Infectious mononucleosis Flashcards

1
Q

Define infectious mononucleosis.

A

Clinical syndrome caused by primary EBV infection. Also known as glandular fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the aetiology of IM?

A
  • EBV is spread by saliva/respiratory droplets
  • Predilection for B lymphocytes, incorporation of viral DNA into host DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How common is IM?

A
  • Affects 90-95% of people at some point in their lives (seroprevalence in 35-40yr age group is 90%)
  • Peaks at age 15-19yrs
  • Tends to occur later in developed countries

AKA the “kissing” disease because usually spread through saliva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is Epstein Barr virus?

A

Herpes simplex virus 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do you distinguish infectious mononucleosis from tonsillitis?

A

Tonsillitis -anterior cervical lymphadenopathy

IM - posterior cervical lymphadenopathy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the pathophysiology of glandular fever?

A

EBV has lytic and latent phase

Lytic - EBV infects oropharyngeal B cells via tonsillar crypts. B cells spread the infection to liver/spleen/lymph nodes → humoral response to the virus → antibodies against EBV structural proteins VCAs, EAs, EBNA. T cell response is essential for suppression of infection

Latent - self-replicating extra-chromosomal nucleic acid; EBV immortalises infected lymphocytes (in a seropositive adult 0.005% of circulating B cells will be EBV infected)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the triad of infectious mononucleosis?

A
  • Pyrexia
  • Pharyngitis
  • Lymphadenopathy with atypical lymphocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the signs and symptoms of IM?

A
  • Cervical/generalised lymphadenopathy (posterior cervical)
  • Pharyngitis (tonsillar exudates)
  • Fever
  • Splenomegaly (50%)
  • Malaise, anorexia, headache

Other:

  • Palatal petechiae
  • Rash (10%) - erythematous, maculopapular, or morbilliform; or maculopapular pruritic rash IF AMOXICILLIN taken
  • Hepatitis, transient rise in ALT
  • Jaundice

Symptoms resolve after 2-4 weeks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do you diagnose IM?

A
  • Classical triad of fever, pharyngitis, lymphadenopathy
  • In 2nd week: FBC - atypical lymphocytosis (highest in week 2-3)
  • In 2nd week: Heterophil antibody test (Monospot test) - confirms diagnosis; IgM agglutinates red cells from other species.

Other:

  • Blood film - atypical lymphocytes
  • heterophile antibodies - Monospot test;
  • EBV-specific antibodies - positive for VCA-IgM, VCA-IgG, EA, EBV EBNA
  • real-time PCR - EBV DNA detection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do you manage infectious mononucleosis?

A
  • Supportive care - paracetamol or ibuprofen
  • Corticosteroids -e.g. prednisolone for severe cases (e.g haemolytic anaemia, severe tonsillar swelling, obstructive pharyngitis)

Amoxicillin/ampicillin CONTRAINDICATED –> maculopapular pruritic rash

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the prognosis with IM?

A

Good prognosis for healthy people.

EBV infection can be asymptomatic, cause mild, non-specific symptoms, or cause IM with symptoms and fatigue lasting up to 6 months or more.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How would you interpret these results?

A
  1. IgM – infection present now
  2. IgG – capsid antigen
  3. ENBA - only after the infection is gone completely

BUT this is rarely tested in practice.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the Paul Bunnell test?

A

A heterophil antibody test - sensitive but not specific for the causative EBV.

False positive results can occur with other viruses and leukaemia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How long until return to contact sports?

A

3-8 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the complications of IM?

A
  • fatigue -may last up to 6 months or more
  • severe upper airway obstruction,
  • depression
  • meningitis
  • splenic rupture,
  • fulminant hepatitis,
  • encephalitis,
  • severe thrombocytopenia,
  • and haemolytic anaemia.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What types of test is the monospot test?

A

Blood test