What are the criteria to clear a teenager with mononucleosis for sports participation?

Criteria for Clearing a Teenager with Mononucleosis for Sports Participation

Teenagers with mononucleosis should not participate in contact or strenuous sports for at least 3-4 weeks from symptom onset and should only return when splenomegaly has resolved, as confirmed by physical examination or ultrasound. 1

Assessment Before Return to Sports

Clinical Evaluation

• Ensure complete resolution of acute symptoms (fever, severe fatigue, pharyngitis) before considering return to any physical activity 2
• Perform a thorough abdominal examination to assess for splenomegaly, which is present in approximately 50% of mononucleosis cases 3
• Assess for any signs of persistent fatigue, as this may indicate incomplete recovery 3

Laboratory Testing

• Confirm diagnosis with appropriate testing:
  • Complete blood count with differential (looking for >40% lymphocytes and >10% atypical lymphocytes) 1
  • Heterophile antibody test (Monospot) or EBV-specific antibody testing if Monospot is negative 2
  • Liver function tests to assess for hepatic involvement 3

Imaging

• Abdominal ultrasound at 4 weeks post-diagnosis is recommended to confirm resolution of splenomegaly before clearing for contact sports 4
• If splenomegaly persists at 4 weeks, repeat ultrasound at 8 weeks 4

Return to Play Timeline

Initial Period (0-3 weeks)

• No participation in any contact sports or strenuous physical activity 1
• Light, non-contact activities may be gradually introduced based on symptom resolution 5

Intermediate Period (3-4 weeks)

• If clinically improved with no splenomegaly on physical exam, consider ultrasound to confirm normal splenic size 4
• Studies show that 84% of athletes have normal splenic dimensions by 4 weeks post-diagnosis 4

Extended Period (>4 weeks)

• If splenomegaly persists at 4 weeks, continue sports restriction until splenic dimensions normalize 4
• Most patients with persistent splenomegaly at 4 weeks will have normal dimensions by 8 weeks 4

Risk Assessment and Precautions

High-Risk Activities to Avoid

• Contact sports with risk of abdominal trauma (football, hockey, lacrosse, rugby) should be strictly avoided until clearance 5
• "Burst" exertion activities with rapid acceleration/deceleration should be avoided during recovery 6

Complications to Monitor

• Splenic rupture is the most feared complication, typically occurring within the first month of illness 3
• Risk of splenic rupture is approximately 0.1-0.5% in mononucleosis patients 3
• Persistent fatigue may indicate incomplete recovery or development of post-viral fatigue syndrome 3

Decision-Making Algorithm

1. Confirm complete resolution of acute symptoms (minimum 3 weeks from onset) 1
2. Perform physical examination to assess for splenomegaly 3
3. If no palpable splenomegaly and ≥4 weeks from symptom onset:
   • Consider abdominal ultrasound to confirm normal splenic size 4
   • If normal splenic size: Clear for gradual return to all sports 4
4. If persistent splenomegaly at 4 weeks:
   • Continue sports restriction 4
   • Repeat ultrasound at 8 weeks 4
   • Clear only when splenic dimensions normalize 4

Special Considerations

• Athletes with more severe presentations (significant hepatosplenomegaly, extreme fatigue) may require longer recovery periods 5
• Return to play should follow a gradual progression, starting with light aerobic activity and progressing to sport-specific training before full competition 5
• Educate athletes about the importance of reporting any abdominal pain, as this could indicate splenic injury 3