Etiology and pathogenesis of the disease
The development of tuberculous lymphadenitis directly depends on social conditions and the overall epidemiological situation regarding tuberculosis. The disease does not occur in isolation, but is a consequence of the spread of infection throughout the body.
The pathogen enters primarily via the lymphohematogenous route. The source of infection is typically pre-existing tuberculous involvement of intrathoracic lymph nodes, lungs, or other organs. Frequently, the tonsils serve as the entry gate for mycobacteria. In such cases, the cervical and submandibular lymph node groups are primarily involved in the pathological process.
Age-specific clinical features
The clinical presentation and disease course vary significantly across different age groups.
In children, the disease presents as a manifestation of primary tuberculosis.
- The process is frequently accompanied by involvement of intrathoracic lymph nodes.
- Peripheral nodes are involved when active extrapulmonary forms are present.
- The onset of the disease is usually acute: body temperature rises sharply, and symptoms of tuberculous intoxication increase. The lymph nodes enlarge significantly, undergoing inflammatory and necrotic changes with pronounced perifocal infiltration.
In adults, lymphadenitis presents as a form of secondary tuberculosis.
- It develops against the background of old, inactive tuberculous changes in other organs.
- Relatively isolated involvement of certain node groups is possible.
- The disease has a gradual onset.
- Lymphadenopathy is less pronounced, with a predominance of productive inflammation, making fistula formation rare.
Clinical forms and localization
Specific inflammation is most commonly localized in the cervical, submandibular, and axillary regions. Involvement can be either unilateral or bilateral, affecting several lymph node groups simultaneously.
A hallmark of tuberculous etiology is the development of periadenitis. Lymph nodes of varying sizes fuse together to form a single, dense, lobulated conglomerate.
Depending on the nature of morphological changes, three main classification forms of tuberculous lymphadenitis are distinguished:
- Infiltrative.
- Caseous (may occur with or without fistula formation).
- Indurative.
Diagnostic methods
Diagnostic workup requires a comprehensive approach and differentiation from non-specific purulent lymphadenitis, lymphogranulomatosis (Hodgkin's lymphoma), and malignant metastases.
The main stages of examination include:
- Anamnesis: identification of contact with tuberculosis patients.
- Immunodiagnostics: the Mantoux test in such patients is strongly positive in the majority of cases.
- Systemic examination: active screening for tuberculosis foci in the lungs and other organs.
- Morphological examination: fine-needle aspiration biopsy of the affected lymph node plays a key role in confirming the diagnosis.
- X-ray imaging: allows the detection of dense shadows (calcifications) in the soft tissues of the neck, axillary, submandibular, and inguinal regions.
Principles of treatment
Treatment tactics depend on the form of lymph node involvement and the condition of the patient's other organs.
In active disease, the mainstay of treatment is conservative specific therapy. First-line antibacterial drugs are prescribed in combination with aminosalicylic acid (PAS) or other agents (ethionamide, prothionamide, pyrazinamide, ethambutol). The course of treatment is very long, lasting 8, 12, or 15 months. If a secondary purulent infection joins the specific process, the regimen is supplemented with broad-spectrum antibiotics.
Surgical treatment has strict indications. It is used for caseous lymph node involvement. Lymphadenectomy (removal of nodes) and excision of formed fistulas are performed. A mandatory condition for surgery is that it must be performed against the background of a continuous general course of antituberculosis therapy.
Briefly: answers to topical questions
What complications can develop in chronic tuberculous lymphadenitis?
With a prolonged course of tuberculous lymphadenitis, the following complications may develop:
- Fistulas — chronic cases may lead to the formation of cutaneous fistulas with persistent lymphorrhea.
- Secondary purulent infection — treated with broad-spectrum antibiotics.
- Involvement of new lymph node groups — resulting from lymphogenic dissemination of a chronic ongoing process.
What microscopic elements form the specific tuberculous granuloma in the affected lymph node?
The specific tuberculous granuloma is formed by the following microscopic elements arranged in layers:
- Caseous necrosis — the central zone of cheese-like tissue breakdown.
- Epithelioid cells — transformed macrophages forming an inner palisade-like cellular wall.
- Pirogov–Langhans cells — multinucleated giant cells formed by the fusion of epithelioid cells.
- T-lymphocytes — sensitized cells forming the outer cellular wall together with macrophages.
- Fibroblasts — elements forming the outer layer of the granuloma.
Pathogens — mycobacteria (M. tuberculosis) — may be detected inside macrophages and epithelioid cells.
Which specific drugs constitute the first-line specific antituberculosis therapy?
The first-line (primary) specific antituberculosis therapy consists of the following drugs:
- Isoniazid.
- Rifampicin.
- Pyrazinamide.
- Ethambutol.
- Streptomycin.
The intensive phase includes a combination of isoniazid, rifampicin, pyrazinamide, and ethambutol. In the continuation phase, isoniazid and rifampicin are prescribed in combination with pyrazinamide or ethambutol.
The forms of tuberculous lymphadenitis are easy to remember by the acronym ICI: Infiltrative, Caseous, Indurative.
Class and exam questions
What is the main clinical difference between tuberculous lymphadenitis and common pyogenic lymphadenitis?
The key distinction is the presence of periadenitis. In tuberculosis, lymph nodes of varying sizes fuse together to form a dense, bumpy conglomerate.
Is it possible to simply remove a lymph node affected by tuberculosis?
Surgical treatment (lymphadenectomy) is indicated only for the caseous form. Furthermore, any surgery must be performed strictly against the background of a general course of specific antituberculosis therapy.
Why are cervical lymph nodes frequently affected in tuberculous lymphadenitis?
Cervical and submandibular lymph nodes are frequently involved when the tonsils serve as the entry gate for mycobacteria.
What else to study on this topic
- Features of fine-needle aspiration biopsy and cytological picture in tuberculosis
- Mechanism of development of caseous necrosis in lymphoid tissue
- Differential diagnosis with lymphogranulomatosis
- Specific anti-tuberculosis drugs: mechanism of action and side effects
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