Abdominal Pain
at the bedside
- check vitals: HR, BP, RR, Temp, SpO₂, RBS
- O₂ if hypoxic
- IV access; fluids if hypotensive
escalate early
- peritonitis or suspected perforation: guarding, rigidity, rebound, rigid silent abdomen → surgery now
- obstruction with strangulation signs (fever, tachycardia, focal severe pain, peritonism) → surgery now
- pain out of proportion to examination → think mesenteric ischemia; normal lactate does not exclude it
- known AAA, or pain + hypotension in patient old enough for one → vascular surgery now
- possible ruptured ectopic (positive pregnancy test, adnexal tenderness, instability) → gynecology now
- hemodynamic instability, severe sepsis / shock, or significant GI bleeding → resuscitate in parallel, call for help before full workup
- pain worsening despite analgesia
focused check
- onset: sudden (perforation?) vs gradual
- provocation: worse/better with movement or food
- quality: sharp, dull, colicky
- radiation: back → pancreatitis, dissection; shoulder → diaphragm irritation
- severity: pain score
- timing: constant vs intermittent
| finding | suggests |
|---|---|
| pain radiating to back | pancreatitis, PUD, dissection |
| shoulder tip pain | gallbladder, splenic pathology |
| distension + constipation | obstruction |
| vomiting | obstruction, pancreatitis |
| jaundice | hepatobiliary |
| recent surgery | adhesions, ileus |
| alcohol / NSAIDs | pancreatitis, ulcers |
examination
- distension, tenderness, guarding / rebound, surgical scars
- pattern: still patient → peritonitis; restless → colicky pain (stones)
- targeted signs: Murphy’s → cholecystitis; McBurney’s / Rovsing’s / Psoas → appendicitis
- PR exam → bleed / ischemia; pelvic exam → PID / ectopic
differentials
think by pattern; dangerous causes first. location is a clue, not a diagnosis.
| pattern | important causes | clues | next step |
|---|---|---|---|
| epigastric | ACS/MI, perforated PUD, pancreatitis, aortic dissection | cardiac risk factors, back radiation, alcohol/NSAID use | ECG + troponin, lipase; CTA if dissection suspected |
| RUQ | cholecystitis, cholangitis, hepatitis, perforated PUD | Murphy’s sign; fever + jaundice + RUQ pain (Charcot’s triad) → cholangitis | RUQ ultrasound, LFTs; urgent ERCP if cholangitis |
| LUQ | splenic rupture / infarct, gastritis | trauma history, shoulder-tip pain (referred), instability | bedside ultrasound if trauma, CT abdomen |
| RLQ | appendicitis, ovarian torsion / cyst rupture, ectopic pregnancy | McBurney’s / Rovsing’s / Psoas signs, pregnancy potential | pregnancy test, CT or ultrasound, surgical review |
| LLQ | diverticulitis, ovarian pathology | fever, altered bowel habit, pregnancy potential | pregnancy test, CT abdomen/pelvis |
| suprapubic / lower | UTI/cystitis, urinary retention, PID, ectopic | dysuria, discharge, pregnancy potential | urinalysis, pregnancy test, pelvic exam |
| flank | nephrolithiasis, pyelonephritis, AAA can mimic it | colicky, radiates to groin, hematuria; instability → think AAA | urinalysis, non-contrast CT KUB; bedside aortic scan if unstable or risk factors |
| diffuse / generalized | obstruction, mesenteric ischemia, DKA, perforation | distension + vomiting; rigid silent abdomen (perforation) | erect CXR/CT for free air, lactate, glucose/ketones |
| pain out of proportion | mesenteric ischemia | minimal tenderness despite severe pain, AF or known vascular disease | urgent CTA mesenteric vessels + surgical review, don’t wait for lactate to confirm |
| pain + shock | ruptured AAA, ruptured ectopic, massive GI bleed, perforation with septic shock | hypotension, pulsatile mass, positive pregnancy test | resuscitate + immediate surgical/gynecology involvement; skip imaging if unstable and diagnosis clinically likely |
| pregnancy potential | ectopic pregnancy, ovarian torsion | positive β-hCG, adnexal tenderness, syncope | urine β-hCG on every woman of reproductive age; urgent gynecology if positive + unstable or peritonitic |
quick actions once a diagnosis is suspected
- AAA rupture: vascular surgery now, alongside resuscitation; permissive hypotension while awaiting theatre
- unstable + known AAA or positive bedside aortic ultrasound → theatre on clinical diagnosis; CT only if stable enough for the delay
- CTA is for surgical planning, not a prerequisite for calling surgery
- perforation: NPO, resuscitate, antibiotics (below), urgent surgery; rigid silent abdomen → call surgery before imaging
- mesenteric ischemia: normal lactate does not exclude it (poor early sensitivity); CTA without delay once suspected
- IV fluids, empiric antibiotics; IV unfractionated heparin unless contraindicated, per surgical / vascular input
- overt peritonism → surgery now, do not wait for CTA
- ruptured ectopic: emergency → resuscitate + gynecology
- ascending cholangitis (distinct from uncomplicated cholecystitis): Charcot’s triad, IV antibiotics + biliary drainage (ERCP), timing by severity → full detail on LFT
- appendicitis: NPO, IV fluids, antibiotics, surgical consult
- obstruction: NPO, IV fluids, surgical review; NGT if significant vomiting, marked distension, or high-grade/complete obstruction (not automatic for partial); strangulation → surgery now (see escalate)
- pancreatitis: diagnosis = 2 of 3: typical pain, lipase / amylase >3× ULN, consistent imaging; CT only for diagnostic uncertainty or failure to improve
- moderate IV fluids (avoid over-resuscitation, WATERFALL); analgesia
- early oral feeding as tolerated within 24–48 hr, not bowel rest, unless ileus or uncontrolled vomiting: bowel rest worsens outcomes
- diverticulitis: IV fluids, diet as tolerated
- uncomplicated + immunocompetent + well-appearing → antibiotics selectively, not routinely (AGA): withhold if no frailty, comorbidity, vomiting, or marked inflammation
- antibiotics for complicated disease, immunocompromise, or anyone outside that low-risk picture
- PUD: IV PPI, H. pylori treatment
- nephrolithiasis: IV fluids, NSAID first-line (e.g. diclofenac 75 mg IM / ketorolac) unless contraindicated, tamsulosin
- gastroenteritis: hydration, antiemetics
send now
severity- and differential-driven; well-appearing patient with obvious benign cause doesn’t need all of this
| category | test | why |
|---|---|---|
| starting panel for moderate severity or diagnostic uncertainty | CBC, CRP | infection / inflammation |
| U&E, Creatinine | dehydration, AKI, baseline before contrast | |
| RBS | hypo / hyperglycemia, DKA | |
| cause-specific | LFTs, lipase | hepatobiliary / pancreatitis |
| lactate | ischemia / shock; normal result does not exclude mesenteric ischemia | |
| troponin, ECG | ACS presenting as epigastric pain; not every epigastric pain | |
| urine β-hCG | pregnancy biologically possible and would change differential or management | |
| urinalysis | infection, hematuria (stones) | |
| pre-intervention | coagulation panel | bleeding risk / liver disease; before procedure or anticoagulation |
| group & crossmatch | suspected bleeding / likely surgery |
treat
- NPO if surgical cause suspected
- IV fluids if hypotension, vomiting, or pancreatitis
- symptom control
- give analgesia early: opioids do not delay diagnosis or mask surgical findings; paracetamol 1 g PO/IV (oral if tolerating); avoid NSAIDs if renal injury, bleeding risk, active/suspected PUD, or perforation risk; morphine 2–5 mg IV titrated if severe
- antiemetics: Ondansetron 4–8 mg IV
- supportive
- NGT → if obstruction
- constipation: Lactulose / Movicol / enema
- antibiotics: peritonitis, complicated intra-abdominal infection, or SBP (not automatic for uncomplicated diverticulitis, see above) → regimens on Empiric Antibiotics; cholangitis → LFT
- persistent shock despite source control and resuscitation → Advanced: Shock, Advanced: Vasopressors & Inotropes if vasoactive support needed
evidence
| source | type |
|---|---|
| ACG / AGA acute pancreatitis guidance | international guideline |
| AGA 2020 diverticulitis practice update | international guideline |
| WSES mesenteric ischemia guideline | international guideline |
| Tokyo Guidelines, acute cholangitis | international guideline |
| Ruptured AAA / POCUS literature | specialty-society guidance |
| Analgesia and diagnostic accuracy, meta-analysis literature | evidence review |
Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.
go deeper MOC+ Vol 4 · Acute GI & Hepatology covers this in the full reference. or the complete set.
free the on-call checklist covers the whole shift on one printable page.
studying for the IM exam? the IM Rapid Review covers the acute abdomen in the same format. see the sample chapter.
reviewed Jun 2026updated Sep 2026file complaint/abdominal-pain