🫁 TOACS FCPS Station · BCG Adenitis (Regional Lymphadenitis)
📷 Clinical Photograph – BCG Adenitis
🔍 Key clinical features:
- ✓ Enlarged, matted lymph nodes – ipsilateral to BCG vaccination site
- ✓ Commonly axillary – sometimes supraclavicular or cervical
- ✓ Onset – 1–6 months after BCG vaccination
- ✓ May be suppurative – fluctuant, draining sinus tract
- ✓ Self-limited – usually resolves spontaneously or with isoniazid
📋 Clinical scenario (examiner prompt)
A 3‑month‑old infant is brought to the clinic with a painless, enlarged lump in the left axilla that has been slowly increasing in size over the past 3 weeks. The mother reports that the child received the BCG vaccine in the left arm 2 months ago. On examination, there is a firm, matted lymph node measuring 3 cm in diameter. The overlying skin is not erythematous or warm, and the infant is afebrile and feeding well. The BCG vaccination site shows a small scar.
🧑⚕️ Examiner tasks · TOACS
1. Identify the diagnosis from the clinical image and context.
2. Describe the clinical features (regional lymphadenitis following BCG, ipsilateral, non-tender, often axillary).
3. Explain the pathogenesis (reaction to live-attenuated BCG bacilli in regional lymph nodes).
4. Discuss management (observation, isoniazid, aspiration, and surgical excision for suppuration).
🎯 Expected answers (for examiners)
- • Diagnosis: BCG adenitis (regional lymphadenitis following BCG vaccination)
- • Clinical features: Unilateral, painless, enlarged lymph nodes (usually axillary) in the 1–6 months after BCG vaccination; infant is afebrile and well; skin over node may be non-erythematous initially
- • Pathogenesis: Reaction to live-attenuated Mycobacterium bovis BCG in the regional lymph nodes; represents a local immune response, not a complication of immunodeficiency
- • Management: Most resolve spontaneously; observe. If large (>3 cm) or persistent, consider isoniazid (10 mg/kg/day) for 3–6 months. If suppurative (fluctuant), aspirate with a wide-bore needle to prevent sinus formation. Avoid surgical excision.
- • Differential: Tuberculous lymphadenitis (scrofula), nontuberculous mycobacterial (NTM) adenitis, pyogenic adenitis, lymphoma, malignancy
• Incidence: 1–10% of BCG-vaccinated infants
• Onset: 1–6 months after vaccination
• Location: Ipsilateral axillary (most common), supraclavicular, cervical
• Clinical: Painless, firm, matted nodes; afebrile child
• Suppuration: May occur (fluctuant, draining sinus)
• Treatment: Observation → isoniazid → aspiration (if suppurative) → avoid excision
• Prognosis: Excellent; usually self-limiting
⚡ Quick FCPS‑style MCQ
A 4-month-old infant presents with a painless, enlarged axillary lymph node (3 cm) that appeared 2 months after BCG vaccination. The infant is afebrile and well. The most appropriate management is:
A. Observation with reassurance B. Excisional biopsy C. Start empirical antibiotics for bacterial adenitis D. Urgent surgical excision📌 Topic summary · BCG Adenitis
Regional lymphadenitis post-BCG
1–6 months after vaccination
Axillary (ipsilateral)
Painless, matted nodes; afebrile infant
Observation → isoniazid → aspiration
Excellent, self-limiting
| Feature | BCG Adenitis |
|---|---|
| Etiology | Reaction to live-attenuated Mycobacterium bovis (BCG) |
| Incidence | 1–10% of vaccinated infants |
| Onset | 1–6 months after vaccination |
| Lymph node characteristics | Painless, firm, matted, unilateral, ipsilateral to vaccination site |
| Suppuration | May occur (fluctuant, draining sinus) |
| Management | Observation (most resolve); isoniazid for large/persistent nodes; aspiration for suppurative nodes; avoid surgical excision |
| Differential diagnosis | Scrofula (TB), NTM adenitis, pyogenic adenitis, lymphoma |
| Prognosis | Excellent; self-limiting |