This document provides an overview of interstitial lung diseases (ILD), also known as diffuse parenchymal lung diseases (DPLD). It begins by defining the pulmonary interstitium and reviewing the spectrum of ILD. Common clinical presentations are discussed. The document then reviews approaches to diagnosis, including history, physical exam, imaging like chest x-ray and CT, pulmonary function tests, and lung sampling. Common radiographic patterns seen in ILD like ground glass, reticulation, nodules and cysts are also summarized.
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Approach To Diffuse Parenchymal Lung Diseases
1.
2. Approach To
Interstitial Lung Diseases
or
Diffuse Parenchymal Lung
Diseases
Gamal Rabie Agmy, MD, FCCP
Professor of Chest Diseases, Assiut university
ERS National Delegate of Egypt
3. Objectives
• Review the spectrum of ILD or DPLD
• Identify clues on presentation to make
the diagnosis
• Review common radiographic findings
in ILD
• Come up with an algorithm to make
the diagnosis
4.
5. • Interstitial compartment is
the portion of the lung
sandwiched between the
epithelial and endothelial
basement membrane
• Expansion of the interstitial
compartment by
inflammation with or without
fibrosis
– Necrosis
– Hyperplasia
– Collapse of basement
membrane
– Inflammatory cells
What is the Pulmonary
Interstitium?
6.
7. The interstitium of the lung is not normally visible radiographic-
ally; it becomes visible only when disease (e.g., edema,
fibrosis, tumor) increases its volume and attenuation.
The interstitial space is defined as continuum of loose
connective tissue throughout the lung composed of three
subdivisions:
(i) the bronchovascular (axial), surrounding the bronchi,
arteries, and veins from the lung root to the level of the
respiratory bronchiole
(ii) the parenchymal (acinar), situated between the alveolar
and capillary basement membranes
(iii) the subpleural, situated beneath the pleura, as well as in
the interlobular septae.
The Lung Interstitium
9. The terminal bronchiole in the center
divides into respiratory bronchioles with
acini that contain alveoli.
Lymphatics and veins run within the
interlobular septa
Centrilobular area in blue (left)
and perilymphatic area in yellow
(right)
12. Clinical Presentation
• Dyspnea on exertion or a persistent non
productive cough
• Abnormal CXR
• Pulmonary symptoms associated with
another disease, such as CVD
• PFT abnormalities
13. Approach to DPLD
DPLD of known
Cause
Idiopathic Interstitial
Pneumonias
Granulomatous
Lung Diseases
(Sarcoidosis)
Drugs Exposure CVD IPF IIP other than IPF
Desquamative Interstitial
Pneumonia
Non SpecificInterstitial
Pneumonia
Respiratory Bronchiolitis-
Interstitial Lung disease
Acute Interstitial
Pneumonia
CryptogenicOrganizing
Pneumonia
LymphocyticInterstitial
Pneumonia
Hypersensitivity
Pneumonitis
Pneumoconiosis
Others
LAM
Histiocytosis X
Malignancy
RadiationToxic Inhalation
IPF: 47-64%
NSIP: 14 to 36%
RBILD/DIP: 10-
17%
COP: 4-12%
AIP: 2%
LIP: 2%
14. Incident Cases of ILD
Sarcoidosis
8%
Occupation
11% DILD
5% DAH
4%
CTD
9%
Other
11%
Pulmonary Fibrosis
52%
CoultasAJRCCM 1994; 150:967
(Incidence of IPF=26-31 per 100,000)
15. Adapted from Ryu JH, et al. Mayo Clin Proc. 1998;73:1085-1101.
Adapted from ATS/ERS. Am J Respir Crit Care Med. 2002;165:277-304.
1970
Liebow and Carington
2002
ATS/ERS
UIP
NSIP
DIP-RBILD
AIP
UIP/IPF
NSIP
DIP
RB-
ILD
AIP
Cellular
Fibrotic
COP
LIP
Historical Classification of IIP
UIP
DIP
UIP-BO
LIP
Giant cell IP
1997
Katzenstein
16. Clinical Assessment
• History
• Physical Exam
• Chest Radiograph
• Pulmonary Function Testing
– At Rest
– Exercise
• Serologic Studies
• Tissue examination
17. History
• Age
• Gender
• Smoking history
• Medications
• Duration of symptoms
• Environmental exposure
• Occupational exposure
• Family history
18. History: Age and Gender
– LAM
– Tuberous sclerosis
– Pneumoconiosis
Age Gender
19. History: Smoking
• All of the following
DPLD are associated
with smoking :
a) IPF
b) RBILD
c) DIP
d) Histiocytosis X
e) Syndrome of IPF &
emphysema
• In Goodpasture’s
syndrome
– 100% of smokers vs. 20%
of nonsmokers
experience pulmonary
hemorrhage
• Individuals exposed to
asbestos who smoke are
more likely to develop
asbestosis
33. CXR: LlMITATIONS
• CXR is normal:
– in 10 to 15 % of symptomatic patients with
proven infiltrative lung disease
– 30% of those with bronchiectasis
– ~ 60 % of patients with emphysema
• CXR has a sensitivity of 80% and a
specificity of 82% percent for detection
of DPLD
• CXR can provide a confident diagnosis
in ~ 23 % of cases
34. A normal CXR does not rule
out the presence of DPLD
45. Other findings
Spider appearance of the interlobular
vessels due to interstitial opacities
around the vessels
Thickened interlobar fissures
Sub-pleural lines [curvilinear arc
lines parallel to the pleura]
Ground glass density
Interstitial lung disease
55. F 59Y, with radical mastectomy
Lymphangitis carinomatosa
56. • Interstitial pattern similar to interstitial edema
which progresses to alveolar pattern
[busulfan, bleomycin, cytoxan,..]
• Alveolar in filtrates similar to pulmonary
edema [penicillin, sulfonamides,..]
• Pleural and pericardial effusion + basal
infilterates [isonaizid,…]
• Hilar adenopathy [antionvulsant,..]
Drug induced lung diseases
Immunologic reaction to drugs
Busulfan
interstitial lung disease
57. Air space filling disease
Replacement of alveolar air by fluid, cells, other material
Represents an ongoing potentially treatable lesion
Ground glass density [geographic
distribution] morphologic changes below
the resolution of CT due to
Ground glass pattern
AlveolarInterstitial
58. ERS 2008
HISTOLOGIC CORRELATIONS IN
GGO
a) granulomata beyond special resolution
b) thickening of the interstitium (cellularphase OR fibrosis)
c) partial filling of the alveoli (associatedwith cellular phase
at BAL)
d) increased blood volume
e) combination of all the above
59. ERS 2008
GROUND GLASS OPACITIES
CT-pathologic correlation
•Partially filled alveoli
•Active interstitial inflammation
•Fine fibrotic process
•Hyperemia
variety of interstitial, alveolar and vascular diseases
below the threshhold of spatial resolution of HRCT
Leung AN, Miller RR, Muller NL. Radiology 1993;188:209 –214
RULE OUT FINE
FIBROSIS:
traction
bronchiectasis
TO FURTHER FOCUS DD
TIMING
CLINICAL SETTING
BAL
Vessel caliber
60. ERS 2008
DIP
• onset of symptoms : ~ 40 yrs
• dyspnoea and cough
• male predominance: 2>1
• inspiratory crackles : 60%
• digital clubbing :50%
90% of patients with DIP smoked or had smoked cigarettes
-in children DIP it is probably a different disease not related to smoking
-DIP also occurs in non-smokers (of 40 cases of Carrington et al: 10%)
-association with systemic disorders or infections
-DIP element (focal pigmented macrophage accumulation) histologically
in all smokers - “DIP-like reaction”
RARE DISEASE
Hartman et al Radiology 1993 (n=22 from 5 centers)
64. ERS 2008
EAA
1. Centilobular nodules
• Ill defined (unlike
sarcoidosis)
2. Patchy or diffuse GGO
3. Superimposition of (1)
and (2)
4. Geographic low
density areas on
inspiratory HRCT
5. Regional air trapping
on expiratory HRCT
Outpatients with Slowly Progressive Dyspnea
66. Ground glass pattern
[ Increased attenuation of the lung with preserved broncho vascular marking]
Patients with AIDS, ground glass
opacities= P.carinii pneumonia
Patients with lung transplant
ground glass opacities=
cytomegalovirus pneumonia or rejection
P.carinii pneumonia in
an AIDS patient
67. Air bronchogram sign
Air filled bronchi passing through opaque lung parenchyma
Pulmonary
lesion
Alveolar
pathology
Consolidation
72. Diffuse pulmonary hemorrhage
Hemoptysis, anemia and air space opacities
Appear rapidly and clear within few days
Spare the lung apex and peripheral zones
Bilateral, may be asymmetric, air bronchogram
Repeated attacks → pulmonary fibrosis
Pulmonary hemorrhage
(normal heart) [3 days, 6
days, one month]
74. Bronchoalveolar carcinoma
6-10% of primary lung cancer
Cough, sputum, weight loss, hemoptysis, bronchorrhea
Radiographic patterns :
Single or multiple pulmonary nodules[ Air bronchogram]
Segmental or lobar consolidation.
Diffuse air space disease .
CT angiogram (non specific)
Other causes: Lymphoma,
pulmonary edema, some
types of pneumonia
[obstructive, lipoid]
Visualization of
pulmonary vessels
within airless lung
79. F 72 Y with chest pain dyspnea and
frothy expectoration
80. Alveolar proteinosis
Alveolar filling by proteinaceous material
Male : female 4:1
Possible causes:
Idiopathic Occupational (silica)
Drug- induced Immune compromise
Geographic distribution of areas of ground
glass opacities + thickened interlobular septa
within crazy paving appearance
Air bronchogram is uncommon
81. Photograph of a pavement street in Buenos Aires, Argentina (left), drawings
of the lungs (center) and lung tissue (top right), and close-up high-resolution
CT scan (bottom right) show the crazy-pavingpattern.
87. • Fine interstitial opacities with B Kerley’s lines (early)
• Multiple nodular shadows scattered in the lungs (classic)
• Sparing apex and base
• Calcification may occur
Silicosis
Inhalation of high concentrations of silicon dioxide
88. Progressive massive fibrosis
Nodules enlarge and coalesce to form masses
Bilateral, almost symmetrical
• Almost always in the upper ½ of the lungs
• The more the fibrosis, the less apparent
nodules
90. • Most patients are asymptomatic
• Dense sharply defined nodules
• The density is greatest in the lung bases
• Black pleura sign [unaffected pleura
between lung and ribs]
Pulmonary alveolar microlithiasis
Innumerable tiny calcific particles are diffusely distributed in the alveoli
107. Langerhans Cell Histiozytosis
Key Features
Upper lobe predominance
Combination of cysts and noduli
Characteristic stages
Increased Lung volume
Sparing of costophrenic angle
S
M
O
K
I
N
G
114. LIP = Lymphocytic Interstitial
Pneumonia
Rarely idiopathic
In association with:
Sjögren’s syndrome
Immune deficiency syndromes, AIDS
Primary biliary cirrhosis
Multicentric Castlemean’s disease
115. Sjoegren disease
Dry eye and dry mouth
Fibrosis, bronchitis and bronchiolitis
LIP
Overlap
Sarcoid, DM/PM, MXCT
SLE, RA (pleural effusion)
Up to 40 x increased risk for lymphoma (mediastinal
adenopathy) and
2 x times increased risk for neoplasma
120. Outline
Typical HRCT patterns of lung diseases
with cysts
Mosaic pattern and its differential
Emphysema
Atypical HRCT patterns
Quiz
121.
122. Where is the pathology ???????
in the areas with increased density
meaning there is ground glass
in the areas with decreased density
meaning there is air trapping
123. Pathology in black areas
Airtrapping: Airway
Disease
Bronchiolitis obliterans (constrictive bronchiolitis)
idiopathic, connective tissue diseases, drug reaction,
after transplantation, after infection
Hypersensitivity pneumonitis
granulomatous inflammation of bronchiolar wall
Sarcoidosis
granulomatous inflammation of bronchiolar wall
Asthma / Bronchiectasis / Airway diseases
124. Airway Disease
what you see……
In inspiration
sharply demarcated areas of seemingly increased
density (normal) and decreased density
demarcation by interlobular septa
In expiration
‘black’ areas remain in volume and density
‘white’ areas decrease in volume and increase in
density
INCREASE IN CONTRAST
DIFFERENCES
AIRTRAPPING
131. Pathology in white Areas
Alveolitis / Pneumonitis
Ground glass
desquamative intertitial pneumoinia (DIP)
nonspecific interstitial pneumonia (NSIP)
organizing pneumonia
In expiration
both areas (white and black) decrease in
volume and increase in density
DECREASE IN CONTRAST
DIFFERENCES
142. CT findings:
• Relatively well-defined, low attenuation areas
with very thin (invisible) walls, surrounded by
normal lung parenchyma.
• As disease progresses:
– Amount of intervening normal lung decreases.
– Number and size of the pulmonary vessels
decrease.
– +/- Abnormal vessel branching angles (>90o), with
vessel bowing around the bullae.
143. Emphysema
•Curved arrow: area of low attenuation.
•Solid arrow: zones of vascular disruption.
•Open arrow: area of lung destruction.
145. Quantitative CT:
• Spirometically triggered images at 10% and
90% vital capacity (VC) have been reported
to be able to distinguish patients with chronic
bronchitis from those with emphysema.
– Patients with emphysema had significantly lower
mean lung attenuation at 90% VC than normal
subjects or patients with chronic bronchitis.
– Attenuation was the same for normal subjects and
those with chronic bronchitis.
149. Most frequent CT findings of
bronchiactasis:
• Lack of tapering of the bronchial
lumen
• Bronchial wall thickening
• Bronchial dilatation
• Visualized peripheral bronchi
• Mucus plugging
Most frequent
Less frequent
157. …..black holes……
Clues to Diagnosis
Is there a wall ?
What is the shape and size ?
Smoker ?
Other signs
(e.g., bronchiectasis, pulmonary hypertension)
158.
159. ERS 2008
Reversed Halo Sign on High-Resolution CT of Cryptogenic
Organizing Pneumonia
Kim et al AJR 2003; 180:1251-1254
90% of their pts!
reversed halo signs (central ground-glass opacity and surrounding air-space consolidation of
crescentic and ring shapes)
Voloudaki et al
GGO ring : septal inflammation
cellular debris
organising pneumonia
160. Uncommon cause of respiratory distress in young males
Patients have history of significant cigarette smoking
Multiple large bullae impair the pulmonary mechanics
Bullous lung disease
Primary bullous disease – Vanishinglung syndrome
50Y M
174. Linear Pattern
A linear pattern is seen when there is
thickening of the interlobular septa,
producing Kerley lines.
Kerley B lines
KerleyA lines
The interlobular septa contain
pulmonary veins and lymphatics.
The most common cause of interlobular
septal thickening, producing Kerley A
and B lines, is pulmonary edema, as a
result of pulmonary venous
hypertension and distension of the
lymphatics.
Kerley B lines
Kerley A lines
175. DD of Kerly Lines:
Pulmonary edema is the most common cause
Mitral stenosis
Lymphangitic carcinomatosis
Malignant lymphoma
Congenital lymphangiectasia
Idiopathic pulmonary fibrosis
Pneumoconiosis
Sarcoidosis
176.
177. b. Reticular Pattern
A reticular pattern results from the summation
or superimposition of irregular linear
opacities.
The term reticular is defined as meshed, or in
the form of a network. Reticular opacities can be
described as fine, medium, or coarse, as the
width of the opacities increases.
A classic reticular pattern is seen with pulmonary fibrosis,
in which multiple curvilinear opacities form small
cystic spaces along the pleural margins and lung
bases (honeycomb lung)
178. This 50-year-old man presented with end-stage lung fibrosis
PA chest radiograph shows medium to coarse reticular
B: CT scan shows multiple small cysts (honeycombing) involving
predominantly the subpleural peripheral regions of lung. Traction
bronchiectasis, another sign of end-stage lung fibrosis.
179. c. Nodular pattern
A nodular pattern consists of multiple round opacities,
generally ranging in diameter from 1 mm to 1 cm
Nodular opacities may be described as miliary (1 to 2 mm,
the size of millet seeds), small, medium, or large, as the
diameter of the opacities increases
A nodular pattern, especially with predominant
distribution, suggests a specific differential diagnosis
181. Hematogenous metastases and nodular ILD. This 45-year-
old woman presented with metastatic gastric carcinoma.
The PA chest radiograph shows a diffuse pattern of
nodules, 6 to 10 mm in diameter.
183. d. Reticulonodular pattern results
A reticulonodular pattern results from a
combination of reticular and nodular opacities.
This pattern is often difficult to distinguish from
a purely reticular or nodular pattern, and in
such a case a differential diagnosis should be
developed based on the predominant pattern.
If there is no predominant pattern, causes of
both nodular and reticular patterns should be
considered.
185. An acute appearance suggests pulmonary
edema ,miliary TB,DAD or pneumonia
Rule no. 1
186. Disseminated histoplasmosis and reticulonodular ILD.
A: PA chest radiograph, close-up of right upper lung, shows reticulonodular
ILD.
B: CT scan shows multiple circumscribed round pulmonary nodules, 2 to 3
mm in diameter.
190. Systemic sclerosis.
A: PA chest radiograph shows a bibasilar and subpleural distribution of fine
reticular ILD. The presence of a dilated esophagus (arrows) provides a clue
to the correct diagnosis.
B: CT scan shows peripheral ILD and a dilated esophagus (arrow).
191. A middle or upper lung predominant distribution
suggests: (Mycobacterium Settle Superiorly in
Lung)
1. Mycobacterial or fungal disease
2. Silicosis
3. Sarcoidosis
4. Langerhans Cell Histiocytosis
Rule no. 3
192. Complicated silicosis. PA chest radiograph shows multiple
nodules involving the upper and middle lungs, with coalescence
of nodules in the left upper lobe resulting in early progressive
massive fibrosis
193. Sarcoidosis. CT scan shows nodular thickening of the bronchovascular
bundles (solid arrow) and subpleural nodules (dashed arrow), illustrating the
typical perilymphatic distribution of sarcoidosis.
194. Langerhan cell histiocytosis.
This 50-year-old man had a
30 pack-year history of
cigarette smoking.
A: PA chest radiograph
shows hyperinflation of the
lungs and fine bilateral
reticular ILD.
B: CT scan shows multiple
cysts (solid arrow) and
nodules (dashed arrow).
199. Cardiogenic pulmonary edema.
PA chest radiograph shows enlargement of the cardiac
silhouette, bilateral ILD, enlargement of the azygos vein
(solid arrow), and peribronchial cuffing (dashed arrow).
200. Lymphangitic carcinomatosis. This 53-year-old man
presented with chronic obstructive pulmonary disease and
large-cell bronchogenic carcinoma of the right lung.
CT scan shows unilateral nodular thickening (arrows) and a
malignant right pleural effusion.
202. Lymphangioleiomyomatosis
(LAM).
A: PA chest radiograph shows a
right basilar pneumothorax and
two right pleural drainage
catheters. The lung volumes are
increased, which is
characteristic of LAM, and there
is diffuse reticular ILD.
B: CT scan shows bilateral thin-
walled cysts and a loculated
right pneumothorax (P).
205. 5. A middle or upper lung predominant
1. Mycobacterial or fungal disease
2. Silicosis
3. Sarcoidosis
4. Langerhans Cell Histiocytosis
6. Associated lymphadenopathy
1.Sarcoidosis
2.neoplasm (lymphangitic
carcinomatosis, lymphoma,
metastases)
3. infection (viral, mycobacterial, or
fungal)
4. Silicosis 5.CHF
7. Pleural Thickening
and or Calcification
•Asbestosis
206.
207. Approach to the ILD Patient
Martinez F, Flaherty K. Available at: http://www.chestnet.org/education/online/pccu/vol18/lessons03_04/lesson03.php.
Patient with Suspected
ILD
Hx, PE, CXR, PFT, Labs
STOP
HRCT
Hx and HRCT
consistent
with IPF
Hx and HRCT
Dx of other
ILD
Suspected
other ILD
Atypical
clinical or CT
features of IPF
STOP STOP
STOP
VATS
UIP Non IIPLIPOPDADDIPNSIP RBILD
Yes
No
Yes
No
Dx likely by
bronch?
Is bronch
diagnostic?
Dx likely by
bronch?
Is bronch
diagnostic?
Yes
Yes
No