Tuberculous lymphadenitis (or tuberculous adenitis) is the most common form of

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, ...

infections that appears outside the

lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of ...

s. Tuberculous lymphadenitis is a chronic, specific

granulomatous A granuloma is an aggregation of macrophages that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectiou ...

inflammation of the

lymph node A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that includ ...

with

caseation Caseous necrosis or caseous degeneration () is a unique form of cell death in which the tissue maintains a cheese-like appearance.Robbins and Cotran: Pathologic Basis of Disease, 8th Ed. 2010. Pg. 16 It is also a distinctive form of coagulative nec ...

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated diges ...

, caused by infection with ''

Mycobacterium tuberculosis ''Mycobacterium tuberculosis'' (M. tb) is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, ''M. tuberculosis'' has an unusual, waxy coating on it ...

'' or related bacteria. The characteristic morphological element is the tuberculous

granuloma A granuloma is an aggregation of macrophages that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectious o ...

(caseating tubercule). This consists of

giant multinucleated cell Tuberculosis (TB) is an infectious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, i ...

s and ( Langhans cells), surrounded by

epithelioid cell According to a common point of view epithelioid cells (also called epithelioid histiocytes) are derivatives of activated macrophages resembling epithelial cells. Structure and function Structurally, epithelioid cells (when examined by light m ...

s aggregates, T cell

lymphocytes A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic ada ...

and

fibroblasts A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework ( stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells ...

. Granulomatous tubercules eventually develop central caseous necrosis and tend to become confluent, replacing the lymphoid tissue.

Symptoms and signs

In addition to swollen lymph nodes, called

lymphadenitis Lymphadenopathy or adenopathy is a disease of the lymph nodes, in which they are abnormal in size or consistency. Lymphadenopathy of an inflammatory type (the most common type) is lymphadenitis, producing swollen or enlarged lymph nodes. In cl ...

, the person may experience mild fevers, not feel like eating, or lose weight.

Cause

It is usually caused by the most common cause of tuberculosis in the lungs, namely ''

''. It has sometimes also been caused by related bacteria, including '' M. bovis'', '' M. kansasii'', ''

M. fortuitum ''Mycobacterium fortuitum'' is a nontuberculous species of the phylum Actinomycetota (Gram-positive bacteria with high guanine and cytosine content, one of the dominant phyla of all bacteria), belonging to the genus ''Mycobacterium''. Backgrou ...

'', '' M. marinum'', and ''

Mycobacterium ulcerans ''Mycobacterium ulcerans'' is a species of bacteria found in various aquatic environments. The bacteria can infect humans and some other animals, causing persistent open wounds called Buruli ulcer. ''M. ulcerans'' is closely related to '' Mycob ...

''.

Stages

Stages of tubercular lymphadenitis: # Lymphadenitis # Periadenitis # Cold abscess # 'Collar stud' abscess # Sinus Tuberculous lymphadenitis is popularly known as collar stud abscess, due to its proximity to the

collar bone The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the righ ...

and its superficial resemblance to a

collar stud A detachable collar is a shirt collar separate from the shirt, fastened to it by studs. The collar is usually made of a different fabric from the shirt, in which case it is almost always white, and, being unattached to the shirt, can be starch ...

, 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 (caseating tubercule): giant multinucleated cells (Langhans 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 A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a dise ...

.subscription required Other possible diagnostic steps include: positive tuberculin test, chest radiograph, CT scan, cytology/biopsy (FNAC), 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.

References

External links

Anatomical pathology Tuberculosis {{infectious-disease-stub