalation of testing or medications in the absence of a clear benefit.
• Introduce nonpharmacological treatment (e.g., brain-gut psychotherapy) early in care.
• Optimize symptomatic management based on the underlying disease.
• Consider central neuromodulators.

Avoid opioid therapy for treatment of chronic abdominal pain. ^[3]

Brain-gut psychotherapy ^[3]

• Cognitive behavioral therapy
• Gut-directed hypnotherapy
• Mindfulness-based stress reduction
• Acceptance and commitment therapy

Central neuromodulators ^[3]

• Low-dose tricyclic antidepressants (off-label), e.g., amitriptyline , nortriptyline ^[3]
• SNRIs (off-label), e.g., duloxetine ^[3]
• Mirtazapine (off-label) ^[3]