What is the appropriate workup for a unilateral non-tender cervical lymph node in a thriving child?

Workup for Unilateral Non-Tender Cervical Lymph Node in a Thriving Child

Excisional biopsy without chemotherapy is the recommended diagnostic and therapeutic approach for a unilateral non-tender cervical lymph node in a thriving child, as this presentation is highly suspicious for nontuberculous mycobacterial (NTM) lymphadenitis, with a surgical success rate of approximately 95%. 1, 2

Initial Evaluation

• Age consideration: Most cases of NTM cervical lymphadenitis occur in children under 3 years of age 1

• Physical examination findings:

  • Node size: Nodes ≥1.5 cm warrant further evaluation 2
  • Location: Unilateral involvement is seen in 95% of NTM lymphadenitis cases 2
  • Characteristics: Non-tender, firm nodes that may enlarge rapidly and potentially rupture with sinus tract formation 2
  • Skin changes: Look for violaceous discoloration over the node 3

• Key historical elements:

  • Duration of lymphadenopathy (persistent >4 weeks raises concern) 4
  • Constitutional symptoms (fever, weight loss, night sweats)
  • Recent infections or exposures
  • Previous antibiotic treatment and response

Diagnostic Testing

First-line investigations:

1. Ultrasonography: Initial imaging modality of choice 5

   • Look for: Round shape, irregular margins, heterogeneous echogenicity, absence of hilum, and increased vascularity
   • Regular margins and ovoid shape suggest benign reactive lymphadenopathy 4

2. Laboratory studies:

   • Complete blood count with differential
   • C-reactive protein and erythrocyte sedimentation rate
   • Tuberculin skin test to rule out tuberculosis

When to proceed directly to excisional biopsy:

• Node size >2 cm 5
• Supraclavicular location 5
• Multiple levels of adenopathy 5
• Persistent or progressive enlargement despite appropriate antibiotic therapy
• Suspicious ultrasound features (round shape, irregular margins) 4
• Symptoms persisting >10 weeks 4

Management Algorithm

1. For classic presentation of NTM lymphadenitis (unilateral, non-tender, cervical node in a thriving child):

   • Proceed with complete excisional biopsy - this serves as both diagnostic and therapeutic intervention 1, 2
   • Avoid incisional biopsy alone due to risk of chronic drainage and sinus tract formation 1

2. For recurrent disease after excision:

   • Consider a second surgical procedure 1
   • For high surgical risk cases (e.g., risk of facial nerve involvement with preauricular nodes), consider a clarithromycin-based multidrug regimen 1

3. For cases with positive tuberculin skin test:

   • If granulomatous disease is found with or without AFB on examination of excised lymph nodes and PPD is strongly positive (e.g., 15 mm), consider anti-TB therapy while awaiting culture results 1
   • Discontinue anti-TB therapy if cultures fail to yield mycobacteria, unless significant TB risk factors exist 1

Important Considerations

• Differential diagnosis:

  • Viral infections (most common cause of cervical lymphadenopathy in children) 2
  • Bacterial infections (Streptococcal, Staphylococcal)
  • Tuberculosis (accounts for approximately 10% of culture-proven mycobacterial cervical lymphadenitis) 2
  • Kawasaki disease (may present with unilateral cervical lymphadenopathy ≥1.5 cm) 1, 2
  • Malignancy (lymphoma, leukemia) - consider if multiple suspicious features present 4, 5

• Common pitfalls:

  • Misdiagnosing as bacterial lymphadenitis and treating with antibiotics
  • Performing incisional biopsy rather than complete excision, which may lead to chronic drainage and sinus tract formation 1
  • Delaying diagnosis in children with persistent lymphadenopathy >10 weeks 4
  • Failing to consider Kawasaki disease in a child with fever and unilateral enlarged cervical lymph node 1

• Alternative approach:

  • Some studies suggest observation alone may be effective for managing NTM lymphadenitis in immunocompetent children, with total resolution within 6-12 months, though this is not the current guideline recommendation 3

By following this structured approach to the workup of unilateral non-tender cervical lymphadenopathy in a thriving child, clinicians can efficiently diagnose and treat NTM lymphadenitis, which represents the most likely diagnosis in this clinical scenario.