Describe tuberculous cervical lymphadenitis.

Tuberculous Cervical Lymphadenitis

• Tuberculous cervical lymphadenitis (scrofula) is the commonest form of extrapulmonary tuberculosis and the commonest cause of chronic cervical lymphadenopathy in INDIA.
• It must be considered in any persistent neck node here.
• Route — lymphatic spread from a primary focus in the tonsil, adenoid, teeth or pharynx, or haematogenous from a pulmonary focus; the upper deep cervical (jugulodigastric) nodes are most often affected
• Mycobacterium tuberculosis in the great majority; atypical (non-tuberculous) mycobacteria in young children.
• The natural history passes through five stages, and describing them is the clearest way to answer:
• 1. Lymphadenitis — firm, discrete, mobile, painless enlarged nodes
• 2. Periadenitis and matting — the capsule is breached and adjacent nodes become matted together into a fixed mass.
• 3. Cold abscess — caseation and liquefaction produce a fluctuant swelling without the redness, heat or tenderness of an acute abscess, hence "cold"
• 4. Collar-stud abscess — pus tracks through the deep fascia to form a superficial collection connected to the deep one by a narrow track, giving the characteristic dumb-bell shape
• 5. Sinus formation — the skin breaks down giving a chronic discharging sinus with undermined, bluish edges and thin watery pus, healing eventually with a puckered scar
• Systemic features — evening rise of temperature, night sweats, weight loss, anorexia and malaise; though many patients are systemically well.
• Investigation — FNAC is the first-line test and is highly informative, showing epithelioid cell granulomas, langhans giant cells and caseation
• Send the aspirate for ZIEHL-neelsen staining, mycobacterial culture and GeneXpert (Xpert MTB/RIF).
• Note that acid-fast bacilli are seen in only a minority of specimens, so a negative smear does not exclude the diagnosis
• Also — ESR; mantoux or an interferon-gamma release assay, remembering that these indicate exposure, not active disease, and are of limited value where BCG is universal; chest radiograph, which may show active or healed pulmonary disease; HIV testing, which should be offered to all; and ultrasound
• Excision biopsy is reserved for cases where FNAC is non-diagnostic
• Treatment is medical — standard antitubercular chemotherapy, under the national programme, 2 months of intensive four-drug therapy followed by 4 months of continuation, though lymph node disease is frequently treated for longer
• The great majority resolve on drugs alone, and surgery is not the primary treatment