What is the appropriate emergency evaluation and management for a 14‑year‑old Asian female presenting with periumbilical pain and vomiting?

Emergency Evaluation and Management of Periumbilical Pain with Vomiting in a 14-Year-Old Female

Obtain contrast-enhanced CT abdomen and pelvis with IV contrast immediately as the primary diagnostic imaging modality, as this patient's presentation of periumbilical pain with vomiting represents classic early appendicitis until proven otherwise. 1, 2

Initial Clinical Assessment

This presentation demands urgent evaluation because:

• Periumbilical pain with vomiting is the classic early presentation of acute appendicitis, which typically begins with periumbilical or epigastric pain before migrating to the right lower quadrant 1, 3
• Appendicitis represents the most common abdominal surgical emergency in adolescents, with peak incidence during this age group 1
• Clinical assessment alone misdiagnoses appendicitis in 34-68% of cases, making imaging essential 2
• The absence of fever does NOT exclude appendicitis—fever is absent in approximately 50% of cases 2

Critical Physical Examination Findings to Document

• Right lower quadrant tenderness (pain may not have migrated yet) 1
• Rebound tenderness or guarding indicating peritoneal irritation 2, 4
• Psoas sign (pain with hip extension/flexion) suggesting retroperitoneal irritation from retrocecal appendix 3
• McBurney point tenderness (one-third distance from anterior superior iliac spine to umbilicus) 2
• Assess for abdominal distention, bowel sounds, and signs of obstruction 4, 5

Diagnostic Algorithm

Step 1: Immediate Laboratory Testing

• Complete blood count with differential 3, 5
• C-reactive protein—significantly elevated in appendicitis; normal inflammatory markers have 100% negative predictive value for excluding appendicitis 3
• Urinalysis to exclude urinary tract infection or urolithiasis 5
• Pregnancy test (mandatory in all adolescent females) 6, 7

Step 2: Imaging Strategy

Primary recommendation: CT abdomen and pelvis with IV contrast (without enteral contrast) 2, 3

This achieves:

• Sensitivity of 85.7-100% and specificity of 94.8-100% for appendicitis 1, 8, 2
• Rapid acquisition without delays from oral contrast administration 3
• Identification of alternative diagnoses in 23-45% of cases with similar presentations 8, 2
• Assessment for perforation, abscess formation, and periappendiceal inflammation 8

Alternative approach if institutional protocol favors ultrasound-first: 1, 8

• Start with graded compression ultrasound of right lower quadrant 8
• If ultrasound is nondiagnostic, equivocal, or technically limited (common in adolescents due to body habitus), proceed immediately to CT 8, 2
• Staged ultrasound followed by CT achieves 99% sensitivity and 91% specificity 2

Step 3: Interpretation of CT Findings

Positive for appendicitis if: 2, 3

• Appendiceal diameter >8.2 mm (maximum outer diameter cutoff) 2
• Periappendiceal fat stranding 2
• Absence of intraluminal gas 2
• Presence of appendicolith 2

If CT confirms appendicitis: Immediate surgical consultation for appendectomy 3

If perforated appendicitis with abscess: Consider percutaneous drainage followed by interval appendectomy 3

If CT negative but clinical suspicion remains high: Diagnostic laparoscopy has both diagnostic and therapeutic value 2, 3

Critical Alternative Diagnoses to Consider in Adolescent Females

Given the patient's demographics, gynecologic pathology must be actively excluded: 1, 6, 7

• Ovarian torsion—presents with acute onset pain, nausea/vomiting; requires emergent surgical intervention to preserve ovarian viability 6, 7
• Ectopic pregnancy (if sexually active) 1
• Ovarian cyst rupture or hemorrhage 1, 6
• Pelvic inflammatory disease 1

CT with IV contrast identifies gynecologic pathology in 21.6% of alternative diagnoses in patients presenting with abdominal pain 2

Immediate Supportive Management

While awaiting imaging: 3, 5

• IV fluid resuscitation with normal saline 20 mL/kg if signs of dehydration from vomiting 3, 5
• Antiemetics: ondansetron (serotonin antagonist) or metoclopramide (dopamine antagonist) 3
• NPO status (nothing by mouth) 5
• Nasogastric tube if significant vomiting or abdominal distention 5
• Analgesia is appropriate and does NOT mask surgical findings—avoid withholding pain control 2, 5

Common Pitfalls to Avoid

• Do NOT discharge based solely on absence of fever or normal white blood cell count—these findings do not exclude appendicitis 2
• Do NOT delay imaging if symptoms persist or worsen during observation 2
• Do NOT rely on clinical assessment alone—negative appendectomy rate is 14.7-25% without preoperative imaging versus 1.7-7.7% with CT 2
• Do NOT order colonoscopy—it has no role in acute appendicitis diagnosis 2
• Do NOT assume gastroenteritis without imaging confirmation in a patient with persistent periumbilical pain and vomiting 1

Disposition Decision-Making

If imaging confirms surgical pathology: Immediate surgical consultation and admission 2, 3

If imaging is negative and patient clinically improved: 2

• Discharge only if: normal CT scan, absence of peritoneal signs, able to tolerate oral intake, reliable follow-up access 2
• Mandatory 24-hour follow-up due to measurable false-negative rates 2
• Strict return precautions: worsening pain, fever development, persistent vomiting, inability to tolerate oral intake 2

If imaging is equivocal: Hospital observation with serial abdominal examinations every 6-12 hours and repeat imaging if symptoms progress 2