A patient with four days of no bowel movement and new right lower quadrant abdominal pain without nausea or vomiting—what is the appropriate evaluation and management?

Evaluation and Management of Right Lower Quadrant Pain with Constipation

Obtain a contrast-enhanced CT scan of the abdomen and pelvis with IV contrast immediately—this is the definitive diagnostic test that will identify appendicitis, bowel obstruction, diverticulitis, or other surgical emergencies with 85.7-100% sensitivity and 94.8-100% specificity. 1, 2

Initial Diagnostic Approach

Immediate Imaging

• CT abdomen/pelvis with IV contrast (no oral contrast needed) is the single most appropriate next step, providing rapid acquisition without delays while maintaining excellent diagnostic accuracy 1, 2
• This imaging identifies alternative diagnoses in 23-45% of patients presenting with right lower quadrant pain, fundamentally changing management 1, 2
• CT will simultaneously evaluate for:
  • Appendicitis (most common surgical emergency in this presentation) 3, 4
  • Bowel obstruction (given 4-day history of no bowel movement) 3
  • Right-sided colonic diverticulitis (can present with RLQ pain and constipation) 3
  • Stercoral perforation (risk with prolonged constipation) 3
  • Cecal volvulus (presents with obstruction and RLQ pain) 3

Critical Laboratory Testing

• Complete blood count and C-reactive protein should be obtained, as CRP levels are significantly higher in appendicitis versus other etiologies, and normal inflammatory markers have 100% negative predictive value for excluding appendicitis 1, 4
• Basic metabolic panel to assess for dehydration and electrolyte abnormalities from prolonged constipation 1

Physical Examination Findings to Document

• Test for psoas sign (pain with hip extension or flexion), which suggests appendicitis or retroperitoneal pathology 1, 4
• Assess for peritoneal signs (guarding, rigidity, rebound tenderness) which indicate need for urgent surgical evaluation 3
• Evaluate for abdominal distension and high-pitched bowel sounds suggesting mechanical obstruction 3

Key Diagnostic Considerations

Appendicitis Remains High on Differential Despite Atypical Features

• Fever is absent in approximately 50% of appendicitis cases, so lack of fever does not exclude this diagnosis 1, 2
• The absence of nausea/vomiting is atypical but does not rule out appendicitis, particularly in early or retrocecal presentations 3, 4
• Clinical assessment alone misdiagnoses appendicitis in 34-68% of cases, making imaging essential 2

Bowel Obstruction Must Be Excluded

• Four days without bowel movement combined with RLQ pain raises concern for small bowel obstruction (commonly from adhesions if prior surgery) or large bowel obstruction (from malignancy, volvulus, or fecal impaction) 3
• History of previous abdominal surgery has 85% sensitivity and 78% specificity for predicting adhesive small bowel obstruction 3

Right-Sided Diverticulitis

• Can present with RLQ pain and constipation, mimicking appendicitis 3
• May occur with normal inflammatory markers 2
• CT findings include intestinal wall thickening, pericolonic fat stranding, and potential abscess formation 3

Management Algorithm Based on CT Findings

If Appendicitis Confirmed

• Immediate surgical consultation for appendectomy 2, 4
• If perforated with abscess, consider percutaneous drainage followed by interval appendectomy 2, 4

If Bowel Obstruction Identified

• NPO status, nasogastric decompression, IV fluid resuscitation 3
• Surgical consultation for potential operative intervention depending on obstruction severity and etiology 3

If Right-Sided Diverticulitis

• Antibiotic therapy for 4-7 days in immunocompetent patients if no abscess 3
• If abscess <4cm, antibiotics alone may suffice; if >4cm, percutaneous drainage plus antibiotics 3

If Severe Constipation/Fecal Impaction Without Obstruction

• Manual disimpaction if needed, followed by aggressive bowel regimen 3
• Rule out underlying obstructing lesion (malignancy) in this age group 3

Critical Pitfalls to Avoid

• Do not rely on absence of fever or nausea/vomiting to exclude appendicitis—these classic features are frequently absent 1, 2
• Do not delay imaging for oral contrast administration—IV contrast alone is sufficient and avoids dangerous delays that increase perforation risk 1, 2
• Do not discharge without definitive imaging given the 4-day constipation history and localized peritoneal signs 3, 1
• Do not assume simple constipation without excluding mechanical obstruction or inflammatory/infectious processes 3

If CT is Negative But Clinical Suspicion Remains High

• 24-hour observation with serial abdominal examinations every 6-12 hours to assess for progression of peritoneal signs 2
• Repeat complete blood count to monitor leukocytosis trend 2
• Diagnostic laparoscopy may be warranted if symptoms persist or worsen, as it provides both diagnostic and therapeutic value 2, 4