evaluating-abdominal-emergencies - SKILL.md Agent Skill

name: evaluating-abdominal-emergencies language: en description: Structures abdominal pain workups with differential by quadrant and surgical consultation criteria. Use when assessing acute abdomen, determining imaging needs, or identifying surgical emergencies. tags:

analysis
emergency-medicine
surgical metadata: author: casemark practice_areas:
- Emergency Medicine document_types:
- Evaluation Report skill_modes:
- Analysis
- Assessment

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)

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

Diagnosis	Key Features	Workup
Acute cholecystitis	RUQ pain, positive Murphy sign, fever	RUQ ultrasound (sensitivity 88%, specificity 80%); CBC, hepatic panel
Choledocholithiasis	RUQ pain, jaundice, elevated bilirubin/ALP	MRCP or EUS if ultrasound equivocal; GI consult for ERCP
Ascending cholangitis (Charcot triad)	RUQ pain + fever + jaundice	Blood cultures, emergent ERCP; add hypotension + AMS = Reynolds pentad
Hepatitis	RUQ pain, elevated transaminases (>1000 suggests viral/toxin)	Hepatic panel, hepatitis serologies, toxicology
Hepatic abscess	Fever, RUQ pain, recent travel or biliary disease	CT with contrast, blood cultures

Right Lower Quadrant (RLQ)

Diagnosis	Key Features	Workup
Appendicitis	Periumbilical pain migrating to RLQ, anorexia, low-grade fever	CT abdomen/pelvis (sensitivity 98%); Alvarado score ≥7 highly suggestive
Ovarian torsion	Sudden severe unilateral pelvic pain, nausea	Pelvic ultrasound with Doppler (sensitivity 85-90%); gynecology consult
Ectopic pregnancy	Missed period, vaginal bleeding, pelvic pain, positive hCG	Transvaginal ultrasound; quantitative hCG; if ruptured → emergent OR
Mesenteric adenitis	RLQ pain in young patient, often viral prodrome	CT may mimic appendicitis; clinical observation

Left Upper Quadrant (LUQ)

Diagnosis	Key Features	Workup
Splenic infarct/rupture	LUQ pain, history of hematologic disorder, trauma	CT with IV contrast
Gastric ulcer perforation	Sudden epigastric/LUQ pain, peritonitis	Upright CXR (free air), CT if CXR negative
Pancreatitis	Epigastric/LUQ pain radiating to back, nausea, vomiting	Lipase (>3× upper limit), CT for complications if no improvement at 48-72h

Left Lower Quadrant (LLQ)

Diagnosis	Key Features	Workup
Diverticulitis	LLQ pain, fever, leukocytosis; common in age >50	CT abdomen/pelvis with IV contrast (sensitivity >95%)
Sigmoid volvulus	Elderly, institutionalized, chronic constipation, distension	Abdominal X-ray (bent inner tube sign); CT confirms; rectal tube decompression
Ovarian pathology	Unilateral pelvic pain, menstrual irregularity	Pelvic ultrasound, beta-hCG

Diffuse / Periumbilical

Diagnosis	Key Features	Workup
Small bowel obstruction	Colicky pain, vomiting, distension, prior surgery	CT abdomen/pelvis; look for transition point
Mesenteric ischemia	Severe pain out of proportion to exam, AFib, age >60	CT angiography; lactate (late finding); vascular surgery consult
Ruptured AAA	Sudden severe pain, pulsatile mass, hypotension, age >60, male	Bedside ultrasound (if stable); emergent OR if unstable (do NOT delay for CT)
Peritonitis	Rigid abdomen, guarding, rebound, involuntary guarding	Surgical consult immediately; imaging secondary to clinical diagnosis

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

Clinical Scenario	First-Line Imaging	Notes
RUQ pain, suspected biliary	RUQ ultrasound	Do NOT order CT first for biliary disease
RLQ pain, suspected appendicitis	CT abdomen/pelvis with IV contrast	Ultrasound first in pediatric, pregnant, or young thin females
Suspected bowel obstruction	CT abdomen/pelvis with IV contrast	X-ray has poor sensitivity for partial SBO
Suspected renal colic	CT abdomen/pelvis without contrast	Low-dose CT protocol preferred; ultrasound first if pregnant
Suspected AAA	Bedside POCUS (if unstable → OR)	CT angio if stable and diagnosis uncertain
Female pelvic pain	Pelvic ultrasound (transvaginal)	Always obtain beta-hCG first
Suspected free air	Upright CXR → CT if CXR negative	CT is more sensitive than X-ray

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)

Was the differential diagnosis organized by pain location and pattern?
Was beta-hCG obtained for all females of childbearing age?
Was imaging selection appropriate for the leading diagnosis (not reflexive CT for all complaints)?
Were surgical consultation criteria applied and consult obtained when indicated?
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

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.
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.
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.
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.
Elderly and immunosuppressed patients present atypically — perforated appendicitis may present with minimal tenderness, and peritonitis may lack rebound or guarding in patients on steroids.
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.
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.
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.