Diagnosis of Tuberculosis Disease
Pulmonary TB disease should be suspected in persons who have fever; chills; night sweats; fatigue; loss of appetite; weight loss; a productive, prolonged cough (duration of 3 weeks or longer); or hemoptysis (bloody sputum). Persons suspected of having TB disease should be evaluated with a medical history, a physical examination, a Mantoux tuberculin skin test, a chest X-Ray, and a sputum smear and culture. A positive culture for Mycobacterium tuberculosis confirms the diagnosis of TB. However, a positive culture is not always necessary to begin or continue treatment for TB. In addition, a negative tuberculin skin test does not rule out TB disease because the active disease inhibits the immune system reaction to the PPD solution.
Persons with HIV infection and TB may have atypical (unusual) chest X-Rays, and they are more likely to have extrapulmonary TB than are persons without HIV infection. (However, pulmonary TB is the most common form of TB in all persons, including HIV-infected persons). The symptoms of extrapulmonary TB depend on the site affected. For extrapulmonary TB, sometimes a biopsy is obtained to smear and culture for TB.
Diagnostic Laboratory Tests
The presence of acid-fast bacilli (AFB) on a sputum smear often indicates TB. Acid-fast microscopy is easy and quick, but it does not confirm a diagnosis of TB because some acid-fast bacilli are not M. tuberculosis. Therefore, a culture is done to confirm the diagnosis. Culture examinations should be done on all specimens, regardless of AFB smear results. Laboratories should report positive smears and positive cultures within 24 hours by telephone or fax to the primary health care provider.
For all patients, the initial M. tuberculosis isolate should be tested for drug resistance. It is crucial to identify drug resistance as early as possible in order to ensure appropriate treatment. Drug susceptibility patterns should be repeated for patients who do not respond adequately or who have positive culture results despite 2 months of therapy. Susceptibility results from laboratories should be promptly forwarded to the health department.
Treatment of Active TB Disease
Active TB Disease must be treated for a long time (at least 6 months for most clients) compared with many other infectious diseases.
For most persons, the preferred regimen for treating TB disease consists of an initial 2 month phase of four drugs: isoniazid, rifampin, pyrazinamide, and ethambutol followed by a 4 month continuation phase of isoniazid and rifampin.
This regimen can be altered depending on the response of the client, the drug susceptibility patterns that emerge from the culture, the existence of other conditions (ie. HIV infection), and the extent of the disease. Thus every client is ensured close medical attention throughout the course of treatment.
This approach to treating TB disease was developed to rapidly kill the TB germs as fast as possible and to prevent the emergence of drug-resistant strains of the TB bacteria.
Directly Observed Therapy (DOT)
Directly Observed Therapy (DOT) is the standard of care for treatment of all active TB disease clients in Broome County. DOT means that a health care worker watches the client swallow each dose of TB medicine. This usually entails 14 days of daily medicines then changes to 2 - 3 times a week for the duration of therapy.
DOT provides personal support to the sick client in order to cure the TB disease and to prevent drug resistant strains from developing. Primarily, we wish to enlist the client cooperation and goodwill to ensure a full and final cure of the disease and to stop the spread of this infection to our community. However, if a client is unwilling to cooperate then we can enlist the aid of the courts and law enforcement to force the client to comply because of the risk to the community as stated in public health law. Fortunately, this is rarely the situation.
DOT is our Standard of Care!