What is the appropriate management for a patient presenting with lower quadrant abdominal pain, considering their demographic and medical history?

Management of Lower Quadrant Abdominal Pain

Obtain contrast-enhanced CT of the abdomen and pelvis immediately as the primary diagnostic modality, which achieves 85.7-100% sensitivity and 94.8-100% specificity for identifying the underlying pathology. 1, 2, 3

Initial Clinical Assessment

The approach differs based on which lower quadrant is affected and the patient's demographic profile:

Right Lower Quadrant Pain

• Appendicitis is the most likely diagnosis requiring urgent evaluation, presenting classically with periumbilical pain migrating to the right lower quadrant, accompanied by anorexia, nausea, and vomiting. 2, 3
• Examine for psoas sign (pain with hip extension or flexion), which suggests appendicitis or retroperitoneal pathology and may explain associated back pain. 2, 3
• Order C-reactive protein and complete blood count, as CRP levels are significantly higher in appendicitis versus other etiologies, and normal inflammatory markers have 100% negative predictive value for excluding appendicitis. 2, 3

Left Lower Quadrant Pain

• In older patients (>45 years), diverticulitis is the primary concern, especially with the classic triad of left lower quadrant pain, fever, and leukocytosis. 1
• Imaging may not be necessary in patients with classic presentation and mild symptoms, particularly those with known history of diverticulitis. 1
• However, imaging plays a definitive role when the etiology is unclear or complications are suspected. 1

Imaging Strategy

CT Abdomen and Pelvis with IV Contrast (Preferred)

• This is rated 8/9 ("usually appropriate") by the American College of Radiology for both right and left lower quadrant pain evaluation. 1, 3
• Use IV contrast without enteral contrast to achieve 90-100% sensitivity and 94.8-100% specificity while avoiding delays associated with oral contrast administration. 2, 3
• Do not delay imaging for oral contrast, as this increases time to diagnosis and potentially increases perforation risk without improving diagnostic accuracy. 3
• CT changes management in 51% of patients and admission decisions in 25% of patients with abdominal pain. 1

Alternative Imaging Considerations

• Pelvic ultrasonography is preferred in women of childbearing age to evaluate gynecologic causes. 1
• CT without contrast is rated 6/9 ("may be appropriate") if IV contrast is contraindicated. 1
• Plain radiography has limited utility, with only 49% sensitivity for bowel obstruction and low sensitivity for sources of abdominal pain and fever. 1

Special Clinical Scenarios

Acute Abdominal Pain with Fever

• Fever heightens suspicion for intra-abdominal infection, abscess, or surgical emergency, making rapid definitive diagnosis critical. 1
• This is especially important in elderly patients, where laboratory tests may be nonspecific and normal despite serious infection. 1
• In neutropenic or immunocompromised patients, typical signs of abdominal sepsis may be masked, diagnosis may be delayed, and mortality is high. 1

Right Lower Quadrant Specific Pathology

• If appendicitis is confirmed, proceed directly to appendectomy as standard treatment. 2, 3
• For perforated appendicitis with abscess, consider percutaneous drainage followed by delayed surgery. 2, 3
• If CT is negative but clinical suspicion remains high, diagnostic laparoscopy has both diagnostic and therapeutic value. 2

Left Lower Quadrant Specific Pathology

• Mild diverticulitis can be treated medically with antibiotics, while severe cases may require emergent surgery for complications such as perforation, peritonitis, abscess, or fistula formation. 1
• The severity of the initial attack is an excellent predictor of recurrence likelihood. 1
• Recurrent diverticulitis occurs in approximately 25% of patients with initial diverticulitis. 1

Critical Pitfalls to Avoid

• Do not rely on clinical scoring systems alone, as they may not accurately exclude appendicitis, particularly with atypical presentations. 3
• Do not use contrast enema as it is less sensitive than CT for diagnosing diverticulitis and is seldom used. 1
• Consider a broad differential diagnosis including psoas muscle pathology (especially with history of heavy lifting), infectious enterocolitis, mesenteric adenitis, and malignancies. 3, 4
• In patients with fever and abdominal pain, imaging is essential as the differential includes conditions requiring immediate surgical or medical attention. 1