Evaluating Abdominal Emergencies

Evaluating Abdominal Emergencies

Structures abdominal pain workups with differential diagnosis by quadrant location, laboratory and imaging selection, and surgical consultation criteria for acute abdomen.

Why This Skill Exists

Abdominal pain is the most common chief complaint in US emergency departments, accounting for approximately 8% of all ED visits (11 million annually). The differential diagnosis spans over 50 conditions across multiple organ systems, and the diagnostic challenge is compounded by the fact that history and physical exam alone have limited sensitivity for surgical conditions — clinical accuracy for appendicitis, for example, ranges from 70-87% without imaging. Missed surgical emergencies (ruptured AAA, mesenteric ischemia, perforated viscus) carry mortality rates of 40-80% if treatment is delayed.

Overtesting is equally problematic: CT abdomen/pelvis exposes patients to 10 mSv of radiation (equivalent to ~500 chest X-rays), and contrast-induced nephropathy affects 1-6% of patients with renal insufficiency. This skill provides a systematic framework for efficient, accurate abdominal pain evaluation that avoids both undertesting and overtesting.

Checkpoint A: Pre-Draft Intake (Mandatory)

1. What is the location, onset, and character of the abdominal pain? (Default: document using OLDCARTS)
2. What are the patient's vital signs? (Default: full set; flag fever, tachycardia, hypotension)
3. Is the patient pregnant or of childbearing age? (Default: obtain beta-hCG for all females 12-55)
4. What is the patient's surgical history? (Default: document all prior abdominal surgeries — critical for adhesive obstruction)
5. What is the timing of last oral intake? (Default: relevant for NPO status if surgery likely)
6. Are there associated GI symptoms (nausea, vomiting, diarrhea, constipation, melena, hematochezia)? (Default: query and document each)
7. Are there urinary symptoms? (Default: query dysuria, frequency, hematuria)
8. What medications is the patient taking (NSAIDs, anticoagulants, immunosuppressants, steroids)? (Default: these mask examination findings)

Documents to Request

• Complete vital signs with serial measurements
• Prior abdominal imaging for comparison
• Surgical history documentation
• Medication list (NSAIDs, steroids, immunosuppressants mask peritonitis)
• Lab results: CBC, BMP, lipase, hepatic panel, lactate, urinalysis, beta-hCG
• Prior ED visits for abdominal complaints

Step 1: Differential Diagnosis by Quadrant

Right Upper Quadrant (RUQ)

Right Lower Quadrant (RLQ)

Left Upper Quadrant (LUQ)

Left Lower Quadrant (LLQ)

Diffuse / Periumbilical

Step 2: Laboratory and Imaging Selection

Standard ED Abdominal Lab Panel

• CBC with differential (leukocytosis, anemia, bandemia)
• BMP (creatinine for contrast, electrolytes for vomiting)
• Hepatic function panel (AST, ALT, ALP, total bilirubin, albumin)
• Lipase (>3× ULN diagnostic for pancreatitis)
• Lactate (>2.0 mmol/L concerning for ischemia or sepsis)
• Urinalysis (UTI, stones, hematuria)
• Beta-hCG (all females of childbearing age — non-negotiable)
• Type and screen if surgical intervention likely

Imaging Decision Framework

Step 3: Surgical Consultation Criteria

Immediate Surgical Consult Required

• Peritonitis: diffuse tenderness with involuntary guarding, rigidity, or rebound
• Free air on imaging (perforated viscus)
• Bowel ischemia suspected (pain out of proportion to exam, elevated lactate, CT findings)
• Ruptured AAA: hypotension + pulsatile mass + abdominal/back pain
• Ruptured ectopic pregnancy: positive hCG + free fluid + hemodynamic instability
• Testicular torsion: sudden onset scrotal pain, absent cremasteric reflex, high-riding testis (urology consult — do not delay for imaging if >6 hours)

Urgent Surgical Consult (within hours)

• Appendicitis confirmed on CT
• Complicated diverticulitis (abscess, perforation, fistula)
• Small bowel obstruction with signs of strangulation (fever, tachycardia, localized tenderness, elevated lactate)
• Incarcerated hernia not reducible
• Cholecystitis with sepsis or gangrenous features

Step 4: Pain Management and Reassessment

Analgesic Approach

• Administer analgesia early — withholding pain medication does NOT improve diagnostic accuracy (multiple RCTs confirm this)
• IV opioids for severe pain: morphine 0.1 mg/kg or hydromorphone 0.015 mg/kg
• IV acetaminophen 1g (opioid-sparing; safe in most abdominal conditions)
• IV ketorolac 15-30 mg for renal colic (avoid if creatinine elevated, GI bleeding, or surgical candidate)
• Antiemetics: ondansetron 4 mg IV

Serial Examination

• Reassess and document abdomen after analgesia and after imaging results
• Improvement with analgesia does not exclude surgical pathology
• Worsening examination on reassessment = escalate urgency

Checkpoint B: Post-Draft Alignment (Mandatory)

1. Was the differential diagnosis organized by pain location and pattern?
2. Was beta-hCG obtained for all females of childbearing age?
3. Was imaging selection appropriate for the leading diagnosis (not reflexive CT for all complaints)?
4. Were surgical consultation criteria applied and consult obtained when indicated?
5. Was the patient reassessed after treatment and imaging with findings documented?

Quality Audit

• Pain location and character documented with OLDCARTS framework
• Complete vital signs including temperature documented
• Beta-hCG obtained for all females of childbearing age
• Differential diagnosis listed by anatomic location
• Laboratory studies appropriate to the differential obtained
• Imaging modality matches the suspected diagnosis (ultrasound for biliary, CT for appendicitis, etc.)
• Surgical consultation obtained for peritonitis, free air, ischemia, or ruptured viscus
• Pain management provided and documented with response
• Serial abdominal examination documented with times
• Lactate obtained if mesenteric ischemia or sepsis considered
• NSAIDs/steroids/immunosuppressant use documented (mask peritoneal signs)
• Disposition rationale documented with surgical clearance if applicable
• Discharge instructions include specific return precautions for worsening pain, fever, vomiting

Guidelines

1. Always obtain beta-hCG in females of childbearing age presenting with abdominal or pelvic pain — ruptured ectopic pregnancy is the most dangerous missed diagnosis in this population.
2. Administer analgesia early and aggressively — the outdated practice of withholding pain medication to preserve the abdominal exam has been definitively disproven by multiple randomized controlled trials.
3. A normal lactate does not exclude mesenteric ischemia — lactate elevation is a late finding indicating bowel necrosis; CT angiography is the test of choice for early diagnosis.
4. Use ultrasound before CT for suspected biliary disease, suspected ovarian pathology, and suspected ectopic pregnancy — ultrasound is more sensitive, faster, and avoids radiation for these specific diagnoses.
5. Elderly and immunosuppressed patients present atypically — perforated appendicitis may present with minimal tenderness, and peritonitis may lack rebound or guarding in patients on steroids.
6. Abdominal pain "out of proportion to physical examination findings" is the classic presentation of mesenteric ischemia until proven otherwise — this phrase should trigger immediate CT angiography.
7. Serial examination is the most valuable diagnostic tool in undifferentiated abdominal pain — if the initial evaluation is non-diagnostic, reassess in 4-8 hours rather than discharge prematurely.
8. Document the patient's surgical history in detail — adhesive small bowel obstruction is the most common cause of SBO and occurs almost exclusively in patients with prior abdominal surgery.