Abdominal Pain

at the bedside

airway, breathing, circulation; full vitals, cardiac monitor if unwell, IV access, glucose
why admitted, what changed → recent surgery or endoscopy, chemotherapy, anticoagulation, known obstruction, pancreatitis, cirrhosis, IBD; last imaging, stool, urine output, MAR, drains, NG
look and press → distension, guarding, rigidity, rebound; still with pain on movement suggests peritoneal irritation, restless fits colic, neither confirms or excludes
pulses and the aorta → pulsatile mass, femoral pulses, both arms’ BP if the pain is tearing
pregnancy test → if biologically possible and status uncertain; ECG if epigastric pain or cardiac risk
analgesia early; opioids do not hide surgical signs → stabilize

escalate now if

rigid, silent abdomen, guarding or rebound → perforation or peritonitis → surgery now
pain with hypotension → ruptured AAA, ruptured ectopic, perforation with septic shock, massive GI bleed → resuscitate and call, hypotension
pain out of proportion to the exam, AF or vascular disease → mesenteric ischemia; a normal lactate excludes nothing
distension, vomiting, no flatus, with fever or focal severe pain → strangulating obstruction
fever, jaundice, RUQ pain → cholangitis, antibiotics and drainage
positive pregnancy test with pain or instability → ectopic, gynecology now

by region, dangerous first

epigastric → ACS, perforated ulcer, pancreatitis, dissection (tearing, to the back)
RUQ → cholecystitis (Murphy’s sign), cholangitis (fever, jaundice, pain), hepatitis
LUQ → splenic infarct or rupture, gastritis; shoulder-tip pain, trauma
RLQ → appendicitis, ovarian torsion or cyst rupture, ectopic
LLQ → diverticulitis, ovarian pathology
suprapubic → cystitis, retention, PID, ectopic → dysuria, urinary retention
flank → stones (colic, hematuria), pyelonephritis; AAA mimics renal colic in the older patient
diffuse → obstruction, mesenteric ischemia, perforation, DKA, constipation → hyperglycemia, constipation

not the abdomen

inferior MI, lower-lobe pneumonia, DKA, hypercalcemia, adrenal crisis, herpes zoster before the rash

pain → onset (sudden: perforation, rupture, torsion), site and radiation (back: pancreas, aorta; shoulder: diaphragm), colicky vs constant, worse with movement
symptoms → vomiting (bilious, feculent), last stool and flatus, fever, jaundice, dysuria, vaginal bleeding, melena
history → previous surgery (adhesions), gallstones, ulcer, alcohol, AF or vascular disease, known aneurysm, last period
MAR → NSAIDs, steroids, anticoagulants (retroperitoneal bleed), opioids (ileus), recent antibiotics (C. difficile)
exam → scars, hernial orifices, bowel sounds, Murphy’s and McBurney’s points, PR if bleeding or obstruction, pelvic exam if PID or ectopic is possible

stable, mild, likely benign → focused exam; tests only if they change tonight’s plan
new, severe or unexplained → CBC, electrolytes, RFT, urinalysis, then targeted tests
pancreatitis or biliary → lipase (> 3× upper limit), LFT, ultrasound
ischemia or shock → VBG, lactate, urgent imaging; a normal lactate is not reassuring
epigastric, possible cardiac → ECG ± troponin → chest pain
bleeding → CBC, coagulation, group and save or crossmatch → GI bleed
obstruction or perforation → surgical evaluation and imaging together, not one then the other

imaging follows diagnosis and stability

erect CXR → free air; absence does not exclude perforation
ultrasound → gallbladder and ducts; aorta if unstable with a suspected aneurysm; pelvis if ectopic or torsion
CT with contrast → perforation, obstruction, undifferentiated severe pain; CTA for aorta or mesenteric vessels; non-contrast for stones
unstable with a likely diagnosis → operating room on clinical grounds; imaging only if stable enough for the delay

1 · immediate stabilization

analgesia → paracetamol 1 g PO/IV q6h; morphine 2–5 mg IV titrated if severe; no NSAID with AKI, bleeding, ulcer or possible perforation → analgesia
fluids → by volume status, oral tolerance and losses; bolus if hypotensive; NPO only if surgery or intervention is possible → IV fluids
vomiting → ondansetron 4–8 mg IV → nausea and vomiting
unstable → surgery and ICU from the bedside, not after results → hypotension, advanced: shock

2 · suspected surgical or vascular emergency

NPO, two large-bore lines, crossmatch if bleeding is possible; surgery or vascular called in parallel with imaging
perforation or peritonitis → antibiotics covering gut flora and anaerobes → empiric antibiotics; surgery before imaging if rigid
ruptured AAA → vascular now; controlled resuscitation agreed with them, no single BP target; CT only if stable
mesenteric ischemia → CTA now, surgery and vascular already called; fluids, antibiotics; IV unfractionated heparin (WSES 2022) after a bleeding and contraindication check
obstruction → NG tube, correct K → potassium; strangulation → operating room
appendicitis, cholecystitis → antibiotics, surgery for timing; ruptured ectopic → gynecology now

3 · suspected medical or hepatobiliary cause

cholangitis → antibiotics now → empiric antibiotics; GI for ERCP by severity
pancreatitis → 2 of 3: typical pain, lipase > 3×, imaging; moderate fluids by volume status, analgesia, early feeding (ACG 2024)
peptic ulcer → PPI, oral if stable and tolerating enteral meds; bleeding → GI bleed
renal colic → ketorolac 30 mg IV/IM only if no contraindication and kidneys allow, else opioid → analgesia; infected obstructed kidney → urology now
diverticulitis → antibiotics only if complicated, immunocompromised or frail (AGA 2020)
DKA, constipation, gastroenteritis → hyperglycemia, constipation, diarrhea

4 · reassess

when → 30 min after IV analgesia, then each round and every repeat call
what → abdomen (new guarding or rigidity is a new call), vitals, analgesia response, vomiting, urine output, pending imaging, specialty review time
not settling → back to the escalate box; repeated opioid need with a soft abdomen still needs a diagnosis

hand over → working diagnosis, analgesia given, who was called, imaging time, what the treating team must review, escalation trigger

source	type
ACG 2024 acute pancreatitis guideline	international guideline
AGA 2020 diverticulitis practice update	international guideline
WSES 2022 acute mesenteric ischemia guideline update	international guideline
Tokyo Guidelines 2018, acute cholangitis and cholecystitis	international guideline
2022 ACC/AHA aortic disease guideline	international guideline

Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.

free the on-call checklist covers the whole shift on one printable page.

studying for the IM exam? the IM Rapid Review covers this in the same format. see the sample chapter.

reviewed Jun 2026updated Oct 2026file complaint/abdominal-pain