In a febrile patient what is the most likely cause of a miliary pattern? What is the differential?
Miliary tuberculosis is by far the most likely cause. Other causes include fungal, viral pneumonitis, nocardosis and salmonella. Hypersensitivity pneumonitis can cause a miliary sort of pattern but if a fever is present it is usually mild.
CT of the chest confirms the presence of innumerable small pulmonary nodules, which have a centrilobular predilection. Dependent changes are also present. The mediastinum is unremarkable.
CT of the upper abdomen demonstrates splenomegaly with multiple hypo-attenuating nodules, best seen on the portal venous phase.