What is the best approach to diagnose and manage a 46-year-old woman with chronic, worsening abdominal pain, normal laboratory tests (Complete Blood Count (CBC), Comprehensive Metabolic Panel (CMP), lipase, and urinalysis), and normal imaging studies (Computed Tomography (CT) abdomen/pelvis and right upper quadrant ultrasound)?

Management of Chronic Abdominal Pain with Negative Workup

In this 46-year-old woman with 10 weeks of worsening abdominal pain and repeatedly normal imaging and laboratory studies, the priority is to obtain a pelvic ultrasound with Doppler to evaluate for gynecologic pathology that CT may have missed, while simultaneously addressing potential narcotic bowel syndrome from daily marijuana use and considering functional pain disorders.

Immediate Diagnostic Steps

Obtain Pelvic Ultrasound with Doppler

• Transvaginal and transabdominal pelvic ultrasound with color Doppler should be performed as the next imaging study 1
• CT imaging has limitations in detecting gynecologic pathology; ultrasound provides superior spatial and contrast resolution for female reproductive organs 1
• Specific conditions better detected by ultrasound include:
  • Ovarian torsion (enlarged ovary, peripheral follicles, abnormal venous flow) 1
  • Pelvic inflammatory disease (pelvic fluid, hydrosalpinx, inflammatory masses) 2, 1
  • Pelvic venous disorders/congestion syndrome (engorged periuterine veins, altered flow patterns) 2, 1
• The combined transabdominal and transvaginal approach with Doppler is essential and provides the most comprehensive pelvic assessment 2, 1

Consider MRI if Ultrasound is Non-Diagnostic

• If ultrasound remains inconclusive but clinical suspicion persists, MRI pelvis with contrast provides excellent soft tissue characterization 2
• MRI can diagnose conditions ranging from bowel inflammation and obstruction to gynecologic processes with 99% accuracy 2
• MRI is particularly useful for detecting subtle abnormalities not visible on CT or ultrasound 1

Critical Consideration: Cannabis Hyperemesis vs. Narcotic Bowel Syndrome

Daily Marijuana Use as a Key Factor

• Daily marijuana use can cause narcotic bowel syndrome, characterized by chronic, worsening abdominal pain despite continued substance use 2
• This syndrome induces a hyperalgesic effect where pain worsens with continued use 2
• The pattern of escalating pain (from 4/10 to 7/10 over three weeks) despite negative workup is highly consistent with this diagnosis 2

Therapeutic Approach to Substance-Related Pain

• Recognition of the disorder and establishing a trusting therapeutic relationship are essential first steps 2
• Controlled reduction of marijuana use with replacement using neuropathic pain medications (gabapentin, duloxetine) 2
• Consider clonidine to reduce withdrawal symptoms during cessation 2

Evaluate for Mechanical Obstruction

Adhesive Disease Despite No Prior Surgery

• Localized bowel obstruction from adhesions can occur even without extensive surgical history and is frequently misdiagnosed 2
• Clinical clues include intermittent colicky pain, abdominal distension, and pain worsening after meals 2
• The key radiologic finding is a distinct transition point between dilated and normal bowel, but this may not be apparent if obstruction has resolved 2
• Obtain CT during an acute pain episode if possible, as imaging between episodes may be falsely negative 2

Trial of Low-Residue Diet

• If adhesive obstruction is suspected, a trial of low-residue or liquid diet may reduce symptoms 2
• Success with dietary modification serves as a supportive diagnostic test for intermittent obstruction 2

Address the Low Diagnostic Yield of Repeat CT

Understanding CT Limitations in This Context

• Repeat abdominal CT after initially negative studies has very low diagnostic yield, dropping from 22% on initial presentation to 5.9% on the fourth CT or greater 2
• The negative predictive value of CT for nonspecific abdominal pain is only 64%, with commonly missed diseases including gastritis, duodenitis, and pancreaticobiliary inflammatory processes 2
• Further CT imaging is not indicated unless new symptoms develop or leukocytosis appears 2

Consider Functional Pain Disorders

When Structural Pathology is Excluded

• If both CT and ultrasound are normal, functional pain disorders that do not show structural abnormalities on imaging should be considered 1
• These include visceral hypersensitivity, centralized pain syndromes, and disorders of gut-brain interaction 1
• Treatment focuses on neuromodulators (tricyclic antidepressants, SNRIs) and cognitive-behavioral approaches 2

Avoid Common Pitfalls

Do Not Order More CT Scans

• Two normal CT scans with contrast are sufficient; additional CT imaging has minimal yield and increases radiation exposure 2
• CT should only be repeated if clinical presentation changes significantly or complications develop 2

Do Not Miss Gynecologic Pathology

• Failing to obtain pelvic ultrasound after negative CT is a critical error, as CT has limited sensitivity for many gynecologic conditions 1
• Both transabdominal and transvaginal approaches with Doppler must be performed together 2, 1

Address the Substance Use Directly

• Daily marijuana use must be discussed as a potential contributor to her pain syndrome 2
• Avoiding this conversation perpetuates the cycle of worsening pain and healthcare utilization 2

Recognize the Pattern of Healthcare-Seeking Behavior

• Four ED visits in 2 months with one canceled clinic appointment suggests possible anxiety about symptoms or secondary gain issues 2
• Establishing continuity of care in the outpatient setting is essential to break this pattern 2

Management Algorithm

1. Order transvaginal and transabdominal pelvic ultrasound with color Doppler immediately 2, 1
2. Discuss daily marijuana use and its potential role in causing or worsening abdominal pain 2
3. If ultrasound is negative, consider MRI pelvis for further evaluation 2, 1
4. If all imaging remains negative, initiate trial of neuropathic pain medication (gabapentin or duloxetine) while tapering marijuana use 2
5. Consider gastroenterology referral for evaluation of functional pain disorders if structural pathology is excluded 1
6. Establish regular follow-up appointments to provide continuity and reduce ED utilization 2