How do glandular fever and bacterial tonsillitis present differently?

Differentiating Glandular Fever from Bacterial Tonsillitis

Glandular fever (infectious mononucleosis) and bacterial tonsillitis present with distinct clinical features that can guide diagnosis and management, with glandular fever typically showing more generalized symptoms including significant lymphadenopathy and splenomegaly compared to the more localized presentation of bacterial tonsillitis.

Key Clinical Differences

Bacterial Tonsillitis

• Onset and Duration:

  • Sudden onset of symptoms 1
  • Typically shorter duration (3-7 days)

• Primary Symptoms:

  • Severe sore throat with pain on swallowing 1
  • Fever (usually 101°F to 104°F) 1
  • Headache 1
  • Abdominal pain, nausea, and vomiting (especially in children) 1

• Physical Examination Findings:

  • Tonsillopharyngeal erythema with or without exudates 1
  • Anterior cervical lymphadenitis (localized) 1
  • Soft palate petechiae ("doughnut" lesions) 1
  • Beefy red, swollen uvula 1
  • Typically no hepatosplenomegaly 2

Glandular Fever (Infectious Mononucleosis)

• Onset and Duration:

  • More gradual onset 3
  • Prolonged duration (2-4 weeks or longer) 3

• Primary Symptoms:

  • Classic triad: fever, pharyngitis, and lymphadenopathy 3
  • Profound fatigue and malaise 3
  • Headache
  • Less prominent abdominal pain compared to bacterial tonsillitis

• Physical Examination Findings:

  • Membranous tonsillitis (white exudative patches) 4
  • Generalized lymphadenopathy (not just anterior cervical) 5
  • Splenomegaly (50-60% of cases) 5
  • Hepatomegaly (10-15% of cases) 5
  • Possible maculopapular rash (especially if treated with ampicillin)

Laboratory Findings

Bacterial Tonsillitis

• Positive throat culture for Group A β-hemolytic streptococci (GAS) 1
• Positive rapid antigen detection test (RADT) for GAS 1
• Normal or elevated white blood cell count with neutrophilia
• Normal liver function tests

Glandular Fever

• Atypical lymphocytosis (>10% of lymphocytes) 3
• Positive heterophile antibody test (Monospot) 5
• Positive EBV-specific antibodies (VCA IgM, VCA IgG) 5
• Elevated liver enzymes (common even without clinical hepatitis) 3
• Negative throat culture for bacterial pathogens (unless co-infection)

Complications

Bacterial Tonsillitis

• Peritonsillar abscess (quinsy) 1
• Acute otitis media, sinusitis 1
• Acute rheumatic fever (rare in developed countries) 1
• Acute glomerulonephritis 1

Glandular Fever

• Splenic rupture (rare but serious) 3
• Airway obstruction due to severe tonsillar hypertrophy 3
• Neurological complications (rare): Guillain-Barré syndrome, encephalitis 3
• Hematological complications: hemolytic anemia, thrombocytopenia 3
• Prolonged fatigue syndrome 3

Common Pitfalls in Diagnosis

1. Misdiagnosis of glandular fever as bacterial tonsillitis: This is a common error that leads to unnecessary antibiotic use 3. Look for generalized lymphadenopathy, splenomegaly, and atypical lymphocytosis to avoid this mistake.

2. Ampicillin/amoxicillin rash: Administration of these antibiotics to patients with undiagnosed glandular fever can cause a characteristic maculopapular rash in up to 90% of cases, which is not an allergic reaction but a specific interaction between the drug and the viral infection.

3. Co-infection: Patients with glandular fever may have bacterial superinfection of the tonsils, making diagnosis more challenging 4.

4. Atypical presentations: Both conditions can present atypically, especially in very young or elderly patients, or those with compromised immunity 3.

5. Reliance on clinical features alone: Laboratory confirmation is essential, as clinical features alone have limited specificity 1.

Diagnostic Algorithm

1. Initial assessment: Evaluate for the presence of:

   • Generalized vs. localized lymphadenopathy
   • Hepatosplenomegaly
   • Duration and progression of symptoms
   • Age of patient (glandular fever most common in adolescents and young adults)

2. Laboratory testing:

   • Complete blood count with differential
   • Throat culture and/or rapid strep test
   • If glandular fever suspected: heterophile antibody test (Monospot) and/or EBV-specific serology
   • Liver function tests if glandular fever suspected

3. Interpretation:

   • Positive throat culture/rapid test + absence of generalized symptoms = bacterial tonsillitis
   • Atypical lymphocytosis + generalized lymphadenopathy ± hepatosplenomegaly = glandular fever
   • Negative tests for both may indicate viral pharyngitis from other causes

By carefully assessing these distinctive clinical and laboratory features, clinicians can accurately differentiate between glandular fever and bacterial tonsillitis, leading to appropriate management and avoiding unnecessary antibiotic use.