Tuberculosis (TB) is a well-known infectious disease that can affect more than just the lungs. When Mycobacterium tuberculosis bacteria infect the lymph nodes, it results in tuberculosis lymph nodes, also known as tuberculous lymphadenitis. This is an extrapulmonary manifestation, meaning it occurs outside of the lungs.
What Are Tuberculosis Lymph Nodes?
Tuberculosis lymph nodes, also known as scrofula when affecting the neck, occur when Mycobacterium tuberculosis bacteria infect the lymphatic system. This infection leads to the enlargement of one or more lymph nodes, most frequently observed in the neck, though they can also appear in areas like the armpits or groin. The bacteria typically enter the body, often through the lungs, and then spread to the lymph nodes via the bloodstream or lymphatic system.
The infection’s progression can vary. Some individuals harbor the bacteria in a latent, inactive state without symptoms. In others, particularly those with weakened immune systems, the dormant bacteria can become active, leading to enlarged lymph nodes. Only active TB causes symptoms and is transmissible.
Recognizing the Signs
The most common sign of tuberculosis lymph nodes is a gradual, usually painless swelling of one or more lymph nodes. Initially, the skin over the swollen nodes may appear normal, but it can change over time.
As the condition progresses, the swollen nodes may become firmer or rubbery to the touch. Pus can form within the nodes, potentially leading to an abscess. If left untreated, these abscesses may rupture and drain through the skin, forming a sinus tract that can be difficult to heal. Beyond localized swelling, individuals may also experience general symptoms, including low-grade fever, night sweats, unexplained weight loss, and fatigue.
How It Is Diagnosed
Diagnosing tuberculosis lymph nodes involves clinical evaluation, imaging, and laboratory tests to confirm the presence of Mycobacterium tuberculosis. A healthcare professional typically begins with a physical examination, checking for enlarged lymph nodes and inquiring about symptoms. This initial assessment guides further diagnostic steps.
Imaging studies, such as ultrasound, CT scans, or MRI, are used to visualize the affected lymph nodes and identify characteristic features like matting, necrosis, or hypoechoic areas. While these imaging techniques can suggest TB, they are not definitive on their own. Blood tests, including interferon-gamma release assays (IGRAs) or tuberculin skin tests, can indicate exposure to TB bacteria but cannot differentiate between a latent infection and active disease.
A definitive diagnosis often requires obtaining a tissue sample from the affected lymph node for laboratory analysis. Fine-needle aspiration cytology (FNAC) involves extracting a small sample of lymph node tissue using a thin needle, which is then examined under a microscope for acid-fast bacilli (AFB) and cultured. If FNAC results are inconclusive, a more extensive excisional or incisional lymph node biopsy may be performed to obtain a larger tissue sample for histopathological examination, which typically reveals granulomatous inflammation with caseous necrosis. Microbiological culture of the tissue remains the gold standard for confirming the diagnosis, though results can take several weeks. Molecular tests, such as GeneXpert MTB/RIF, can provide rapid detection of Mycobacterium tuberculosis and assess rifampicin resistance within hours.
Treatment and Recovery
Treatment for tuberculosis lymph nodes involves a multi-drug regimen of anti-tuberculosis medications. The standard protocol includes a combination of drugs such as isoniazid, rifampicin, pyrazinamide, and ethambutol. Treatment usually spans 6 to 9 months, depending on the specific regimen and the patient’s response. Adherence to the full course of medication is important to ensure complete eradication of the bacteria, prevent recurrence, and minimize the risk of developing drug resistance.
Patients are monitored throughout the treatment period for potential side effects, which can vary depending on the specific medications used. For instance, some drugs may cause liver-related issues like nausea or jaundice, while others might lead to visual disturbances or joint pain. Regular follow-up appointments assess treatment effectiveness and manage any adverse reactions. After completing the full course of therapy, most patients experience a complete resolution of the swollen lymph nodes. Surgical removal of affected lymph nodes alongside antibiotic therapy is not typically recommended unless specific complications arise, such as very large nodes, abscesses, or fistulas.