Chronic abdominal pain

🩺 Chronic abdominal pain usually means abdominal pain persisting or recurring for ≥3 months. It is common in primary care and gastroenterology, and the causes range from functional gut–brain disorders such as IBS and functional dyspepsia to inflammatory, structural, metabolic, vascular, gynaecological, renal, and malignant disease. The aim is not to “scan everyone”, but to use a careful history, examination, and targeted investigations to identify red flags while avoiding low-value over-investigation.

📖 Core approach

• Start by deciding whether the pattern sounds functional, organic, or referred / extra-abdominal.
• Always screen for red flags: GI bleeding, iron-deficiency anaemia, unintentional weight loss, persistent vomiting, dysphagia, abdominal or rectal mass, nocturnal symptoms, fever, jaundice, or a strong family history of GI cancer.
• Remember that functional disorders are common, especially IBS and functional dyspepsia, but they are not diagnoses of dismissal.
• Use a biopsychosocial model: pain perception is influenced by inflammation, motility, visceral hypersensitivity, stress, anxiety, trauma, sleep, and health behaviours.

🧭 Causes of chronic abdominal pain

📝 History

1. Time course
   • When did it start? Is it continuous, intermittent, or cyclical?
   • Is it clearly meal-related, bowel-related, or menstrual-related?
2. Site and radiation
   • Epigastric → dyspepsia / PUD / pancreas
   • RUQ → biliary / hepatic
   • Periumbilical or diffuse → functional bowel pain
   • Lower abdomen / pelvis → IBS, IBD, gynae, bladder
   • Back radiation → pancreas or aortic disease
3. Character
   • Burning = reflux / dyspepsia
   • Colicky = obstructive, biliary, renal
   • Aching / cramping = IBS or inflammatory causes
   • Localised superficial tenderness = abdominal wall pain
4. Associated symptoms
   • Weight loss, GI bleeding, iron deficiency, persistent vomiting, fever, jaundice
   • Diarrhoea, constipation, bloating, urgency, nocturnal stooling
   • Urinary symptoms, menstrual symptoms, dyspareunia
5. Background context
   • NSAIDs, steroids, anticoagulants, GLP-1 drugs, opioids, antibiotics, alcohol
   • Previous surgery, gallstones, pancreatitis, diabetes, coeliac disease, IBD
   • Family history of colorectal, ovarian, gastric, pancreatic, or coeliac disease
   • Psychological stress, anxiety, trauma, sleep disturbance, disordered eating

🚩 Red flags

• Unintentional weight loss
• Iron-deficiency anaemia or overt GI bleeding
• Persistent vomiting
• Dysphagia
• Abdominal, pelvic, or rectal mass
• Jaundice
• Nocturnal symptoms or pain waking the patient from sleep
• Family history of GI or ovarian cancer
• Age / risk profile out of keeping with a simple functional diagnosis

🩺 Examination

• General: pallor, weight loss, jaundice, dehydration, cachexia, anxiety, fever
• Abdominal: distension, scars, hernias, focal or diffuse tenderness, guarding, organomegaly, ascites, masses
• Abdominal wall: consider a positive Carnett sign if pain remains or worsens when the abdominal muscles are tensed
• Rectal examination when indicated by bleeding, altered bowel habit, anaemia, or suspected mass
• Pelvic examination where appropriate, especially if symptoms are cyclical or pelvic

🔎 Initial investigations

Baseline tests should be guided by the history. A sensible initial panel often includes FBC, CRP, U&Es, LFTs, coeliac serology, urinalysis, and pregnancy testing where relevant. Add stool or imaging tests selectively rather than routinely ordering everything.

🩻 Imaging and endoscopy

• Ultrasound for suspected gallbladder, liver, renal, pelvic, or ovarian pathology
• CT abdomen/pelvis when malignancy, chronic pancreatitis complications, inflammatory disease, obstruction, or vascular pathology is suspected
• OGD for upper-GI alarm symptoms or persistent dyspepsia when indicated
• Colonoscopy / CT colonography for lower-GI alarm symptoms, abnormal FIT, anaemia, rectal bleeding, chronic diarrhoea, or suspected IBD / cancer

🧠 High-yield diagnostic patterns

💊 Management principles

1. Treat the underlying cause
   • IBS → diet, lifestyle, antispasmodics, laxatives/antidiarrhoeals as appropriate
   • Dyspepsia / GORD → lifestyle measures, PPI trial, H. pylori testing/eradication where indicated
   • IBD → specialist-guided anti-inflammatory / immunomodulatory therapy
   • Coeliac disease → lifelong gluten-free diet after diagnosis is confirmed
   • Gallbladder disease → analgesia, imaging, and surgery if appropriate
   • Chronic pancreatitis → alcohol abstinence, analgesia, pancreatic enzyme replacement, nutrition support
   • Endometriosis → analgesia, hormonal strategies, and referral where needed
2. Avoid harm
   • Avoid defaulting to long-term opioids for chronic abdominal pain
   • Avoid repeated low-yield scans when the pattern is stable and functional
   • Reassess the diagnosis if the clinical pattern changes
3. Use a biopsychosocial plan
   • Explain the diagnosis clearly
   • Address diet, bowel habits, sleep, anxiety, and function
   • Consider dietitian, psychology, pain team, or gastroenterology input when needed

📌 Referral / escalation triggers

• Any red flag symptom or sign
• Abnormal FIT, iron-deficiency anaemia, GI bleeding, or mass
• Suspected IBD, coeliac disease with significant malnutrition, pancreatic disease, ovarian pathology, or endometriosis
• Persistent unexplained pain despite appropriate first-line assessment

💡 Teaching pearls
• IBS is a positive clinical diagnosis when the symptom pattern is typical and red flags are absent.
• Faecal calprotectin is useful when deciding between IBD and IBS, but it is not a cancer test.
• FIT has largely replaced older stool occult blood strategies in symptomatic colorectal cancer pathways.
• Do not forget endometriosis, especially when pain is cyclical or associated with painful periods, dyspareunia, or painful bowel motions during menstruation.
• Chronic abdominal pain deserves explanation, validation, and safety-netting, not dismissal.