Type of viral infection that mostly affects young adults

Aetiology

• Infectious mononucleosis (glandular fever) is caused by the Epstein-Barr virus (EBV, also known as human herpes virus 4, HHV-4) in 90% of cases
• Less frequent causes include cytomegalovirus and HHV-6
• It is most common in adolescents and young adults

Clinical features

• Malaise, anorexia, headache
• Palatal petechiae
• Splenomegaly - occurs in around 50% of patients and may rarely predispose to splenic rupture
• Hepatitis, transient rise in ALT
• Lymphocytosis: presence of 50% lymphocytes with at least 10% atypical lymphocytes
• Haemolytic anaemia secondary to cold agglutins (IgM)
• A maculopapular, pruritic rash develops in around 99% of patients who take ampicillin/amoxicillin whilst they have infectious mononucleosis
• Symptoms typically resolve after 2-4 weeks

Investigations

• Heterophil antibody test (Monospot test)
  • NICE guidelines suggest FBC and Monospot in the 2nd week of the illness to confirm a diagnosis of glandular fever

Management

• Rest during the early stages, drink plenty of fluid, avoid alcohol
• Simple analgesia for any aches or pains
• Consensus guidance in the UK is to avoid playing contact sports for 4 weeks after having glandular fever to reduce the risk of splenic rupture