There has been a gradual decline in the incidence of tuberculosis in technically advanced countries since the turn of the century. In developing countries accurate statistics are lacking, but there is no doubt that tuberculosis is a significant public health problem. Mycobacterium tuberculosis has also emerged as a major pathogen in patients infected with the human immunodeficiency virus (HIV). There has been a marked increase in the incidence of tuberculosis in HIV patients in the United States of America, and an even greater increase in sub-Saharan Africa.

The falling incidence of tuberculosis in more advanced societies can be attributed as much to environmental and social factors as to specific prophylactic and chemoctherapeutic measures (Fig. 1) 1978. Measures to prevent and control the spread of disease are important aspects of management, and should be used in conjunction with drug treatment for patients with active disease.

A variety of methods have been adopted to prevent and control the spread of tuberculosis.

This is given to uninfected tuberculin negative individuals to increase host resistance. It offers partial protection only, and although an active vaccination policy has been used in the United Kingdom, it has not been adopted in North America and some other European countries. The vaccination of school children between the ages of 10 and 14 has been standard practice in the United Kingdom since the early 1950s. With the decreasing incidence of tuberculosis, this policy is becoming less effective and may soon be abandoned in favour of offering vaccination to specific high-risk groups, such as health workers, tuberculin negative contacts, and immigrants from countries where tuberculosis is common. One disadvantage of routine BCG vaccination is that it diminishes the usefulness of tuberculin testing as a diagnostic tool.

This is an effective case finding method: approximately 10 per cent of close contacts of patients with smear-positive pulmonary tuberculosis develop the disease. Patients with smear-negative or non-pulmonary disease can be regarded as non-infectiuous. Close contacts are usually people living in the same household, although contact at work is occasionally close enough to represent a significant risk. Casual contacts run a low risk, although a highly infectious index case can cause an outbreak of tuberculosis.

Contacts, as well as immigrants from areas with a high incidence of tuberculosis, are investigated by Heaf testing and chest radiograph. Interpretation of the Heaf test depends on knowledge of prior BCG vaccination. Chemoprophylaxis should be considered in those with a strongly positive Heaf test (grades 3 and 4) but no clinical or radiological evidence of disease. For individuals not receiving chemoprophylaxis a 2-year follow-up with periodic radiographic examination is recommended. More detailed guidelines relating to the control and prevention of tuberculosis in Britain have been issued by the British Thoracic Society.

The treatment of tuberculosis depends on the use of appropriate combination chemotherapy. Supervision and monitoring are necessary since successful treatment is crucially dependent on the patient's compliance. A combination of antituberculous drugs is required to minimize the risk of emergence of resistant organisms, and because of the slow growth of mycobacteria, a prolonged course of treatment is essential for therapeutic success. In the last 20 years there have been a number of modifications in treatment regimens with the result that an 18-month course of treatment has been replaced by short course treatment for periods of between 6 and 9 months.

The standard drugs used in the treatment of tuberculosis are listed in Table 1 544. For pulmonary disease, a 6-month course comprising an initial 2 months of rifampicin, isoniazid, pyrazinamide, and ethambutol followed by a further 4 months of rifampicin and isoniazid is recommended. Use of ethambutol in the initial phase may be unnecessary unless there is a risk of isoniazid resistance. In patients who may not take their medication reliably, supervised chemotherapy can be given three times a week, using all four drugs initially and continuing with high-dose isoniazid (15 mg/kg) and rifampicin (600–900 mg).

Chemotherapy using standard drugs is highly effective in the treatment of spinal and joint tuberculosis. Although 6 months' treatment is regarded as adequate, there have been few controlled studies and treatment is often continued for a total of 9 months. Surgery is rarely necessary except to relieve early spinal cord compression or to correct instability or deformity.

This represents the most common form of extrapulmonary disease and the chance of relapse seems greater than with pulmonary disease unless adequate chemotherapy has been given. For this reason after the initial 2-month course of triple or quadruple chemotherapy, rifampicin and isoniazid are continued for a total of 9 months.

Tuberculosis meningitis represents the most serious form of the disease and prompt treatment is essential. The British Thoracic Society now recommends isoniazid, rifampicin, and pyrazinamide daily for 2 months followed by a further 10 months of isoniazid and rifampicin. A traditional regimen also includes streptomycin intramuscularly daily for the first 3 months, although this is probably unnecessary. Intrathecal therapy is hazardous and no longer recommended. The value of corticosteroids remains uncertain but they are often administered to unconscious patients and those who have cerebral oedema.

The standard regimen recommended for pulmonary tuberculosis seems to be adequate when given over a total of 6 months. Prednisolone may confer some benefit in patients with obstruction of the urinary tract.

Patients with renal failure requiring treatment can be given standard doses of rifampicin, isoniazid, and pyrazinamide. Both streptomycin and ethambutol are best avoided, although they can be used in reduced dosage with monitoring of serum concentrations.

Rifampicin, isoniazid, and pyrazinamide are all potentially hepatotoxic. They can be used in patients with liver disease but careful monitoring of liver function is mandatory.

Standard antituberculous chemotherapy seems to be effective in the treatment of tuberculosis in patients who are HIV positive. Subsequent life-long isoniazid prophylaxis is an appropriate precaution against relapse. It is also recommended that any HIV-positive patients with a tuberculin test of greater than 5 mm induration should also receive isoniazid prophylaxis.

Standard treatment is safe in pregnancy. None of the first-line drugs is teratogenic. Streptomycin can be ototoxic to the fetus and ethionamide and prothionomide are best avoided.

Tuberculosis can be effectively treated using combination chemotherapy. An initial induction phase of 2 months using three or four drugs in combination is followed by a further 4-month treatment using rifampicin and isoniazid. If treatment is to be effective and the chances of emergence of drug resistance are to be minimized, it is essential that the patient takes a full course of treatment. Supervision is best undertaken by those experienced in the management of tuberculosis and who have facilities for monitoring the disease and for contact tracing.

Chemotherapy and management of tuberculosis in the United Kingdom: Recommendations of the Joint Tuberculosis Committee of the British Thoracic Society. Thorax 1990; 45: 403–8.

Control and prevention of tuberculosis in Britain: an updated code of practice. Joint Tuberculosis Committee of the British Thoracic Society. Br Med J 1990; 300: 995–9.

Communicable Disease Centre. Tuberculosis and HIV infection: recommendation of the advisory committee for the elimination of tuberculosis (ACET). MMWR 1990; 38: 236–8, 243–50.