Abdominal pain
Learn to think through the acute abdomen, step by step. How the assessment flows — what to look for, what not to miss, and how the plan comes together. Built for revision, not live patient decisions.
Settle them, and check the basics
all at once, calmlyRed flags — what each should make you think
Two habits that catch the killers: a pregnancy test in anyone who could be pregnant, and thinking "AAA" in any older patient with abdominal, flank or back pain. Miss either and the diagnosis walks out the door.
Your first moves — all at once, calmly
- A–EAssess A–Etreat shock and sepsis as you find them
- ✚IV access, fluids + bloodsFBC, U&E, LFT, lipase, CRP, G&S/crossmatch, VBG/lactate
- βhCGPregnancy test — always, if possiblea negative test takes ectopic off the table
- ℞Analgesia + antiemeticpain relief doesn't mask a surgical abdomen — give it
- ♥ECG + urinalysisinferior MI can present as epigastric pain
- NBMKeep nil by mouth if surgery possibleand consider an NG tube if obstructed
Understand the pain & the person
site routes youTake a focused history — the site routes you
- Epigastric — pancreatitis, peptic ulcer, MI
- RUQ — biliary (cholecystitis, cholangitis)
- RIF — appendicitis, ovarian, ectopic
- LIF — diverticulitis, colitis
- Central, out of proportion — mesenteric ischaemia
- Loin-to-groin — renal colic (exclude AAA in the older patient)
Background that shifts the odds: last menstrual period and pregnancy status, alcohol, gallstones, AF or vascular disease, previous surgery, bowel habit and vomiting.
Work A–E — assess and act as you go
Examine top to bottom; at each step you're both sorting the causes and treating what you find.
Pain that's far worse than the abdomen looks — a soft belly but a patient in agony — is mesenteric ischaemia until proven otherwise, especially with AF. Easy to miss, and lethal.
Rule out the killers
tap to open eachEach card gives you what points toward it, what would rule it in, what lets you stand it down, and how to manage it.
Older patient, hypertension or smoking, sudden severe abdominal/flank/back pain, collapse, a pulsatile expansile mass, hypotension. Easily mistaken for renal colic.
Known/suspected AAA + instability → straight to theatre. CT aorta if stable enough.
Large-bore access, crossmatch, permissive hypotension (don't over-transfuse). Immediate vascular/theatre. Don't delay for imaging if unstable.
Anyone who could be pregnant with abdominal or pelvic pain, ± PV bleeding, amenorrhoea, or shoulder-tip pain.
Positive βhCG + transvaginal ultrasound with no intrauterine pregnancy (or an adnexal mass).
If ruptured/shocked → resuscitate and straight to theatre. Otherwise urgent gynaecology. The βhCG is the test that keeps you safe.
Sudden severe pain, a rigid "board-like" abdomen, the patient lying very still, unwell or septic.
Free air under the diaphragm on an erect CXR, or free air/fluid on CT.
Nil by mouth, IV fluids + broad-spectrum antibiotics, analgesia, NG tube, urgent surgical referral.
AF or vascular disease, severe pain out of proportion to a soft abdomen, later peritonism, and a metabolic acidosis with a raised lactate.
CT angiogram of the mesenteric vessels.
Aggressive resuscitation, antibiotics, urgent surgical referral. Mortality is high — the win is thinking of it early.
Severe epigastric pain radiating to the back, vomiting, and a history of gallstones or alcohol.
Lipase (or amylase) more than three times the upper limit with a consistent picture (± CT).
IV fluids, analgesia, antiemetics, close monitoring. Score severity (e.g. Glasgow–Imrie) and involve HDU/ITU if severe. Treat the cause.
Appendicitis: central pain migrating to the RIF, anorexia, low fever. Obstruction: colicky pain, vomiting, distension, absolute constipation. Cholangitis: RUQ pain + fever + jaundice (Charcot's triad).
CT or ultrasound, guided by the picture.
Nil by mouth, IV fluids, antibiotics if infective, surgical referral. Obstruction → "drip and suck" (IV fluids + NG tube).
Don't forget the time-critical and the mimics
Testicular (and ovarian) torsion is a clock-ticking diagnosis — examine and refer fast. And remember the medical mimics: inferior MI and DKA can both present as abdominal pain.
Investigate — what to order, when, and what it tells you
test with a question in mindBloods (including βhCG)
Urinalysis & ECG
Erect CXR & ultrasound
CT abdomen
How the plan comes together
disposition · handoverYou've resuscitated, taken the bloods and the pregnancy test, and examined properly. Now: is this surgical, and where do they go?
discharge
A benign, self-limiting cause, comfortable, eating and drinking, with normal observations and bloods.
Safety-net: clear return advice, GP follow-up.
refer / admit
Any surgical concern, unresolved pain, abnormal bloods, or an unwell patient → surgical or gynae referral, nil by mouth.
Hand over: working diagnosis, resuscitation given, pregnancy status, what would change the plan.
Your handover is part of the plan. "Abdominal pain, working diagnosis X, pregnancy test Y, lactate Z, kept nil by mouth, referred to surgery" is the clean line that keeps them safe. Nicely done getting here.