What is the management approach for a pregnant patient presenting with right upper quadrant (RUQ) pain?

Management of Pregnant Patient with Right Upper Quadrant Pain

Begin with ultrasound as the initial imaging modality for any pregnant patient presenting with RUQ pain, as it is safe, readily available, and can diagnose the most common causes including acute cholecystitis, biliary disease, and identify alternative diagnoses. 1

Initial Diagnostic Approach

Clinical Assessment

• Evaluate for acute cholecystitis, which is the most common diagnosable cause of RUQ pain in the general population and a significant concern in pregnancy 1, 2, 3
• Assess vital signs carefully, particularly looking for fever, tachycardia, and tachypnea, as these combinations indicate serious complications requiring immediate attention 4
• Consider the full differential diagnosis including appendicitis (the most common non-obstetric surgical emergency in pregnancy), urolithiasis, pancreatitis, ovarian torsion, and obstetric complications 1, 4

Laboratory Studies

• Obtain complete blood count, liver function tests, lipase/amylase, and urinalysis to help narrow the differential diagnosis 4
• Note that gallstone pancreatitis risk increases in pregnancy due to estrogen-induced cholesterol formation and delayed gallbladder emptying 5

Imaging Algorithm

First-Line: Ultrasound

Ultrasound abdomen is the primary and initial imaging modality for pregnant patients with RUQ pain 1, 4

Key advantages include:

• No radiation exposure to the fetus 1
• 96% accuracy for detecting gallstones 1
• Can identify gallbladder wall thickening, pericholecystic fluid, and sonographic Murphy sign 1
• Evaluates multiple organ systems including liver, pancreas, kidneys, and can identify alternative diagnoses 3
• Rapid, cost-effective, and widely available 1, 3

Second-Line: MRI Without Contrast

If ultrasound is non-diagnostic or equivocal, proceed to MRI abdomen without IV contrast 1, 4

MRI is preferred over CT because:

• Avoids ionizing radiation to the fetus 1, 4
• Provides excellent soft tissue characterization 1
• Can identify complications of cholecystitis including perforation, abscess formation, and biliary obstruction 1
• Useful for evaluating alternative diagnoses including appendicitis, pancreatitis, and urolithiasis 1, 4

Third-Line: Additional Imaging When Needed

For suspected acute cholecystitis specifically, if both US and MRI remain equivocal and clinical suspicion is high, hepatobiliary scintigraphy (HIDA scan) can be considered as it is the gold standard for diagnosing acute cholecystitis 1

CT should generally be avoided due to radiation exposure, but should not be withheld in life-threatening situations where maternal survival is at stake 4

• Low-dose CT (LDCT) may be considered when MRI is unavailable and clinical suspicion for appendicitis or other surgical emergency is high 1

Specific Diagnostic Considerations

Acute Cholecystitis

• US findings: Look for gallstones, gallbladder wall thickening >3mm, pericholecystic fluid, and sonographic Murphy sign 1
• Sensitivity and specificity: US demonstrates 88% sensitivity and 80% specificity for acute cholecystitis 1
• If US is equivocal: Consider HIDA scan (97% sensitivity, 90% specificity) or MRI/MRCP for better visualization of biliary tree and surrounding structures 1

Acute Cholangitis

• Clinical triad: Jaundice, fever, and RUQ pain with laboratory evidence of biliary obstruction 1
• US should demonstrate: Biliary dilatation and evidence of obstruction (stone, stricture, mass) 1
• MRI/MRCP provides superior visualization of the biliary tree when cholangitis is suspected 1

Alternative Diagnoses to Consider

• Appendicitis: May present atypically in pregnancy with pain location varying due to anatomical changes; if suspected based on clinical presentation, follow appendicitis imaging algorithm (US first, then MRI) 1, 4
• Pancreatitis: Increased risk in pregnancy due to gallstones and hypertriglyceridemia 5
• Urolithiasis: Common in pregnancy and well-visualized on US 4
• HELLP syndrome or preeclampsia: Consider in appropriate gestational age with hypertension 4

Critical Management Pitfalls

Do not delay imaging or treatment in pregnant patients with suspected acute cholecystitis or cholangitis, as complications including perforation carry significant maternal and fetal morbidity and mortality 1

Do not assume pain is physiologic without appropriate imaging workup, as over one-third of patients with RUQ pain have diagnoses other than cholecystitis 2, 3

Do not withhold necessary CT imaging if the clinical situation is life-threatening and other modalities are non-diagnostic or unavailable, as maternal survival takes priority 4

When to Escalate Care

Immediate surgical consultation is warranted for:

• Confirmed acute cholecystitis with complications (perforation, abscess, emphysematous cholecystitis) 1
• Acute cholangitis requiring biliary decompression 1
• Hemodynamic instability with severe pain 4
• Any surgical emergency identified on imaging 4