What are the common causes of cervical lymphadenitis in a 6-year-old?

Common Causes of Cervical Lymphadenitis in a 6-Year-Old Child

The most common causes of cervical lymphadenitis in a 6-year-old child are viral upper respiratory infections, followed by bacterial infections (primarily Staphylococcus aureus and Streptococcus species), and nontuberculous mycobacterial infections, particularly Mycobacterium avium complex (MAC). 1, 2

Infectious Causes

Viral Infections

• Most common overall cause of cervical lymphadenopathy in children 3
• Usually bilateral and associated with upper respiratory tract infections
• Common viral pathogens include:
  • Epstein-Barr virus
  • Adenovirus
  • Enterovirus
  • Measles virus

Bacterial Infections

• Acute unilateral cervical lymphadenitis is caused by bacterial infection in 40-80% of cases 3
• Key bacterial pathogens:
  • Staphylococcus aureus (predominant cause of suppurative lymphadenitis) 4
  • Group A beta-hemolytic streptococci
  • Group C and G streptococci (associated with pharyngitis) 1
• Often presents with warmth, erythema, tenderness, and systemic signs of infection 1
• May be associated with:
  • Pharyngitis
  • Dental infections
  • Skin infections

Mycobacterial Infections

• Nontuberculous mycobacterial (NTM) infections:

  • Approximately 80% of culture-proven NTM lymphadenitis cases are due to Mycobacterium avium complex (MAC) 2, 1
  • Most common in children between 1-5 years old 2
  • Typically presents as unilateral (95%), non-tender lymphadenopathy 2, 1
  • Nodes may enlarge rapidly and even rupture with sinus tract formation 2
  • Children likely acquire infection from environmental sources like soil and water 2
  • In the US and Australia, remaining NTM cases are caused by M. scrofulaceum 2

• Tuberculosis:

  • In the US, only about 10% of culture-proven mycobacterial cervical lymphadenitis in children is due to M. tuberculosis (compared to >90% in adults) 2
  • Critical to distinguish from NTM as treatment and public health implications differ 2

Non-Infectious Causes

Kawasaki Disease

• Can present with unilateral cervical lymphadenopathy (≥1.5 cm diameter) as one of its principal clinical features 2
• Typically accompanied by:
  • Fever persisting at least 5 days
  • Changes in extremities (erythema, edema, peeling)
  • Polymorphous exanthem
  • Bilateral bulbar conjunctival injection without exudate
  • Changes in lips and oral cavity 2

Malignancies

• Less common but important to consider, especially with:
  • Supraclavicular or posterior cervical lymphadenopathy 3
  • Persistent or progressive enlargement
  • Hard, fixed nodes
  • Associated constitutional symptoms (weight loss, night sweats)

Diagnostic Approach

The diagnostic approach should focus on distinguishing between these causes:

1. For suspected viral etiology:

   • Look for associated upper respiratory symptoms
   • Bilateral, mobile, non-tender nodes are typical
   • Usually self-limiting

2. For suspected bacterial infection:

   • Evaluate for warmth, erythema, tenderness, fluctuance
   • Check for source of infection (throat, teeth, skin)
   • Consider fine needle aspiration for culture in suppurative cases 5

3. For suspected NTM infection:

   • Typically unilateral, non-tender, gradually enlarging nodes
   • Tuberculin skin test (may show variable results in NTM) 2
   • Definitive diagnosis requires culture or PCR 5

4. For suspected Kawasaki disease:

   • Evaluate for other diagnostic criteria
   • Echocardiography if suspicion is high 2

Common Pitfalls in Diagnosis

• Mistaking mycobacterial cervical lymphadenitis for bacterial adenitis 2
• Overlooking Kawasaki disease when cervical lymphadenitis is the predominant feature 2
• Attributing fever and pyuria in a young child to urinary tract infection when it may be part of Kawasaki disease 2
• Failure to consider malignancy in cases with supraclavicular or posterior cervical involvement 3

By systematically evaluating the clinical presentation, location, and associated symptoms, the cause of cervical lymphadenitis in a 6-year-old can be accurately determined, leading to appropriate treatment and improved outcomes.