Infectious Mononucleosis

Question 1

Define:

Answer 1

• Clinical syndrome caused by primary EBV infection

o AKA glandular fever

Question 2

Aetiology/risk factors:

Answer 2

• EBV is a gamma-Herpes virus (dsDNA)
• It is found in the pharyngeal secretions of infected individuals and is transmitted by close contact (e.g. kissing, sharing eating utensils)
• The infected B cells disseminate EBV across the body leading to a humoral and cellular immune response
• Atypical lymphocytes in the peripheral blood are a classic feature of infectious mononucleosis
• EBV remains latent in lymphocytes
• Reactivation may occur following stress or immunosuppression

Question 3

Epidemiology:

Answer 3

• COMMON
• TWO age peaks:
o 1-6 yrs
o 14-20 yrs

Question 4

Symptoms:

Answer 4

•	Incubation period: 4-5 weeks 
•	Abrupt onset of symptoms:
o	Sore throat 
o	Fever 
o	Fatigue 
o	Headache 
o	Malaise 
o	Anorexia 
o	Sweating 
o	Abdominal pain

Question 5

Signs:

Answer 5

• PYREXIA
• Oedema and erythema of the pharynx
• White/creamy exudate on the tonsils
• Palatal petechiae
• Cervical/generalised lymphadenopathy – esp posterior triangle of neck
• Splenomegaly
• Hepatomegaly
• Jaundice (5-10%)
• Widespread maculopapular rash (in patients who have received ampicillin)

Question 6

Investigations:

Answer 6

• Bloods
o FBC - leucocytosis
o LFTs - high AST/ALT

Blood Film - lymphocytosis with atypical lymphocytes (large, irregular nuclei)

• Heterophil Antibody Test (aka Monospot Test)
o Mixing blood of an EBV-positive human with animal blood will make the animal’s red cells aggregate and precipitate out of solution.

• Throat swabs - exclude streptococcal tonsillitis

• IgM or IgG to EBV viral capsid antigen
• IgG against Epstein-Barr nuclear antigen (EBNA)

Question 7

Management:

Answer 7

• Bed rest
• Paracetamol and NSAIDs - helps with fever, malaise
• Corticosteroids +/- acyclovir in SEVERE cases
• IMPORTANT: do NOT give AMPICILLIN or AMOXICILLIN if infectious mononucleosis is suspected - nearly 100% of patients with glandular fever develop a maculopapular rash
• Advice - avoid contact sports for 2 weeks (because of risk of rupturing your spleen)

Question 8

Complications:

Answer 8

• Lethargy for several months
• Respiratory - airway obstruction from oedematous pharynx, secondary bacterial throat infection, pneumonitis
• Haematological - haemolytic or aplastic anaemia, thrombocytopenia
• GI/Renal - splenic rupture, fulminant hepatitis, pancreatitis, mesenteric adenitis, renal failure
• CNS - Guillain-Barre syndrome, encephalitis, viral meningitis, cerebellitis, CN lesions
• EBV-associated malignancy - Burkitt’s lymphoma (in sub-Saharan Africa), nasopharyngeal cancer, Hodgkin’s lymphoma

Question 9

Prognosis:

Answer 9

• Most make uncomplicated recovery (within 3 weeks)

* Immunodeficiency and death are VERY RARE