Chronic/Recurrent Abdominal Pain in Adults

Differential Diagnosis

Common Diagnoses

Occasional Diagnoses

Rare Diagnoses

Mesenteric Artery Ischaemia (Abdominal Angina)
Chronic Pancreatitis
Subacute Obstruction (Adhesions, Malignancy and Diverticulitis)
Functional (Psychogenic) Abdominal Pain
Malignancy
Metabolic Causes, e.g. Addison’s Disease, Porphyria, Lead Poisoning

Ready Reckoner

Key distinguishing features of the most common diagnoses

	IBS	UTI	PU	Constipation	Diverticulitis
High Abdominal Pain	Possible	No	Yes	Possible	Possible
Colicky	Yes	No	No	Yes	Yes
Weight Loss	No	Possible	Possible	No	No
Diarrhoea	Yes	No	No	Possible	Yes
Rectal Bleeding	No	No	No	Possible	Possible

Possible Investigations

Likely:Urinalysis, FBC, ESR/CRP, MSU, H. pylori testing

Possible:U&E, LFT, amylase, coeliac screen, CA-125, FIT, faecal calprotectin, plain abdominal X-ray, ultrasound, renal imaging, hospital-based lower GI investigations, gastroscopy.

Small Print:Specialised investigations such as mesenteric angiography and further tests for rare medical causes.

Urinalysis: Blood alone with stone; blood, pus cells and nitrite in UTI.
MSU: To confirm urinary infection and guide treatment.
FBC and ESR/CRP: May suggest inflammatory bowel disease, PU or malignancy. Raised platelets associated with oesophageal or stomach cancer.
U&E may be deranged in hydronephrosis, renal stones or Addison’s disease.
LFT and amylase: LFT may be abnormal if carcinoma present. Amylase may be raised in pancreatitis and bowel ischaemia.
Coeliac screen: Anti-endomysial and anti-gliadin antibodies – suggest coeliac disease if positive.
CA-125: Especially in women aged 50 or more, may help exclude ovarian cancer.
H. pylori testing: Strong association with peptic ulcer disease.
FIT: A useful colorectal cancer ‘rule out’ test in patients at low risk. Also commonly required now when arranging a two-week referral to help secondary care stratify urgency of investigation.
Faecal calprotectin: To help rule out inflammatory bowel disease, especially if recurrent or persistent diarrhoea is also a feature.
Plain abdominal X-ray: May reveal constipation, subacute obstruction or kidney stones.
Renal imaging: For renal stones or recurrent UTI.
Ultrasound: Will show hydronephrosis and gallstones. Pelvic/abdominal ultrasound also indicated if CA-125 elevated.
Hospital-based lower GI investigations: For various lower bowel disorders.
Gastroscopy: May be required to confirm PU and exclude gastric carcinoma.
Further tests such as angiography (for mesenteric ischaemia) or investigations for rare medical causes may be arranged after specialist referral.

Top Tips

Simply establishing what provokes or relieves the problem can provide helpful pointers – pain occurring after eating suggests gallstones, PU, gastric carcinoma or mesenteric ischaemia; if relieved by defecation, the likely diagnoses are IBS or constipation.
In an otherwise well patient, the longer the history the less likely there is to be significant underlying disease.
Avoid repeated investigation if a patient has already been thoroughly assessed in the past – unless the individual becomes unwell or develops new symptoms. Be frank with the patient by explaining about the ‘law of diminishing returns’ in investigating chronic unexplained abdominal pain.
Be prepared to make a positive diagnosis of IBS in a fit young patient if the symptoms are classical and basic investigations are negative; explanation and education are the keys to effective management.

Red Flags

Weight loss in association with recurrent abdominal pain suggests significant pathology.
Hard enlarged left supraclavicular nodes (Troisier’s sign) are pathognomic of gastric carcinoma.
Beware that constipation itself is often a symptom rather than a diagnosis. Be sure to establish and treat any underlying cause if it doesn’t respond to simple treatment.
IBS is the commonest diagnosis – but consider other possibilities if the pain is always in the same site, wakes the patient at night or is associated with rectal bleeding or weight loss.