Tuberculosis is a contagious infection caused by Mycobacterium tuberculosis. While often associated with younger populations in high-prevalence countries, tuberculosis remains a significant health concern in older adults. Age-related immune decline, coexisting chronic diseases, and institutional living increase the risk of infection and reactivation. Tuberculosis in older adults often presents differently, which can delay diagnosis and treatment.
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Prevalence of tuberculosis in older adults
Globally, tuberculosis affects people of all ages, but older adults form a growing proportion of cases in many countries. In high-income nations, most tuberculosis cases in older adults are due to reactivation of latent tuberculosis acquired earlier in life. In Asia, including Singapore, older adults are more likely to have been exposed in their youth when tuberculosis prevalence was higher. In nursing homes or long-term care facilities, outbreaks are possible if screening and infection control measures are inadequate.
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Types and stages of tuberculosis
Latent tuberculosis infection (LTBI): The bacteria remain inactive in the body without causing symptoms. Individuals are not infectious at this stage but may progress to active tuberculosis if immunity declines.
Active tuberculosis : The bacteria multiply and cause symptoms. This stage is infectious if it involves the lungs (pulmonary tuberculosis ).
Pulmonary tuberculosis : Affects the lungs, the most common and contagious form.
Extrapulmonary tuberculosis : Affects other organs such as lymph nodes, bones, or kidneys. More common in older adults and those with weakened immunity.
Risk factors of tuberculosis
Older adults are at higher risk of tuberculosis due to several interrelated factors. Many have been exposed to tuberculosis earlier in life when prevalence was higher, leading to latent infections that may reactivate with age-related immune decline, known as immunosenescence. Chronic conditions such as diabetes, chronic kidney disease, cancer, and malnutrition further weaken the immune system, increasing susceptibility. Long-term use of corticosteroids or other immunosuppressive therapies also raises the risk. Lifestyle factors such as smoking or excessive alcohol intake contribute to vulnerability. Living in crowded or institutional environments, including nursing homes, facilitates transmission, especially when infection control measures are insufficient.
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Signs and symptoms of tuberculosisÂ
In older adults, tuberculosis symptoms can be subtle and easily mistaken for other illnesses.
Persistent cough lasting more than 3 weeks
Coughing up blood or sputum
Unexplained weight loss
Fever and night sweats
Fatigue and loss of appetite
Confusion or functional decline in frail elderly (atypical presentation)
Implications if tubercolosis is untreated
If left untreated, tuberculosis can cause severe damage to the lungs and other organs. It may lead to respiratory failure, systemic infection, and death.
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Older adults face higher mortality rates from untreated tuberculosis. Infected individuals also pose a risk of spreading tuberculosis to others, particularly in shared living environments.
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Treatments options
Tuberculosis is treatable with a combination of antibiotics over several months. Standard treatment for active tuberculosis involves a 6-month course of isoniazid, rifampicin, pyrazinamide, and ethambutol in the initial phase, followed by isoniazid and rifampicin in the continuation phase.
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For latent tuberculosis , preventive therapy such as isoniazid for 6–9 months or rifampicin for 4 months may be prescribed. Adherence to the full treatment course is essential to prevent drug resistance. Older adults may require closer monitoring due to potential side effects and interactions with other medications.
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Prevention for tuberculosis
Early detection through regular tuberculosis screening in high-risk populations, especially in nursing homes
Prompt treatment of latent tuberculosis to prevent reactivation
Infection control measures such as adequate ventilation, respiratory hygiene, and isolation of infectious cases
The Bacille Calmette-Guérin (BCG) vaccine provides some protection against severe tuberculosis in children but has limited effectiveness in preventing pulmonary tuberculosis in adults. It is not routinely given to older adults in most countries unless in high-risk situations.
Conclusion
Tuberculosis in older adults is often under-recognised but can have serious consequences if missed. Age-related vulnerabilities, chronic illnesses, and institutional living increase both the risk and complexity of management. Early diagnosis, strict adherence to treatment, and preventive measures are key to controlling tuberculosis in this population. Regular screening and awareness among healthcare providers and caregivers play a vital role in reducing the burden of tuberculosis in the elderly.
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