Miliary tuberculosis (TB) refers to clinical disease resulting from the hematogenous dissemination of Mycobacterium tuberculosis. The term miliary was coined in 1700 by John Jacobus Manget, who likened the appearance of the involved lung, with its surface covered with firm small white nodules, to millet seeds (picture 1). Originally a pathologic and then a radiographic description, the term miliary TB is now used to denote all forms of progressive, widely disseminated hematogenous TB. Miliary TB can arise as a result of progressive primary infection or via reactivation of a latent focus with subsequent spread.
The clinical manifestations, diagnosis, treatment, and prevention of miliary TB will be reviewed here. The pathogenesis and epidemiology of miliary TB are discussed separately. (See "Epidemiology and pathology of extrapulmonary and miliary tuberculosis".)
Several large retrospective series provide much of the data on the clinical features of miliary tuberculosis (TB) (table 1) [1-6]. While these studies include a relatively large number of patients, they differ markedly by year, inclusion criteria, country, and type of medical center, so direct comparison is difficult.
The clinical presentation of miliary TB is highly variable; manifestations can be acute but are more likely to be subacute or chronic. In highly endemic areas, miliary TB may be associated with reinfection. Development of miliary TB during primary infection can present with relatively acute onset and rapid clinical course. Acute disease may be fulminant, including multiorgan system failure , a syndrome of septic shock , and acute respiratory distress syndrome (ARDS) [9,10].
The subacute or chronic presentations of miliary TB are more common than acute disease. These patients may present with failure to thrive , fever of unknown origin , or dysfunction of one or more organ systems . The most common extrapulmonary sites of disease include the lymphatic system, bones and joints, and the liver. Night sweats are frequent. Rigors are unusual but have been described [12,13]. In one series including 38 patients, the median duration of illness was two months . Symptoms and signs of miliary TB are described in the Tables (table 2 and table 3).