Tuberculosis (TB) is traditionally associated with high-risk populations such as immunocompromised individuals, people living in endemic regions, and those with socioeconomic vulnerabilities.
However, recent clinical observations and epidemiological data reveal that TB can and does occur in patients considered low-risk, posing diagnostic and therapeutic challenges.
Rethinking Risk: TB Beyond the Usual Suspects
The conventional risk stratification for tuberculosis often excludes individuals without known exposure, immunodeficiency, or residence in high-prevalence areas.
Dr. Jessica Seidelman, MD, MPH explains, "For emergency physicians, the Kansas outbreak is not merely a public health footnote; it is an urgent clinical reminder. Patients presenting to EDs with persistent coughs, unexplained fevers, weight loss, or hemoptysis can no longer be presumed as routine respiratory illnesses without due consideration for TB, particularly among high-risk groups and in communities witnessing resurgence."
Clinical Presentation in Low-Risk Individuals: Subtle and Atypical
Tuberculosis in low-risk patients frequently manifests with nonspecific symptoms such as prolonged cough, mild weight loss, or intermittent low-grade fever—symptoms easily mistaken for other respiratory conditions. Moreover, extrapulmonary TB presentations, including lymphadenitis or skeletal involvement, are more common in these patients, complicating diagnosis.
Diagnostic delays often occur because healthcare providers may not initially consider TB, leading to advanced disease stages at detection. The subtlety of signs demands a high index of suspicion, especially in patients with persistent respiratory symptoms unresponsive to standard treatments.
Diagnostic Advances: Enhancing Detection in Low-Risk Groups
Recent innovations in diagnostic modalities have improved TB detection accuracy in low-risk populations. Molecular assays such as Xpert MTB/RIF Ultra offer rapid identification of Mycobacterium tuberculosis with high sensitivity, even in paucibacillary cases common among low-risk patients.
Interferon-gamma release assays (IGRAs) are useful for screening latent TB because they don't have the cross-reactivity problems common with tuberculin skin tests, especially in people vaccinated with BCG.
Dr. Jessica Seidelman, MD, MPH, highlights that the recent Kansas outbreak serves as a critical reminder for emergency physicians: patients arriving with persistent cough, unexplained fever, weight loss, or coughing up blood should not be dismissed as having routine respiratory issues without considering tuberculosis—especially in high-risk populations and areas experiencing a resurgence.
Emerging Risk Factors: Beyond Traditional Profiles
New research identifies factors that may predispose low-risk individuals to TB reactivation or infection. These include:
Chronic stress and malnutrition: Subclinical immune modulation can impair host defenses.
Environmental exposures: Urban pollution and occupational hazards may increase susceptibility.
Subtle immunological changes: Aging and certain medications, even if not overtly immunosuppressive, can contribute.
Treatment Considerations and Outcomes
Treatment regimens for TB remain standardized, however, low-risk patients often experience better outcomes due to fewer comorbidities and better adherence potential. Nonetheless, delayed diagnosis can lead to complications requiring prolonged therapy.
Close monitoring for drug resistance is crucial, as emerging multidrug-resistant TB strains have been reported even in low-risk demographics, emphasizing the need for comprehensive antimicrobial stewardship.
Recognizing TB in low-risk patients challenges existing public health paradigms. Enhanced surveillance systems incorporating molecular epidemiology can track transmission patterns more effectively. Moreover, raising awareness among healthcare providers about TB's potential in all patient groups is vital.
Dr. Henry M. Blumberg, MD concludes, "Tuberculosis remains a global challenge that transcends traditional risk categories. Effective control requires expanding diagnostic efforts and surveillance beyond high-risk populations to detect and treat cases early, preventing further transmission."
