Tuberculous lymphadenitis


Tuberculous lymphadenitis is the most common form of tuberculosis infections that appears outside the lungs. Tuberculous lymphadenitis is a chronic, specific granulomatous inflammation of the lymph node with caseation necrosis, caused by infection with Mycobacterium tuberculosis or related bacteria.
The characteristic morphological element is the tuberculous granuloma. This consists of giant multinucleated cells and, surrounded by epithelioid cells aggregates, T cell lymphocytes and fibroblasts. Granulomatous tubercules eventually develop central caseous necrosis and tend to become confluent, replacing the lymphoid tissue.

Cause

It is usually caused by the most common cause of tuberculosis in the lungs, namely Mycobacterium tuberculosis. It has sometimes also been caused by related bacteria, including M. bovis, M. kansasii, M. fortuitum, M. marinum, and M. ulcerans.

Symptoms

In addition to swollen lymph nodes, called lymphadenitis, the person may experience mild fevers, not feel like eating, or lose weight.

Stages

Stages of tubercular lymphadenitis:
  1. Lymphadenitis
  2. Periadenitis
  3. Cold abscess
  4. 'Collar stud' abscess
  5. Sinus
Tuberculous lymphadenitis is popularly known as collar stud abscess, due to its proximity to the collar bone and its superficial resemblance to a collar stud, although this is just one of the five stages of the disease. One or more affected lymph nodes can also be in a different body part, although it is most typical to have at least one near the collar bone.
The characteristic morphological element is the tuberculous granuloma : giant multinucleated cells, surrounded by epithelioid cells aggregates, T cell lymphocytes and few fibroblasts. Granulomatous tubercules evolve to central caseous necrosis and tend to become confluent, replacing the lymphoid tissue.

Diagnosis

The diagnosis of tuberculous lymphadenitis may require a biopsy. Other possible diagnostic steps include: positive tuberculin test, chest radiograph, CT scan, cytology/biopsy, AFB staining, and mycobacterial culture.

Treatment

Drainage is not necessary if followed by anti-tubercular medication.
Treatment with anti-tubercular medications normally lasts up to one year. Symptoms may temporarily get worse during treatment.

Epidemiology

Tuberculous lymphadenitis is seen in most developing countries, especially in the context of HIV/AIDS.