Miliary Tuberculosis

Pathophysiology:  Miliary tuberculosis may occur during unchecked primary tuberculosis or during reactivation tuberculosis.  Very rare in atypical tuberculosis.  May be most florid in immuno-compromised hosts: patients on steroids, HIV, etc…

CXR Findings:  The classic “miliary” pattern, named after the millet seed which is a few millimetres in diameter.

Diffuse, dense micro-nodular pattern throughout the lungs.

Adenopathy and pleural effusions may be present.

Approach to a “Micronodular” Pattern on CXR:

ALWAYS exclude tuberculosis, clinically and bacteriologically

“Aunt Sophies”:  miliary sarcoidosis, miliary mycoplasma pneumonia, silicosis, vasculitis, microdular metastases (eg. thyroid, pulmonary histiocytosis X in upper lung) and drugs (eg. methotrexate)