Infectious Mononucleosis

Question 1

Define Infectious Mononucleosis

Answer 1

Clinical syndrome most commonly caused by EBV

AKA glandular fever

Question 2

Aetiology of Infectious Mononucleosis

Answer 2

EBV (Human Herpes 4) in 80-90% of cases. It is a dsDNA virus

Others: HHV-6, CMV, HSV-1, Strep. Pyogenes, Toxoplasma, connective tissue disorders, malignances

Transmission is through saliva (kissing disease) and sexual transmission
Those with Hx of EBV shed virus for 15 months
EBV remains latent in lymphocytes and reactivation can occur following stress or immunosuppression

Question 3

Symptoms of Infectious Mononucleosis

Answer 3

Fever
Sore throat
Neck lumps
Malaise
Rash (on first day of illness)
Jaundice
Myalgia

Question 4

Signs of Infectious Mononucleosis on examination

Answer 4

Pharyngitis (exudative or non)
Cervical or generalised lymphadenopathy (nodes typically tender, non-erythematous and discrete, most prominent over the second week)
Splenomegaly
Rash (Eyrthematous, maculopapular or morbilliform)
Signs of hepatitis

Question 5

Investigations for Infectious Mononucleosis

Answer 5

EBV Abs: +ve for EV-specific antibodies
Monospot testing: positive heterophile antibodies

FBC: lymphocytosis, anaemia + reticulocytosis (haemolytic anaemia secondary to EBV)
Blood film: atypical lymphocytes
LFTs: elevated transaminases
PCR: EBV DNA detection (no commonly used)

CT/USS abdomen: splenomegaly or splenic rupture

Question 6

Management for infectious mononucleosis

Answer 6

Supportive

• Paracetamol or buprofen
• Hydration
• NO aspirin (children - Reye’s syndrome) or Amoxicillin/ampicillin (widespread maculopapular rash)
• Refrain from strenuous physical activity and contact sports (splenomegaly)

Upper airway obstruction or haemolytic anaemia: oral corticosteroids

Thombocytopenia oral corticosteroids or IVIg

Question 7

Complications of Infectious Mononucleosis

Answer 7

Antibiotic-induced rash from ampicillin, amoxicillin, beta lactan Abs, azithromycin 
Splenic rupture 
Neurological complications 
Chronic active EBV infection 
Auto-immune disease e.g. SLE, RA 
Malignancy  
Chronic fatigue  
Acute acalculous cholecystitis  
Renal complications  
Haemophagocytic lymphohistiocytosis (HLH)

Question 8

Prognosis for Infectious Mononucleosis

Answer 8

Prognosis is very good in healthy people

Death is caused by airway obstruction, splenic rupture, neuro complications, haemorrhage or secondary infection