Miliary tuberculosis is a potentially life-threatening type of tuberculosis that occurs when a large number of the bacteria travel through the bloodstream and spread throughout the body.
Tuberculosis is a contagious infection caused by the airborne bacteria Mycobacterium tuberculosis. Tuberculosis usually affects the lungs in one or a few locations. Miliary tuberculosis is so named because the innumerable tiny spots that form in the lungs are the size of millet, the small round seeds in bird food.
Miliary tuberculosis may affect one organ or several organs or occur throughout the body. It most often affects the lungs, liver, and bone marrow but may affect any organ, including the tissues that cover the brain and spinal cord (meninges) and the two-layered membrane around the heart (pericardium).
Miliary tuberculosis occurs most often in the following:
Children under 4 years old
People with a weakened immune system
Older people
Symptoms of Miliary TB
Symptoms of miliary tuberculosis can be vague and difficult to identify. They include weight loss, fever, chills, weakness, general discomfort, and difficulty breathing.
Infection of the bone marrow may cause severe anemia and other blood abnormalities, suggesting leukemia.
If bacteria are intermittently released into the bloodstream from an unrecognized infection, people may have a fever that comes and goes and may gradually lose weight, wasting away.
Diagnosis of Miliary TB
Examination and culture of a sample from the infected area
When available, nucleic acid amplification tests
Tuberculin skin test or blood tests to detect tuberculosis
A chest x-ray
Diagnosis of miliary tuberculosis is similar to the diagnosis of pulmonary tuberculosis.
Samples of infected fluids may be examined under a microscope and/or sent to a laboratory to be grown (cultured) and tested. Samples may be
Blood
Cerebrospinal fluid, obtained by spinal tap (lumbar puncture)
Urine
Fluid from the space between the two layers of the membrane that surrounds the lungs (pleura)
Fluid from the space between the two layers of the membrane that surrounds the heart (pericardium)
Joint fluid
Bone marrow
Mycobacterium tuberculosis can sometimes be identified by doing nucleic acid amplification tests (NAATs) on certain types of samples. NAATs look for an organism's unique genetic material, its DNA or RNA (which are nucleic acids). NAATs use a process that increases the amount of the bacteria's DNA or RNA so that it can be more easily identified.
The tuberculin skin test or blood tests to detect tuberculosis (interferon-gamma release assay) are done.
A chest x-ray may show the thousands of small spots that are typical in miliary tuberculosis. Other imaging tests are done depending on which areas of the body are affected. They may include computed tomography (CT), ultrasonography, and magnetic resonance imaging (MRI).
Treatment of Miliary TB
Antibiotics
Sometimes corticosteroids
Sometimes surgery
Generally, treatment of miliary tuberculosis is similar to the treatment of pulmonary tuberculosis.
Antibiotics are given usually given for 6 to 9 months, unless the meninges are affected. Then antibiotics are given for 9 to 12 months.
Tuberculosis bacteria can easily develop resistance to antibiotics, particularly when people do not take the drugs regularly or for as long as they are supposed to.
Corticosteroids may help if the pericardium or meninges are affected.
Surgery is needed for some complications of miliary tuberculosis.
