When should Liver Function Tests (LFTs) be repeated after infectious mononucleosis?

From the Guidelines

Liver function tests (LFTs) should be repeated approximately 4-6 weeks after the initial diagnosis of infectious mononucleosis if the initial tests showed abnormalities, as most patients experience spontaneous resolution of transaminase elevations within this timeframe 1. When considering the management of abnormal liver blood tests in the context of infectious mononucleosis, it is essential to weigh the costs and benefits of repeated testing. According to the guidelines on the management of abnormal liver blood tests, a strategy of simply repeating abnormal tests can only be justified where there is a high degree of certainty that the abnormality will resolve in response to an identified acute insult 1.

Key Considerations

• The presence of unexplained clinical jaundice or suspicion of possible hepatic or biliary malignancy should lead to an immediate referral 1.
• In cases where liver enzyme elevations were significant (more than 5 times the upper limit of normal), more frequent monitoring every 2 weeks may be appropriate until improvement is observed.
• Patients with persistent symptoms such as jaundice, right upper quadrant pain, or significant fatigue should have their LFTs checked sooner.

Rationale

The Epstein-Barr virus, which causes infectious mononucleosis, typically affects the liver transiently, and monitoring ensures proper resolution of hepatic inflammation without unnecessary testing.

Additional Recommendations

• A thorough clinical history, including age, ethnicity, specific symptoms, comorbidity, drug history, travel history, occupational exposure, and family history, should be obtained to determine the cause of abnormal liver blood tests 1.
• Investigations should include a standard liver aetiology screen or core panel to identify the cause of damage and exclude additional pathologies 1.

From the Research

Liver Function Tests (LFTs) in Infectious Mononucleosis

• LFTs are commonly abnormal in patients with infectious mononucleosis, with studies showing that 57-65% of patients have elevated aspartate transaminase, alanine transaminase, and alkaline phosphonate levels 2, 3.
• The median time to resolution of LFT abnormalities is around 8 weeks, but can range from 6-12 weeks or even longer than 6 months 2.
• Studies suggest that serial assessment of LFTs is not required in immunocompetent adults with subclinical derangement of LFTs 2, 3.

Repeat LFTs After Infectious Mononucleosis

• There is no clear guideline on when to repeat LFTs after infectious mononucleosis, but studies suggest that it may not be necessary to repeat LFTs in immunocompetent patients with subclinical derangement of LFTs 2, 3.
• One study found that the median time to resolution of LFT results was 32 days, with a maximum time of 10 months 3.
• Another study found that LFT values returned to normal within 6-12 weeks in most patients 2.

Abdominal Ultrasound in Infectious Mononucleosis

• Abdominal ultrasound is not routinely required in patients with infectious mononucleosis, unless there are clinical indications such as hepatomegaly or splenomegaly 2, 3.
• Studies have shown that abdominal ultrasound can be normal even in patients with abnormal LFTs 3, 4.