Why Abdominal Pain Requires Characterisation, Not Just Management
The reflex of reaching for an antacid or antispasmodic for any abdominal pain makes sense for mild, short-lived discomfort with an obvious trigger. But treating the symptom without understanding what's causing it is a problem when the cause needs specific treatment, when delay worsens outcomes, or when a serious cause is being masked.
Abdominal pain has a broader differential diagnosis than almost any other symptom: it can originate from organs inside the abdomen (gut, liver, pancreas, gallbladder, kidneys, reproductive organs), from the abdominal wall itself, from thoracic pathology that refers to the abdomen (lower pneumonia, myocardial infarction), or from systemic disease (diabetic ketoacidosis, adrenal crisis). The clinical history, done properly, will narrow this down significantly before any investigation is ordered.
Where exactly is the pain? What does it feel like (burning, cramping, stabbing, pressure, colic)? When does it start (after eating, related to bowel movements, cyclical)? What makes it better or worse? Has it changed over time? What comes with it (nausea, vomiting, diarrhoea, blood, fever, bloating)? These questions are not optional extras. They are the investigation.
Acute vs Chronic Abdominal Pain: Different Problems
Acute abdominal pain (coming on suddenly and requiring same-day assessment) and chronic or recurring abdominal pain (ongoing over weeks to months) are effectively different clinical problems, even though they share the same anatomical location.
Acute pain with red flag features, as listed in the FAQ below, requires urgent assessment. The priority is ruling out surgical emergencies: appendicitis, perforation, bowel obstruction, ruptured ectopic pregnancy, aortic aneurysm, mesenteric ischaemia. These conditions are time-critical.
Chronic recurring pain is more often from conditions like IBS, IBD, peptic ulcer disease, endometriosis, or gallstones, and allows for a more systematic outpatient investigation approach. But persistent pain that has never been investigated is not the same as pain that has been investigated and found to have a benign cause. The absence of investigation is not reassurance.
Pain Patterns and What They Suggest
Comes in waves, related to gut contractions. Classic for IBS, gas, constipation, early bowel obstruction, gastroenteritis. Usually benign in the absence of red flags.
Epigastric location suggests gastritis or peptic ulcer. Right upper quadrant burning after meals suggests gallbladder. Worsened by lying flat suggests GORD.
Perforation, ovarian cyst rupture, kidney stone, aortic dissection. Requires urgent assessment. A pain maximal from the start is particularly concerning.
Central with nausea suggests pancreatitis (radiates to back) or early appendicitis. Right upper constant ache suggests hepatitis or liver pathology.
Pain relieved by defaecation is strongly suggestive of IBS or constipation. Pain that comes with diarrhoea or blood suggests IBD or infectious colitis.
Pain that tracks with the menstrual cycle suggests endometriosis, ovarian cysts, or primary dysmenorrhoea. Midcycle pain (Mittelschmerz) is from ovulation. Always ask about menstrual timing in women with recurring abdominal pain.
When Abdominal Pain Comes From Outside the Abdomen
A few causes of apparent abdominal pain that are often overlooked: lower lobe pneumonia or pleurisy can cause referred pain in the upper abdomen, sometimes without obvious chest symptoms. Heart attacks, particularly in diabetic or elderly patients, can present with epigastric pain rather than chest pain. Diabetic ketoacidosis causes diffuse abdominal pain as a prominent feature. Shingles (herpes zoster) causes unilateral band-like pain in the dermatomal distribution, sometimes before the rash appears.
Abdominal wall pain, from the muscles and fascia rather than the viscera inside, is also consistently underdiagnosed. It is worsened by movement, tension of the abdominal muscles, and direct pressure on a specific point. Carnett's test helps identify it: if pain increases when the patient tenses their abdominal muscles while pressing on the point, the source is the wall, not the viscera. Abdominal wall pain is often managed with local anaesthetic injection into the tender point.