Which Part of the Human Body Does Tuberculosis NOT Infect?
Tuberculosis can infect virtually every organ system in the human body, and there is no specific anatomical site that is completely immune to TB infection. 1
Understanding TB's Dissemination Potential
Tuberculosis has the potential to infect almost every organ system via lymphohematogenous dissemination during the initial pulmonary infection. 1 This means that once Mycobacterium tuberculosis enters the body through the airborne route and establishes pulmonary infection, it can spread through the bloodstream and lymphatic system to reach distant sites. 2
Sites Commonly Affected by Extrapulmonary TB
While TB is primarily considered a pulmonary disease, extrapulmonary manifestations are well-documented and include: 1, 3
- Lymph nodes (lymphatic TB)
- Central nervous system (meninges causing tuberculous meningitis, brain parenchyma causing tuberculomas, spinal cord) 4
- Bones and joints (skeletal TB, including spondylodiscitis) 1, 3
- Gastrointestinal tract (intestinal TB) 3
- Genitourinary system 1
- Skin and subcutaneous tissues 1, 3
- Liver and spleen (miliary TB) 1
- Pericardium 1
Clinical Significance
The absence of any anatomically protected site means that TB must be considered in the differential diagnosis of unexplained pathology in virtually any organ system, particularly in high-risk populations. 1 This is especially critical in:
- Immunocompromised individuals (particularly HIV-infected patients), who have increased risk for extrapulmonary and disseminated TB 1, 4
- Patients from high TB-burden countries 2
- Close contacts of infectious TB cases 2, 5
Diagnostic Implications
The clinical manifestations of extrapulmonary TB are often nonspecific and insidious, with diagnosis potentially delayed for years. 1 A high index of suspicion is essential because:
- Chest radiographs may show signs of old or active pulmonary TB even when presenting with extrapulmonary disease 1
- Microscopic examination and culture of infected body fluids and/or tissue from the affected site are necessary for definitive diagnosis 1, 4
- Tuberculin skin testing should be performed on all suspected cases, though negative results do not exclude the diagnosis 1