Tuberculosis (TB)

Tuberculosis (TB) is an infectious disease caused by a type of bacteria called Mycobacterium. Mycobacterium Tuberculosis is the commonest bacteria causing Tuberculosis in humans. Tuberculosis usually affects the lungs (Pulmonary TB) but it can also occur in other parts of the body. (Extra Pulmonary TB)

How does TB spread?

TB is an airborne disease. When a patient with Pulmonary TB coughs, sneezes, spits or talks, very small droplets containing TB bacteria are released into air. These droplets, which float in the air, if inhaled by another person, may cause infection in his/her lungs.

Every person who inhales the droplets will not develop TB disease unless his immunity status is poor. It is estimated that only 10% of infected people will develop the disease. Extra pulmonary TB is virtually never infectious. Transmission generally occurs indoors, where droplets foci can stay in the air for a long time. Ventilation removes droplets foci. Direct sunlight quickly kills TB bacteria, but they can survive in dark for several hours.

Who are at risk?

• HIV/AIDS patients
• Poorly controlled Diabetics
• Malnourished people
• Heavy smokers
• People on steroid therapy
• Cancer patients
• People with advanced kidney disease
• People with chronic lung diseases such as chronic bronchitis, sillicosis
• Elderly
• Alcoholics

Symptoms of TB

• The main symptoms of TB of the lungs (Pulmonary TB)
• Cough for 2 weeks or more
• Low-grade fever
• Blood stained sputum (phlegm)
• Chest pain

Symptoms of Extra pulmonary TB depends on the organ involved.

Other symptoms common to both types of TB

• Loss of appetite
• Loss of weight
• Weakness of the body

Dr. Robert Koch & his Discoveries:

Name:                  Dr. Robert Koch (1843-1910)

Place of Birth:     Klaustal (Germany)

Date of Birth:      Dec. 11, 1843

Country:              Germany

Education:           Studied at Gotteingeon to become a physician and surgeon, M.D.degree in    1862. Passed District Medical officers’ Examination in 1869.

Affiliation:

• Assistant in the General Hospital at Hamburg in 1867.
• District Medical Officer at Wollstein, Germany in 1872
• Discovered cause of Anthrax in 1870s
• Served as volunteer in Franco-Prussian war 1872-80.
• Appointed member of Imperial Health Bureau in Berlin in 1880, and invented new method of cultivating pure cultures of bacteria in solid media.
• Appointed as government advisor with the Imperial Department of Health in Berlin in 1880.
• Started using methylene-blue for staining technique developed by his colleague in 1880.
• Discovered tuberculosis bacillus and method of growing it in pure culture in 1882.
• Led a German expedition to Egypt and India, where he discovered the cholera bacillus (1883)
• Hygienic Institute in Berlin (Professor and Director, 1885)
• Discovered the cause of bacterial infections of wounds in 1887
• Appointed Brigadier General (Generalaazt) and Freeman of the City of Berlin in 1890.
• Institute for Inektions- Krankheiten (Institute of Infectious Disease, Berlin – Director 1891)
• Became Honourary Professor of medical faculty and Director of the new institute of infectious diseases.
• Announced new tuberculin- discovery of substances of diagnostic value of tuberculosis in 1896.
• He worked in India and Africa on Malaria, Black-water fever, Sera of cattle and horses and Plague in 1898.
• Worked on Typhus
• Earned many awards and prizes.
• Retired from Director of Berlin’s Institute of Infectious Diseases in 1904.
• Awarded by Nobel Prize for medicine in 1905.
• Returned Central Africa for experimental work on bacteriology and serology in 1906.
• Married, Emmy Fraats in 1866.
• Second Marriage with Hedwig Freiberg in 1893.
• Died at the German Health Resort of Baden-baden on May 27, 1910.

History of Tuberculosis

Before Discovery of TB bacilli by Sir Robert Koch

Mycobacterium Tuberculosis has been present in the human population since antiquity – fragments of the spinal column from Egyptian mummies from 2400 B.C. show definite pathological signs of tubercular decay. It has also been referred to in the Vedas and Ayurvedic Samhitas.

The term phthisis, consumption, appears first in Greek literature. Around 460 B.C., Hippocrates (“the father of medicine”) identified phthisis as the most widespread disease of the times, and noted that it was almost always fatal.

Exact pathological and anatomical descriptions of the disease began to appear in the seventeenth century. In his Opera Medica of 1679, Sylvius was the first to identify actual tubercles as a consistent and characteristic change in the lungs and other areas of consumptive patients. He also described their progression to abscesses and cavities. Manget described the pathological features of miliary tuberculosis in 1702.

In 1720, the English physician Benjamin Marten was the first to conjecture, in his publication, A New Theory of Consumption that TB could be caused by “wonderfully minute living creatures”, which, once they had gained a foothold in the body, could generate the lesions and symptoms of the disease. For the early eighteenth century, Dr. Marten’s writings display a great degree of epidemiological insight.

In contrast to this significant level of understanding about the etiology of consumption, which was already enabling prevention and a break in the chain of infection, those attempting to cure the disease were still groping in the dark.

The introduction of the sanatorium cure provided the first really step against TB. Hermann Brehmer, a Silesian botany student suffering from TB, was instructed by his doctor to seek out a healthier climate. He traveled to the Himalayan Mountains where he could pursue his botanical studies while trying to rid himself of the disease. He returned home cured and began to study medicine. In 1854 he presented his doctoral dissertation bearing the auspicious title, Tuberculosis is a Curable Disease. In the same year, he built an institution in Gorbersdorf where, in the midst of fir trees, and with good nutrition, patients were exposed on their balconies to continuous fresh air. This setup became the blueprint for the subsequent development of sanatoria, a powerful weapon in the battle against an insidious opponent.

New advances then followed in rapid succession. In 1865, the French military doctor Jean-Antoine Villemin single-handily demonstrated that consumption could be passed from humans to cattle and from cattle to rabbits. On the basis of this revolutionary evidence, he postulated a specific microorganism as the cause of the disease, finally laying to rest the centuries-old belief that consumption arose spontaneously in each affected organism.

For several reasons, it was not possible to obtain accurate data on the prevalence and incidence of tuberculosis prior to recent times. Until late in the 19th century, many wasting diseases of the chest, cancer, silicosis, lung abscesses, were confused with tuberculosis. Furthermore, any extra-pulmonary forms of the disease were not recognized as being caused by the tubercle bacillus. Even if clinical diagnosis had been accurate, most areas did not have good disease surveillance system until the 20th century. When such systems did come into existence, many physicians refused to report cases. The public viewed tuberculosis as a stigma and patients did not wish others to know of their disease for fear of ostracism, loss of a job, and decreased eligibility for marriage.

Despite these limitations, recorded deaths from tuberculosis are useful indicators of the burden of the disease during the 17th to 19th centuries. Rene and Jean Dubos state that, in England and Wales, pulmonary tuberculosis was rare in the country districts around 1640 but caused some 20% of all deaths in urban areas. But TB mortality then decreased and accounted for only 13% of deaths in 1715 but began to increase again around 1730, reaching a peak toward the end of the 18th century.

Discovery of TB bacilli by Sir Robert Koch

In 1882, Robert Koch discovered a staining technique that enabled him to see Mycobacterium tuberculosis. What excited the world was not so much the scientific brilliance of Koch’s discovery, but the accompanying certainty that now the fight against humanity’s deadliest enemy could really begin.

After Discovery of TB bacilli by Sir Robert Koch till Discovery of First Anti TB Drug

After discovery of TB bacilli by Sir Robert Koch in 1882, the measures available to doctors were still modest. Improving social and sanitary conditions and ensuring adequate nutrition were all that could be done to strengthen the body’s defenses against the TB bacillus. Sanatoria, now to be found throughout Europe and the United States, provided a dual function: they isolated the sick, the source of infection, from the general population, while the enforced rest, together with a proper diet and the well-regulated hospital life assisted the healing processes.

These efforts were reinforced by the observation of the Italian Forlanini that lung collapse tended to have a favorable impact on the outcome of the disease. With the introduction of artificial pneumothorax and surgical methods to reduce the lung volume, the depressing era of helplessness in the face of advanced TB was over, and active therapy had begun.

A further significant advance came in 1895 when Wilhelm Konrad von Rontgen discovered the radiation that bears his name. Now the progress and severity of a patient’s disease could be accurately followed and reviewed with X-rays.

The French bacteriologist Calmette, who, together with Guerin, used specific culture media to lower the virulence of the bovine TB bacterium, creating the basis for the BCG vaccine still in widespread use today, provided another important development.

Efforts to prevent tuberculosis by inducing resistance to infection began early in this century. Calmette and Guerin produced an attenuated strain of mycobacterium bovis after 231 passages through media containing glycerin and oxbile. This vaccine was safely administered to a child in 1921 and its use spread quickly across quic across Europe. It was first administered by mouth but later given by the intradermal route. A disaster in Lubeck, Germany in 1930, in which 72 children died as a result of vaccination with BCG contaminated with a virulent strain, generated years of controversy concerning the safety of the vaccine. However, subsequent clinical observations, uncontrolled studies and clinical trials established the safety BCG for immunocompetent individuals.

Then, in the middle of World War II, came the final breakthrough, the greatest challenge to the bacterium that had threatened humanity for thousands of years – chemotherapy.

Prior to the development of effective chemotherapy in the 1950s, a variety of remedies had been used to treat tuberculosis but none showed significant efficacy. Koch’s early effort to develop an effective immunotherapy i.e. by the injection of tuberculin was an embarrassing failure (Koch, 1890), although it did lead to the development of the tuberculin skin test. The intradermal skin test method developed by Mantoux (Mantoux 1910) is still the preferred method for identifying persons infected with M. tuberculosis. Koch’ failure did not, however, dampen enthusiasm for controlling the disease a few years before Koch’s discovery of the tubercle bacillus, bed rest had been advocated as a treatment of tuberculosis and the sanatorium movement began in Europe, Asia and United States. Two men, Sir Robert W. Philip in Edinburgh and Dr. Hermann M. Biggs in New York, were prime movers in establishing organized system for the control of tuberculosis dispensary in the world was opened by Sir Robert W. Philip in Edinburgh in 1887. Two years later, Dr. Biggs created a plan for administrative control of tuberculosis in New York City which involved reporting of cases to health authorities, official inspection of cattle, public education and disinfection of rooms, which had been occupied by patients with pulmonary tuberculosis.

In 1904, the national association for the Study and Prevention of Tuberculosis (now the American Lung Association) was formed to educate the public and stimulate programmes for the control of tuberculosis. The organization was highly successful in promoting the maintaining public interest in tuberculosis through hundreds of local and state affiliates, and over the next several decades, each state and most large cities had organized tuberculosis control programmes. Voluntary movements also sprang up in Europe Asia and other areas. In 1920, the International Union Against Tuberculosis (now lung diseases also) was formed.

National Programmes for eradication of tuberculosis in cattle were instituted in many countries in the early 20th century. This involved tuberculin skin testing to identify infected cattle and slaughter of those cattle found to be infected. Pasteurization of milk also contributed to the control of bovine tuberculosis.

After Discovery of First Anti TB Drug till WHO declared TB as Global Emergency in 1993

By the early 20th century, treatment of TB patients with usually involved bed rest. A dry climate and fresh air were considered important by many clinicians and many of the sanatoria were located in rural areas at higher elevations. Nutritional therapies, fresh air, sunlight, mental tranquility and optimism were also promoted.

Then, in the middle of World War II, came the final breakthrough, the greatest challenge to the bacterium that had threatened humanity for thousands of years – chemotherapy. In fact, the chemotherapy of infectious diseases, using sulfonamide and penicillin, had been underway for several years, but these molecules were ineffective against Mycobacterium tuberculosis. Since 1914, Selman A. Waksman had been systematically screening soil bacteria and fungi, and at the University of California in 1939 had discovered the marked inhibitory effect of certain fungi, especially actinomycete, on bacterial growth. In 1940, he and his team were able to isolate an effective anti-TB antibiotic, actinomycin; however, this proved to be too toxic for use in humans or animals.

Success came in 1943. In test animals, streptomycin, purified from Streptomyces griseus, combined maximal inhibition of M. tuberculosis with relatively low toxicity. On November 20, 1944, the antibiotic was administered for the first time to a critically ill TB patient. The effect was almost immediately impressive. His advanced disease was visibly arrested, the bacteria disappeared from his sputum, and he made a rapid recovery. The new drug had side effects – especially on the inner ear – but the fact remained, M. tuberculosis was no longer a bacteriological exception, it could be assailed and beaten into retreat within the human body. A rapid succession of anti-TB drugs appeared in the following years. These were important because with streptomycin monotherapy, resistant mutants began to appear with a few months, endangering the success of antibiotic therapy. However, it was soon demonstrated that this problem could be overcome with the combination of two or three drugs.

Following Koch’s discovery of the tubercle bacillus, an intense interest in chemotherapy of the disease developed. None of the drugs studied in animals and in man showed great promise, however until the discovery of streptomycin by Waksmann and Coworkers in 1944 trials by the British Medical Research Council (MRC), the United State Public Health Service and the US Veterans Administration-Armed Forces Cooperative Trails Group confirmed its efficacy, but drug resistance emerged as a serious drawback. Therefore, in an effort to prevent resistance, in 1948 the MRC undertook a successful trial of combined streptomycin-PAS therapy (medical Research Council 1950). By 1952, isoniazid had become an important part of the initial treatment regimen. It was not until the early 1960s that a MRC trial settled the optimal duration of treatment-2 years. A number of trails conducted during the 1950s and 1960 also demonstrated that treatment could be effectively given on and out patient basis and that hospitalization and bed rest were unnecessary.

Another major advance in chemotherapy in the 1960s was the discovery that therapy could be just as effective when given intermittently (two or three times weekly times weekly) as when given daily. Supervision of administered therapy is much easier and less costly than supervision of daily therapy. The next major advance was the development of so-called short course chemotherapy-usually understood to mean treatment regimens of 9 months or less- in the 1970s. Short- course regimens with high cure rates became possible only after the introduction of rifampicin. With the introduction of this drug, the chemotherapeutic armamentarium for TB included two bacterial drugs –rifampicin and isoniazid-and it was subsequently shown that high cure rates could be obtained by giving both these drugs for only 9 months. The development of successful 6-month treatment regimens occurred when pyrazinamide (PZA) was added. This drug was first introduced in 1952 but not widely used because of heaptotoxicity.

With the development of chemotherapy for tuberculosis, it became possible to consider treatment of infected persons to prevent the development of disease. Chemoprophylaxis had their genesis in the observations by Lincoln that isoniazid could prevent complications, e.g. meningitis, in recently infected children with clinical manifestations of disease. Subsequently, at least 14 placebo-controlled trails involving more than 100,000 subjects were conducted. The USPHS trials demonstrated that 1 year of isoniazid chemoprophylaxis reduced the incidence of clinical disease by 55-83% (1970). The primary determinant of effectiveness was patient compliance. Among highly compliant individuals, the effectiveness of isoniazid was greater than 90% (IUATLD, 1982).

Following streptomycin, p-aminosalicylic acid (1949), isoniazid (1952), pyrazinamide (1954), cycloserine (1955), ethambutol (1962) and rifampin (rifampicin; 1963) were introduced as anti-TB agents. Aminoglycosides such as capreomycin, viomycin, kanamycin and amikacin, and the newer quinolones (e.g. ofloxacin and ciprofloxacin) are only used in drug resistance situations. Combinations of a B-lactam antibiotic with a B-lactamase inhibitor enhance treatment effectiveness, but the newer drugs, including the macrolides, have not received much clinical testing.

Studies done in the 1980s, evaluated the treatment regimens of less than six months duration. These studies demonstrated high relapse rate in patients with sputum smear positive pulmonary TB.Govt. of Madras India, WHO and British Medical Research Council (BMRC) conducted study on sanatorium versus domiciliary treatment in 1956. It demonstrated that the time-honoured virtues of sanatorium treatment such as bed rest, well-balanced diet and good accommodation where remarkably unimportant provided adequate chemotherapy was prescribed and taken. Further, there was no evidence that close family contacts of patients treated at home incurred an increased risk of contracting TB. Therefore, it would be appropriate to treat infectious patients in their own homes. This finding revolutionized TB treatment the world over.

In 1945, Karel Styblo, a Dutch Physician, contracted a severe case of tuberculosis. Following this recovery, he dedicated his life for studying the disease. For the next 30 years, Styblo watched as TB deaths dramatically decreased in post-war Europe with the availability of new TB medicines. Even so, the TB epidemic continued to spread uncontrolled in less-developed countries. Styblo applied his research to understanding how modern anti-TB medicines and control strategies could be successfully used in developing countries.

In 1977, Styblo, then scientific director of the International Union against Tuberculosis and Lung Disease (IUATLD), gained the active support of the Tanzania Ministry of Health in pilot project using a new TB control strategy he had been resting. Some health officials protested, claiming there was no practical way to control TB in poor communities until socioeconomic conditions improved and more hospital were built. Styblo disagreed, believing there was a way to provide affordable – yet supervised – TB treatment primarily on an outpatient basis. Even though there was considerable pressure against Styblo’s new approach, Tanzania’s government agreed to test it in two districts.

The first ground breaking clement in the pilot project proposed by Styblo was to use a new combination of anti-TB drugs called short-course chemotherapy on a large scale in developing countries. By using the drugs isoniazid, rifampicin, pyrazinamide and streptomycin in combination, it was possible to cut treatment time in half, there by encouraging more TB patients to successfully complete their treatment.

The second new element was an innovative recording and reporting system. The reporting system was simple enough to be completed properly, but detailed enough to provide useful information for ongoing evaluation of the progress of each patient and of the Programme. Styblo believed this new reporting system would help keep health workers accountable for directly observing that TB patients take their medicines, making it unnecessary to hospitalize most TB patients during the entire treatment period.

To the surprise of many, cure rates in pilot project increased from 43 percent to nearly 80 percent. Even more impressive, these results were achieved for a very small additional cost. It was calculated that the average cost for curing one patient – including staff costs, transportation and other infrastructure costs – was under $ 200.

The new TB project worked so well that other districts surrounding the pilot areas wanted to participate. Financing for the most costly components of the Programme – drugs and transportation – was found through external donors such as the Swiss Government, the German Leprosy Relief Association and the Netherlands TB and Leprosy Associations.

The Tanzanian Government also committed itself to implementing the Programme and provided 50 percent of the financing. Over the next decade, Styblo and the IUATLD replicated Tanzania’s success in Nicaragua and in seven additional African countries.

It is evident that administering directly observed Short-course chemotherapy to people with TB, the epidemic can be successfully controlled without hospitalizing most patients, in even the poorest regions of the world.

After WHO declared TB as Global Emergency in 1993

The World Health Organization declared TB a global emergency in 1993 in recognition of its growing importance as a public health problem. Governments in many high burden countries have neglected TB Control in the past. Tuberculosis Programmes have failed to achieve high detection and cure rates for infectious (smear-positive) patients. Besides poverty, population growth and migration and increase in the number of TB cases attributable to the HIV epidemic in some countries, the persistence of TB has been chiefly due to: 1) Failure to ensure accessible diagnosis and treatment services, including directly observed therapy; 2) Inadequate treatment regimens and failure to use standardized treatment regimens; 3) Lack of supervision and an information management system for the rigorous evaluation of treatment outcomes of TB patients and 4) Misguided policies for health sector reform with cuts in health care budgets and resultant reduction in financial support to peripheral health services.

In response to this situation, a new framework for effective TB control was developed and a global strategy called DOTS was introduced.Five Components of the DOTS strategy are: 1) Sustained political commitment; 2) Access to quality assured sputum microscopy; 3) Standardized short course chemotherapy for all cases of TB under proper case management conditions, including direct observation of treatment; 4) Uninterrupted supply of quality assured drugs and 5) Recording and reporting system enabling outcome assessment of all patients and assessment of overall Programme performance.

The organizational principles of the DOTS strategy are: 1) Availability of a decentralized diagnostic and treatment network based on existing health facilities and integrated with PHC; 2) Good Programme management based on accountability and supervision of health care workers and 3) An evaluation system of case finding and cohort analysis of treatment outcomes.

The WHO framework for effective TB Control includes the objectives and targets, DOTS strategy, a policy package, key operations for implementation and indicators to measure progress.The objectives of an NTP are to reduce TB mortality, morbidity and disease transmission, while preventing the development of drug resistance.The main intervention for TB control is standardized short-course chemotherapy provided under direct observation at least during the initial phase of treatment for all identified smear positive TB cases the main source of infection The global targets for TB control, adopted by the World Health Assembly, are to cure 85% of newly detected cases of sputum smear-positive TB and to detect 70% of the estimated incidence of sputum smear positive TB.

The essential services needed to control TB, based on diagnosis and treatment of infectious cases and incorporating the essential management tools, were developed and packaged as the DOTS strategy in the early 1990s. DOTS has been promoted as a global strategy since the mid-1990s.

Properly applied TB chemotherapy is effective in curing infectious cases, thereby interrupting the chain of transmission. The best prevention of TB is therefore the cure of infectious TB cases. The World Bank recognizes the DOTS strategy as one of the most cost effective health intervention and recommends that effective TB treatment be a part of the essential clinical services package available in primary health care (PHC). Governments are responsible for ensuring the provision of effective TB control through the DOTS strategy.

In 1998, WHO launched “The Global Partnership to Stop TB” to face TB threat. Partnership has developed First Global Plan to Stop TB – the five-year (2001-2005) action plan for implementation. It examines existing TB control Programmes around the world and provides a sound business plan to accelerate TB control between 2001 and 2005 to reach WHO’s global TB control targets. It proposes to: 1) expand DOTS so that all have access to effective diagnosis and treatment; 2) adapt DOTS to meet the challenges of HIV/AIDS and TB drug resistance; 3) improve existing tools by developing better diagnostics, new drugs and a new vaccine; and 4) strengthen the Global Partnership to Stop TB so that proven TB control strategies are applied effectively throughout the world.

Countries applying DOTS on a wide scale have witnessed remarkable results. Transmission has declined in several countries; in Peru, for example incidence has dropped by approximately 6% per year over the past decade. Mortality has fallen in China; some 30000 deaths have been averted each year in districts implementing DOTS. Drug resistance fell by 75% following intensive intervention to improve patient management and reduce TB transmission.

The need to improve tools for diagnosis, treatment and prevention of TB to make TB Control more effective is well recognized. Initiatives have been launched to develop new diagnostics, drugs and vaccines, and the international community has started to increase investment in TB research.

Types of TB

The type of tuberculosis is defined by the site of the disease in the body. 80% of tuberculosis occurs in the lungs and is called pulmonary TB.

1. Pulmonary TB

Sputum smear-positive pulmonary tuberculosis.

A patient with at least two sputum smears positive for acid-fast bacilli by microscopy
OR
a patient with at least one sputum specimen positive for acid fast bacilli, and X-ray abnormalities consistent with pulmonary TB.

Sputum smear-negative pulmonary tuberculosis

A patient with three sputum smears negative for AFB on microscopy, but X-ray evidence consistent with active tuberculosis, which does not clear with non-tuberculosis antibiotics
OR
A patient whose sputum smears are all negative for AFB on microscopy, but culture positive for mycobacterium tuberculosis.

People with sputum smear-positive pulmonary TB are 10 times more infectious than people with sputum smear-negative TB. People with sputum smear-positive TB have a higher mortality without treatment than people with sputum smear-negative TB.

2. Extra-pulmonary tuberculosis

A patient with at least one positive culture for mycobacterium tuberculosis from an extra-pulmonary site
OR
A patient with X-ray or histological or clinical evidence consistent with active tuberculosis at an extra-pulmonary site (that is, at a site other than the lungs).

Pulmonary tuberculosis refers to disease involving the lung parenchyma. Therefore TB of the lymph nodes in the chest and TB of the pleura are classified as extra-pulmonary TB.

There are many types of extra-pulmonary TB. These include pleurisy, gland, intestinal, miliary, meningitis, bone, urogenital, skin, and eye TB. They are not infectious.

Diagnosis of extra-pulmonary TB is difficult. It must be confirmed by an experienced medical officer.

If a patient has TB affecting several different extra-pulmonary sites, classify him according to the most severe form of the disease. For example, if a patient has gland TB and abdominal TB, classify him as abdominal TB.

If you diagnose pulmonary and extra-pulmonary TB in the same patient(eg gland TB and sputum smear-positive pulmonary TB) then categorise him as pulmonary TB.

How TB can be detected?

Pulmonary TB can be detected by sputum Smears examination under Microscope. Chest X‑ray also helps in detection of TB of the lungs. At present, bacteriological examination of sputum is the best method of diagnosis of pulmonary TB. The smear microscopy is better method of diagnosis than X‑ray because it is simple, easy to perform, less expensive and has much less inter observer variability. It is much more reliable and specific. It also provides information regarding bacteriological status of patients that help us to treat them on a priority basis. It is also used for follow up examinations to judge the progress of patients during the course of treatment. Culture of Micobacteria as standard test to diagnose to get results of culture. The Xpert MTB/RIF is also in use.

Tuberculiun Skin Test

Dr. Robert Koch also used extract of TB bacilli for detection of TB. This test is known as Tuberculin Test. Its use is limited to detect TB.

Chest X-ray

Tuberculosis creates cavities visible in x-rays like this one in the patient’s right upper lobe.

In active pulmonary TB, infiltrates or consolidations and/or cavities are often seen in the upper lungs with or without mediastinal or hilar lymphadenopathy or pleural effusions ( tuberculous pleurisy). However, lesions may appear anywhere in the lungs. In disseminated TB a pattern of many tiny nodules throughout the lung fields is common – the so-called miliary TB. In HIV and other immunosuppressed persons, any abnormality may indicate TB or the chest X-ray may even appear entirely normal.

Abnormalities on chest radiographs may be suggestive of, but are not necessarily diagnostic of, TB. However, chest radiographs may be used to rule out the possibility of pulmonary TB in a person who has a positive reaction to the tuberculin skin test and no symptoms of the disease.

Tuberculosis creates cavities visible in x-rays like this one in the patient’s right upper lobe.