Immediate Management of Left Abdominal Pain
For patients presenting with left abdominal pain, obtain CT abdomen and pelvis with IV contrast as the primary diagnostic imaging study, as this is the most appropriate initial test with sensitivity greater than 95% for detecting diverticulitis and other serious pathology. 1, 2
Initial Clinical Assessment
Perform focused evaluation looking for these specific features:
- Left lower quadrant tenderness combined with fever and leukocytosis strongly suggests acute diverticulitis, though this classic triad is present in only 25% of cases 1, 2
- CRP > 50 mg/L significantly increases likelihood of diverticulitis; CRP > 170 mg/L predicts severe disease with 87.5% sensitivity and 91.1% specificity 1
- Rebound tenderness with abdominal distension occurs in 82.5% of patients with peritonitis and mandates immediate surgical evaluation 3
- Absence of vomiting combined with left lower quadrant tenderness and elevated CRP has 97% positive predictive value for diverticulitis 1
Critical Red Flags Requiring Emergency Intervention
- Recent colonoscopy within 48 hours with pain, distension, and rebound tenderness strongly suggests perforation 3
- Fever with rebound tenderness and distension indicates perforation or abscess 3
Imaging Strategy
CT abdomen and pelvis with IV contrast is rated 8/9 (usually appropriate) by the American College of Radiology and should be obtained in most cases. 1
When Imaging Can Be Deferred
Imaging may not be necessary only in these specific scenarios:
- Classic triad present (left lower quadrant pain, fever, leukocytosis) with high clinical suspicion for uncomplicated diverticulitis 1
- Known history of diverticulitis with mild recurrent symptoms 1
However, clinical diagnosis alone has positive predictive value of only 0.65, while CT improves this to 0.95. 1
CT Findings and Their Implications
- Free intraperitoneal air indicates perforation requiring immediate surgical consultation 3
- Abscess < 4 cm can typically be managed medically 1
- Abscess ≥ 4 cm may require percutaneous drainage or surgery 1
- Distant free gas (> 5 cm from inflamed bowel) indicates complicated diverticulitis requiring surgical evaluation 1
Alternative Imaging Considerations
- Ultrasonography has limited utility for left-sided pain due to overlying bowel gas and rib shadowing, though it may identify splenic or renal pathology 3
- MRI has sensitivity of 86-94% and specificity of 88-92% for diverticulitis but is expensive, time-consuming, and not readily available 1
- Plain radiography has no role in evaluation of left abdominal pain 3
Immediate Management Actions
While arranging imaging:
- Start broad-spectrum antibiotics immediately after blood cultures if sepsis is suspected 3
- NPO status, IV fluid resuscitation, and nasogastric decompression if obstruction or perforation suspected 3
- Administer opioid analgesia - this decreases pain intensity without affecting diagnostic accuracy 4
Special Population Considerations
In women of childbearing age, obtain pelvic ultrasound (transvaginal) first to exclude gynecologic pathology before proceeding to CT 1, 2
Common Pitfalls to Avoid
- Do not rely on clinical assessment alone - misdiagnosis rates are 34-68% for diverticulitis based on clinical evaluation without imaging 2
- Do not wait for the classic triad - it is present in only approximately 25% of diverticulitis cases 2
- Do not withhold analgesia pending diagnosis - this is safe and improves patient comfort 4
- Do not use contrast enema - it is less sensitive than CT and rarely indicated 1
Disposition Based on CT Results
Uncomplicated Diverticulitis
- Outpatient management with oral antibiotics if patient can tolerate oral intake and has no comorbidities 1