What is the appropriate management for a female patient with hypertension and Polycystic Ovary Syndrome (PCOS) presenting with acute right lower quadrant pain suspected to be diverticulitis?

Management of Acute Right Lower Quadrant Pain in a Female Patient with Suspected Diverticulitis

For a female patient presenting with acute right lower quadrant pain, the priority is to obtain CT abdomen and pelvis with IV contrast immediately to differentiate between right-sided diverticulitis, appendicitis, gynecologic pathology, and other causes—clinical examination alone has a 34-68% misdiagnosis rate. 1, 2

Critical Initial Diagnostic Considerations

Right-Sided vs. Left-Sided Pathology

• Right lower quadrant pain is atypical for diverticulitis, which classically presents with left lower quadrant pain in 75% of cases 1, 2
• The differential diagnosis for right lower quadrant pain in a female patient includes appendicitis, right-sided diverticulitis (cecal or ascending colon), ovarian pathology (cyst, torsion, ectopic pregnancy), pelvic inflammatory disease, inflammatory bowel disease, and right renal colic 1
• Right-sided colonic diverticulitis occurs but is less common in Western populations, accounting for approximately 10-15% of diverticulitis cases 1

Immediate Imaging Strategy

• CT abdomen and pelvis with IV contrast is rated 8/9 (usually appropriate) by the American College of Radiology and should be ordered immediately with 98% diagnostic accuracy for diverticulitis and superior ability to identify alternative diagnoses 1, 2
• For premenopausal women, obtain a pregnancy test before CT imaging 2
• If the patient is pregnant, ultrasound and MRI are preferred over CT to avoid radiation exposure 2
• Transvaginal ultrasound should be considered as initial imaging if gynecologic pathology is strongly suspected clinically, though it is not appropriate as the sole test for suspected diverticulitis 1, 2

Key CT Findings to Guide Management

Diverticulitis Confirmation

• CT findings diagnostic of diverticulitis include colonic wall thickening >5mm, inflamed diverticula, pericolonic fat stranding, and potential complications (abscess, perforation, fistula) 1, 3, 4
• Small-volume pericolic air (<5 cm from affected segment) can be managed medically, whereas spilled feces generally requires surgical intervention 1

Distinguishing Diverticulitis from Colon Cancer

• Pericolonic lymphadenopathy >1 cm in short axis with or without pericolonic edema suggests colon cancer rather than diverticulitis 1, 2
• Inflammatory changes with edema in the root of the mesentery and absence of pericolonic lymphadenopathy adjacent to thickened colon wall favors diverticulitis 1

Treatment Algorithm Based on CT Findings

Uncomplicated Diverticulitis (No Abscess, Perforation, or Fistula)

• For immunocompetent patients: Conservative management WITHOUT antibiotics is recommended—clear liquid diet advancement and pain control with oral analgesics (typically acetaminophen) 2, 3, 4
• For immunocompromised, elderly (>80 years), or pregnant patients: Antibiotics for maximum 7 days 2, 3, 4
• First-line oral antibiotics: Amoxicillin/clavulanic acid OR cefalexin plus metronidazole 4
• Alternative regimen: Ciprofloxacin 500mg every 12 hours plus metronidazole 500mg every 8 hours 5, 6
• Outpatient management is appropriate for >95% of uncomplicated cases, reducing hospital admissions by >50% and saving approximately €1,600 per patient 1, 2, 6, 7

Complicated Diverticulitis with Small Abscess (<3-4 cm)

• Antibiotics alone for 7 days without drainage 2, 3
• Ertapenem 1g every 24 hours OR Eravacycline 1mg/kg every 12 hours 2
• If unable to tolerate oral intake: IV ceftriaxone or cefuroxime plus metronidazole, OR ampicillin/sulbactam 4, 5

Complicated Diverticulitis with Large Abscess (≥3-4 cm)

• Percutaneous CT- or ultrasound-guided drainage PLUS antibiotics for 4 days 1, 2, 3
• Stop antibiotics at 4 days if source control is adequate in immunocompetent, non-critically ill patients 2
• Continue antibiotics up to 7 days in immunocompromised or critically ill patients, guided by clinical response and inflammatory markers 2

Red Flags Requiring Emergency Surgery

• Free air on CT indicating perforation with diffuse peritonitis requires emergent laparotomy 2, 3
• Fecal peritonitis mandates immediate surgical consultation 2
• Signs of septic shock: Escalate to broad-spectrum carbapenem therapy (meropenem 1g every 6 hours by extended infusion, doripenem 500mg every 8 hours, or imipenem/cilastatin 500mg every 6 hours) 2
• Surgical options: Primary resection and anastomosis with or without diverting stoma (clinically stable patients) OR Hartmann's procedure (critically ill patients with major comorbidities) 2

Special Considerations for This Patient

Hypertension and PCOS Context

• Hypertension is a known risk factor for diverticular disease 4
• PCOS increases the likelihood of ovarian pathology (cysts, torsion) as an alternative diagnosis requiring gynecologic evaluation 2
• Ensure pregnancy is excluded before proceeding with CT imaging 2

Laboratory Markers to Obtain

• Complete blood count with differential (left shift >75% suggests bacterial infection) 2
• C-reactive protein (CRP >170 mg/L predicts severe diverticulitis with 87.5% sensitivity and 91.1% specificity; CRP >50 mg/L combined with left lower quadrant tenderness and absence of vomiting has 97% accuracy, though this triad occurs in only 24% of patients) 2, 5
• Basic metabolic panel and urinalysis 5

Critical Pitfalls to Avoid

• Do not rely on clinical examination alone—the classic triad of fever, left lower quadrant pain, and leukocytosis is present in only 25% of diverticulitis cases 1, 2
• Do not order routine colonoscopy after CT-confirmed uncomplicated diverticulitis except for age-appropriate screening not yet performed, abnormal pericolic lymph nodes on CT, luminal colon mass on CT, or presence of abscess, perforation, or fistula 1, 2
• Do not continue antibiotics beyond 7 days in uncomplicated cases—this increases resistance without improving outcomes 2
• Do not use antibiotics routinely for uncomplicated diverticulitis in immunocompetent patients—they do not accelerate recovery or prevent complications 4, 5
• If signs of infection persist beyond 7 days, obtain repeat imaging to assess for inadequate source control rather than simply continuing antibiotics 2

Hospitalization Criteria

• Signs of peritonitis (diffuse tenderness, guarding, rebound tenderness, absent bowel sounds) 2, 5
• Inability to tolerate oral intake 2, 4
• Severe or progressively worsening pain 2
• Persistent fever or chills despite initial management 4
• Increasing leukocytosis 4
• Immunocompromised state (chemotherapy, high-dose steroids, organ transplant) 4
• Chronic medical conditions (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 4