What are the symptoms and treatment of mononucleosis (mono)?

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Symptoms of Mononucleosis (Mono)

Mononucleosis is characterized by fever, sore throat, swollen lymph nodes in the neck, fatigue, and hepatosplenomegaly, with symptoms typically lasting several weeks. 1, 2

Common Symptoms

  • Fever: Often persistent or intermittent, can reach as high as 40°C 1
  • Sore throat: Typically severe and may include pharyngitis or tonsillitis 3
  • Lymphadenopathy: Primarily affecting cervical lymph nodes, but can include posterior cervical or auricular nodes 2
  • Fatigue: Often debilitating and may persist for months after acute infection resolves 2
  • Hepatosplenomegaly: Enlargement of liver and spleen is common 1, 4

Laboratory Findings

  • Blood abnormalities: Elevated white blood cell count with atypical lymphocytosis (≥20% atypical lymphocytes or ≥10% atypical lymphocytes with ≥50% lymphocytosis) 1, 2
  • Liver function: Mild elevations in liver function tests are common 1
  • Serological markers: Positive heterophile antibody test (Monospot) in most adolescents and adults, though false negatives can occur early in infection 1, 2
  • EBV-specific antibodies: Presence of VCA IgM (with or without VCA IgG) in the absence of EBNA antibodies indicates recent primary infection 1

Less Common Symptoms

  • Palatal petechiae: Small red spots on the roof of the mouth 2
  • Skin rash: Maculopapular rash may occur, especially in patients treated with antibiotics 1
  • Neurological symptoms: Headache and rarely more severe neurological complications 1
  • Respiratory issues: Interstitial pneumonitis can develop in some cases 1
  • Ocular symptoms: Various eye-related complications may occur 1

Complications

  • Splenic enlargement: Poses risk of rupture, particularly with physical exertion 5
  • Airway obstruction: Severe pharyngeal edema can compromise breathing 2, 3
  • Peritonsillar abscess: Can develop as a complication of severe tonsillitis 5
  • Hematologic complications: Including anemia, thrombocytopenia, and neutropenia in severe cases 1
  • Splenic infarction: A rare complication that can occur due to transient hypercoagulable state 5

Treatment Approach

  • Supportive care: The mainstay of treatment includes adequate hydration, analgesics, and antipyretics 2
  • Rest: Should be guided by the patient's energy level rather than enforced bed rest 2
  • Activity restriction: Patients should be withdrawn from contact or collision sports for at least four weeks to prevent splenic rupture 2
  • Corticosteroids: Not recommended for routine treatment but may benefit patients with respiratory compromise or severe pharyngeal edema 2
  • Antiviral medications: Acyclovir is not recommended for routine treatment of infectious mononucleosis 2

Special Considerations

  • Age differences: While adolescents and young adults typically present with the classic triad of symptoms, children under 10 years often have milder or asymptomatic infections 4
  • Duration: Acute symptoms typically last 2-4 weeks, but fatigue may persist for several months 2
  • Differential diagnosis: Consider other causes of similar symptoms, including streptococcal infection, cytomegalovirus, toxoplasmosis, and other viral infections when heterophile antibody tests are negative 2

When to Seek Medical Attention

  • Severe abdominal pain: May indicate splenic rupture requiring immediate medical attention 5
  • Difficulty breathing: Could indicate airway compromise requiring urgent intervention 2, 3
  • Persistent high fever: Unresponsive to antipyretics 1
  • Severe dehydration: Due to inability to swallow liquids 2
  • Prolonged symptoms: Symptoms persisting beyond 4-6 weeks may warrant further investigation 2

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Epstein-Barr virus infectious mononucleosis.

American family physician, 2004

Research

[Infectious mononucleosis--a "childhood disease" of great medical concern].

Medizinische Monatsschrift fur Pharmazeuten, 2013

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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