What is tuberculosis?
Tuberculosis is an infection caused by the bacterium Mycobacterium tuberculosis. It most commonly affects the lungs, where it is called pulmonary tuberculosis, but it can involve almost any organ, including the pleura, lymph nodes, spine and other bones, abdomen, brain and its coverings, kidneys and pericardium. India carries the largest share of the global tuberculosis burden, and the disease remains common in Hyderabad across all social and economic groups.
Most people who inhale the bacterium do not fall ill. Their immune system contains the infection, which then persists in a dormant state called latent tuberculosis infection. Such people have no symptoms and cannot transmit the disease, but a proportion will develop active tuberculosis later, particularly if immunity falls because of diabetes, HIV, malnutrition, steroid or biologic therapy, cancer treatment, chronic kidney or liver disease, or smoking.
Tuberculosis is curable in the great majority of patients when it is diagnosed accurately and treated to completion. Failures are usually the result of delayed diagnosis, treatment started without confirmation, incorrect drug combinations, or treatment stopped early once the patient feels better.
Symptoms of tuberculosis
Pulmonary tuberculosis typically develops over weeks to months rather than days. Classic features include:
- Cough lasting two weeks or longer, at first dry and later productive.
- Fever, characteristically low grade and worse in the evening, often with drenching night sweats.
- Unexplained weight loss and loss of appetite.
- Fatigue and general weakness.
- Coughing up blood, which may be streaks in the sputum or, less often, larger volumes.
- Chest pain, typically sharp and worse on deep breathing when the pleura is involved.
- Breathlessness in extensive disease or when fluid collects around the lung.
Extrapulmonary tuberculosis produces symptoms specific to the organ involved: painless neck swelling in lymph node disease, persistent back pain with or without neurological symptoms in spinal disease, abdominal pain and ascites in abdominal disease, headache with fever and vomiting in meningitis, and joint pain and swelling in bone and joint disease. Fever with weight loss and no obvious source should always prompt consideration of tuberculosis in this region.
How tuberculosis spreads and who is at risk
Tuberculosis spreads through the air when a person with untreated infectious pulmonary or laryngeal disease coughs, sneezes, sings or speaks, releasing tiny droplet nuclei that remain suspended for hours in poorly ventilated rooms. It does not spread through shaking hands, sharing food or utensils, toilet seats or mosquito bites. Prolonged close contact in a crowded indoor space carries the greatest risk, which is why household members and workplace contacts are screened.
Risk of progression from infection to disease is higher in people with diabetes, which is very common in Telangana, in those with HIV, in smokers and heavy alcohol users, in people who are undernourished, and in patients on corticosteroids, anti-TNF biologics, chemotherapy, or dialysis. Silica exposure in stone cutting and construction also markedly increases risk.
How tuberculosis is diagnosed
Wherever possible, treatment should begin only after microbiological confirmation, because empirical anti-tuberculosis therapy given for an unconfirmed shadow on a chest X-ray delays the diagnosis of lung cancer, interstitial lung disease, fungal infection and other conditions that mimic tuberculosis.
| Test | Role |
|---|---|
| Chest X-ray | Initial screening. Shows infiltrates, cavities, effusion or miliary shadowing but cannot confirm the diagnosis |
| Sputum smear microscopy | Rapid and inexpensive, but misses many cases with low bacterial load |
| Nucleic acid amplification test (CBNAAT / Xpert MTB/RIF) | Confirms the organism within hours and simultaneously detects rifampicin resistance. The recommended first test |
| Mycobacterial culture and drug susceptibility testing | The reference standard. Defines the full resistance pattern and guides regimen choice |
| Line probe assay | Rapid detection of resistance to first- and second-line drugs |
| Bronchoscopy with lavage or biopsy | Used when the patient cannot produce sputum or when smear and NAAT are negative despite strong suspicion |
| EBUS-TBNA or lymph node aspiration | Samples enlarged mediastinal or peripheral nodes for microbiology and histology |
| Pleural fluid analysis and pleural biopsy | Adenosine deaminase, cell count, culture and thoracoscopic biopsy in pleural tuberculosis |
| CT chest, MRI, ultrasound | Define the extent of disease and guide sampling in extrapulmonary sites |
| Tuberculin skin test or IGRA | Detect latent infection, but they do not distinguish latent from active disease |
Every patient diagnosed with tuberculosis should also be tested for HIV and screened for diabetes, and should have baseline liver and kidney function, weight, vision assessment where ethambutol is used, and a nutritional assessment.
Treatment of tuberculosis
Drug-sensitive pulmonary tuberculosis is treated with a combination of isoniazid, rifampicin, pyrazinamide and ethambutol for an intensive phase, followed by a continuation phase, most commonly for a total of six months. Combinations are essential because a single drug used alone rapidly produces resistance. Doses are weight-based and are recalculated as weight improves during treatment.
Certain forms need longer or modified treatment. Tuberculous meningitis and bone or joint disease usually require extended courses, and corticosteroids are added in meningitis and pericarditis. Patients with liver disease, kidney disease, pregnancy or HIV need individualised regimens and, in HIV, careful timing of antiretroviral therapy.
Monitoring during treatment
Follow-up includes symptom and weight review, adherence support, sputum examination at defined intervals, and monitoring for side effects: nausea and hepatitis, rash, joint pain, peripheral neuropathy prevented by pyridoxine, visual disturbance from ethambutol, and orange discoloration of urine from rifampicin, which is harmless. Any jaundice, persistent vomiting, severe rash or visual change should prompt immediate contact with the treating doctor rather than self-stopping the tablets.
Completing treatment
Symptoms usually improve within two to four weeks, well before the bacteria are eradicated. Stopping treatment at that point is the commonest cause of relapse and of acquired drug resistance. Treatment must run its full course, with documented completion and follow-up afterwards for symptom recurrence.
Drug-resistant tuberculosis
Resistance is suspected when treatment fails, when disease recurs after a previous course, or when a patient has been in contact with a drug-resistant case, and it is confirmed by rapid molecular testing and culture-based susceptibility testing. Multidrug-resistant tuberculosis, defined by resistance to isoniazid and rifampicin, is treated with newer all-oral regimens containing agents such as bedaquiline, linezolid and other companion drugs, chosen according to the susceptibility pattern. These regimens are more effective and far better tolerated than the older injectable-based treatment, but they demand strict monitoring, including ECG and blood counts, and expert supervision throughout.
Prevention and contact screening
Household and close contacts of an infectious patient should be evaluated for active disease and, once that is excluded, considered for preventive therapy, which markedly reduces the chance of developing tuberculosis later. Good ventilation at home and at work, cough hygiene, prompt evaluation of a cough lasting more than two weeks, control of diabetes, adequate nutrition, and stopping smoking all reduce transmission and progression. BCG vaccination given in infancy protects children against severe forms such as miliary tuberculosis and meningitis.
Frequently asked questions
How long am I infectious after starting treatment?
Most patients with drug-sensitive pulmonary tuberculosis become substantially less infectious within about two weeks of effective treatment, provided they are improving and taking the drugs correctly. Until then, cover coughs, keep rooms well ventilated, and limit close contact with infants, elderly relatives and anyone immunosuppressed.
Can tuberculosis be completely cured?
Yes. Drug-sensitive tuberculosis is cured in the large majority of patients who complete a correct regimen. Even drug-resistant disease is curable with modern all-oral regimens, although treatment is longer and needs closer monitoring.
Why must I take so many tablets together?
Tuberculosis bacteria exist in different metabolic states, and using a single drug allows resistant organisms to multiply. A combination attacks the population from several directions at once, which both cures the disease and prevents resistance.
Is tuberculosis only a disease of the poor?
No. It is airborne and can affect anyone. Diabetes, smoking, stress, irregular meals, immunosuppressive treatment and crowded indoor workplaces put people of every income group at risk.
Can I work during treatment?
Most patients return to work after the initial infectious period, once symptoms improve and the treating doctor agrees. Work in schools, hospitals, childcare or crowded closed environments may need a longer period away.
Does a positive tuberculin or IGRA test mean I have tuberculosis?
No. These tests only show that the immune system has met the organism at some point. Active disease is diagnosed by symptoms, imaging and microbiological confirmation. A positive test with no evidence of disease indicates latent infection, which may warrant preventive therapy in high-risk individuals.
Will my lungs recover fully after treatment?
Many patients recover completely. Some are left with residual scarring, bronchiectasis or airflow obstruction, described as post-tuberculosis lung disease, which can cause ongoing cough and breathlessness and benefits from pulmonary follow-up, inhaled therapy, vaccination and rehabilitation.
Related conditions and procedures
Consult Dr. Gogineni Ratnakara Rao
Apollo Hospitals, Financial District: Monday to Saturday, 8:30 AM to 5:00 PM. Anything in Lung Clinic, Chanda Nagar: Monday to Saturday (Thursday closed), 6:00 PM to 9:00 PM.