Infectious mononucleosis

Question 1

What is infectious mononucleosis? What is it also known as?

Answer 1

Clinical syndrome caused by primary EBV infection

AKA glandular fever “kissing disease”

Question 2

Explain the aetiology of infectious mononucleosis

Answer 2

HHV4
In pharyngeal secretions of infected individuals + transmitted by close contact
EBV infects epithelial cells of oropharynx, leads to B cell infection
Infected B cells disseminate EBV across the body leading to humoral + cellular immune response

Question 3

Summarise the epidemiology of infectious mononucleosis

Answer 3

COMMON
2 age peaks:
1-6 yrs
14-20 yrs

Question 4

List 8 presenting symptoms of infectious mononucleosis

Answer 4

Abrupt onset of symptoms: 
Sore throat  
Fever  
Fatigue  
Headache  
Malaise  
Anorexia  
Sweating  
Abdominal pain

Question 5

List 9 signs of infectious mononucleosis on physical examination

Answer 5

PYREXIA 
Oedema + erythema of the pharynx 
White/ creamy exudate on the tonsils  
Palatal petechiae  
Cervical/ generalised lymphadenopathy  
Splenomegaly  
Hepatomegaly  
Jaundice
Widespread maculopapular rash (in pts who have received ampicillin)

Question 6

What bloods are tested in infectious mononucleosis?

Answer 6

FBC: leukocytosis
LFTs: high AST + ALT
Blood Film: lymphocytosis with atypical lymphocytes

Question 7

What are the possible respiratory, haematological, GI and CNS complications of infectious mononucleosis?

Answer 7

Lethargy (months)
Resp: airway obstruction
Haem: haemolytic or aplastic anaemia, thrombocytopenia
GI/Renal: splenic rupture, hepatitis, mesenteric adenitis, renal failure
CNS: GBS, encephalitis, viral meningitis
Malignancy: Burkitt’s lymphoma (sub-Saharan Africa), nasopharyngeal cancer, Hodgkin’s lymphoma

Question 8

What is the prognosis for patients with infectious mononucleosis?

Answer 8

Most make uncomplicated recovery (within 3 weeks)

Immunodeficiency + death are VERY RARE

Question 9

How is infectious mononucleosis managed?

Answer 9

Bed rest
Paracetamol + NSAIDs: helps with fever, malaise
Corticosteroids in SEVERE cases
Advice: avoid contact sports for 2 weeks (because of risk of splenic rupture)

Question 10

How long is the incubation period for infectious mononucleosis?

Answer 10

4-8 weeks

Question 11

What other investigations are required for infectious mononucleosis?

Answer 11

Monospot Test/ Paul Bunnell Test: detects presence of heterophiles antibodies produced in response to EBV infection but are not actually against EBV antigens
Throat swabs: exclude streptococcal tonsillitis
IgM or IgG to EBV viral capsid antigen: at onset
IgG against Epstein-Barr nuclear antigen (EBNA): 6-12 weeks after onset

Question 12

What is a classic feature seen in the peripheral blood of a patient with infectious mononucleosis ?

Answer 12

Atypical lymphocytes

Question 13

Describe the life of EBV

Answer 13

Remains latent in lymphocytes

Reactivation may occur following stress or immunosuppression

Question 14

What happens if you give ampicillin or amoxicillin to a patient with infectious mononucleosis?

Answer 14

Develop a maculopapular rash

Question 15

What immunoglobulins would be present in someone with a negative EBV status?

Answer 15

VCA IgM: Negative
VCA IgG: Negative
EBNA IgG: Negative

Question 16

What immunoglobulins would be present in someone early in primary EBV infection?

Answer 16

VCA IgM: Positive
VCA IgG: Negative
EBNA IgG: Negative

Question 17

What immunoglobulins would be present in someone in acute primary EBV infection?

Answer 17

VCA IgM: Positive
VCA IgG: Positive
EBNA IgG: Negative

Question 18

What immunoglobulins would be present in someone who had EBV in the past?

Answer 18

VCA IgM: Negative
VCA IgG: Positive
EBNA IgG: Positive