What is the appropriate management for a patient with severe right lower quadrant pain?

Management of Severe Right Lower Quadrant Pain

Obtain contrast-enhanced CT of the abdomen and pelvis with IV contrast immediately as the primary diagnostic and management tool, which achieves 85.7-100% sensitivity and 94.8-100% specificity for identifying appendicitis and alternative diagnoses. 1, 2

Initial Diagnostic Approach

Clinical Assessment

• Assess for classic appendicitis presentation: periumbilical or epigastric pain migrating to the right lower quadrant, accompanied by nausea, vomiting, and anorexia 1, 3
• Check for peritoneal signs including rebound tenderness, guarding, and rigidity, which indicate established peritoneal irritation 3
• Test for psoas sign (pain with hip extension or flexion), which suggests retroperitoneal irritation from a retrocecal appendix 1
• Do not exclude appendicitis based on absence of fever alone—fever is absent in approximately 50% of appendicitis cases 3

Laboratory Testing

• Order complete blood count and C-reactive protein, as CRP levels are significantly higher in appendicitis versus other etiologies, and normal inflammatory markers have 100% negative predictive value 1
• Recognize that normal WBC count does not exclude appendicitis but reduces probability when combined with benign clinical presentation (negative likelihood ratio 0.25) 3

Imaging Algorithm

Primary Imaging Modality

Proceed directly to CT abdomen and pelvis with IV contrast without waiting for oral contrast, which provides 90-100% sensitivity and 94.8-100% specificity while avoiding delays associated with enteral contrast administration 1, 2, 3

Alternative Imaging Considerations

• In children and young adults: Consider starting with point-of-care ultrasound as first-line to avoid radiation exposure, then proceed to CT if ultrasound is nondiagnostic or equivocal 2, 3
• In pregnant patients: Use MRI instead of CT, which demonstrates 96% sensitivity and specificity without radiation exposure 3
• In obese patients: Proceed directly to CT with IV contrast, as ultrasound has limited diagnostic performance with higher false diagnosis rates (46.2% vs 38.5% in non-obese patients) 2

CT Interpretation Criteria

• Appendiceal diameter >8.2 mm is highly suggestive of appendicitis with >90% probability 3
• Evaluate for periappendiceal fat stranding, absence of intraluminal gas, and presence of appendicoliths 3
• CT identifies alternative diagnoses in 23-45% of patients with right lower quadrant pain, fundamentally changing management 3, 4, 5

Management Based on Imaging Results

If Appendicitis Confirmed (Appendix >8.2mm with Periappendiceal Infiltration)

• Obtain immediate surgical consultation for appendectomy, which remains the standard treatment 1, 3
• Initiate IV fluid resuscitation for dehydration from vomiting 1
• Administer antiemetics (metoclopramide, prochlorperazine, or serotonin antagonists) for nausea control 1
• If perforated appendicitis with abscess is present, consider percutaneous drainage followed by delayed surgery 1

If CT Shows Borderline Findings (Appendix 7-8mm Without Clear Infiltration)

• Admit for 24-hour hospital observation with serial abdominal examinations every 6-12 hours 3
• Repeat complete blood count to monitor leukocytosis trend 3
• Proceed to surgery if symptoms progress or peritoneal signs develop 3

If CT is Negative But Clinical Suspicion Remains High

• Consider diagnostic laparoscopy, which has both diagnostic and therapeutic value 1, 2
• This approach is particularly important given that clinical determination of appendicitis is notoriously poor, with negative appendectomy rates as high as 25% when relying on clinical assessment alone 3

If CT Identifies Alternative Diagnosis

• CT frequently detects other surgical and non-surgical conditions including: right colonic diverticulitis (8% of cases), ureteral stones, intestinal obstruction (3%), gynecologic pathology (21.6%), and other gastrointestinal conditions (46%) 3, 4, 6
• Manage according to the specific diagnosis identified 4, 5

Critical Pitfalls to Avoid

• Never discharge patients with severe right lower quadrant pain without definitive imaging, as preoperative CT reduces negative appendectomy rates from 14.7-25% to 1.7-7.7% 3
• Do not rely on absence of fever to exclude appendicitis—fever is absent in approximately 50% of cases 3
• Avoid delaying imaging if symptoms worsen during observation period 3
• Do not use plain radiography, contrast enema, or upper GI series as primary diagnostic tools—these have limited sensitivity for sources of abdominal pain and fever 7
• Never proceed directly to appendectomy without imaging in the modern era, as this results in unacceptably high negative appendectomy rates and misses alternative diagnoses 3

Follow-Up for Negative or Inconclusive Imaging

• Provide clear emergency return precautions for worsening symptoms, including development of fever, vomiting, or increased abdominal tenderness 3
• Arrange mandatory 24-hour follow-up due to measurable false-negative rates in low-risk presentations 3
• If symptoms persist or worsen at follow-up, repeat imaging or proceed to diagnostic laparoscopy 1, 3