Tuberculosis risk factors
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
The risk factors for the development of tuberculosis include: weakened immune system (patients taking immunosuppressive medication or with immunosuppressive diseases, such as HIV or diabetes); history of contact with infected patients, bad hygiene conditions, and evidence of previous disease. Risk factors for multidrug-resistant TB include: non-adherence to treatment regimen, inadequate medication for that strain of bacteria, and contact with patients with multidrug-resistant TB.
Risk Factors
Primary TB disease occurs soon after infection, however, the majority of cases occur with a latent infection, where there are no obvious symptoms. The dormant bacilli can cause tuberculosis in 2 to 23% of the latent cases, often many years after infection.[1] The risk of reactivation increases with immunosuppression, such as that caused by infection with HIV. In patients co-infected with HIV, the risk of reactivation increases to 10% per year.
The following people are at higher risk for active TB:
- Elderly
- Infants
- People with weakened immune systems, such as:
- Hematologic and reticuloendothelial disease
- Or those taking medications, such as:
- Chemotherapy
- Immunosuppressive medications, such as corticosteroids, tumor necrosis factor-alpha blockers[2]
The risk of contracting TB increases in cases where there is:
The following factors may increase the rate of TB infection in a population:
- Chest X-ray with evidence of previous TB disease
- Increase in HIV infections
- Increase in number of homeless people
- The appearance of drug-resistant strains of TB
Multidrug-Resistant Tuberculosis
Drug resistance is more common in people who:[3]
- Do not take their TB medicine regularly
- Do not take all of their TB medicine as told by their doctor or nurse
- Develop TB disease again, after having taken TB medicine in the past
- Come from areas of the world where drug-resistant TB is common
- Have spent time with someone known to have drug-resistant TB disease
References
- ↑ Parrish N, Dick J, Bishai W (1998). "Mechanisms of latency in Mycobacterium tuberculosis". Trends Microbiol. 6 (3): 107–12. PMID 9582936.
- ↑ Mutlu G, Mutlu E, Bellmeyer A, Rubinstein I (2006). "Pulmonary adverse events of anti-tumor necrosis factor-alpha antibody therapy". Am J Med. 119 (8): 639–46. PMID 16887405.
- ↑ "Multidrug-resistant tuberculosis".