Miliary Tuberculosis

Miliary tuberculosis (TB) results from a massive lymphohematogenous dissemination of Mycobacterium tuberculosis bacilli and is characterized by tiny tubercles evident on gross pathology resembling millet seeds in size and appearance. The global HIV/AIDS pandemic and widespread use of immunosuppressive drugs and biologicals have altered the epidemiology of miliary TB. Considered to be predominantly a disease of infants and children in the pre-antibiotic era, miliary TB is increasingly being encountered in adults as well. The clinical manifestations of miliary TB are protean and nonspecific. Atypical clinical presentation often delays the diagnosis. Clinicians, therefore, should have a low threshold for suspecting miliary TB. 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. Imaging modalities help in recognizing the miliary pattern, defining the extent of organ system involvement. Examination of sputum, body fluids, image-guided fine-needle aspiration cytology or biopsy from various organ sites, needle biopsy of the liver, bone marrow aspiration, and biopsy should be done to confirm the diagnosis. Cytopathological, histopathological, and molecular testing (e.g., Xpert MTB/RIF and line probe assay), mycobacterial culture, and drug susceptibility testing must be carried out as appropriate and feasible. Miliary TB is uniformly fatal if untreated; therefore, 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 such as drug-induced liver injury, and drug-drug interactions (especially in patients coinfected with HIV/AIDS), is warranted.