From the Research
Miliary tuberculosis typically develops within 2-6 months after initial infection with Mycobacterium tuberculosis, though it can occur at any time. This severe form of disseminated TB results when the immune system fails to contain the primary infection, allowing bacteria to spread through the bloodstream throughout the body. The pathophysiology involves hematogenous spread of mycobacteria, creating numerous small lesions resembling millet seeds throughout multiple organs, as described in a study published in Microbiology spectrum 1.
Risk factors for rapid progression include:
- Immunocompromised states (HIV infection, malnutrition, diabetes)
- Extremes of age (very young or elderly)
- Genetic factors affecting immune response
While most people infected with M. tuberculosis develop latent TB without progression to active disease, approximately 5-10% will develop active TB during their lifetime, with miliary TB representing one of the most severe manifestations of this progression. A study published in The Indian journal of medical research noted that untreated miliary TB has a fatal outcome within one year 2.
The clinical manifestations of miliary TB are protean and nonspecific, and atypical clinical presentation often delays the diagnosis, as mentioned in a study published in Microbiology spectrum 1. Therefore, clinicians should have a low threshold for suspecting miliary TB, and early initiation of specific anti-TB treatment can be lifesaving. Monitoring for complications, such as acute kidney injury, air leak syndromes, acute respiratory distress syndrome, adverse drug reactions, and drug-drug interactions, is warranted, especially in patients coinfected with HIV/AIDS, as described in a study published in Journal of postgraduate medicine 3.
In terms of diagnosis, focused, systematic physical examination helps in identifying the organ system(s) involved, particularly early in TB meningitis, as this has therapeutic significance. Fundus examination for detecting choroid tubercles offers a valuable clinical clue for early diagnosis, as their presence is pathognomonic of miliary TB, as noted in a study published in Microbiology spectrum 1. Imaging modalities help in recognizing the miliary pattern, defining the extent of organ system involvement.
Given the potential for severe outcomes, early recognition and treatment of miliary tuberculosis are crucial to improve morbidity, mortality, and quality of life. A study published in Intensive care medicine highlighted the importance of considering miliary tuberculosis in patients with adult respiratory distress syndrome of unknown etiology, and simple diagnostic procedures should be followed by invasive diagnostic procedures to confirm this etiology 4.