Clinical Features of Tuberculosis Lymphadenitis
Tuberculosis lymphadenitis presents primarily with painless, unilateral cervical lymphadenopathy that develops insidiously, often without systemic symptoms. 1, 2
Key Clinical Manifestations
- Lymph node involvement is predominantly unilateral (95% of cases) and typically affects the cervical region (57%) or supraclavicular area (26%) 1, 3
- Nodes are generally non-tender but may enlarge rapidly and even rupture, forming sinus tracts with prolonged local drainage 1
- The disease develops insidiously with minimal systemic symptoms in most cases 1
- When present, systemic symptoms may include fever, night sweats, weight loss, and decreased appetite 3, 4
- Mediastinal lymph nodes may occasionally be involved 1
Demographic and Risk Factors
- In adults, more than 90% of mycobacterial lymphadenitis is caused by Mycobacterium tuberculosis, while in children it's more commonly due to non-tuberculous mycobacteria 1, 5
- TB lymphadenitis occurs predominantly in young, foreign-born individuals, with a female-to-male ratio of 1.4:1 3, 6
- Peak age range is 30-40 years in adults 6
- Immunocompromised patients (HIV infection, those on immunosuppressive therapy) are at higher risk 4
- TB lymphadenitis typically occurs about 5 years after arrival in the United States for foreign-born individuals 3
Diagnostic Features
- Tuberculin skin tests are positive in approximately 94% of cases 3
- Chest radiographs may be abnormal in about 38% of patients, showing findings consistent with granulomatous infection 3
- Contrast-enhanced CT typically shows asymmetric adenopathy with ring-enhancing masses that may involve surrounding fat and skin, but with minimal inflammatory stranding of subcutaneous fat 1
- Fine needle aspiration (FNA) shows granulomas in 61% of cases, with positive cultures for M. tuberculosis in 62% of samples 3
- Excisional biopsy has higher sensitivity (80%) for diagnosis compared to FNA 6
- Histopathology typically shows caseating granulomas with or without acid-fast bacilli 1
Disease Course and Complications
- Response to treatment is slower than with pulmonary tuberculosis 6
- Paradoxical expansion of adenopathy (upgrading reaction) occurs in approximately 20% of patients during treatment, more commonly in HIV-positive individuals 3, 6
- Without proper treatment, nodes may suppurate and form draining sinuses 7
- In HIV-infected patients starting antiretroviral therapy, TB lymphadenitis may present as part of immune reconstitution inflammatory syndrome (IRIS) 2, 5
Differential Diagnosis
- The most important differential diagnosis is non-tuberculous mycobacterial lymphadenitis, especially in children 1
- In adults over 40 years, malignancy should be seriously considered 2
- Other conditions to consider include bacterial lymphadenitis, sarcoidosis, lymphoma, and metastatic carcinoma 7, 8
- In patients with systemic symptoms, autoimmune conditions like systemic lupus erythematosus should be considered 4