By Laura Maisvoreva
What is the big deal with tuberculosis anyway?
The figures observed demonstrate how this disease is ravaging through our country and an appreciation of how tuberculosis manifests and can be avoided will assist greatly in reducing its transmission. The purpose of this article is to investigate tuberculosis, from its pathophysiology to how it can be treated.
Pathophysiology
Mycobacterium tuberculosis, commonly shortened to tuberculosis, is caused by rod-shaped bacteria. The bacterium is resistant to weak disinfectants due to the production of mycolic acid which assists in its survival for extended periods of time, especially on dry surfaces. Most infected individuals are oblivious to infection because they may possess the latent type of tuberculosis. This type of tuberculosis can be debilitated by AIDS or old age to the active type of tuberculosis.
Once transmitted, the bacterium is engulfed by alveolar macrophages. Once phagocytosed, it produces a substance that prevents lysosomal fusion and ultimately prevents its digestion and destruction by lysosomal hydrolytic enzymes. It is therefore able to proliferate and spread to infect other cells.
Drug-resistant strains of this bacterium have been observed, particularly the multiple drug resistant TB (MDR-TB) strain and the extreme drug resistant TB(XDR-TB) strain.
Transmission
Tuberculosis is transmitted via droplets in the air expelled in cough spells and contracted via inhalation.
Clinical Presentation
Flu-like symptoms are classically displayed in primary tuberculosis. Most people at this stage are asymptomatic, however, in immunocompromised individuals the tuberculosis can spread to the lungs and cause bronchopneumonia. The infection can also spread to the vascular system where it manifests as systemic miliary tuberculosis: –
Signs and symptoms
Common signs and symptoms include coughing, weight loss, fever and night sweats
Diagnostics and Testing
Testing is commonly done using a purified protein derivative (PPD) intradermal skin test also known as a tuberculin test, Mantoux test or tuberculosis test. An immune reaction can be observed on the skin surrounding the area of injection within 48 to 72 hours if the individual is infected with tuberculosis. A more specific test for TB which shows evidence of tuberculosis proteins in blood is the interferon gamma release assay (IGRA). A positive test for tuberculosis will then further require a chest x-ray.
Treatment
The latent type of tuberculosis can be treated using a single antibiotic – isoniazid for 9 months. The active type requires a combination of antibiotics for successful treatment. With a rise in antibiotic resistance, it is imperative to, for effective treatment, ensure drugs are specific to a particular strain of the bacteria. Additionally, multiple drugs should be used simultaneously and for the full course of therapy.
Other useful drugs include rifampin, pyrazinamide and streptomycin.
Factors that increase susceptibility to tuberculosis
Certain factors increase the risk of contracting this disease:
Preventative measures
People living with infected individuals are encouraged to wear N-95 masks to prevent transmission.
Key Organizations that assist in TB research and treatment programmes
There is still so much to know about tuberculosis and it would be worthwhile. For further information to read these recommended articles referenced below.
Tuberculosis treatment delays and associated factors within theZimbabwe national tuberculosis programme Takarinda et al. BMC Public Health (2015) 15:29
DOI 10.1186/s12889-015-1437-7
Comparison of two active case-finding strategies forcommunity-based diagnosis of symptomatic smear-positive tuberculosis and control of infectious tuberculosis in Harare, Zimbabwe (DETECTB): a cluster-randomised trial Lancet 2010; 376: 1244–53 Published Online October 4, 2010DOI:10.1016/S0140- 6736(10)61425-0
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