What is the best course of action for a patient with a history of possible appendicitis, presenting with constipation and right lower quadrant pain that worsens with coughing?

Right Lower Quadrant Pain with Coughing and Constipation: Diagnostic and Management Approach

This patient requires urgent CT abdomen and pelvis with IV contrast to evaluate for appendicitis and other serious pathology, as pain worsened by coughing indicates parietal peritoneal irritation—a hallmark of surgical disease that cannot be safely dismissed despite the absence of fever. 1

Understanding the Pain Mechanism

The pain pattern described here is critical for risk stratification:

• Pain accentuated by coughing or movement represents somatic (parietal peritoneal) pain, which is precisely localized and indicates inflammation of the peritoneum overlying an intra-abdominal structure 1
• This pain mechanism is distinctly different from visceral pain and strongly suggests a surgical process requiring urgent imaging evaluation 1
• The presence of peritoneal signs mandates CT imaging regardless of other clinical features 1

Why Fever Absence Does Not Exclude Serious Disease

A common and dangerous pitfall is dismissing appendicitis based on lack of fever:

• Fever is absent in approximately 50% of appendicitis cases, making it an unreliable exclusion criterion 2, 1
• Clinical determination of appendicitis without imaging has an unacceptably high negative appendectomy rate of 14.7-25% 2
• The negative appendectomy rate drops to 1.7-7.7% when preoperative CT is performed 2

Recommended Diagnostic Approach

Order CT abdomen and pelvis with IV contrast immediately as the definitive next step:

• CT demonstrates 95% sensitivity (95% CI: 0.93-0.96) and 94% specificity (95% CI: 0.92-0.95) for appendicitis 3
• IV contrast without enteral contrast achieves 90-100% sensitivity and 94.8-100% specificity, allowing rapid diagnosis without delays from oral contrast administration 2
• CT identifies alternative diagnoses in 23-45% of patients with right lower quadrant pain, fundamentally changing management in nearly half of cases 2, 4

Alternative Diagnoses CT Will Detect

Beyond appendicitis, CT frequently identifies other conditions requiring specific management:

• Right colonic diverticulitis (8% of cases) and intestinal obstruction (3% of cases) 3, 2
• Ureteral stones, colitis, inflammatory bowel disease, and infectious enterocolitis 3
• In women of reproductive age: ovarian torsion, ruptured ovarian cyst, tubo-ovarian abscess, or ectopic pregnancy 4
• Constipation itself can be visualized, though constipation with peritoneal signs warrants investigation for underlying pathology 3

Pre-Imaging Essential Steps

Before proceeding to CT, obtain:

• Complete blood count to assess for leukocytosis (though normal WBC does not exclude appendicitis) 4, 5
• Urinalysis to exclude urinary tract infection or nephrolithiasis 4
• Urine pregnancy test in women of reproductive age to exclude ectopic pregnancy before imaging 4

Management Algorithm Based on CT Results

If CT Confirms Appendicitis (Appendix >8.2 mm):

• Immediate surgical consultation for appendectomy 2, 6
• Initiate broad-spectrum IV antibiotics (piperacillin-tazobactam or cephalosporin/fluoroquinolone plus metronidazole) 6
• Do not delay surgery based on clinical improvement—an enlarged appendix carries >90% probability of true appendicitis requiring intervention 2

If CT Shows Alternative Diagnosis:

• Right colonic diverticulitis: IV antibiotics and surgical consultation 3
• Intestinal obstruction: NPO status, nasogastric decompression, surgical evaluation 3
• Gynecologic pathology: Emergency gynecologic consultation for torsion; conservative management or drainage for other conditions 4
• Constipation without other pathology: Aggressive bowel regimen, but maintain high suspicion if peritoneal signs persist 3

If CT is Negative or Indeterminate:

• Hospital observation for 24 hours with serial abdominal examinations every 6-12 hours 2
• Repeat complete blood count to monitor leukocytosis trend 2
• Mandatory follow-up within 24 hours if discharged, with strict return precautions for worsening pain, fever, vomiting, or inability to tolerate oral intake 2

Critical Pitfalls to Avoid

• Never discharge without establishing clear follow-up and return precautions, as false-negative rates exist even in low-risk presentations 2
• Do not rely on NSAIDs for symptom control without imaging, as they can mask evolving peritoneal signs and delay diagnosis 2
• Avoid delaying imaging if symptoms persist or worsen during observation period 2
• Do not use colonoscopy for acute appendicitis diagnosis—it has no role and delays definitive treatment 2

Special Considerations

In pregnant patients with similar presentation:

• MRI is preferred over CT, demonstrating 96% sensitivity and specificity for appendicitis while avoiding radiation exposure 2, 4
• Pregnant patients require timely surgical intervention to decrease complication risk 7