Infectious Mononucleosis

Question 1

Define Infectious Mononucleosis

Answer 1

Infectious mononucleosis (IM), also known as glandular fever, is a clinical syndrome most commonly caused by Epstein-Barr virus (EBV) infection in 80% to 90% of cases and CMV accounts for about 7% of IM

Question 2

Explain the aetiology / risk factors of infectious mononucleosis

Answer 2

• Epstein-Barr virus (EBV), also known as human herpes virus 4, is the aetiological agent in approximately 80% to 90% of IM cases - this infects B lymphocytes
• CMV can also be cause of IM but this is heterophile negative and has milder pharyngitis and lacks posterior cervical lymphadenopathy
• EBV is most commonly transmitted through saliva, hence the name ‘‘kissing’’ disease.
• There is also evidence of sexual transmission of EBV

Risk factors:

• Kissing
• Multiple sexual partners in women

Question 3

Epidemiology of IM

Answer 3

people aged 15 to 24 years are the most affected age grou

Question 4

Recognise the presenting symptoms of infectious mononucleosis

Answer 4

• High fever
• Pharyngitis ± exudate
• Cervical lymphadenopathy (posterior)
• Malaise
• Sore throat

Question 5

Recognise the signs of infectious mononucleosis on physical examination

Answer 5

• Fever
• Splenomegaly
• Hepatomegaly

Question 6

Identify appropriate investigations for infectious mononucleosis and interpret the results

Answer 6

• FBC: Lymphocytosis w/ atypical lymphocytosis seen on peripheral blood smear
• Heterophile antibody test: the antibodies against EBV can also react with antigens in bovine/horse blood (agglutination) - this is a quick bedside test
• EBV-Specific antibodies (serology)
  
  • Viral capsid antigen-IgM (VCA-IgM) in most patients is detectable with symptom onset; peaks at 2 to 3 weeks
  • VCA-IgG peaks at 2 to 3 months; persists for life.
  • Nuclear antigen (EBNA) antibodies rise in resolution phase, and remain detectable for life. These antibodies develop after 6 to 8 weeks and can be used to identify past infection, or as evidence to rule out acute EBV infection.
• LFTs: raised transaminase

Question 7

Generate a management plan for infectious mononucleosis

Answer 7

• Supportive care: Paracetamol/NSAIDs (Analgesia & Antipyrexial)
• Corticosteroid (if tonsilar lymphadenopathy is causing obstruction)
• If mistaken for a Group A strep sore throat and amoxicillin, Penicillin or ampicillin are given then a maculopapular rash appears

Question 8

Identify the possible complications of infectious mononucleosis and its management

Answer 8

• Pruritic maculopapular rash associated with antibiotics
• Splenic rupture
• Encephalitis
• Malignancy:
  
  • Nasopharyngeal carcinoma
  • Gastric carcinoma
  • Burkitt’s lymphoma
  • Hodgkin’s lymphoma