However , pulmonary fibrosis can also appear without any known cause .
Examples include autoimmune disorders , viral infections and bacterial infection like tuberculosis which may cause fibrotic changes in both lung 's upper or lower lobes and other microscopic injuries to the lung .
Pulmonary fibrosis can also appear without any known cause .
Examples include autoimmune disorders , viral infections and bacterial infection like tuberculosis which may cause fibrotic changes in both lung 's upper or lower lobes and other microscopic injuries to the lung .