🤰 Abdominal Pain

Abdominal pain accounts for ~5% of all GP consultations; the challenge is that serious diagnoses are uncommon but catastrophic if missed. AAA rupture carries very high mortality without intervention. Ectopic pregnancy remains a leading cause of first-trimester maternal death in the UK — which is why anyone with pregnancy potential gets a pregnancy test when clinically relevant, including on contraception if pregnancy cannot confidently be excluded, and why NG126 separates the unstable patient (999) from the stable positive test with tenderness (EPU today). Mesenteric ischaemia is missed because the examination is normal: "pain out of proportion to signs" is the cue. Torsion is time-critical, but the destination differs — testicular torsion is an immediate surgical/urological emergency, ovarian torsion a same-day gynaecological one. DKA on an SGLT2 inhibitor can be euglycaemic, so the test is ketones, not glucose.

A systematic pain history using SOCRATES correctly identifies the diagnosis in 60–70% of abdominal pain presentations before examination. The migration of pain from periumbilical to RIF is present in 60% of confirmed appendicitis cases. Colicky pain with complete absence in between strongly suggests hollow viscus obstruction or colic rather than inflammation. Understanding onset speed (seconds vs hours) is the single most important discriminator between surgical emergency and subacute disease.

Acuity classification drives the time-critical decision: Can this patient safely wait for primary care workup, or do they need hospital today? Pancreatitis severity (GLASGOW score in hospital) determines HDU admission need. Mild diverticulitis (no systemic upset, able to eat) can be managed in primary care, often without antibiotics (NICE NG147); complicated or severe disease requires admission. Anyone with pregnancy potential presenting with lower abdominal pain should have a pregnancy test when clinically relevant — a missed ectopic pregnancy can be fatal.

A positive Murphy's sign supports acute cholecystitis but raises its probability only modestly (positive likelihood ratio around 2.8), and a negative sign does not exclude it. Involuntary guarding (rigidity) is the single most important sign of peritonitis — it is not suppressible by the patient and indicates surgical emergency. Carnett's test differentiates visceral from abdominal wall pain with 78–88% accuracy — positive Carnett's (worsens on raising head) suggests abdominal wall haematoma, hernia, or nerve entrapment, avoiding unnecessary investigations. A missed irreducible femoral hernia (most common in elderly women) causing obstruction is a preventable surgical emergency.

Lipase is preferred to amylase where available because it stays elevated longer, but neither makes the diagnosis alone: acute pancreatitis requires two of characteristic pain, an enzyme over three times the upper limit, or characteristic imaging. A pregnancy test should be done when clinically relevant in anyone with pregnancy potential — and a negative test does not exclude a very early ectopic (serum beta-hCG is more sensitive). Faecal calprotectin is recommended in NICE HTG320 (formerly DG11, 2013) for distinguishing IBD from IBS and is a powerful primary-care test before referral. FIT is now the gateway to most colorectal referrals, but it is a rule-in test with a floor, not a rule-out: a mass, or persistent concerning symptoms, is referred whatever the number. CA-125 is interpreted against age-specific thresholds alongside ultrasound, never in isolation, and CA 19-9 has no place in primary-care assessment of abdominal pain.

The most dangerous error in abdominal pain is delayed referral. The classic Alvarado score for appendicitis (score ≥7 → surgery) is not validated for primary care use — clinical gestalt and examination findings should drive the referral decision. Cholecystitis with fever indicates bacterial superinfection and requires IV antibiotics and early laparoscopic cholecystectomy (within a week of diagnosis — NICE CG188). NICE NG12's criteria are set at a 3% positive-predictive-value threshold from UK primary-care evidence — adherence reduces time-to-treatment and improves survival outcomes. A threshold of uncertainty = refer: primary care cannot rule out surgical emergencies.

Analgesia does not mask diagnosis — multiple RCTs show opioids and NSAIDs in the acute abdomen do not reduce diagnostic accuracy and improve the patient's experience and cooperation with examination. Withholding analgesia is harmful. The safety work is in the contraindications, not the withholding: NSAIDs cause bleeding in ulcer disease, AKI alongside an ACE inhibitor and diuretic, and carry perforation risk in diverticular disease, where NICE NG147 (2019) advises avoiding NSAIDs and opioids where possible. H. pylori eradication substantially reduces ulcer recurrence, but the regimen depends on previous macrolide and metronidazole exposure and on local resistance — hence the link to local guidance rather than a fixed triple therapy. Alpha-blockers have a modest adjunctive effect on passage of distal stones under 10 mm, which is why they are not offered for all renal colic.

Low-FODMAP diet (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols) is a dietitian-led option when first-line dietary advice (regular meals, fibre adjustment, limiting caffeine, alcohol and fizzy drinks) is insufficient. CBT or other psychological therapy is worth considering for persistent IBS or chronic primary pain, particularly with distress or functional impairment. After a stone has passed, good hydration is the main preventive measure; smoking cessation supports ulcer healing and reduces recurrence.

Diverticulitis that is not improving by 72 hours needs reassessment in hospital rather than a further primary-care course — perforation, abscess and fistula are the reasons. H. pylori eradication should be confirmed per local protocol, because treatment failure is common and undetected failure means continuing ulceration; testing needs a 2-week PPI washout and no antibiotics for 4 weeks. Structured review improves symptom control and satisfaction in IBS compared with as-needed appointments. Safety-netting must be documented — an RCGP SCA competency and medicolegally critical. Interval investigation after diverticulitis follows local policy and the CT findings rather than a blanket malignancy figure.