For a 15-year-old patient with abdominal pain, what should I focus on during the interview, differential diagnosis, assessment, and plan?

Approach to a 15-Year-Old with Abdominal Pain

For a 15-year-old with abdominal pain, immediately focus your interview on identifying red-flag symptoms that indicate surgical emergencies, then systematically rule out appendicitis (the most common surgical cause in this age group), followed by age-specific conditions including gynecologic pathology in females and functional disorders.

Interview Focus

Critical Red Flags to Identify Immediately

• Pain characteristics: Severe, localized pain that increases in intensity; pain that preceded vomiting 1
• Vomiting pattern: Bilious vomiting (suggests obstruction or malrotation) 1, 2
• Stool characteristics: Hematochezia (bloody diarrhea) 1, 2
• Fever presence: Raises concern for infection, abscess, or appendicitis 3

Detailed Pain History

• Onset and duration: When did symptoms start? Acute versus gradual onset 4
• Location and migration: Periumbilical pain migrating to right lower quadrant is classic for appendicitis 5, 2
• Relationship to bowel habits: Does pain change with defecation? Associated with constipation or diarrhea? 4
• Temporal pattern: Constant versus intermittent (intermittent may suggest volvulus, even in adolescents) 6

Age-Specific Considerations for Adolescents

In females (critical to assess):

• Last menstrual period and sexual activity history
• Possibility of pregnancy, ectopic pregnancy, pelvic inflammatory disease, ovarian cyst rupture, or ovarian torsion 2

In males:

• Testicular or scrotal pain (testicular torsion can present as abdominal pain) 1

Associated Symptoms

• Gastrointestinal: Anorexia, nausea, bloating, visible distension 4, 5
• Urinary: Dysuria, frequency (urinary tract infection) 1, 2
• Systemic: Weight loss, night sweats (concern for inflammatory bowel disease or malignancy)

Triggering Factors

• Recent infection or gastroenteritis (post-infectious IBS can occur) 4
• Recent antibiotic use 4
• Psychological stress or trauma 4
• Dietary patterns and recent changes

Differential Diagnosis by Likelihood

Most Common (Rule Out First)

1. Appendicitis - Most common surgical cause, peaks in adolescence 5, 2
2. Constipation - Very common, often overlooked 1, 2
3. Gastroenteritis - Infectious causes common in school-age and adolescents 1, 2
4. Functional abdominal pain/IBS - Common but diagnosis of exclusion 4

Age-Specific for Adolescents

1. Gynecologic (females): Ovarian cyst, ovarian torsion, pelvic inflammatory disease, ectopic pregnancy 2
2. Urinary tract infection 1, 2
3. Inflammatory bowel disease (Crohn's disease, ulcerative colitis)

Less Common but Critical

1. Sigmoid volvulus - Rare but documented in adolescents 6
2. Testicular torsion (males) - Can present as abdominal pain 1
3. Pancreatitis, cholecystitis - Less common in this age but possible 3
4. Small bowel obstruction 3
5. Malignancy - Rare but must consider with constitutional symptoms

Physical Assessment

Systematic Examination Priorities

Vital signs:

• Fever, tachycardia, hypotension (sepsis concerns)

Abdominal examination for surgical abdomen:

• Bowel sounds: Decreased or absent suggests appendicitis or obstruction 1, 2
• Guarding and rigidity: Voluntary guarding increases surgical likelihood 1, 2
• Rebound tenderness: Especially right lower quadrant 1
• Specific signs for appendicitis:
  • Rovsing sign (RLQ pain with LLQ palpation) 1
  • Psoas sign (pain with hip extension) 1
  • Obturator sign (pain with hip flexion/internal rotation) 1

Extra-abdominal:

• Testicular examination in males
• Consider pelvic examination in sexually active females (or defer to gynecology)

Assessment Plan

Initial Laboratory Evaluation

Order these tests based on clinical suspicion:

• Complete blood count - Leukocytosis suggests infection/inflammation 4, 1, 2
• Urinalysis - Rule out UTI 1, 2
• Pregnancy test (β-hCG) - Mandatory in all females of reproductive age before imaging 7, 1
• C-reactive protein or ESR - Elevated in inflammatory conditions 4, 1, 2
• Consider: Comprehensive metabolic panel, lactate (if sepsis concern) 1

Imaging Strategy

For suspected appendicitis (most common surgical cause):

• First-line: Ultrasound - Preferred initial modality in children/adolescents due to no radiation 5, 1, 2
• If ultrasound non-diagnostic: CT abdomen/pelvis with contrast 5, 2
• Consider Pediatric Appendicitis Score to risk-stratify before imaging 1

For right upper quadrant pain:

• Ultrasound for cholecystitis evaluation 7

For diffuse, non-localized pain with fever:

• CT abdomen/pelvis with IV contrast - Best for broad differential including abscess, obstruction, perforation 3

For suspected gynecologic pathology:

• Pelvic ultrasound for ovarian pathology, ectopic pregnancy 7, 2

Avoid routine plain radiographs - Limited diagnostic value except for suspected obstruction or constipation 7, 2

Clinical Decision Algorithm

High-risk features present (bilious vomiting, hematochezia, peritoneal signs, severe localized pain): → Urgent surgical consultation + imaging (CT or ultrasound based on suspected diagnosis) 1, 2

Suspected appendicitis (RLQ pain, fever, anorexia, migration of pain): → Calculate Pediatric Appendicitis Score → Ultrasound → CT if equivocal → Surgical consultation 5, 1

Female with pelvic symptoms: → β-hCG + pelvic ultrasound → Gynecology consultation if positive findings 2

Non-specific pain, no red flags, stable vitals: → Basic labs (CBC, urinalysis, inflammatory markers) → Consider functional etiology if workup negative → May discharge with close follow-up 4

Critical Pitfalls to Avoid

1. Anchoring bias: Don't assume functional pain without excluding surgical causes 6, 8
2. Missing pregnancy: Always test β-hCG in females before imaging 7
3. Atypical presentations: Adolescents may not present classically; maintain broad differential 5
4. Radiation exposure: Use ultrasound first when appropriate; avoid unnecessary CT 5, 2
5. Delayed diagnosis: If initial workup normal but pain severe/persistent, re-examine the patient 8
6. Testicular torsion: Remember this can present as abdominal pain without obvious scrotal symptoms 1

Disposition Guidance

Admit or urgent surgical referral if:

• Peritoneal signs present
• Confirmed or highly suspected appendicitis
• Confirmed surgical pathology (volvulus, torsion, obstruction)
• Sepsis or hemodynamic instability

Discharge with close follow-up if:

• Benign examination
• Normal or reassuring labs/imaging
• Reliable family for monitoring
• Clear return precautions provided
• Follow-up arranged within 24-48 hours for persistent symptoms

Consider IBS diagnosis only after:

• Baseline investigations normal (CBC, CRP/ESR, celiac serology) 4
• Fecal calprotectin normal (if diarrhea present and age <45) 4
• Symptoms meet Rome IV criteria with clear pain-bowel habit relationship 4