Painful Swollen Neck Mass with Necrotic Lymph Nodes in a Child

1. Diagnoses to Consider

Primary Diagnosis: Tuberculous Lymphadenitis (Scrofula)

• Most commonly involves the posterior cervical and supraclavicular nodes
• Early nodes are discrete, rubbery, and freely mobile with normal overlying skin
• Over time, nodes become matted and harder; the overlying skin becomes inflamed
• Fluctuance, abscess, or a sinus tract draining caseous material may develop if the node erodes through the skin
• Systemic symptoms (fever, night sweats, weight loss) are uncommon except in HIV-positive patients
• Associated pulmonary disease is present in fewer than 50% of cases

Other Important Differential Diagnoses

2. Investigations

Imaging

• Ultrasound (already done): Necrotic/caseating nodes have a characteristic appearance with central liquefaction and absent hilum. Doppler may show peripheral vascularity. Can also guide FNA.
• Chest X-ray: Look for pulmonary TB (hilar adenopathy, consolidation, cavitation) - though pulmonary disease is present in <50% of TB lymphadenitis cases.
• CT neck/chest: Better delineates extent, identifies matted nodes, abscess formation, and mediastinal involvement.

Microbiological / Immunological

• Fine-Needle Aspiration (FNA) - the cornerstone diagnostic procedure:
  • Send for: AFB smear (positive in ~20% only), mycobacterial culture (positive in 70-80%), cytology/histology
  • Overall sensitivity 77%, specificity 93% for TB
  • Yield up to 80% in Harrison's series
• Tuberculin Skin Test (TST/Mantoux) or IGRA (Interferon-Gamma Release Assay): Supports TB diagnosis; IGRA preferred in BCG-vaccinated children
• AFB smear and culture on aspirated material
• Nucleic Acid Amplification Test (NAAT/PCR for MTB): Rapid, useful when AFB smear is negative
• GeneXpert MTB/RIF: Rapid TB detection plus rifampicin resistance in <2 hours

Haematological / Biochemical

• CBC with differential: Leukocytosis suggests acute bacterial infection; lymphocytosis/atypical lymphocytes in EBV
• ESR, CRP: Elevated in most infectious causes; markedly elevated in lymphoma
• Monospot / EBV serology: If infectious mononucleosis is suspected
• Bartonella henselae serology: If cat-scratch disease suspected
• LDH, uric acid: If lymphoma is in the differential

Histopathology

• Excisional biopsy (when FNA is non-diagnostic or lymphoma is suspected): Caseating granulomas with Langhans giant cells are characteristic of TB. Kikuchi disease shows necrotizing histiocytic lymphadenitis without granulomas.

3. Treatment

Tuberculous Lymphadenitis

• Standard anti-TB regimen (same as pulmonary TB):
  • Intensive phase (2 months): Isoniazid (H) + Rifampicin (R) + Pyrazinamide (Z) + Ethambutol (E) - 2HRZE
  • Continuation phase (4 months): Isoniazid + Rifampicin - 4HR
  • Total 6-month regimen (9 months if meningeal or bone TB)
• Nodes not responding to medical treatment should be excised
• Incision and drainage (I&D) is contraindicated - causes permanent sinus formation and prolonged drainage

Atypical Mycobacteria (NTM)

• Excisional biopsy is both diagnostic and curative - the treatment of choice
• Appropriate antibiotics based on culture sensitivities (e.g., macrolides, rifabutin)
• Incisional drainage is contraindicated - leads to chronic fistulization

Acute Bacterial Lymphadenitis

• Antibiotics targeting Staph. aureus and Streptococcus (e.g., amoxicillin-clavulanate, flucloxacillin)
• Treat the primary focus (tonsillitis, dental abscess)
• If fluctuant abscess: incision and drainage is appropriate
• Nodes not responding after 4-6 weeks should be referred for further evaluation

Cat-Scratch Disease

• Self-limited; conservative management
• Azithromycin may shorten the course in moderate-severe cases

Key Practical Points

1. Do not incise and drain a suspected TB or NTM node - this invariably causes a chronic discharging sinus.
2. Necrotic nodes on ultrasound in a child = TB until proven otherwise in high-prevalence settings.
3. FNA is the first-line diagnostic step for suspected scrofula - it avoids the need for open surgery in most cases.
4. Always rule out lymphoma before attributing chronically enlarged nodes to infection.
5. In immunocompromised children (HIV), TB lymphadenitis tends to be generalized with heavier bacterial loads and atypical granulomas.

• Harrison's Principles of Internal Medicine 22E, Ch. 183
• Bailey and Love's Short Practice of Surgery 28th Ed., Ch. 52
• Rosen's Emergency Medicine, Ch. 24
• Textbook of Family Medicine 9e, Ch. 18
• Robbins & Kumar Basic Pathology, Ch. 11