One-liner#

Evaluate acute abdominal pain (<72 hours) to identify surgical emergencies and serious pathology requiring urgent intervention, while efficiently managing the common benign causes seen in primary care.

Quick nav#

• Red flags / send to ED
• Key history
• Focused exam
• Differential (quick pattern recognition)
• Workup
• Initial management
• Management by diagnosis
• Follow-up
• Patient instructions
• Smartphrase snippets

Red flags / send to ED#

• Hemodynamic instability: hypotension, tachycardia, altered mental status
• Peritoneal signs: rigid abdomen, rebound tenderness, guarding
• Severe pain out of proportion to exam (mesenteric ischemia)
• Fever + severe abdominal pain (perforation, abscess, cholangitis)
• Bilious or feculent vomiting (obstruction)
• Abdominal distension with obstipation (obstruction)
• Pulsatile abdominal mass (AAA rupture)
• Positive pregnancy test + abdominal pain (ectopic until proven otherwise)
• GI bleeding with hemodynamic compromise
• Elderly or immunocompromised with acute abdomen (atypical presentations—lower threshold for imaging and ED referral)

Elderly-specific concerns: Patients >65 may have minimal tenderness, no fever, and normal WBC despite serious pathology. Maintain high suspicion for cholecystitis, appendicitis, and mesenteric ischemia even with subtle findings.

Key history#

Pain characteristics:

• Location and radiation: RUQ (biliary, hepatic), epigastric (gastric, pancreatic, cardiac), RLQ (appendicitis, ovarian), LLQ (diverticulitis, ovarian), periumbilical→RLQ migration (classic appendicitis)
• Onset: sudden (perforation, rupture, vascular) vs gradual (inflammatory, infectious)
• Quality: colicky/crampy (obstruction, biliary, renal) vs constant (peritonitis, pancreatitis)
• Severity: 10/10 sudden onset concerning for vascular emergency or perforation
• Timing: relation to meals (biliary, mesenteric ischemia), menstrual cycle

Associated symptoms:

• Nausea/vomiting: timing relative to pain onset (pain first in surgical conditions)
• Fever/chills: infectious or inflammatory process
• Bowel changes: diarrhea (infectious, IBD), constipation/obstipation (obstruction)
• Urinary symptoms: dysuria, frequency, hematuria (UTI, nephrolithiasis)
• Vaginal bleeding/discharge: ectopic, PID, ovarian pathology
• Last menstrual period: ALWAYS ask in reproductive-age women

Risk factors:

• Prior abdominal surgery (adhesive obstruction)
• Gallstones, alcohol use (pancreatitis)
• NSAIDs, anticoagulation (GI bleed, perforation)
• Vascular disease, atrial fibrillation (mesenteric ischemia)
• Recent antibiotics (C. diff)
• Travel, sick contacts (infectious)

Focused exam#

• Vitals: fever, tachycardia, hypotension (sepsis, hemorrhage, dehydration)
• General: degree of distress, position (peritonitis patients lie still; colicky pain causes writhing)
• Abdominal inspection: distension, surgical scars, visible peristalsis, ecchymosis (Cullen’s, Grey Turner’s)
• Auscultation: absent bowel sounds (ileus, late obstruction), high-pitched/tinkling (early obstruction)
• Palpation: start away from pain; assess for tenderness, guarding, rigidity, rebound, masses, organomegaly
• Special signs: Murphy’s (RUQ), McBurney’s/Rovsing’s (RLQ), psoas/obturator (appendicitis), CVA tenderness
• Pelvic exam: if gynecologic cause suspected (cervical motion tenderness, adnexal mass/tenderness)
• Rectal exam: if GI bleed, obstruction, or prostate pathology suspected
• Hernia check: inguinal and femoral regions for incarceration

Differential (quick pattern recognition)#

Common/likely (outpatient)#

Can’t-miss / urgent#

Workup#

In-office (stable patients with non-surgical presentation):

• Urine pregnancy test: ALL reproductive-age women with abdominal pain
• Urinalysis: if urinary symptoms or flank pain
• Point-of-care glucose: if diabetic or altered mental status

Labs to order (results same day if possible):

• CBC: WBC elevation (infection, inflammation); anemia (bleeding)
• BMP: dehydration, renal function, electrolyte abnormalities
• Lipase: if pancreatitis suspected (>3x upper limit diagnostic)
• LFTs/bilirubin: if biliary pathology suspected
• Lactate: if mesenteric ischemia or sepsis concern (send to ED if ordering this)

Imaging:

• RUQ ultrasound: first-line for biliary pathology; gallstones, wall thickening, CBD dilation
• CT abdomen/pelvis with contrast: most useful for undifferentiated acute abdominal pain; appendicitis, diverticulitis, obstruction, pancreatitis complications
• KUB: limited utility; may show obstruction (air-fluid levels), free air, or large stones
• Pelvic ultrasound: ovarian pathology, ectopic pregnancy

When NOT to image:

• Classic gastroenteritis with sick contacts, no red flags, improving
• Obvious constipation responding to treatment
• Uncomplicated UTI with classic symptoms
• Mild, resolving pain with benign exam

When to send to ED for imaging:

• Any concern for surgical emergency
• Hemodynamically unstable
• Severe pain requiring IV pain control
• Need for CT with IV contrast and close monitoring

Initial management#

• Hemodynamically unstable or peritoneal signs: Call 911 or direct to ED immediately
• Stable but concerning: Send to ED for expedited workup (CT, labs, surgical consult)
• Stable, low-risk: Initiate workup from office; symptomatic treatment; close follow-up

Symptomatic treatment (stable, non-surgical patients):

• Oral hydration for mild dehydration
• Antiemetics: ondansetron 4–8 mg ODT PRN
• Pain control: acetaminophen first; avoid NSAIDs if GI bleed or renal concern; avoid opioids until diagnosis clear (can mask peritoneal signs)
• NPO if surgical diagnosis possible

Management by diagnosis#

Acute gastroenteritis#

Education:

• Usually viral; resolves in 1–3 days
• Focus on hydration—small frequent sips
• Contagious; hand hygiene important

Treatment:

• Oral rehydration: clear fluids, electrolyte solutions (Pedialyte, sports drinks diluted)
• Diet: advance as tolerated; BRAT diet not necessary but bland foods often better tolerated
• Antiemetics if needed (see table below)
• Antibiotics NOT indicated for most viral gastroenteritis

Follow-up: Return if not improving in 48–72 hours, bloody stool, high fever, or unable to keep fluids down.

Biliary colic (uncomplicated)#

Education:

• Gallstones causing temporary blockage; pain resolves when stone passes
• High risk of recurrence (70% within 2 years)
• Elective surgery recommended to prevent complications (cholecystitis, pancreatitis)

Treatment:

• Low-fat diet may reduce frequency of attacks
• Pain control during episodes: NSAIDs (ketorolac, ibuprofen) more effective than opioids for biliary pain
• Surgical referral for elective cholecystectomy

Follow-up: Surgical referral within 2–4 weeks; return immediately if pain >6 hours, fever, or jaundice.

Uncomplicated diverticulitis#

Education:

• Infection/inflammation of a diverticulum (outpouching in colon)
• Most cases resolve with antibiotics; ~30% recur
• After recovery: high-fiber diet may reduce recurrence

Treatment:

• Outpatient management appropriate if: immunocompetent, tolerating PO, no complications on CT (Hinchey 0 or Ia), pain controlled with oral meds, reliable follow-up
• Clear liquid diet initially, advance as tolerated
• Antibiotics for 7–10 days (though recent evidence suggests antibiotics may not be necessary for uncomplicated cases—discuss with patient)
• ED referral if: abscess >3cm, perforation, obstruction, fistula, immunocompromised, unable to tolerate PO, failed outpatient treatment

Follow-up: 2–3 days to ensure improvement; colonoscopy 6–8 weeks after resolution (if not done recently) to rule out malignancy.

Peptic ulcer disease / Gastritis#

Education:

• Caused by H. pylori infection, NSAIDs, or stress
• Avoid NSAIDs, alcohol, smoking
• Most heal with 4–8 weeks of PPI therapy

Treatment:

• Stop NSAIDs if possible
• PPI therapy (see GERD page for full medication table)
• Test for H. pylori and treat if positive

H. pylori treatment if positive: See dyspepsia/GERD page for eradication regimens.

Follow-up: 4–8 weeks; EGD if alarm features, refractory symptoms, or need to confirm healing of gastric ulcer.

Nephrolithiasis (uncomplicated)#

Education:

• Kidney stone causing pain as it passes; most <5mm pass spontaneously
• Increase fluid intake to 2–3 L/day
• Strain urine to catch stone for analysis

Treatment:

• Aggressive hydration
• Pain control (NSAIDs preferred over opioids for renal colic)
• Medical expulsive therapy for stones 5–10mm

Follow-up: Urology referral if stone >6mm, not passing after 4 weeks, infection, or obstruction. Metabolic workup (24-hour urine) for recurrent stone formers.

Follow-up#

• Gastroenteritis: Return if not improving in 48–72 hours, bloody stool, high fever, or dehydration
• Biliary colic: Surgical referral within 2–4 weeks; return immediately if pain >6 hours, fever, jaundice
• Diverticulitis: Recheck in 2–3 days; colonoscopy 6–8 weeks post-resolution
• PUD/gastritis: 4–8 weeks on PPI; EGD if not improving or alarm features
• Nephrolithiasis: 1–2 weeks; urology if not passing or complicated

Return precautions (all patients):

• Worsening pain or new severe pain
• Fever >101°F (38.3°C)
• Inability to keep fluids down
• Blood in vomit or stool
• Abdominal distension or inability to pass gas
• Dizziness, lightheadedness, or fainting

Patient instructions#

• If you develop severe pain, high fever, bloody vomit or stool, or feel faint, go to the emergency room or call 911.
• Take small sips of clear fluids to stay hydrated. Avoid solid food until nausea improves.
• Avoid NSAIDs (ibuprofen, naproxen, aspirin) if you have stomach pain or ulcer symptoms unless your doctor says it’s okay.
• Take all prescribed medications as directed, even if you start feeling better.
• Follow up as scheduled, even if symptoms improve.
• Call the office if symptoms are not improving within 2–3 days or if you develop new symptoms.

Smartphrase snippets#

.ABDPAINACUTELOWRISK Acute abdominal pain, low risk. Benign exam without peritoneal signs. Vital signs stable. Suspect [gastroenteritis/constipation/biliary colic]. Plan: supportive care, symptomatic treatment. Discussed return precautions including worsening pain, fever, vomiting blood, or inability to keep fluids down.

.ABDPAINACUTEWORKUP Acute abdominal pain requiring workup. Ordered [CBC, BMP, LFTs, lipase, UA, RUQ US/CT abdomen-pelvis]. Patient stable, tolerating PO. Will follow up results and reassess. Discussed return precautions and when to go to ED.

Related pages#

• Abdominal pain (chronic) — if symptoms persist >4 weeks
• GERD (problem) — chronic acid reflux management
• Irritable Bowel Syndrome (problem) — functional abdominal pain
• Nausea/Vomiting — if vomiting is prominent
• Dyspepsia/GERD — if epigastric pain
• Constipation — if constipation-related pain
• Diarrhea (acute) — if diarrhea is prominent
• Dysuria — if urinary symptoms
• Pelvic pain (female) — if gynecologic cause suspected

.ABDPAINACUTEED Acute abdominal pain with concerning features. [Describe findings: peritoneal signs/hemodynamic instability/severe pain]. Referred to ED for expedited evaluation including imaging and surgical consultation. Patient instructed to go directly to ED.