Miliary tuberculosis: clinical manifestations, diagnosis and outcome in 38 adults

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).

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).

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.

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.