Abdominal pain is one of the most challenging and broad complaints in emergency and outpatient medicine. It ranges from benign gastritis to life-threatening conditions like ruptured AAA, bowel perforation, appendicitis, ectopic pregnancy, or pancreatitis.
Abdominal Pain: Red Flags & Early Thoughts
Life-Threatening Conditions
- Myocardial infarction (MI)
- Abdominal aortic aneurysm (AAA)
- Mesenteric ischemia (MES-I)
- Ovarian torsion
- Perforated viscus
- Ascending cholangitis
- Splenic rupture
Early Clinical Approach
- Make NPO (nothing by mouth)
- Upper abdominal pain + cardiac risk → EKG
- Female age 12–50 → Urine pregnancy test (UPreg)
- Lower abdominal female → Urine dip + pelvic exam
- Lower abdominal male → GU exam
- Diffuse pain → Check glucose (r/o DKA)
- Elderly → Likely need CT or ultrasound (r/o AAA)
- Peritoneal signs → Upright CXR + surgical consult
- Considering CT? Give oral contrast early
“Very Sick” Abdominal Pain → Aggressive Approach
If unstable:
- 2 large-bore IVs
- Fluid resuscitation
- NPO & pain control
Broad workup including:
- EKG
- FS glucose
- Lactate
- CBC, BMP, LFTs
- Lipase
- Troponin
- UA (HCG for females)
- FOBT when needed
- Upright CXR
- Prepare for CT
- Early surgical consultation
LOCATION-BASED APPROACH TO ABDOMINAL PAIN
The abdomen is divided into:
- Upper
- Diffuse + Flank
- Lower
Each has characteristic diagnoses and workups.
ABDOMINAL PAIN – UPPER
Upper abdominal pain includes epigastric, RUQ, and LUQ pain.
A. ACS / MI (Cardiac Causes)
Often presents as epigastric “burning” or pressure pain, especially in older adults or diabetics.
Workup: EKG, troponins
Treatment: Follow Chest Pain protocol
B. GERD
Burning pain radiating upward into the throat.
Workup: Clinical
Treatment: GI cocktail, PPIs, H2 blockers
C. Peptic Ulcer Disease (PUD)
Risk factors:
- Chronic NSAID use
- Alcohol
- H. pylori
If perforated → sudden severe pain, rigid abdomen.
Workup:
- CBC
- FOBT
- Upright CXR (air under diaphragm)
Treatment:
- GI cocktail, PPIs
- Surgery if perforated
D. Pancreatitis
Pain: Sharp, radiates to the back
Risks: Alcohol use, gallstones
Workup:
- Lipase
- LFTs
- RUQ ultrasound
- Ranson’s criteria
Treatment:
- NPO
- Aggressive IV fluids
- ICU if severe
E. Gallbladder Disease
Includes:
- Cholelithiasis
- Cholecystitis
- Cholangitis
1. Cholangitis
Reynold’s triad:
- Fever
- RUQ pain
- Jaundice
Charcot’s + AMS + shock = acute cholangitis emergency
Workup: LFTs, US, CT
Treatment:
- IV antibiotics
- GI consult for ERCP
2. Cholecystitis
RUQ tenderness + positive Murphy’s sign.
Fever, nausea.
Workup: RUQ ultrasound
Treatment: IV antibiotics → surgery
3. Gallbladder Colic
Intermittent RUQ pain, no fever.
Treatment: NSAIDs, outpatient surgical follow-up
F. Pneumonia
Especially lower-lobe pneumonia can mimic upper abdominal pain.
Workup: CXR
Treatment: Antibiotics (follow Chest Pain section)
ABDOMINAL PAIN – DIFFUSE + FLANK
Diffuse or flank abdominal pain can be caused by dangerous metabolic, vascular, or surgical conditions.
A. Abdominal Aortic Aneurysm (AAA)
Clues:
- Elderly
- Male
- Tobacco history
- Back/flank pain
Workup:
- Ultrasound for screening
- CT-A for unstable or concerning cases
Treatment:
- Emergency surgery
- Type & screen
- Prepare PRBCs
B. Diabetic Ketoacidosis (DKA)
Symptoms:
- Nausea, vomiting
- Tachypnea
- AMS
Workup:
- FS glucose
- Urine dip
- Ketones
- Anion gap
- pH
Treatment:
- IV fluids
- Insulin
- Potassium replacement
- ICU for severe cases
C. Mesenteric Ischemia
High suspicion in AFib patients
Pain out of proportion to exam.
Workup: Lactate (late), CT-A
Treatment: Emergency surgery
D. Perforated Viscus
Symptoms:
- Sudden severe pain
- Peritoneal signs
- Guarding/rebound
Workup: Upright CXR (free air), CT
Treatment: IV antibiotics + surgery
E. Small Bowel Obstruction (SBO)
History of:
- Prior surgeries
- Constipation
- ↓ flatus
Workup: AXR, CT
Treatment: NG tube + Surgery consult
F. Acute Gastroenteritis
Diarrhea, vomiting, fever, travel history.
Treatment: IV fluids, antiemetics, consider antibiotics if needed
G. Kidney Stones (Nephrolithiasis)
Pain: Colicky, radiates to groin
Symptoms: Writhing, unable to find comfortable position
Workup: UA, ultrasound, CT
Treatment: Ketorolac, tamsulosin
H. Pyelonephritis
- CVA tenderness
- Fever
- Urinary symptoms
Workup: UA, culture
Treatment: Antibiotics (admit high-risk patients)
ABDOMINAL PAIN – LOWER
Lower abdominal pain includes appendicitis, GU causes, and GYN causes.
A. Dangerous Causes
1. Appendicitis (APPY)
Fever, nausea/vomiting, anorexia, pain migrating to McBurney’s point.
Workup: CT
Treatment: Antibiotics + surgery
2. Hernia (Incarcerated or Strangulated)
Pain, mass, vomiting, ↓ bowel movements.
Workup: Clinical, CT
Treatment: Reduce? Surgery if strangulated
3. Diverticulitis (D-TICS)
LLQ pain + fever.
Workup: Clinical ± CT
Treatment: Antibiotics
4. Testicular torsion (Male)
Sudden severe scrotal pain
No cremasteric reflex
Workup: Ultrasound
Treatment: Immediate detorsion + urology
5. Ectopic Pregnancy
Woman age 12–50 with abdominal pain = must rule out ectopic.
Workup: UPreg + hCG
Treatment: Emergency OB/GYN management
6. Ovarian torsion
Sudden severe pain, nausea/vomiting.
Workup: Ultrasound
Treatment: Emergency OB/GYN consult
7. Ovarian Cyst
Adnexal pain, often mid-cycle or chronic.
Workup: US
Treatment: NSAIDs, OBGYN follow-up
8. PID / Tubo-ovarian abscess
Young sexually active female with:
- Vaginal discharge
- Cervical motion tenderness
Workup: Pelvic exam, GC/Chlamydia
Treatment: IM antibiotics
B. Common Lower Abdominal Causes
1. Mittelschmerz
Mid-cycle ovulation pain.
Treatment: Reassurance
2. Period / Fibroids
Pelvic pain with bleeding.
Workup: US (if outpatient stable)
Treatment: NSAIDs
3. UTI
Dysuria, frequency, no CVA tenderness.
Workup: UA
Treatment: Antibiotics
4. Constipation
History of ↓ bowel movements, opioid use.
Treatment: Diet, laxatives, disimpaction if severe
5. Epididymitis / Orchitis (Male)
Tenderness, discharge.
Workup: Clinical, GC/Chlamydia
Treatment: IM antibiotics
High-Yield Pearls & Pitfalls
- Always consider cardiac causes for upper abdominal pain.
- SBO suspicion? Avoid metoclopramide—use ondansetron.
- Appendicitis, diverticulitis, kidney stones, and torsion may start as diffuse pain.
- If severe or toxic → NPO, IV fluids, early surgery consult.
- PID treatment → avoid 1-dose azithromycin (needs doxycycline 2 weeks).
- All women of child-bearing age → UPreg.
- Gallbladder pain → quick bedside ultrasound.
- Pain out of proportion → Mesenteric ischemia until proven otherwise.
Documentation Essentials
PMH
- AFib (mesenteric ischemia)
- Prior surgeries (SBO)
- Diabetes (DKA)
- Bowel movement patterns
- Dysuria/urinary frequency (UTI/kidney stone)
- Tobacco (AAA risk)
General Exam
- Dehydration
- Toxic appearance
- Guarding or rebound tenderness
Abdomen
- Location of tenderness
- Peritoneal signs
- Distention
- Murphy’s sign
- McBurney’s point tenderness
Pelvic (Females)
- Discharge
- CMT
- Adnexal tenderness
Testicular (Males)
- Tenderness
- Position
- Cremasteric reflex
FAQs About Abdominal Pain
1. When is abdominal pain an emergency?
When associated with peritoneal signs, fever, vomiting, hypotension, pregnancy, or suspected torsion.
2. Should all patients get a CT scan?
No—but elderly, severe, or unclear cases often require CT.
3. Can heart problems cause abdominal pain?
Yes—MI, pericarditis, and pneumonia frequently mimic abdominal pain.
4. Do women always need a pregnancy test?
All females 12–50 with abdominal pain must receive UPreg unless absolutely impossible.
5. What is the most dangerous missed diagnosis?
AAA, ectopic pregnancy, mesenteric ischemia, torsion, and perforated bowel.
