What is the best course of treatment for a teenager with abdominal pain, diarrhea, and a history of vomiting, suspected of having a gastrointestinal infection or appendicitis?

Management of Suspected Appendicitis vs. Gastrointestinal Infection in a 15-Year-Old Male

The most appropriate management for this 15-year-old male with left lower quadrant abdominal pain, alternating diarrhea and constipation following consumption of cafeteria food is to proceed with CT imaging of the abdomen with IV contrast while providing clear emergency instructions to seek immediate care if symptoms worsen. 1

Clinical Assessment

• The patient's presentation with left lower quadrant pain (rather than right lower quadrant), one-week duration, association with altered bowel habits after eating cafeteria food, and absence of fever suggests a gastrointestinal infection rather than appendicitis 2, 3
• Classic appendicitis typically presents with periumbilical pain migrating to the right lower quadrant, accompanied by nausea/vomiting, fever, and leukocytosis 1
• The absence of fever and preserved appetite further decreases the likelihood of appendicitis 1
• The temporal relationship between eating cafeteria food and symptom onset strongly suggests a foodborne illness 2

Diagnostic Approach

• CT abdomen and pelvis with IV contrast is the recommended imaging procedure for adolescents with suspected appendicitis or to rule out other abdominal pathology 1
• While ultrasound is often recommended as first-line imaging for children to avoid radiation exposure, CT provides superior diagnostic accuracy in adolescents 1, 4
• CT has high sensitivity (85.7-100%) and specificity (94.8-100%) for diagnosing appendicitis and can also identify alternative diagnoses 1
• For patients with suspected appendicitis that cannot be confirmed or excluded by diagnostic imaging, careful follow-up is recommended 1

Management Algorithm

1. Immediate assessment:

   • If severe pain, persistent vomiting, fever develops, or symptoms worsen significantly → Emergency department evaluation 1
   • If stable with mild to moderate symptoms → Proceed with outpatient CT imaging 1

2. Based on CT findings:

   • If appendicitis confirmed → Surgical consultation and antimicrobial therapy 1
   • If gastrointestinal infection confirmed → Supportive care with hydration and appropriate antimicrobials if indicated 1
   • If negative or inconclusive → Follow-up within 24 hours to ensure resolution of symptoms 1

3. Supportive care while awaiting imaging:

   • Maintain hydration
   • Mild pain control (avoid opioids which can mask symptoms)
   • Clear emergency instructions for worsening symptoms 1

Important Considerations

• The patient's symptoms (left-sided pain, diarrhea after cafeteria food) are more consistent with infectious gastroenteritis than appendicitis 2
• However, atypical presentations of appendicitis can occur, especially in children and adolescents 3
• The alternating diarrhea and constipation pattern suggests possible post-infectious irritable bowel 5
• Certain pathogens like E. coli O157 can mimic appendicitis symptoms but show characteristic colonic wall thickening on CT 2

Pitfalls to Avoid

• Assuming appendicitis based solely on abdominal pain without considering the location (left vs. right) and associated symptoms 3
• Delaying imaging in a patient with persistent symptoms despite initial clinical impression suggesting gastroenteritis 1
• Failing to provide clear return precautions for worsening symptoms 1
• Overlooking the possibility of other conditions that can mimic appendicitis, such as inflammatory bowel disease or infectious colitis 2, 6