Thus, hypercalcemia proves to be an important symptom of miliary tuberculosis.Thirdly, chorodial tubercules, pale lesions on the optic nerve, typically indicate miliary tuberculosis in children. These lesions may occur in one eye or both; the number of lesions varies between patients. Chorodial tubercules may serve as important symptoms of miliary tuberculosis, since their presence can often confirm suspected diagnosis.Lastly, between 10 and 30% of adults, and 20–40% of children with miliary tuberculosis have tuberculosis meningitis. This relationship results from mycobacteria from miliary tuberculosis spreading to the brain and the subarachnoid space; as a result, leading to tuberculosis meningitis.The risk factors for contracting miliary tuberculosis are being in direct contact with a person who has it, living in unsanitary conditions, and poor nutrition. In the U.S., risk factors for contracting the disease include homelessness and HIV/AIDS. Cause
Miliary tuberculosis is a form of tuberculosis that is the result of Mycobacterium tuberculosis travelling to extrapulmonary organs, such as the liver, spleen and kidneys. Although it is well understood that the bacteria spread from the pulmonary system to the lymphatic system and eventually the blood stream, the mechanism by which this occurs is not well understood.One proposed mechanism is that tuberculous infection in the lungs results in erosion of the epithelial layer of alveolar cells and the spread of infection into a pulmonary vein. Once the bacteria reach the left side of the heart and enter the systemic circulation, they may multiply and infect extrapulmonary organs. Once infected, the cell-mediated immune response is activated.
The infected sites become surrounded by macrophages, which form granuloma, giving the typical appearance of miliary tuberculosis.Alternatively, the bacteria may attack the cells lining the alveoli and enter the lymph node(s). The bacteria then drain into a systemic vein and eventually reach the right side of the heart. From the right side of the heart, the bacteria may seed—or re-seed as the case may be—the lungs, causing the eponymous "miliary" appearance. Diagnosis
Testing for miliary tuberculosis is conducted in a similar manner as for other forms of tuberculosis, although a number of tests must be conducted on a patient to confirm diagnosis. Tests include chest x-ray, sputum culture, bronchoscopy, open lung biopsy, head CT/MRI, blood cultures, fundoscopy, and electrocardiography. The tuberculosis (TB) blood test, also called an Interferon Gamma Release Assay or IGRA, is a way to diagnose latent TB. A variety of neurological complications have been noted in miliary tuberculosis patients—tuberculous meningitis and cerebral tuberculomas being the most frequent. However, a majority of patients improve following antituberculous treatment. Rarely lymphangitic spread of lung cancer could mimic miliary pattern of tuberculosis on regular chest X-ray. The tuberculin skin test, commonly used for detection of other forms of tuberculosis, is not useful in the detection of miliary tuberculosis. The tuberculin skin test fails due to the high numbers of false negatives.