Infectious mononucleosis

Infectious mononucleosis (also known as glandular fever) is the term for infection with Epstein-Barr Virus (EBV). The infection classically occurs in teenagers and young adults, hence its other name kissing disease. It is usually a clinical diagnosis, with confirmation by serum testing, but may have suggestive findings on imaging.

Epidemiology

Exposure to EBV, but often a subclinical infection, especially in children. Young adults (15-24) are more likely to be symptomatic.

Clinical presentation

• fever
• tonsillitis
• lymphadenopathy and splenomegaly
  • occasionally hepatosplenomegaly
• fatigue
• occasionally: rash

Complications

• splenic rupture: may be spontaneous
• splenic infarction ³

Pathology

It was originally called "mononucleosis" after abnormal mononuclear cells were found in patients with the clinical syndrome.

EBV is in the herpesvirus class. It is thought to be spread primarily through a person-to-person route through salivary secretions. The EBV virus infects B-cells in the lymphoid tissue. Like other herpes viruses, it becomes a lifelong chronic infection with periodic shedding of virus.

Elevated transaminases are occasionally seen.

Radiographic features

Diagnosis is usually through serum lab work which would show lymphocytosis and a positive heterophile antibody test. Imaging is usually not necessary, but certain findings on imaging can be suggestive:

CT

• splenomegaly
  • possible splenic rupture
  • splenic infarction has been reported ³
• generalised lymphadenopathy, including cervical lymphadenopathy
• tonsillar enlargement
• possible hepatomegaly

Treatment and prognosis

Symptomatic therapy is usually sufficient. Athletes are encouraged to discontinue sports during the acute phase (<3-4 weeks) to lower the risk of splenic rupture ².

Complications

• myocarditis rarely seen ⁴
• CNS infections rarely seen ⁴

Differential diagnosis

Imaging differential diagnoses include:

• acute HIV infection
• acute CMV infection (usually more clinically mild than EBV)
• non-Hodgkin lymphoma
• leukaemia