Infectious Mononucleosis (EBV)

Overview – Infectious Mononucleosis (EBV)

Infectious Mononucleosis, commonly known as “glandular fever,” is a viral illness most often caused by the Epstein-Barr Virus (EBV), a member of the herpesvirus family. It is frequently seen in adolescents and young adults, often presenting with prolonged fatigue, pharyngitis, and lymphadenopathy. While usually self-limiting, it has distinct clinical features and potential complications that merit careful recognition. This article outlines its pathogenesis, clinical presentation, diagnostic workup, and management strategies relevant to medical students and junior doctors.

Definition

Infectious Mononucleosis is an acute viral illness characterised by fever, sore throat, and lymphadenopathy, most commonly caused by Epstein–Barr Virus (EBV).

Aetiology

  • Epstein–Barr Virus (EBV), a double-stranded DNA herpesvirus

Pathogenesis

  • Transmission primarily via saliva (hence “kissing disease”)
  • Incubation period: 4–8 weeks
  • Virus infects B-lymphocytes in oropharyngeal epithelium
  • Leads to polyclonal B-cell activation and reactive atypical T-lymphocytes (Downey cells)
  • Triggers a systemic immune response, resulting in characteristic signs and symptoms

Morphology / Haematological Findings

  • Generalised lymphadenopathy (especially posterior cervical nodes)
  • Peripheral blood smear:
    • Lymphocytosis
    • Atypical lymphocytes (large, irregular nuclei)
infectious mononucleosis - Epstein Barr Virus
Creative commons: https://www.flickr.com/photos/euthman/145052721

Clinical Features

Glandular Fever Triad

  • Fatigue / malaise
  • Pharyngitis (severe sore throat, often with tonsillar exudate)
  • Lymphadenopathy (classically posterior cervical)
infectious mononucleosis EBV pharyngitis
James Heilman, MD, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons

Other Common Features

  • Fever
  • Splenomegaly (up to 50% of cases)
  • Hepatitis / elevated LFTs
  • Rash (particularly after administration of ampicillin or amoxicillin)
  • Anorexia, nausea, jaundice, or haemolysis (less common)

Investigations

  • Monospot test (heterophile antibody test)
    • Rapid and specific
    • May be false negative early in disease
  • Peripheral blood smear
    • Atypical lymphocytes
  • EBV serology
    • VCA-IgM: acute infection
    • EBNA: past infection
  • Liver function tests (LFTs)
    • Mild transaminitis common

Management

Supportive Treatment

  • Paracetamol or NSAIDs for fever and pharyngitis
  • Rest is essential during acute phase
  • Hydration and nutrition support

Specific Considerations

  • Avoid amoxicillin/ampicillin → often causes a maculopapular rash
  • Avoid contact sports for 3–4 weeks (due to splenomegaly and risk of rupture)

Complications

  • Splenic rupture (rare but life-threatening)
  • Airway obstruction (from severe tonsillar hypertrophy)
  • Haematological: haemolytic anaemia, thrombocytopenia
  • Neurological: meningitis, encephalitis, cranial nerve palsies (rare)
  • Oncogenic potential:
infectious mononucleosis (EBV) complications
Creative Commons: https://media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fnrc.2016.92/MediaObjects/41568_2016_Article_BFnrc201692_Fig3_HTML.jpg

Differential Diagnosis

  • Acute streptococcal pharyngitis
  • Cytomegalovirus (CMV) infection
  • Toxoplasmosis
  • HIV seroconversion illness
  • Acute tonsillitis

Summary – Infectious Mononucleosis (EBV)

Infectious Mononucleosis is a self-limiting but clinically recognisable syndrome caused by Epstein-Barr Virus, presenting with fever, sore throat, fatigue, and lymphadenopathy. Diagnosis is clinical, supported by the Monospot test and atypical lymphocytosis. Management is supportive, with emphasis on rest and avoidance of contact sports. For broader context, visit our Respiratory Overview page.

Shopping Cart
Scroll to Top