What causes right abdominal pain and excessive gas in an adult with a possible history of gallstones, pancreatitis, or other gastrointestinal disorders?

Right Abdominal Pain and Excessive Gas: Differential Diagnosis and Evaluation

Right upper quadrant abdominal pain with excessive gas most commonly suggests biliary pathology (cholecystitis, choledocholithiasis), but can also indicate peptic ulcer disease, functional dyspepsia, irritable bowel syndrome with overlap, or less commonly pancreatitis—and you should begin with right upper quadrant ultrasound as your first imaging study. 1, 2

Most Common Causes in Adults

Biliary Disease (Most Likely with RUQ Pain)

• Acute cholecystitis presents with right upper quadrant pain, often precipitated by fatty meals, and may be accompanied by bloating and gas 1, 2
• Choledocholithiasis (common bile duct stones) causes RUQ pain with elevated liver enzymes and can present with intermittent symptoms 2
• Gallstones are present in many patients but may be misattributed as the cause of dyspeptic symptoms 1

Functional Gastrointestinal Disorders

• Functional dyspepsia causes epigastric or upper abdominal pain, often with bloating, early satiety, and postprandial fullness—pain is unrelated to defecation 1
• IBS overlap occurs in up to 50% of functional dyspepsia patients, causing two distinct types of abdominal pain: one related to defecation (IBS) and one unrelated (dyspepsia) 1
• Excessive gas and bloating are common features of both functional dyspepsia and IBS 1

Peptic Ulcer Disease

• Upper abdominal pain that may be exacerbated or relieved by eating, often accompanied by dyspeptic symptoms 1

Pancreatitis (Less Common but Important)

• Acute pancreatitis presents with upper abdominal pain radiating to the back, worse with eating, plus nausea and vomiting 3
• Gallstone pancreatitis is caused by transient ampullary obstruction by a migrating stone 4

Critical Historical Features to Elicit

Pain Characteristics

• Location: Right upper quadrant or epigastric suggests biliary disease; diffuse upper abdomen suggests functional dyspepsia 1
• Timing: Pain precipitated by fatty meals suggests cholecystitis; fasting pain or pain unrelated to meals suggests functional dyspepsia 1
• Radiation: Pain radiating to the back suggests pancreatitis 3
• Relationship to defecation: Pain relieved by defecation suggests IBS; pain unrelated to bowel movements suggests dyspepsia or biliary disease 1

Associated Symptoms

• Fever and elevated WBC strongly suggest acute cholecystitis or cholangitis 1, 2
• Jaundice indicates biliary obstruction or cholangitis 2
• Nausea and vomiting occur with both biliary disease and pancreatitis 3
• Bloating, early satiety, postprandial fullness suggest functional dyspepsia 1

Risk Factors and Triggers

• Previous acute gastroenteritis (10% of functional dyspepsia cases) 1
• NSAID use is strongly associated with dyspepsia and can cause gastrointestinal damage 1
• Alcohol use and gallstones are the main causes of pancreatitis 3
• Smoking is a risk factor for postprandial distress syndrome 1

Red Flags Requiring Urgent Evaluation

• Age >40 years with new-onset dyspepsia from high-risk area or family history of gastroesophageal cancer warrants 2-week wait endoscopy 1
• Dyspepsia with weight loss at age ≥25 years requires urgent endoscopy 1
• Abdominal pain with weight loss at age ≥60 years requires urgent CT scan 1

Diagnostic Algorithm

Step 1: Initial Imaging

• Right upper quadrant ultrasound is the first-line imaging test for right upper quadrant pain, rated 9/9 (usually appropriate) by the American College of Radiology 1, 2, 5
• Ultrasound identifies gallstones with 96% accuracy, assesses gallbladder wall thickening, evaluates bile ducts, and detects alternative diagnoses 2
• Ultrasound is noninvasive, portable, lacks radiation exposure, and costs less than CT or MRI 2, 5

Step 2: If Ultrasound Shows Biliary Pathology

• If ultrasound demonstrates gallstones with dilated common bile duct or elevated liver enzymes, proceed directly to MRCP for comprehensive biliary tree evaluation (sensitivity 85-100%, specificity 90%) 2
• If ultrasound suggests acute cholecystitis but is equivocal, consider cholescintigraphy (HIDA scan) which has sensitivity 96% and specificity 90% for acute cholecystitis 1
• HIDA scan is the imaging examination of choice for suspected acalculous cholecystitis 2

Step 3: If Ultrasound is Negative or Non-Biliary Pathology Suspected

• For suspected pancreatitis: Check serum lipase (>3 times normal limit) and consider CT abdomen with IV contrast if diagnosis unclear 3
• For functional dyspepsia: Perform baseline investigations including full blood count (age ≥25 years), coeliac serology (if IBS overlap symptoms), and H. pylori breath or stool testing 1
• Consider non-urgent endoscopy for treatment-resistant dyspepsia in patients ≥25 years 1

Step 4: Advanced Imaging When Needed

• CT abdomen with IV contrast is appropriate for critically ill patients, suspected complications (perforation, abscess), or when ultrasound is inconclusive 1
• MRI abdomen with MRCP is superior to CT for hepatobiliary evaluation and provides comprehensive assessment without radiation 1, 2

Common Pitfalls to Avoid

Imaging Pitfalls

• Do not order CT as initial imaging for right upper quadrant pain—ultrasound is more appropriate and has higher sensitivity for gallstones 2, 5
• Do not skip ultrasound and proceed directly to advanced imaging unless the patient is unstable 5
• Do not order HIDA scan as the primary test for elevated liver enzymes—elevated LFTs indicate biliary obstruction requiring anatomic visualization with MRCP, not functional assessment 2

Diagnostic Pitfalls

• Do not assume gallstones are causing symptoms—they may be incidental findings in patients with functional dyspepsia 1
• Do not miss IBS overlap—patients may have two distinct types of abdominal pain (one related to defecation, one not) 1
• Do not overlook NSAID use—it is strongly associated with dyspepsia in population-based studies 1
• Small gallstones may be overlooked or mistaken for bowel gas—optimize gain settings and scan from multiple directions 1

Management Pitfalls

• Do not perform cholecystectomy for presumed biliary pain without confirming gallstones are the actual cause—misattribution is common 1
• Do not delay feeding in pancreatitis—oral feeding should be initiated within 24 hours as tolerated, not "nothing by mouth" 3
• Do not use antibiotics empirically in pancreatitis—they are indicated only with radiologically confirmed infection 3

When to Consider Functional Dyspepsia

Make a positive diagnosis of functional dyspepsia when the patient has bothersome epigastric pain, postprandial fullness, early satiety, or epigastric burning for >8 weeks, with normal endoscopy and negative H. pylori testing 1. The presence of other functional disorders (IBS, functional constipation, functional bloating) supports this diagnosis 1.