11 Chronic abdominal pain

Definition
Chronic abdominal pain is usually used to refer to pain which
is either longstanding, of prolonged duration or of recurrent/
intermittent nature. Chronic pain may be associated with acute
exacerbations.
KEY POINTS
• Chronic abdominal pain of prolonged duration requires investigation.
• Adhesions as a cause of chronic abdominal pain should be a diagnosis
of exclusion.
• Irritable bowel syndrome is less common than supposedbany
atypical bowel symptoms should be investigated fully before diagnosing
IBS.
• Back pain suggests a retroperitoneal origin.
• Sacral pain suggests a pelvic origin.
• Relationship to food strongly suggests a physical pathology and
requires investigation.
Important diagnostic features
Irritable bowel syndrome
• Syndrome of colicky abdominal pain, bloating, hard pellety or
watery stools, sensation of incomplete evacuation, often associated
with frequency and urgency.
• Blood, mucus, abdominal physical findings, weight loss or
recent onset of symptoms or onset in old age should suggest an
organic cause and require thorough investigation.
Adhesions
• Associated with several syndromes of chronic or recurrent
abdominal symptoms.
• Adhesional abdominal pain: difficult to diagnosis with any
confidence, usually a diagnosis of exclusion, may be suggested
by small bowel enema showing evidence of delayed transit or
fixed strictures, rarely responds well to surgery.
• Recurrent incomplete small bowel obstruction: transient
episodes of obstructive symptoms, often do not have all classical
signs or symptoms present, abdominal signs may be unremarkable,
self limiting.
Mesenteric angina
Classically occurs shortly after eating in elderly patients, colicky
central abdominal pain, vomiting, food fear and weight loss.
Usually associated with other occlusive vascular disease.
Meckel’s diverticulum
May cause undiagnosed central abdominal pain in young adults.
Occasionally associated with obscure PR bleeding, anaemia.
Best diagnosed by radionuclide scanning.
KEY INVESTIGATIONS
• FBC: leucocytosisbchronic infective/inflammatory diseases,
anaemiaboccult malignancy, PUD, lymphocytosisblymphoma.
• LFTs: common bile duct gallstones, hepatitis, liver tumours
(primary/secondary).
• MSU: urinary tract infection (++ve nitrites, blood, protein), renal stone
(++ve blood).
• ECG: ischaemic heart disease.
• Abdominal X-ray: chronic pancreatitis (small calcification throughout
gland):
• Ultrasound:
intra-abdominal abscesses (diverticular, appendicular, pelvic, hepatic)
‘gallstones’, ‘chronic cholecystitis’
ovarian pathology (cyst)
aortic aneurysm renal tumours.
• OGD: PUD, gastritis, gastric or oesophageal carcinoma.
• Colonoscopy: diverticular disease, chronic colonic ischaemia.
• CT scan: chronic pancreatitis, pancreatic carcinoma, aortic aneurysm,
retroperitoneal pathologies (fibrosis, lymphadenopathy, tumours).
• IVU: renal stones, renal tract tumours, renal tract obstruction.
• Visceral angiography: mesenteric vascular disease.
• ERCP: chronic pancreatitis, pancreatic carcinoma.
• Small bowel enema: Crohn’s disease, small bowel tumours, Meckel’s
diverticulum.
• Barium enema: ischaemic strictures, chronic colitis.