Tuberculosis

Tuberculosis TUBERCULOSIS Forms of tuberculosis have been present in the human population since ancient times. Fragments of spinal columns from Egyptian mummies dating back to 2400 BC show definite pathological signs of tubercular decay. Around 460 BC Hippocrates wrote on the subject of a disease which we now know as tuberculosis. In his article he warned his colleagues against visiting cases in the late stages of the disease, because the patients inevitable death might damage the reputations of the attending physicians. The worlds population remained totally defenseless to the lethal effects of tuberculosis for thousands of years. Then, around the 17th century scientists began to hypothesize about the nature of the disease and began to search for a means to prevent it.

In the Republic of Lucca in 1699, the government made the proclamation: Human health should no longer be endangered by objects remaining after the death of a consumptive. The names of the deceased should be reported to the authorities, and measures undertaken for disinfection. This meant that the corpse and any possessions of that person who had been consumed by tuberculosis would be burned to eliminate the risk of spreading the disease to others. This measure was one of the first steps towards the elimination of tuberculosis as an epidemic because the public was now beginning to recognize the contageousness of the disease and began taking measures to prevent it. In 1720, the English physician Benjamin Marten wrote 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.

He also stated, It may be therefore very likely that by a habitual lying in the same bed with a consumptive patient, constantly eating and drinking with him, or by very frequently conversing so nearly as to draw in part of the breath he emits from the Lungs, a consumption may be caught by a sound person..I imagine that slightly conversing with consumptive patients is seldom or never sufficient to catch the disease. Dr. Martens insight proved to be another enormous step towards the understanding and prevention of tuberculosis. In the 19th century Hermann Brehmer, a Silesian botany student whom was suffering from tuberculosis, was instructed by his physician to move to a healthier climate. Brehmer traveled to the Himalayan mountains mainly to pursue his botanical studies. What he didnt know at the time was that this journey would be attributed to curing his disease.

When Brehmer returned home he began to study medicine. In 1854, he wrote his dissertation titled, Tuberculosis is a Curable Disease. He hypothesized that his recovery was directly related to the healthier environment found in the Himalayan mountains. Brehmer built an institution in Gorbersdorf where his patients received a nutritious diet and spent great amounts of time on their balconies where they were exposed to continuous fresh air. This clinic was the first step towards the development of a sanatorium. Sanatoria, could now be found throughout Europe and the United States.

A sanatorium provided two functions. They isolated the ill from the rest of the public while enforcing rest and a healthy diet. Tuberculosis is caused by an organism called Mycobacterium tuberculosis or tubercle bacilli. When a person with the infectious tuberculosis disease coughs or sneezes, droplet nuclei containing tubercle bacilli can be expelled into the air causing the other people that inhale the air containing these droplet nuclei to become infected. The tuberculosis infection begins when the tubercle bacilli multiply in the small air sacs of the lungs. A small number enter the bloodstream and spread throughout the body, but the body’s immune system usually keeps the bacilli under control.

Some patients who have the TB infection develop the TB disease when their immune system cannot keep the tubercle bacilli under control and the bacilli begin to multiply rapidly. This can happen very soon after infection or many years after infection. About 10% of people who have the TB infection will develop the TB disease at some point, but the risk is greatest in the first year or two after infection. The tuberculosis disease usually occurs in the lungs (pulmonary TB), but can also occur in other places of the body (extrapulmonary TB). Miliary TB occurs when tubercle bacilli enter the bloodstream and are carried to all parts of the body, where they grow and cause the disease to form in multiple sites. The infectiousness of a TB patient is directly related to the number of tubercle bacilli that he or she expels into the air.

Patients who expel many tubercle bacilli are more infectious than patients who expel few or no bacilli. Patients are more likely to be infectious if they: * Have TB of the lungs or larynx * Have a cavity in the lung * Are coughing or undergoing cough-inducing procedures * Are not covering their mouth when coughing * Have acid-fast bacilli on the sputum smear The infectiousness of the TB disease appears to decline very rapidly after adequate treatment is started, but how quickly it declines varies from patient to patient. Patients who have been receiving adequate treatment for 2 to 3 weeks, whose symptoms have improved and who have 3 consecutive negative sputum smears from sputum collected on different days can be considered noninfectious. Tuberculosis can be spread in many places, such as homes or worksites. TB can also be transmitted in health care facilities. TB is most likely to be transmitted when health care workers and patients come in contact with patients who have unsuspected TB disease, who are not receiving adequate treatment, and who have not been isolated from others. All health care facilities should take measures to prevent the spread of TB.

There are four steps in diagnosing TB disease: medical history, tuberculin skin test, chest x-ray, and bacteriologic examination. A medical history includes asking the patient whether they have been exposed to a person with TB, symptoms of TB disease, if they have had TB infection or TB disease before, or risk factors for developing TB disease. The symptoms of pulmonary TB disease include: * coughing * pain in the chest when breathing or coughing * coughing up sputum or blood. The general symptoms of TB disease (pulmonary or extrapulmonary) include: * weight loss * fatigue * malaise * fever * night sweats. During the middle of World War II, the greatest development towards the elimination of tuberculosis was developed.

This treatment was known as chemotherapy. Streptomycin was the drug initially used in this treatment and was very effective. However, soon after doctors began administering Streptomycin strands of drug resistant TB began to appear. New drugs rapidly began to be developed which when used in conjunction could prevent the development of drug resistant tuberculosis. 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. Exposed to a single effective anti-TB medication, the predominant bacilli, sensitive to that drug, are killed; the few drug resistant mutants, likely to be present if the bacterial population is large, will, multiply freely. Since it is very unlikely that a single bacillus will spontaneously mutate to resistance to more than one drug, giving multiple effective drugs simultaneously will inhibit the multiplication of these resistant mutants. This is why it is absolutely essential to treat TB patients with the recommended four drug regimen of isoniazid, rifampin, pyrazinamide and ethambutol or streptomycin.

It is essential that the World Health Organization continue to educate the public of all nations on the most current treatments of tuberculosis to prevent the impending spread of drug resistant tuberculosis throughout the world. Bibliography BIBLIOGRAPHY Associated Press. Drug-resistant tuberculosis seen emerging as global threat. San Diego Union-Tribune. October 23, 1997. van Embden JDA, van Soolingen D, Small PM,. and Hermans PWM.

Genetic markers for the epidemiology of tuberculosis. Research in Microbiology 1992; 143: 385-391. Small PM, Shafer RW, Hopewell PC, Singh SP, Murphy M, Desmond E, Sierra M, Schoolnik GK. Exogenous reinfection with Multidrug-resistant Mycobacterium tuberculosis in patients with advanced HIV infection. N Eng J Med. 1993; 328: 1137-44.

Shafer RW, Small PM, Larkin C, Singh SP, Kelly P, Sierra MF, Schoolnik GK, Chirgwin KD. Temporal trends and transmission patterns during the emergence of multidrug-resistant tuberculosis in New York City: A molecular epidemiologic assessment. J Inf Dis 1995;171:170-6. Medicine Essays.