Objective: The aim of the study was to determine the clinical, radiographic and laboratory characteristics, diagnostic methods, and prognostic variables in patients with miliary tuberculosis (TB).
Methodology: The records of 38 patients (15 male, 23 female; mean age 41 years, range 16-76 years) with miliary TB from 1978 to 1998 were analyzed. Patients were evaluated also as to whether they presented with a fever of unknown origin (FUO). Criteria for the diagnosis of miliary TB were (i) miliary pattern on chest X-ray or (ii) biopsy or autopsy evidence of miliary organ involvement. Paraffin-embedded tissues with granulomata (n = 15) were re-evaluated for the presence of Mycobacterium tuberculosis DNA by polymerase chain reaction (PCR).
Results: Predisposing conditions were present in 24% of the patients. The findings were fever, weakness, night sweats, anorexia/weight loss (100% for each), hepatomegaly (37%), splenomegaly (32%), choroidal tubercles (13%), neck stiffness (11%), altered mental status (8%), anaemia (76%), leukopenia (26%), thrombocytopenia (16%), lymphopenia (76%), pancytopenia (8%) and hypertransaminasemia (55%). Eighteen patients (47%) met the criteria for a FUO. Miliary infiltrates were found on chest X-rays of 32 of 38 cases (84%). In six cases without miliary infiltrates, the diagnosis was made by laparotomy in four cases, and autopsy in two cases. Tuberculin skin test was positive in 32% of cases. Acid-fast bacilli were demonstrated in 37% (16/43), and cultures for M. tuberculosis were positive in 90% (9/10) of tested specimens (predominantly sputum and bronchial lavage). Granulomas were found in 85% (11/13) of lung, 100% (15/15) of liver, and 56% (9/16) of bone marrow tissue specimens. Acid-fast bacilli staining was negative in all (0/21), while PCR was positive in 47% (7/15) of specimens with granulomata. Mortality was 18%. Stepwise logistic regression identified male sex (P = 0.005), non-typical miliary pattern (P = 0.015), altered mental status (P = 0.002) and failure to treat for TB (P = 0.00001) as independent predictors of mortality.
Conclusions: Miliary infiltrates on chest X-ray or FUO should raise the possibility of miliary TB. Therapy should be administered urgently to prevent an otherwise fatal outcome.