What is the appropriate treatment for a 32-year-old female with left-sided abdominal pain that worsens when lying down?

Treatment for Left-Sided Abdominal Pain When Lying Down in a 32-Year-Old Female

The treatment approach depends critically on establishing the underlying diagnosis first, as left-sided abdominal pain worsening when lying down in a young woman requires differentiation between diverticulitis, irritable bowel syndrome, musculoskeletal causes, and gynecologic pathology—with CT abdomen/pelvis with IV contrast being the diagnostic test of choice if diverticulitis or other acute intra-abdominal pathology is suspected. 1, 2

Initial Diagnostic Workup

Before initiating treatment, obtain the following:

• CT abdomen and pelvis with IV contrast is the most appropriate initial imaging study for left lower quadrant pain, with 94% sensitivity and 99% specificity for diverticulitis, and can identify alternative diagnoses 1, 2
• Complete blood count to assess for leukocytosis suggesting infection or inflammation 3, 2
• Urinalysis to exclude urinary tract infection or urolithiasis 3
• Pregnancy test in all women of reproductive age before imaging 4
• C-reactive protein if inflammatory process suspected 3

Key clinical features to assess:

• Fever and leukocytosis (suggests diverticulitis, though the classic triad is present in only 25% of cases) 3
• Ability to tolerate oral intake 1
• Presence of peritoneal signs (requires urgent surgical evaluation) 1
• Duration and pattern of symptoms (acute vs. chronic) 2, 4

Treatment Based on Diagnosis

If Acute Uncomplicated Diverticulitis is Confirmed:

Outpatient management is appropriate for selected patients who can tolerate oral intake, have adequate social support, and lack significant comorbidities 1

• Antibiotics may not be necessary for uncomplicated diverticulitis in carefully selected patients, as moderate-certainty evidence shows no difference in critical outcomes between antibiotic and no-antibiotic treatment 1
• If antibiotics are used, options include amoxicillin-clavulanate or cephalosporin-metronidazole combinations 1
• Low-certainty evidence shows no difference in elective surgery rates or recurrence between outpatient and inpatient management 1

If Irritable Bowel Syndrome is Suspected:

For abdominal pain as the predominant symptom:

• First-line treatment: Antispasmodics or peppermint oil, both shown to be safe and effective for abdominal pain relief 1
• Second-line treatment: Tricyclic antidepressants (TCAs) at low doses, which demonstrated significant benefit for abdominal pain compared to placebo in meta-analysis 1
• TCAs should be initiated at low doses and titrated according to symptomatic response 1
• SSRIs offer an alternative if symptoms don't respond to TCAs, and may be preferred if mood disorder is suspected 1

Adjunctive therapies:

• Low FODMAP diet (requires 12+ weeks, ideally with dietitian guidance) 1
• Gut-directed hypnotherapy (7-12 sessions) for psychological stress and maladaptive cognitive processes 1
• Cognitive behavioral therapy for psychological comorbidity 1

Critical Pitfalls to Avoid

• Do not use conventional opioid analgesia for IBS-related abdominal pain, as it is not a successful strategy 1
• Do not delay imaging in patients with severe pain, fever, or inability to tolerate oral intake, as complications like perforation or abscess require different management 1
• Consider gynecologic pathology in premenopausal women—pelvic ultrasonography may be more appropriate as first-line imaging if gynecologic causes are suspected 2
• Avoid routine antibiotics for uncomplicated diverticulitis without considering the evidence that they may not improve outcomes 1
• Do not perform colonoscopy during acute diverticulitis due to perforation risk; defer until 6-8 weeks after resolution 2

Position-Dependent Pain Considerations

The specific worsening with lying down suggests:

• Possible gastroesophageal reflux component (though typically right-sided or midline)
• Musculoskeletal etiology affecting positioning
• Increased intra-abdominal pressure effects on inflamed structures
• These features do not change the diagnostic approach but may guide symptomatic management 5, 6