What Is Tuberculosis?
Tuberculosis (TB) is a bacterial infection caused by Mycobacterium tuberculosis. It is a serious infection that frequently affects the lungs. Tuberculosis is a contagious infection that spreads from one person to another through germs in the air, the infected person’s cough, spit, or sneeze. About 25 percent of the world's population is infected with tuberculosis, meaning they have contracted the TB bacteria. People exposed to the TB bacteria have about a 5 to 10 percent chance of getting sick with the infection. A person's chance of getting sick increases if they have a weakened immune system, including those who consume tobacco, are malnourished, have diabetes or HIV (human immunodeficiency virus), or are obese.
What Is Peripheral Tubercular Lymphadenitis?
Peripheral tubercular lymphadenitis is one of the most common extrapulmonary (occurring outside the lungs) manifestations of tuberculosis infection. Clinical signs are diverse, the epidemiology is distinct from pulmonary tuberculosis, and diagnosis can be difficult. Up to 43 percent of peripheral lymphadenopathy cases in areas with poor resources can be attributed to TB.
What Causes Tubercular Lymphadenitis?
-
The most common cause of tuberculous lymphadenitis is Mycobacterium tuberculosis.
-
Other causes of peripheral tubercular lymphadenitis include nontuberculous mycobacteria- M. scrofulaceum, M. avium, M. haemophilum, etc.
-
Other causative organisms include Toxoplasma and Bartonella species and fungi.
-
M. bovis was once a common cause of tuberculous lymphadenitis, but pasteurization has eliminated this source of human infection in developed nations. Risk still exists from consuming raw and unpasteurized milk.
-
Neoplasms, sarcoidosis, Castleman disease, medication responses, and nonspecific reactive hyperplasia are some of the noninfectious causes of peripheral tubercular lymphadenitis.
-
Most of the time, reactivation of the illness at a site seeded during primary tuberculosis infection causes isolated peripheral tuberculous lymphadenopathy. This can occur years after the primary infection.
How Common Is Peripheral Tubercular Lymphadenitis?
-
In the United States, pulmonary tuberculosis rates have been declining overall, but the proportion of extrapulmonary cases—and their main subcategory, lymphadenitis—has increased.
-
About 8.5 percent of the 12904 tuberculosis cases in the United States reported lymphadenitis.
-
Contrary to the pattern for pulmonary tuberculosis, which affects more men than women, tuberculous lymphadenitis typically affects more women.
-
Recent surveys have found that the peak range of age is between 30 and 40.
What Are the Clinical Features of Peripheral Tubercular Lymphadenitis?
The clinical features of peripheral tubercular lymphadenitis include:
-
A single group of lymph nodes typically enlarge slowly and painlessly during tuberculous lymphadenitis.
-
Symptoms normally last between one and two months at the time of manifestation; however, they can last anywhere between three weeks and eight months.
-
Men have symptoms on average for a lot longer than women do.
-
Although nodes can be up to 8 to 10 centimeters in diameter, the average lymph node size is 3 centimeters.
-
Patients typically do not report substantial pain.
-
About 10 to 35 percent of instances during inspection show node tenderness.
-
A draining sinus might be present in 4 to 11 percent of cases.
-
In 85 percent of cases, unilateral involvement of about 1 to 3 nodes has been reported.
-
Most instances involve the cervical region, which is noted in approximately 45 to 70 percent of the cases.
-
The prevalence of systemic symptoms reported in various research varies, partially dependent on the location and case selection.
-
Fever and weight loss were recorded in a survey in 19 percent and 16 percent of 104 HIV-negative (human immunodeficiency virus-negative) patients from California, respectively.
-
In studies from Qatar and India, 40 to 60 percent of HIV-negative patients reported fever and weight loss.
-
HIV-positive patients report systemic symptoms more frequently than HIV-negative patients do.
How Is Peripheral Tubercular Lymphadenitis Diagnosed?
Peripheral tubercular lymphadenitis can be diagnosed in the following ways:
-
Culture or Polymerase Chain Reaction: By demonstrating M. tuberculosis in an afflicted lymph node via culture or polymerase chain reaction, a conclusive diagnosis of peripheral tuberculous lymphadenitis can be obtained. This allows for differentiation from other mycobacteria that might result in lymphadenitis. Although it can take 2 to 4 weeks to get findings, culture is still the gold standard for diagnosis.
-
Excisional Biopsy: Excisional biopsy is the most invasive method of diagnosis, but it has the best sensitivity and has been suggested in cases involving several nodes. It may also result in a more quick and more favorable clinical response.
-
Fine Needle Aspiration Cytology (FNAC): FNAC has become a first-line diagnostic method, particularly in areas where tuberculosis is endemic, because the test is both sensitive and specific. FNAC is more practical, less intrusive, and safer than biopsy when resources are scarce.
-
Nucleic Acid Amplification Tests (NAATs): This evaluation offers a quick, accurate, and sensitive method of diagnosis.
How Is Peripheral Tubercular Lymphadenitis Treated?
Peripheral tubercular lymphadenitis can be treated in the following ways:
Antibiotic Therapy: The following course of treatment is advised by the Infectious Disease Society of America (IDSA) for lymphadenitis caused by organisms that are drug-sensitive for six months:
-
Two months of therapy with Isoniazid, Rifampin, Pyrazinamide, and Ethambutol.
-
Followed by four more months of Isoniazid and Rifampin.
Steroid Therapy: It is unclear if routine corticosteroid therapy for peripheral tuberculous lymphadenitis is beneficial. In 117 kids with lymph node endobronchial tuberculosis, a double-blind, placebo-controlled trial showed a substantial improvement in those with a 37-day tapering course of steroids. However, the Infectious Diseases Society of America (IDSA) recommends against using steroids to treat tuberculous lymphadenitis.
Paradoxical Upgrading Reactions: The frequency with which patients experience worsening symptoms while undergoing treatment is a distinctive characteristic of successful treatment of drug-susceptible tuberculous lymphadenitis. This is known as a paradoxical upgrading reaction (PUR). Although their use is debatable, steroids have been proposed to weaken PUR's strong immunological response.
Surgical Therapy: Only very seldom do IDSA guidelines recommend surgical excision to treat peripheral tubercular lymphadenitis. No known controlled studies have compared surgical excision with antibiotic therapy alone, even though surgical treatment combined with antibiotic therapy has shown good outcomes. Two factors indicate that early excisional biopsy should be considered more often as a supplement to antibiotic treatment; for patients at risk of PUR and cases without esthetic considerations. Surgical excision should be taken into consideration for infection caused by drug-resistant organisms.
Conclusion:
About 10 percent of tuberculosis cases in the United States are tuberculous lymphadenitis, which frequently represents the only symptom of extrapulmonary tuberculosis. The condition can exhibit variable signs and symptoms. The diagnosis is generally made based on culture tests, polymerase chain reactions, FNAC, and biopsy. The treatment modalities include antibiotic therapy, steroid therapy, and surgical therapy. The condition can be easily cured with proper and timely treatment. The prognosis of peripheral tubercular lymphadenitis is generally good.
