Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis, primarily affecting the lungs but also capable of invading other organs. This disease is highly contagious and of significant public health concern worldwide, especially in resource-limited areas where the threat is greater. According to data from the World Health Organization, millions of people are affected annually, highlighting the urgent need for prevention and control efforts.
Tuberculosis can be classified into two forms: "latent infection" and "active infection." Latent infection individuals do not show symptoms and are not contagious, but they may develop into active cases when their immune system weakens. Active TB causes noticeable symptoms and spreads through respiratory droplets to others. Understanding its transmission, diagnostic methods, and treatment principles is crucial for controlling its spread.
Modern medicine has developed various diagnostic techniques and treatment options, but patient compliance and drug resistance remain challenges. Vaccination, public health surveillance, and early treatment are core strategies for TB control. This article will comprehensively analyze this globally concerning infectious disease from causes, symptoms, diagnosis, to treatment and prevention.
The pathogen of TB is Mycobacterium tuberculosis, mainly transmitted through airborne droplets. When patients cough, sneeze, or talk, bacteria-laden droplets can suspend in the air, and inhalation by others can lead to infection. Whether an infection develops into active TB depends on the strength of the individual's immune system.
Risk factors include:
It is noteworthy that although latent infections are not contagious, a sudden decline in immunity (such as during chemotherapy or HIV infection) may lead to progression to active disease within 10 years. Managing latent TB is a key aspect of preventing outbreaks.
Typical symptoms of active TB include a long-term cough lasting more than three weeks, hemoptysis or blood-stained sputum, unexplained weight loss, persistent fever, and night sweats. These symptoms can be mistaken for common respiratory infections, leading to delayed diagnosis. Some patients may also experience fatigue and loss of appetite, which are non-specific symptoms that can be overlooked.
When TB infects extrapulmonary organs, symptoms vary depending on the affected site:
Latent TB individuals usually have no symptoms but need to be identified through skin tests or blood tests. The severity of symptoms is closely related to immune status; children and immunocompromised patients may present atypical symptoms, requiring heightened vigilance.
Diagnosing TB involves a combination of clinical symptoms, imaging, and microbiological evidence. A chest X-ray is typically performed first; active pulmonary TB often shows characteristic lesions such as upper lobe infiltrates or cavities. Sputum culture is the gold standard but takes 2-6 weeks; modern molecular diagnostics like GeneXpert can provide results within hours.
Skin tests (Tuberculin Skin Test, TST) and interferon-gamma release assays (IGRAs) are used for screening latent TB. Suspected cases require detailed history-taking, including contact history, travel history, and immune status assessment. For suspected extrapulmonary TB, tissue biopsy, cerebrospinal fluid analysis, or CT scans may be necessary.
The diagnostic process must differentiate active TB from other respiratory diseases such as lung cancer or pneumonia. Confirming multidrug-resistant TB (MDR-TB) requires drug susceptibility testing, which influences treatment choices. The application of new molecular diagnostics has significantly improved the speed and accuracy of diagnosis.
TB treatment follows the principle of multi-drug therapy, typically requiring more than 6 months of medication. The standard regimen includes isoniazid, rifampicin, pyrazinamide, and ethambutol. The initial 2 months involve all four drugs, followed by 4 months of core drugs. This approach effectively prevents resistance development.
MDR-TB treatment is more complex, requiring second-line drugs such as kanamycin and moxifloxacin, with treatment durations extending to 18-24 months. Monitoring for adverse effects like hepatotoxicity, optic neuritis, or peripheral neuropathy is essential, and dose adjustments may be necessary.
Directly Observed Therapy (DOT) is a key strategy to ensure adherence, with healthcare workers witnessing each dose. Treatment success is highly dependent on patient compliance; interruption can lead to resistance. Recent advances in genetic testing have promoted personalized treatment plans.
The Bacillus Calmette-Guérin (BCG) vaccine is the primary preventive measure, routinely administered to infants in high TB prevalence countries. It reduces the risk of severe TB forms such as meningitis but offers limited protection against adult pulmonary TB.
Public health measures include:
Personal protective measures include:
Seek medical attention immediately if you experience:
Individuals with high-risk factors (such as HIV infection, contact with confirmed cases, or undergoing immunosuppressive therapy) should also seek early medical evaluation if mild respiratory symptoms occur. Early diagnosis reduces transmission risk and improves treatment outcomes. Many healthcare facilities offer free screening services, encouraging suspected cases to seek medical care proactively.
Healthcare workers and long-term care staff should undergo regular TB screening. Pregnant women, children, and the elderly with weakened immunity should be particularly vigilant when symptoms appear, as they may present atypical signs.
The standard treatment for pulmonary TB usually lasts 6 to 9 months, depending on the type of infection and patient condition. Failure to complete the full course may leave bacteria alive, leading to relapse or drug resistance, which complicates treatment. Patients must follow their doctor's instructions, attend regular follow-ups, and complete the entire regimen.
How can you distinguish TB symptoms from a common cold?Typical TB symptoms include a persistent dry cough lasting over 2 weeks, hemoptysis, unexplained weight loss, and night sweats. Cold symptoms usually resolve within 1-2 weeks and do not cause long-term weight changes. If symptoms persist or recur, seek medical evaluation promptly, including sputum tests or chest X-ray.
Does BCG vaccination completely prevent pulmonary TB?BCG vaccination reduces the risk of severe TB forms like meningitis but does not provide 100% protection against infection. Its efficacy varies among individuals, and vaccinated persons should still practice good hygiene, avoid contact with TB patients, and ensure proper ventilation. High-risk groups, such as healthcare workers or family members of TB patients, should undergo regular health checks.
What precautions should TB patients take in daily life?Patients should wear masks to prevent transmission, cover mouth and nose when coughing, and use separate utensils that are regularly disinfected. Maintaining good ventilation in living spaces, avoiding crowded enclosed areas, and adopting regular routines with a balanced diet can help recovery and reduce spread.
How does treatment differ for drug-resistant TB compared to regular TB?Drug-resistant TB requires second-line medications, with treatment extending beyond 18 months and involving more side effects such as liver damage and hearing loss. Strict monitoring and adjustments are necessary. Preventing resistance involves adherence to prescribed therapy without self-discontinuation or interruption.
%201.svg)
Copyright © 2025 MedFrontiers. All Rights Reserved.
