Abdominal pain is among the most frequent presentations to the Emergency Department, accounting for approximately 5–10% of all attendances. Its causes span a broad spectrum from mild, self-limiting conditions to time-critical, life-threatening emergencies. Abdominal pain is a complex ED presentation because it involves multiple organ systems and a wide range of potential causes, making it sometimes challenging to safely exclude serious pathology.

Our Webinar

This article is based on the brilliant webinar by senior EM registrar Dr Jack Almy – do have a watch!

A brief note on your A-E

No medical education resource would be complete without a reminder of the importance of a structured A-E in assessing a seriously unwell patient. The same is certainly true for obviously unwell patients presenting with abdominal pain: begin with an A–E assessment and consider early transfer to resus. This below pointers are not an exhaustive list but are just some suggestions of considerations when doing your initial assessment – focusing on the initial ABC part.

Airway
Airway compromise is rare in abdominal pain presentations. If there is concern, call for early anaesthetic review.

Breathing
If the patient appears acutely unwell, start high-flow oxygen (15 L via non-rebreathe mask).
Respiratory rate is one of the most sensitive indicators of serious illness and a raised rate should be explained

Circulation
Obtain two large-bore IV accesses early in unwell patients.
Assess fluid status + give fluid boluses as required
Tachycardia or hypotension in the context of abdominal pain is concerning.
Isolated tachycardia should also prompt review — consider pain, dehydration/fluid loss, sepsis or bleeding

History taking

A comprehensive SOCRATES assessment will form a large chunk of your history.

Site

• Sharp, well-localised pain often suggests ‘somatic’ origin (irritation of the parietal peritoneum)
• Vague, poorly localised pain is often visceral, caused by organ stretch or obstruction.
• Visceral pain can also be referred along shared spinal nerve roots. Eg, diaphragmatic irritation may present as shoulder tip pain.

Onset

• Sudden onset: Usually concerning; suggests perforation, rupture, ischaemia, or vascular causes.
• Gradual onset: More likely infectious or inflammatory processes, such as appendicitis, pyelonephritis, or gastroenteritis.

Character

• Colicky/crampy pain: often suggests obstruction (bowel, ureteric)
• Sharp/stabbing pain: Typically indicates peritoneal irritation seen in peritonitis, gallbladder pathology, ruptured ectopic, or advanced appendicitis. Pain may start vague (visceral) and localise as somatic nerves become involved.
• Tearing pain: Classically associated with vascular emergencies such as ruptured AAA or aortic dissection, often radiating to the back.
• Burning pain: Seen in peptic ulcer disease, gastritis and oesophagitis.
• Dull/aching pain: Early visceral pain due to organ stretch. Difficult to localize, often seen in early bowel pathology.

Radiation

• Pancreatitis: typically radiates to the back.
• Gallbladder pathology: pain radiates to the right upper quadrant and back.
• Abdominal aortic aneurysm (AAA): central abdominal pain radiating to the back.
• Ruptured ectopic pregnancy: blood in the peritoneum irritates the diaphragm, causing shoulder tip pain.
• Renal/ureteric colic: pain radiates from the flank down into the ipsilateral groin

Associated symptoms

• Nausea and vomiting – note frequency, relation to meals, presence of blood or bile
• Diarrhoea: Assess frequency, consistency, colour, presence of blood or mucus
• Constipation: absolute (no stool or flatus) vs difficult-to-pass hard stools.
• Urinary symptoms: dysuria, frequency, haematuria
• Gynaecological history: last menstrual period, cycle details, bleeding patterns, clots, PV discharge or odour. Pregnancy history, contraception, possibility of current pregnancy, sexual history, pain on intercourse.
• Jaundice: yellowing of skin/eyes, pale stools, dark urine
• Fevers/rigors: clarify whether measured, subjective hot/cold sensations, or shivering.
• Weight loss: may indicate chronic pathology if present over time.

Time course

• Intermittent: suggests colicky or visceral pain, such as obstruction or renal/ureteric colic.
• Chronic pain: less likely to represent an acute inflammatory cause but persistent pain over months/years may indicate underlying pathology like inflammatory bowel disease or malignancy, even if not acutely life-threatening.
• Acute-on-chronic: consider flares of pre-existing conditions (eg, IBD flare)

Exacerbating factors

• Pain related to eating:
  • Worse after meals: consider gastric ulcers/biliary colic
• Pain related to movement or palpation
  • Pain worsened by movement or touching: suggests peritonitis.
  • Pain unchanged by movement or palpation: may suggest renal/ureteric colic (patients often restless, unable to stay still).
• Menstrual cycle:
  • Pain that varies with cycle: consider gynaecological pathology (e.g., endometriosis, ovarian cysts, fibroids).

Severity

• Severe pain is common in many ED presentations but is not always indicative of life-threatening pathology.
• Pain out of proportion to examination findings is a key red flag. Eg, elderly patients with mesenteric ischaemia may have a soft abdomen, normal urine, and normal labs, yet experience severe pain. So additional clues that something severe is underlying may include tachycardia, raised lactate, and risk factors for thromboembolism or vascular disease.
• New-onset severe pain in a patient without prior abdominal issues should always prompt further investigation.

Emergency causes of abdominal pain

Find below a quick guide to emergency causes of abdominal pain, their ‘classical’ pain presentation and suggested investigations and management strategies.

Vascular

Ruptured AAA (Abdominal Aortic Aneurysm)
– Sudden, severe tearing back/abdominal pain and hypotension in older patients with vascular risk factors.
– Investigations: POCUS, CT angiogram
– Management: IV access and major haemorrhage protocol for transfusion of blood products, although blood loss often exceeds transfusion. Needs urgent vascular surgery.

Mesenteric ischemia
– Patients with mesenteric ischaemia may have a soft abdomen, normal urine, and normal bloods, yet experience severe pain. However, may have tachycardia, raised lactate, and risk factors for thromboembolism or vascular disease.
– Investigations: CT angiogram
– Management: IV fluids, IV abx, surgical referral.

Gastrointestinal

Perforation
– Sudden + severe pain with peritonitis and a rigid abdomen
– Investigations: CT preferred; erect chest X-ray is now largely obsolete.
– Management: Fluids, antibiotics, emergency surgery

Obstruction
– Colicky pain with abdominal distension and vomiting. Typically will have absent flatus. May become peritonitis if progresses to ischaemia. 
– Investigations: CT abdo pelvis
– Management: Fluids, NG decompression, general surgery admission

Hepatobiliary/pancreatic

Pancreatitis
– RUQ pain radiating to the back
– Investigations: Serum lipase, CT abdomen pelvis
– Management: Supportive care, analgesia, risk stratification using Glasgow score, ICU if severe

Ascending cholangitis
– Charcot’s triad: Fever, jaundice, RUQ pain.
– Reynolds pentad: Triad + hypotension + confusion → severe, high mortality.
– Investigations: Ultrasound (first-line), MRCP if stable.
– Management: Antibiotics, fluids, biliary drainage via ERCP.

Gynaecological/obstetric

Ruptured ectopic pregnancy
– Lower abdominal pain radiating to shoulder tip. May also present with collapse
– Investigations: β-hCG, POCUS for free fluid.
– Management: Resuscitation, emergency surgery.

Ovarian torsion
– Investigations: pelvic US, doppler ultrasound (usually outside ED scope).
– Management: Emergency surgery.

Urological

Severe pyelonephritis
– Flank pain, vomiting, may be septic
– Investigations: Ultrasound or non-contrast CT KUB if needed
– Management: Fluids, antibiotics, may need stent or nephrostomy if severe

Renal/ureteric stones
– Loin to groin pain, vomiting, haematuria
– Investigations: Non-contrast CT KUB or ultrasound.
– Management: Analgesia first-line. Conservative management or urology review for intervention.

Cardiovascular Considerations

Myocardial infarction
– Epigastric pain, nausea, diaphoresis.
– Investigations: ECG, troponins
– Management: ACS protocol, PCI

Aortic dissection
– Tearing chest/back pain with pulse deficit and hypotension
– Investigations: CT aortogram
– Management: Cardiothoracic referral, blood pressure control

Examination

General Inspection

• Observe the patient’s general appearance and behaviour: posture, gait, comfort level, whether curled up in pain.
• Look for abdominal distension, jaundice, scars, and ask about previous surgeries.

Palpation

• Examine all quadrants carefully.
• Assess for guarding, localised peritonism, and rebound tenderness (signs of peritoneal irritation).

Auscultation

• Rarely changes management, but can note:
  • Hyperactive bowel sounds → gastroenteritis
  • Absent/sluggish/tinkling bowel sounds → obstruction

Special Tests

• Murphy’s sign → cholecystitis
• Rovsing’s sign → appendicitis
• Grey-Turner and Cullen signs → pancreatitis

Rectal Examination

• Indicated if:
  • Suspected perianal pathology (fissures, hemorrhoids, abscess)Concern for constipation, particularly in elderly (check for impaction)
  • Suspected upper GI bleed (look for melaena or frank blood)

Pelvic Examination (PV / Speculum)

• Less commonly done by EM doctors but essential when suspecting cervical shock which can cause bradycardia and hypotension

Red flags

• Sudden and severe pain
• Haemodynamic instability
• Acute abdomen – rebound tenderness, widespread guarding warrants urgent CT
• Pain out of proportion to findings – suggests mesenteric ischaemia
• Bilious vomiting – raises concerns for surgical pathology
• High-risk patient groups – elderly, diabetic, immunocompromised, non-verbal/patients with learning disability

Investigations

Bloods

• WCC – raised in infectious/inflammatory causes
• Hb – low in bleeding (may be normal in the hyperacute phase)
• Urea – raised in UGIB (out of proportion to creatinine)
• Electrolytes – correct as needed
• Lipase – 3x upper limit of normal is diagnostic for pancreatitis 
• Lactate – non-specific marker of anaerobic metabolism. Particularly raised in ischaemia.
• Beta HCG – blood test more sensitive than urine
• Troponin – raised in ACS

Urine dipstick

• Leucocytes: Non-specific; can be raised in urinary tract infection, appendicitis, or other inflammation.
• Nitrites: More specific for bacterial infection, but absence does not rule it out.
• Blood / Protein: May indicate UTI or renal calculi
• Ketones: Raised in DKA, but also in catabolic states or acute illness
• Glucose: Elevated in DKA.
• β-hCG: Confirms pregnancy, essential in women of childbearing age to rule out ectopic pregnancy.

Bedside imaging

• POCUS – beyond the scope of this talk but can be extremely useful for the workup of patients with acute abdominal pain. Remember that POCUS scans are ‘rule-in’ tests and the absence of positive findings doesn’t reliably rule out pathology. 

Other imaging

• Erect Chest X-ray
  • Rule-in test for free air/perforation. Used less now CT so readily available.
  • Not reliable to rule out perforation. If the XR is negative → need CT if high suspicion
• Abdominal X-ray – increasingly less used for acute pathology.
  • May be useful for faecal impaction and assessing bowel obstruction patterns but most patients with obstruction or perforation need CT first-line
• CT
  • Contrast-enhanced CT is investigation of choice for surgical pathology (perforation, obstruction, appendicitis, pancreatitis)
  • CT Angiography: For vascular causes (AAA, dissection, mesenteric ischemia)
  • Non-contrast CT KUB: For renal/ureteric stones, hydronephrosis, or unexplained AKI.
• Formal ultrasound
  • Used when POCUS is inconclusive or when additional detail is required (eg, ovarian pathology, biliary disease).
  • Limitations: Not a reliable rule-out test for many acute surgical conditions.

Management principles

Early analgesia

• Early pain relief is always appropriate – do not delay for diagnostic uncertainty.
• Multimodal approach: NSAIDs, paracetamol (IV if needed), opioids (IV morphine is generally safe and does not mask diagnoses)
• Adjuncts: antispasmodics (e.g., Buscopan), neuropathic agents if indicated

Anti-emetics

• Choose based on likely cause of nausea/vomiting (mechanism of action can guide selection).

Fluids

• Assess need individually
• Hypovolemia, persistent vomiting → IV bolus (e.g., 500 mL crystalloid) and reassess perfusion, HR, BP, urine output
• Otherwise, encourage oral intake if tolerated; avoid unnecessary IV fluids.

Antibiotics

• Indicated for sepsis or suspected intra-abdominal infection
• Start broad-spectrum if source unknown; tailor if source identified
• Renally adjust if impaired kidney function

Supportive Measures & Monitoring

• Keep NBM until surgical cause ruled out.
• Nasogastric tube if obstructed.
• Monitor vital signs and response to interventions.

Referral & Imaging

• Refer to surgical or specialty teams when indicated.
• Imaging may not always be required if clinical diagnosis is clear (e.g., classic appendicitis).
• Use clinical judgment and communicate with the receiving team regarding investigations and management plans.

Written by Dr Eloise Graham (Junior Clinical Fellow)
With thanks to Dr Jack Almy (Emergency Medicine ST6) for his work on the original webinar