|
Clinical Course
o
Progressive respiratory insufficiency with hypoxemia and
cyanosis
o
Secondary pulmonary hypertension develops due to
extensive fibrosis
o
Cor
pulmonale eventually results
§
This
is hypertrophy of the right ventricle due to a disorder
of the lungs
o
The
disease course is unpredictable and may spontaneously
resolve, but usually there is rapid progression with
significant fibrosis over a period of several weeks to
months
o
Median survival is far less than 5 years
Morphology
o
The
process is patchy and temporally heterogeneous
pulmonary fibrosis
o
organization of the exudate with interstitial fibrosis
o
Diseased areas always alternate with normal-appearing
lung parenchyma
o
honeycomb lung (end-stage fibrosis)
§
after several months or years
§
the
lung is completely non-functional
This is what a honeycomb looks like – you can see areas
that are not involved, on the left, and the honeycombed
lung, on the right.
These patients are usually given steroids to decrease
inflammation to make them feel a little better but there
really isn’t much else you can do for them.
Desquamative Interstitial Pneumonitis (DIP)
Some believe that DIP is the early form of UIP
-
Characterized by marked accumulation of alveolar
macrophages within alveolar spaces
-
There is a mononuclear interstitial infiltrate/
pneumonitis
-
Type
II pneumocyte hyperplasia
-
Cause is unknown
-
Middle aged men and women affected (not specifically
mentioned)
-
The
histologic picture is diffuse and uniform throughout the
lung (not patchy as in UIP)
Clinical Course
o
cough, dyspnea
o
often a history of recent viral respiratory tract
infection (not specifically mentioned)
o
x-ray: migratory patchy opacities or interstitial
infiltrates
o
most
patients improve gradually on steroid therapy (85%
resolve with long term steroids)
o
Some
will go onto UIP
§
>50% have 5 year survival
Within the alveolar space in DIP, we have macrophages
along with interstitial pneumonitis throughout the lung.
Type II pneumocyte hyperplasia can also be seen.
Lymphocytic Interstitial Pneumonia (LIP)
-
Interstitial pneumonitis
in which there are diffuse lymphoid infiltrates in
the interstitium
-
May
be idiopathic
-
dysproteinemia, collagen vascular disease (not
specifically mentioned)
-
Important in HIV infection - LIP is one of the
AIDS-defining illnesses in children
o
a
child with LIP is guaranteed to have HIV
-
diffuse infiltration of the alveolar septa by chronic
inflammatory cells (lymphocytes, plasma cells and
macrophages)
-
the
alveolar architecture is preserved (not specifically
mentioned)
-
cough, progressive dyspnea
-
prognosis varies; disease may regress or progress to
end-stage lung
-
Steroids and cytotoxic agents may help
Back to the Respiratory System
Index
|
