What Is Tuberculosis Lymphadenitis?
Tuberculous lymphadenitis (or tuberculous adenitis) is the most common form of tuberculosis infection that appears outside the lungs. Only 5 percent of people with tuberculosis will develop tuberculous lymphadenitis. It is a chronic, granulomatous lymph node inflammation that has disseminated to local lymph nodes. It is caused by Mycobacterium tuberculosis or related bacterial infection.
This occurs when the tuberculous infection spreads to different body parts through blood or lymph, leading to infection of the lymph nodes, called lymphadenitis. Infection of the lymph node may increase the size of the lymph nodes causing erosion of the overlying skin and drainage of purulent material. It mostly affects people with compromised immune systems, such as HIV (Human immunodeficiency virus) patients or people taking immunosuppressant medications. Children and young adults between 11 to 30 are most frequently affected, and a slight female predilection is noted.
What Are the Causes of Tuberculous Lymphadenitis?
Tuberculous lymphadenitis is mainly caused by rod-shaped bacteria such as Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium scrofulaceum.
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Mycobacterium Tuberculosis - Mycobacterium tuberculosis bacteria are the predominant cause of tuberculous lymphadenitis. Mycobacterium tuberculosis is thought to cause respiratory infection in one-fourth of the world’s population. Breathing in contaminated air is mainly the cause.
It has caused more mortality throughout human history than any other bacteria.
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Mycobacterium Avium - Mycobacterium avium intracellulare is a collection of mycobacteria, including Mycobacterium avium and Mycobacterium intracellulare. It is frequently classed together because of its ability to infect humans, mostly children. It also belongs to the nontuberculous mycobacteria type. In some groups, Mycobacterium avium intracellulare can also lead to tuberculosis lymphadenitis.
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Non-Tuberculosis Bacteria - Non-tuberculous mycobacteria (NTM) are generally present in soil and water in different parts of the world. Anyone who comes into contact with non-tuberculosis bacteria will likely become infected, especially immunosuppressed individuals; however, in people with underlying lung conditions like bronchiectasis or COPD (Chronic obstructive pulmonary disease) or who are elderly. Mostly, children are affected with non-tuberculosis bacteria as they put contaminated objects in their mouths.
What Are the Symptoms of Tuberculosis Lymphadenitis?
The signs and symptoms of tuberculosis lymphadenitis depend upon microorganisms such as Mycobacterium tuberculosis or a non-Mycobacterium tuberculosis bacterium causing it. Breathing in mycobacterium-contaminated air generally causes tuberculosis lymphadenitis. The lymph nodes in the neck are then infected by the mycobacterium after leaving the lungs leading to swelling in certain parts of the neck due to the lymph node infection. Usually, only one side of the neck will be affected by the infection.
The symptoms of tuberculosis lymphadenitis include:
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Slowly progressive, painless swelling of a group of lymph nodes in the neck.
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The swelling may be firm and rubbery, and neck swelling is in the front of the neck.
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Multiple neck swellings that are stuck together may also occur.
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Swellings are usually painless but may cause pain during the examination.
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In 94 percent of infected people, the lymph nodes are less than three centimeters in size.
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In some cases, a draining sinus may be present.
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Generally, the swelling will be unilateral, involving 1 to 3 nodes.
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Fever and chills.
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Malaise, fatigue, or a general feeling of unwellness.
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Night sweat signifies the presence of potentially high infection levels in the body.
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Weight loss.
How Is Tuberculosis Lymphadenitis Diagnosed?
1) Biopsy- Fine needle aspiration and excisional biopsy is stated as the gold standard methods for the diagnosis of tuberculosis lymphadenitis.
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Fine Needle Aspiration - It is a safe, simple, rapid, and inexpensive method. In this method, the material inside the lymph node is aspirated using a needle and sent to the laboratory for polymerase chain reaction testing by the pathologist. Microscopy shows Mycobacteria or epithelioid granuloma with the presence or absence of giant cells. Cell death (necrosis) can also be noted.
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Excisional Biopsy - It is the traditional method with higher morbidity than FNA (Fine needle aspiration). It is a more invasive technique, so it is generally performed if less invasive techniques, such as FNAC (Fine needle aspiration cytology)
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For Ultrasound-Guided FNAC - It cannot be performed. It is preferred over FNAC because there is a higher chance of iatrogenic fistula formation in FNAC.
2) Tuberculin Purified Protein Derivative (PPD) Test - The tuberculin skin test help identify the presence of Mycobacterium tuberculosis; it also includes observing the immunological response to an injection of Purified Protein Derivative (PPD), which has been the most popular method for determining Mycobacterium tuberculosis infection.
Tuberculin fluid is injected into the lower part of the arm to conduct the tuberculin skin test. A healthcare professional will check for a reaction on the arm of a person who has undergone a tuberculin skin test within 48 to 72 hours after injecting tuberculin fluid. The presence of Mycobacterium tuberculosis will be confirmed if the test result is positive.
3) Imaging Tests - Imaging tests such as ultrasound, magnetic resonance imaging (MRI), and computed tomography (CT) scans will help detect tracheal deviation, a cold abscess occurring due to multiple necrotic lymph nodes, and calcifications of lymph nodes.
What Is the Treatment for Tuberculosis Lymphadenitis?
A. Antibiotics - It is the treatment of choice against mycobacterium tuberculosis. A doctor may suggest a combination of medications that will stop the infection. The treatment will usually be longer, for six to nine months. A lengthier course of antibiotics may be necessary for people with HIV or another immune system problem. Isoniazid, Rifampin, Pyrazinamide, and Ethambutol, are commonly used drugs. Oral steroids may also be used to reduce inflammation in afflicted lymph nodes.
B. Surgery - Surgery is an option if the antibiotic therapy does not provide any significant effect and for patients with draining fistula. If there is no concurrent pulmonary tuberculosis and other associated extrapulmonary tuberculosis, excision and removal of the lymph nodes may help treat tuberculosis lymphadenitis in immunocompetent patients. Surgery is also an ideal option for immunocompetent children infected with other mycobacteria. However, surgery may not always be effective as there is a high probability of recurrence, and the chance of fistula development may worsen. So, surgery is recommended to treat patients with discomfort brought on by lymph nodes or failure cases. Children with neck lymphadenitis due to nontuberculous mycobacteria are also recommended to have surgical treatment as surgery produces better outcomes.
Conclusion
Tuberculosis lymphadenitis is a tuberculosis infection that occurs outside the lungs due to inflammation of the lymph nodes of the neck. It is mainly caused by bacteria such as Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium scrofulaceum. The diagnosis based on just clinical evidence is challenging as the majority of the symptoms are nonspecific and mimic other infectious diseases, making diagnosis difficult. Usually, a biopsy and imaging tests are recommended to confirm the condition, and then antibiotic therapy or surgical treatment is carried out.
