What investigations are recommended for a patient with chronic left-sided pain?

Investigations for Chronic Left-Sided Pain

CT abdomen and pelvis with contrast is the most appropriate initial investigation for chronic left-sided pain, as it provides the highest diagnostic accuracy for identifying the common causes of left lower quadrant pain. 1

Initial Diagnostic Approach

First-Line Imaging

• CT Abdomen and Pelvis with IV Contrast: Most useful examination for left-sided pain, providing accurate diagnosis and guiding appropriate management regardless of patient sex or body habitus 1
  • Highly sensitive for detecting small quantities of extraluminal air, bowel wall pathology, pericolic abnormalities, and fluid collections
  • Helps differentiate between common causes of left-sided pain including diverticulitis, colitis, inflammatory bowel disease, epiploic appendagitis, and bowel obstruction 1

Alternative Imaging Options

• CT Abdomen and Pelvis without Contrast: May be appropriate when IV contrast is contraindicated, with accuracy (64-68%) similar to contrast-enhanced CT (68-71%) in elderly patients with acute abdominal pain 1
• Ultrasound (Transabdominal): May be used to reduce unnecessary CT examinations in selected patients, particularly when directed at the area of maximal pain 1
• Ultrasound (Transvaginal): Appropriate first-line investigation in premenopausal women when gynecologic pathology is suspected 1

Less Appropriate Initial Imaging

• MRI Abdomen and Pelvis: Generally not useful for initial evaluation of left-sided pain; less sensitive for extraluminal air and urinary tract calculi, more time-consuming, and more subject to motion artifacts 1
• Radiography (Abdomen and Pelvis): Limited utility as initial imaging test due to lower sensitivity and specificity compared to CT 1
• Fluoroscopic Contrast-Enhanced Enema: Not generally useful as initial imaging for left-sided pain 1

Laboratory Investigations

• Complete Blood Count: To assess for leukocytosis, which may indicate infection or inflammation 1
• Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP): Useful markers of inflammation 2, 3
  • CRP is more useful for acute inflammatory conditions due to its shorter half-life 2
  • ESR is more helpful for monitoring chronic inflammatory conditions 2, 4

Specialized Investigations Based on Clinical Suspicion

For Suspected Diverticulitis

• CT with IV Contrast: Gold standard for diagnosis, with sensitivity and specificity approaching 100% for sigmoid diverticulitis 1
  • Allows assessment of complications such as abscess, phlegmon, fistula, obstruction, or perforation 1

For Chronic Pain with Suspected Neurological Origin

• Diagnostic Nerve Blocks: May be useful in determining the location or etiology of pain (peripheral, central, or psychogenic) 1
• Diagnostic Joint Blocks: For suspected facet joint or sacroiliac joint pain 1

For Persistent Symptoms After Initial Negative Workup

• Colonoscopy: Should be considered after an episode of complicated left-sided colonic diverticulitis in patients who have not had a recent colonoscopy 1
  • Helps rule out colorectal cancer which may present with similar symptoms 1

Clinical Pitfalls and Caveats

• Radiation Exposure: Consider cumulative radiation exposure when ordering multiple CT scans, especially in younger patients 1
• Incidental Findings: CT imaging may reveal incidental findings that could lead to unnecessary additional testing 1
• Diagnostic Accuracy: Remember that clinical assessment alone has a reported misdiagnosis rate of 34-68% for conditions like diverticulitis, emphasizing the importance of appropriate imaging 1
• Psychosocial Factors: Consider psychosocial evaluation in patients with chronic pain, as psychological factors can influence pain perception and treatment outcomes 1, 5

Follow-up Investigations

• Repeat Imaging: Consider if symptoms worsen or change in character 1
• Monitoring Inflammatory Markers: Serial ESR and CRP measurements may help monitor disease activity in chronic inflammatory conditions 4, 6
• Colonoscopy: Consider after resolution of acute symptoms if there is concern for underlying malignancy or if the patient has not had age-appropriate colorectal cancer screening 1