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: traveling or living in areas endemic for TB, immunosuppression (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 tuberculosis. 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 (1-5% cases) occurs soon after infection, however, the majority of cases occur with 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 initial 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 are risk factors for active TB:[2][3]
- Traveling or living in endemic regions (Sub-saharan African, Russia, India, Pakistan, China)
- Elderly
- Infants
- IV drug users
- Immunosuppression:
- AIDS
- Diabetes
- Silicosis
- Malignancy, such as head and neck cancers
- Hematologic and reticuloendothelial disease, such as leukemia and Hodgkin's disease
- Or those taking medications, such as:
- Chemotherapy
- Immunosuppressive medications, such as prolonged corticosteroid therapy, tumor necrosis factor-alpha blockers[4]
- Tocilizumab
The risk of contracting TB increases in cases where there is:[2]
The following factors may increase the rate of TB infection in a population:[2]
- Chest X-ray with evidence of previous TB disease (fibrotic lesions and nodules)
- Increased number of HIV infections
- Increased number of homeless people
- The appearance of drug-resistant strains of TB
Drugs With Increased Risk of Tuberculosis Reactivation
- Treatment with the following drugs have been reported with increased risk of reactivation of latent tuberculosis.
Multidrug-Resistant Tuberculosis
Drug resistance is more common in people who:[5]
- 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.
- ↑ 2.0 2.1 2.2 "Tuberculosis Fact Sheet".
- ↑ Griffith D, Kerr C (1996). "Tuberculosis: disease of the past, disease of the present". J Perianesth Nurs. 11 (4): 240–5. PMID 8964016.
- ↑ 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".