Does a patient with a recent mono diagnosis and lymphocytosis (elevated lymphocyte count) require liver enzyme tests and a spleen ultrasound?

Management of Liver Testing and Ultrasound in Adolescent with Mononucleosis

Liver enzyme tests should be performed in this 15-year-old with confirmed mononucleosis, but a spleen ultrasound is not routinely necessary unless there are specific clinical indications.

Assessment of Liver Function in Mononucleosis

Epstein-Barr virus (EBV) infection commonly affects the liver, with abnormal liver function tests occurring in a high percentage of patients:

• Aspartate aminotransferase (AST) is elevated in 96.7% of EBV cases 1
• Alanine aminotransferase (ALT) is elevated in approximately 62% of cases 2
• Alkaline phosphatase (ALP) is elevated in 94.2% of EBV cases 1

Rationale for Liver Testing

1. High prevalence of hepatic involvement: Liver enzyme abnormalities are extremely common in infectious mononucleosis, even without clinical symptoms of hepatitis 2, 3

2. Establishing baseline: Testing provides a baseline to monitor potential complications, especially since this patient already has lymphocytosis, suggesting systemic involvement

3. Diagnostic value: The presence of elevated liver enzymes increases clinical suspicion for infectious mononucleosis in cases with initial negative heterophile antibody tests 3

Spleen Ultrasound Recommendations

Spleen ultrasound is not routinely indicated in uncomplicated mononucleosis cases and should be reserved for specific clinical scenarios:

• Clinical evidence of significant splenomegaly
• Abdominal pain in the left upper quadrant
• Concern for splenic injury or rupture
• Planning return to contact sports or high-impact activities

Current evidence questions the need for routine ultrasound evaluation in immunocompetent patients with uncomplicated mononucleosis 2.

Management Algorithm

1. Obtain liver function tests:

   • Complete liver panel (AST, ALT, ALP, bilirubin)
   • These will establish a baseline for monitoring

2. Clinical assessment for splenomegaly:

   • Careful abdominal examination focusing on left upper quadrant
   • Document any tenderness or palpable spleen edge

3. Indications for spleen ultrasound (perform only if any of these are present):

   • Inability to reliably assess spleen size on physical exam
   • Significant abdominal pain
   • Planning return to contact sports within 3-4 weeks
   • Suspected splenic injury or rupture

4. Follow-up of abnormal liver tests:

   • If mildly elevated (<5× upper limit of normal): Repeat in 4-6 weeks
   • If moderately elevated (>5× upper limit of normal): Consider earlier follow-up in 2-3 weeks
   • If severely elevated (>10× upper limit of normal): Consider hepatology consultation

Important Considerations

• Liver enzyme abnormalities in mononucleosis typically resolve without specific treatment, with median time to resolution of 8 weeks (range 6-12 weeks) 2
• Tender hepatomegaly and gallbladder thickening may predict significant liver involvement 4
• Multiple transaminase peaks may occur during recovery and do not necessarily indicate need for specific therapy 4
• Decompensated liver disease is extremely rare in immunocompetent patients with mononucleosis 2

Conclusion

While liver enzyme testing is warranted in this adolescent with mononucleosis and lymphocytosis, spleen ultrasound should be performed only if clinically indicated by physical examination findings or specific symptoms. The management approach should focus on monitoring for resolution of abnormal liver tests over time rather than extensive imaging in the absence of concerning symptoms.