For an elderly patient with abdominal pain during palpation, presenting with both upper right quadrant and lower left abdominal pain, would you order an ultrasound or a computed tomography (CT) scan of the abdomen?

CT Abdomen/Pelvis with IV Contrast is the Recommended Initial Imaging

For an elderly patient presenting with both upper right quadrant and lower left quadrant abdominal pain during palpation, order a CT scan of the abdomen and pelvis with intravenous contrast as the initial imaging study. 1, 2

Why CT is Superior in This Clinical Scenario

Addresses Multiple Anatomic Regions Simultaneously

• CT provides comprehensive evaluation of all abdominal quadrants in a single examination, which is critical when pain involves both the right upper quadrant (RUQ) and left lower quadrant (LLQ) 3, 4
• This dual-quadrant presentation requires imaging that can assess gallbladder pathology, hepatobiliary disease, diverticulitis, appendicitis, bowel obstruction, and vascular pathology simultaneously 1, 5
• CT alters the leading diagnosis in 49-51% of patients with abdominal pain and changes management in 42% of cases 1, 3

Elderly Patients Have Unique Considerations

• Elderly patients frequently present with atypical symptoms and delayed diagnoses, leading to higher rates of complicated disease (gangrenous cholecystitis, perforated appendicitis, bowel ischemia) 5
• There is often a discrepancy between benign clinical examination findings and severe pathology on imaging in elderly patients 5
• Bowel obstruction is the most common cause of emergency surgery in the elderly, with higher proportions of colonic obstruction from cancer or sigmoid volvulus 5
• Mesenteric ischemia and ischemic colitis are significantly more common after age 80 and require CT for diagnosis 5

Diagnostic Performance

• CT has >95% sensitivity for detecting diverticulitis (relevant to LLQ pain) 1
• CT has 95% sensitivity and 94% specificity for appendicitis 3
• CT is highly sensitive for detecting extraluminal air indicating perforation, which has critical surgical implications 1
• In elderly patients ≥75 years, unenhanced CT has similar accuracy to contrast-enhanced CT (64-68% vs 68-71%), but IV contrast improves characterization of bowel wall pathology, vascular issues, and fluid collections 1, 2

Why Ultrasound is Inadequate Here

Limited Field of View

• Ultrasound is recommended as first-line imaging only for isolated RUQ pain when gallbladder disease is the primary concern 1, 2
• Ultrasound cannot adequately evaluate the LLQ for diverticulitis or other pathology - it has variable and operator-dependent sensitivity compared to CT 1, 3
• Ultrasound provides no information about bowel obstruction, mesenteric ischemia, or perforation 1, 5

Elderly-Specific Limitations

• Body habitus and bowel gas (common in elderly) significantly limit ultrasound visualization 1
• Ultrasound cannot detect the complicated forms of disease (abscess, perforation, ischemia) that are more common in elderly patients 5

Recommended CT Protocol

Contrast Administration

• Order CT abdomen/pelvis WITH intravenous contrast as the standard protocol 1, 2
• IV contrast improves detection of bowel wall pathology, pericolic abnormalities, vascular pathology, and intraabdominal fluid collections 1, 2
• IV contrast increases diagnostic sensitivity for appendicitis from 90.5% to 100% 6

When to Consider Unenhanced CT

• If IV contrast is contraindicated (renal insufficiency, severe contrast allergy), unenhanced CT is acceptable in elderly patients with similar overall accuracy 1, 2
• Unenhanced CT has near 100% sensitivity/specificity for urolithiasis if that becomes a consideration 1, 2

Critical Pitfalls to Avoid

Do Not Order Plain Radiographs

• Conventional radiography has limited diagnostic value for acute abdominal pain and rarely changes management 1, 3
• Plain films have only 49% sensitivity for bowel obstruction and miss most causes of acute abdomen 7, 3
• The only utility is detecting large-volume pneumoperitoneum, but CT is far more sensitive for this finding 1, 7

Do Not Start with Ultrasound

• Starting with ultrasound in this multi-quadrant presentation will delay definitive diagnosis and likely require CT anyway 3
• The strategy of "ultrasound first, then CT if inconclusive" is appropriate only for isolated RUQ pain in younger patients, not elderly patients with multi-quadrant pain 1, 3

Do Not Delay Imaging

• Elderly patients with acute abdomen have higher morbidity from delayed diagnosis due to atypical presentations and rapid progression to complicated disease 5
• Do not rely on clinical examination alone - there is frequently discrepancy between benign exam and severe pathology on imaging in the elderly 5

Consider Extra-Abdominal Causes

• In elderly patients with upper quadrant pain, consider myocardial infarction, pneumonia, or pulmonary embolism as potential causes 5, 4
• CT chest may be warranted if clinical suspicion exists for cardiopulmonary pathology 5