In a female patient with left lower quadrant abdominal pain, tenderness on right lower quadrant palpation, constipation, and decreased appetite, what is the appropriate initial assessment, differential diagnosis, and management plan?

Rovsing's Sign: Suspect Acute Diverticulitis

This patient is exhibiting Rovsing's sign (pain in the left lower quadrant when palpating the right lower quadrant), which in the context of left-sided abdominal pain, constipation, and reduced appetite strongly suggests acute left-sided colonic diverticulitis as the primary diagnosis. 1

Initial Assessment Priorities

Key Clinical Features to Evaluate

• Duration of symptoms (>5 days predicts complicated disease) 1
• Presence of vomiting (predictor of progression to complicated diverticulitis) 1
• Fever or signs of sepsis (excludes outpatient management) 1
• Immunosuppression status (requires different management pathway) 1
• Recent antibiotic use (alters treatment approach) 1

Essential Laboratory Testing

• C-reactive protein level (>140 mg/L predicts progression to complicated disease) 1
• Complete blood count (assess for leukocytosis indicating severity) 2
• Pregnancy test (mandatory in reproductive-age females) 2

Imaging Strategy

CT abdomen and pelvis with IV contrast is the definitive imaging modality for suspected diverticulitis in this presentation. 1

CT Imaging Rationale

• Superior diagnostic accuracy and reproducibility for diverticulitis diagnosis 1
• Identifies complications including abscess, perforation, pericolic air, and fistula formation 1
• Risk-stratifies patients for operative versus nonoperative management 1
• Guides triage decisions between inpatient and outpatient care 1

Alternative: Ultrasound Considerations

• Transabdominal ultrasound has >90% sensitivity for diverticulitis in experienced hands 1
• Requires minimum 500 examinations for competency, limiting widespread use 1
• Less accurate in obese patients and distal sigmoid involvement 1
• May be used as initial bedside test with CT reserved for inconclusive cases 1

Differential Diagnosis Framework

Primary Considerations for Left Lower Quadrant Pain

• Acute diverticulitis (most likely given clinical presentation) 3
• Colitis (infectious, ischemic, or inflammatory bowel disease) 3
• Fecal impaction (consistent with constipation history) 3
• Epiploic appendagitis (self-limited inflammatory condition) 3

Additional Diagnoses to Exclude

• Left-sided urolithiasis (obtain urinalysis) 3
• Gynecologic pathology (ectopic pregnancy, ovarian torsion, pelvic inflammatory disease in reproductive-age females) 2
• Spontaneous retroperitoneal or rectus sheath hemorrhage 3
• Perforated colonic carcinoma (especially in older patients) 4

Management Algorithm

For Uncomplicated Diverticulitis (No Abscess, Perforation, or Sepsis)

Outpatient management is appropriate for immunocompetent patients without systemic inflammatory response, adequate home support, and ability to follow up. 1

Treatment Without Antibiotics (Select Patients)

• Observation with supportive care (bowel rest, hydration) is reasonable for immunocompetent patients with localized tenderness only 1
• No difference in complications, quality of life, need for surgery, or recurrence between antibiotic and non-antibiotic approaches 1
• Antibiotics may slightly decrease treatment failure rates within 3 months 1
• Watchful waiting requires ability to monitor patient status and provide follow-up 1

When Antibiotics Are Indicated

• Systemic inflammatory response present 1
• Immunosuppression or medical frailty 1
• Inability to ensure close outpatient follow-up 1
• Patient preference after shared decision-making 1

For Complicated Diverticulitis

Inpatient management is mandatory for:

• Abscess formation (may require CT-guided percutaneous drainage) 1
• Pericolic extraluminal air or fluid collection on CT 1
• Longer inflamed colon segment 1
• Signs of perforation or peritonitis 1
• Hemodynamic instability or sepsis 1

Critical Pitfalls to Avoid

• Do not dismiss the possibility of gynecologic emergencies in reproductive-age females without pregnancy testing and consideration of transvaginal ultrasound 2
• Do not assume all left lower quadrant pain is diverticulitis—CT identifies alternative diagnoses in a significant proportion of cases 1
• Do not use unenhanced CT without oral contrast—it is less accurate than contrast-enhanced CT for characterizing complications 1
• Do not routinely use biphasic imaging (unenhanced plus contrast-enhanced CT)—it is unnecessary and increases radiation exposure 1
• Do not hospitalize all patients with uncomplicated diverticulitis—outpatient management is safe and cost-effective for select patients 1

Predictors of Poor Outcomes Requiring Escalation

• Symptoms lasting >5 days 1
• Vomiting 1
• Significant systemic comorbidity 1
• C-reactive protein >140 mg/L 1
• CT findings of pericolic extraluminal air, fluid collection, or longer inflamed segment 1
• Retroperitoneal abscess location 1