The second stage can present two different sets
of abnormalities. Mikity, et all2 reported a second
stage beginning at approximately six weeks and
consisting of enlargement of the cysts at the bases
to form blebs. The lower lobes become hyperexpanded
and hyperlucent, and the diaphragms are
flattened. Cystic changes and the reticular infiltrate
persist in the upper lung fields. Alternatively,