The Problem And Possible Treatments Of Tuberculosis Biology Essay

Biology » The Problem And Possible Treatments Of Tuberculosis Biology Essay

Tuberculosis or simply called TB is an infectious disease caused by the bacteria called Mycobacterium tuberculosis which usually affects the lungs but it can also involve almost any part of the body. This airborne disease is a killer for people mostly those with HIV. In 1993, World Health Organisation (WHO) declared TB a global emergency as it has murdered approximately 2-3 million people per annum. One third of World’s population infected with 5-6% ends fatally. (1) Tuberculosis is an airborne disease which means it is spread through air. When an untreated pulmonary TB patient sneezes or coughs, the air containing pathogen released by patient is breathed in by person nearby causing him or her get infected. (3, 11) About 90% of the cases show that the host’s natural defences prevent any further progression of the infection where the Host-Parasite equilibrium is reached in which many of the mycobacteria are destroyed but some lie dormant in tubercle foci. Upon activation of the dormant bacteria, the patients will suffer chronic cough with sputum-containing-blood, chest pains, fever, night sweats, weakness and weight loss. (2, 11) Since tuberculosis is fatal, what is possible treatment to cure that disease?

Self-administered Therapy (SAT)

Before treatment, the patients must be stressed of the importance of compliance in order to prevent development of resistance of the bacteria towards the drugs used. The duration of drug therapy will take about 6 months or longer. The Full Blood Count (FBC), liver, and renal function have to be checked. The drug therapy usually done by the patients themselves based on prescription given by physicians. (2)

Drug therapy is an effective way in providing chances of fully recovery. The therapy is divided into two phases which are initial phase and continuation phase.

Initial phase:

This phase takes about 8 weeks. 4 drugs are given depending on susceptibilities. The drugs are:

Rifampicin 600-900mg (child 15mg/kg) Per Oral (PO) three times/week

Isoniazid 15mg/kg PO three times/week + pyridoxine 10 mg/24h

Pyrazimide 2.5g PO three times/week

Ethambutol 30mg/kg PO three times/week for 2 months

Continuation phase:

For this phase, it takes about 16 weeks on two types of drugs, rifampicin and isoniazid at same doses. The most common medicine used is Rifinah 300® which contains a combination of 300mg rifampicin and 150mg isoniazid. The patients are advised about the compliance from time to time. The pyridoxine is given throughout the treatment.

Isoniazid is one of the most common drugs used to treat TB. It is effective, inexpensive and easy to take. When it is used with other types of drugs, it can prevent and even cure TB. Thus, isoniazid preventive treatment is recommended to person that:

Have a close contact with person who have infectious TB

Show a positive tuberculin skin test reaction (2, 7)

The drug therapy may need a longer period if the TB patients also suffer another disease like meningitis and osteomyelitis. The HIV positive patients may need to be treated with extra-drugs and longer time. (2)

Why SAT?

The drug therapy works very efficiently when TB patient takes medicine according to doctor’s advice. This is because the mycobacterium tuberculosis will be destroyed from body. The graph below shows how the drug therapy reduces cases of tuberculosis in US.

We can see that the rate of TB cases declined from 1981 to 1984. It has reduced at about 6-7 % annually. The drugs used during the therapy had efficiently recovering many TB patients. This reduces further spreading of that disease to other person as the number of active TB patients keeps reducing. There is fluctuation from 1985 to 1991. This happens due to some reasons like poverty and substance abuse. These reasons raise the rate of infection of TB. However, the drug therapy still able to control the number of TB cases. (9)

Social

Economic

Some people might say that the cost for the initial therapy is relatively affordable that is about $1,206 or RM 3,789.98 but this only include the direct costs of the initial therapy neglecting the further spending required if there is failure in the treatment. (15) This will require more money for treatment. The money that should be used for other necessities have to be spent for the treatment. This becomes a problem in Malaysia as most Malaysians only have a moderate income. Thus, the patients will have a heavy burden to pay for the bills. Besides, as the drugs used for the treatment have side effects, more money will be needed to cure the effects caused by the drugs. This indicates that a lot of money required for the treatment.

During drug therapy treatment, combination of different drugs is used to treat TB. Different drugs will react differently. This improves to rate of survival of the patients. The duration of this treatment which is usually takes about 6-9 months provides sufficient time for antibiotics to destroy the TB bacteria. The drugs also may be combined together as a single tablet. For instance, Rifater contains isoniazid, rifampin and pyrazinamide. The patients can take the medicine effectively and easily. (17)

However, TB drugs can cause very serious side effects. They can cause jaundice (a yellow colour to skin), blurred vision, tenderness in abdomen, loss of appetite and vomiting. They also can be highly toxic to liver. (17) Besides, the treatment of tuberculosis by drug therapy may lead the emerging of drug resistance bacteria. This happens as the patients are allowed to have a self-administrated therapy. They take the medication completely unsupervised. (8) Drug resistance happen when the patients fail to complete drug therapy that lasting about six months or longer. The TB bacteria that manage survive will reproduce and multiply. They become more drug resistance. (16) Consequently, the treatment requires a longer period and a higher cost in order to cure the airborne disease. The number of people get infected will keep increasing (18) Therefore, alternative way shall be taken to prevent this happening.

Directly Observed Therapy (DOT)

It is a treatment where the doses of drugs used are increased for rifampicin, ethambutol and isoniazid from 1-4 days but not with thiacetazone, ethionamide or streptomysin. The process is same as the SAT but it is fully conducted and observed by hospital. (4, 7) This provides better result rather than the patients take the drug without being monitored. In Hospital Albert Schweitzer, 138 TB patients were treated with DOT and 143 TB patients were treated without observation. This gives a higher successive rate for DOT which is 87% while self-administered drug therapy only has 57% successive rate. (5)

Besides, the treatment failure can be reduced and less drug resistance will be acquired. (6) This is because the patients are give doses on schedule. However, the program the programs of directly observed therapy are not easy to conduct. They require a flexible administration.

Immunisation

Prevention is better than cure. With the development of science, the BCG (Bacillus Calmetta-Guerin) vaccine has been invented. BCG is made up of living attenuated strain of Mycobacterium Bovis (M. Bovis) that produces a localised and self-limiting infection. This will stimulate cell-mediated immunity. (12) The young babies and person that have high risk of infection are given BCG injection. BCG will protect infants against tuberculosis. (10) The vaccine is given intradermally by injection to upper left arm. Putting hand on hip so the arm is at 45° will make it easier for the nurse to administer it. After three weeks, a small red spot appears. The site must be kept clean and dry. This eventually heals to form a round flat scar after 3-4 months. (12, 13) The usage of this vaccine is much more money-savings than treatment.



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