Miliary

By Peter Galvin, MD

A 57-year-old man with a history of pulmonary tuberculosis (TB) presented to the emergency department at a medical center in Seoul, South Korea. He had a two-week history of neck pain, headache, and tingling in his right hand. Physical examination revealed decreased grip strength in the right hand. A CT scan of the chest revealed a miliary pattern of nodules in both lungs. An MRI scan of the head with gadolinium contrast revealed numerous, small, spherical, peripheral nodules in the brain that were enhanced by the gadolinium contrast (see Panels A and B). The nodules were seen in both cerebral hemispheres, basal ganglia, cerebellum, and brain stem as well as the upper spinal cord (Panel C).

Analysis of the spinal fluid (obtained via a spinal tap) was normal, and cultures of the fluid showed no growth. A sputum culture grew Mycobacterium tuberculosis, one of the causative agents of tuberculosis. A diagnosis of central nervous system (CNS) tuberculomas in the presence of miliary tuberculosis was made. Tuberculomas are inflammatory lesions that result from the hematogenous (via the bloodstream) spread of tuberculosis. When many such lesions are present in the brain, the pattern seen on CT or MRI imaging is known as a “starry night”. CNS tuberculomas may or may not be associated with tuberculous meningitis (inflammation of the lining of the brain).

Miliary TB was first described in 1700 by John Jacob Manget (he named it milarius because the lesions looked like millet seeds). It is the wide dissemination of tiny lesions (1-5 mm) seen on chest X rays in both lung fields. Miliary TB can also affect other organs including the liver and spleen and may cause tuberculous meningitis. It is usually fatal if untreated. The treatment of TB can be difficult. M tuberculosis grows very slowly (cultures may take up to six weeks to show growth) and resistance to anti-TB meds is common, so treatment of TB must be both prolonged and multiple antibiotics must be used, usually involving 3–4 meds given simultaneously.

The patient in this case was placed on multiple antibiotics and dexamethasone (a potent steroid). The dexamethasone was given to reduce brain swelling. His symptoms began to abate after one month, and a repeat brain MRI 18 months later was normal.

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