Title: INTERSTITIAL LUNG DISEASE: A CLINICAL OVERVIEW AND GENERAL APPROACH
1INTERSTITIAL LUNG DISEASE A CLINICAL OVERVIEW
AND GENERAL APPROACH
- Tasaduk Khan. MD.FRCP(UK).FCCP(USA).
- Senior Consultant pulmonologist.
- Security forces hospital, Riyadh.
2Items
- Definition
- Epidemiology
- Classification
- Pathogenesis
- Diagnosis
- Treatment
- Final comments
3Items
- Definition
- Epidemiology
- Classification
- Pathogenesis
- Diagnosis
- Treatment
- Final comments
4- HAMMAN and RICH were the first to describe (in
1935 and 1944) four patients who died of rapidly
progressive lung disease characterized by diffuse
interstitial pneumonia and fibrosis. -
- Interstitium
- Refers to the microscopic anatomic space bounded
by the basement membrane of epithelial and
endothelial cells. - Within this interstitial space, fibroblast like
cells (mesenchymal and connective tissue cells)
and extracellular matrix components (interstitial
collagens, elastin, proteoglycans) are present
5Items
- Definition
- Epidemiology
- Classification
- Pathogenesis
- Diagnosis
- Treatment
- Final comments
6Epidemiology
- It is more frequent than previously recognized.
- Incidence ranges from 3 to 26 per 100.000 per
year. - The prevalence of preclinical and undiagnosed ILD
in the community is 10 times that of clinically
recognized. - Among these, IPF is the most common, representing
at least 30 of the incident cases.
7Items
- Definition
- Epidemiology
- Classification
- Pathogenesis
- Diagnosis
- Treatment
- Final comments
8Diffuse Parenchymal Lung Disease (DPLD)
Idiopathic interstitial pneumonias
DPLD of known cause, eg, drugs or association,
eg, collagen vascular disease
Granulomatous DPLD, eg, sarcoidosis
Other forms of DPLD, eg, LAM, HX, etc
Idiopathic pulmonary fibrosis
IIP other than idiopathic pulmonary fibrosis
Respiratory bronchiolitis interstitial lung
disease
Desquamative interstitial pneumonia
Cryptogenic organizing pneumonia
Acute interstitial pneumonia
Lymphocytic interstitial pneumonia
Nonspecific interstitial pneumonia (provisional)
ATS/ERS Consensus Statement. Am J Respir Crit
Care Med. 2002165277-304.
9Items
- Definition
- Epidemiology
- Classification
- Pathogenesis
- Diagnosis
- Treatment
- Final comments
10Four proposed mechanisms and potential variations
in lung responses to inhaled agents
Inhaled environmental agents (fumes, dust, smoke)
Delivery persistence
Genetic predisposition
Alveolar epithelial cell injury
Biochemical
Wound healing (inflammation, coagulation,
epithelial/endothelial repair)
Immunologic Fibrotic
Chronic airflow obstruction
Pulmonary fibrosis
Normal
11Recent Hypothesis
- Inflammatory hypothesis
- Epithelial Cell Apoptosis
- Angiogenesis
- Abnormal Matrix Turnover
- Th1 versus Th2 Cytokines
- Growth Factor Production
- Altered Fibroblast Phenotypes
- Myofibroblast Recruitment and Maintenance
12AGEGENETIC FACTORSENVIRONMENTAL FACTORSNATURE
OF INJURY
LUNG INJURY
- Etiologic agent
- Recurrent vs single
- Endothelial vs epithelial
Histopathologic Pattern
DIP
RB-ILD
LIP
COP
NSIP
AIP
UIP
Inflammation
Fibrosis
Thannickal VJ, et al. Annu Rev Med.
200455395-417.
13Items
- Definition
- Epidemiology
- Classification
- Pathogenesis
- Diagnosis
- Treatment
- Final comments
14Approach to the Diagnosis of ILD
- Clinical
- History
- Physical
- Laboratory
- PFTs
- Radiology
- Chest X-ray
- HRCT
- Pathology
- Surgical lung biopsy
Primary care physicians
Pulmonologists
Radiologists
Pathologists
Multidimensional and multidisciplinary
15Diagnosis
- History
- The patient's age, cigarette-smoking status and
sex may provide useful clues. - Thorough medical history that must include a
review of environmental factors, occupations,
exposures, medication, and drug usage and family
medical history. -
16Age
- Infancy and childhood
- Follicular bronchiolitis
- Cellular interstitial pneumonia
- Acute idiopathic pulmonary hemorrhage of infancy
17 Age (cont.)
- Before age 40
- Familial idiopathic pulmonary fibrosis
- Metabolic storage disorders
- Hermansky pudalic syndrome
- Other inherited interstitial lung diseases
- Collagen vascular disease- associated ILD
- LAM
- Pulmonary Langerhanscell granulomatosis
- Sarcoidosis
- After age 50 IPF 1 in 500 people over the age of
75 yrs.
18Race
- Sarcoidosis occurs 10-12 folds among blacks.
19Gender
- Gender clearly affects the way patients present
with pulmonary fibrosis Men tend to present
later in the disease, whereas women tend to
present earlier. - Women
- Collagen vascular disease- associated ILD
- LAM
- Tuberous sclerosis
- Men
- Pneumoconiosis
- IPF
20History (cont.)
- Smoking related ILD
- Desquamative interstitial pneumonia.
- RBILD.
- Pulmonary Langerhans cell histiocytosis.
- IPF.
- Rheumatoid arthritis associated ILD.
- Acute eosinophilic pneumonia.
21ILD by onset and duration
- Acute onset (days to weeks)
- AIP
- Acute pneumonitis from collagen vascular disease
(especially SLE) - COP
- Drugs
- DAH
- Eosinophilic lung disease
- Hypersensitivity pneumonitis
22ILD by onset and duration (cont.)
- Subacute (weeks to months)
- Collagen vascular disease- associated ILD
- COP
- Drugs
- Subacute hypersensitivity pneumonitis
- Chronic (months to years)
- Chronic hypersensitivity pneumonitis
- Collagen vascular diseaes- associated ILD
- IPF and NSIP
- Occupation related lung diseases.
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24Physical examination
- Physical examination of the respiratory system is
rarely helpful in the diagnostic evaluation of
interstitial lung diseases. - The classical Velcro rales or inspiratory
crackles, occur not only in most patients with
IPF but also in many other interstitial lung
diseases. -
25Clubbing
- Eighty percent of patients with clubbing have a
respiratory disorder. - Among patients with ILD clubbing is found in
25-50 of patients with IPF and 50 of patients
with DIP and 75 of patients with ILD from
rheumatoid arthritis.
26Chest Radiographic pattern
- First review previous chest radiographs as this
allows the clinician to ascertain the onset,
progression, chronicity and stability of
patient's disease. - A rare patient with ILD will present with a
normal chest radiograph. - When radiographic abnormalities are noted, their
distribution and appearance are useful in
narrowing the differential diagnosis of ILD.
27Radiographic Clues (cont.)
- Mid/upper lung field disease sarcoidosis,
silicosis, ankylosing spondylitis, histiocytosis
X. - Lower lung field predominance asbestosis,
idiopathic pulmonary fibrosis, collagen vascular
disease. - Kerley B lines congestive heart failure,
lymphangitic carcinoma, LAM. - Pleural plaques/ thickening asbestosis.
28Radiographic Clues (cont.)
- Photographic negative of pulmonary edema Chronic
eosinophilic pneumonia. - Recurrent pneumothorax
- Langerhans cell granulomatosis.
- LAM
- Tuberous sclerosis.
- Neurofibromatosis.
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32Computed tomography and high-resolution CT images
- CT and HRCT scans are more sensitive and have a
greater ability to detect anatomic abnormalities
than do chest radiograph. - Its impressive sensitivity help both in ruling
out a diagnosis of ILD and in defining the
parenchymal, pleural and mediastinal
abnormalities in these disorders. - It helps the surgeon to identify areas of
non-fibrotic, active disease and relatively
unaffected areas to guide appropriate site
selection for biopsy.
33Computed tomography and high-resolution CT images
- HRCT has the potential for differentiating
sarcoidosis, lymphangitic carcinomatosis and
bronchiolitis. - The presence of cystic images within the
parenchyma raises the possibilities of three
major cystic ILD - LAM, Tuberous sclerosis and Langerhans cell
granulomatosis - In LAM and Tuberous sclerosis, the cysts are
numerous, thin walled, typically less than 2 mm
in diameter and distributed throughout the
pulmonary parenchyma. - In Langerhans cell granulomatosis cysts are
bizar shaped and distributed predominantly in the
upper lobes.
34Computed tomography and high-resolution CT images
- In acute hypersensitivity pneumonitis HRCT show
multifocal diffuse ground glass attenuation
despite a normal chest radiograph. - Smokers with symptomatic RBILD typically have
patchy ground glass attenuation on HRCT. - IPF is characterized by patchy subpleural and
basilar fibrosis. - A normal HRCT does not exclude the presence of
microscopic ILD in a patient with a high pretest
probability of the disorder.
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38Pulmonary physiology testing
- Regardless of the cause, a restrictive lung
defect and decreased diffusing capacity (DLco)
are the predominant physiological abnormalities
seen in ILD. - Decreased FEV1, FVC, TLC
- The (PAO2 PaO2) difference, at rest or with
exercise may be normal or increased.
39- Differential diagnosis by function
- When there is a decrease in MVV out of proportion
to the decrease in FEV1 and a decrease in maximal
inspiratory pressures, diseases such as
polymyositis, scleroderma and SLE should come to
mind. - A mixed pattern of obstructive and restrictive
abnormalities may be present when ILD coexists
with COPD or Asthma.
40Routine laboratory tests
- Include
- Complete blood count, leucocytic differential
- ESR
- Chemistry profile (calcium, liver function tests,
electrolytes, renal function tests) - Screening for collagen vascular diseases and
urine analysis. - When appropriate, creatinine kinase, aldolase,
and angiotensin converting enzyme levels should
be measured.
41Bronchoscopy with transbronchial biopsy
- Provide additional information, especially when
tissue abnormalities tend to be distributed in
peribronchiovascular areas e.g. Sarcoidosis, LAM
and Lymphangitic carcinomatosis. - It may disclose certain distinctive abnormalities
e.g. - Tight, uniform, well formed non caseating
granulomas of sarcoidosis. - Smooth muscle proliferation of LAM.
- Lymphatic metastasis of malignant cells.
- Giant cell granulomas are suggestive of hard
metal pneumoconiosis. - It is diagnostic if an infectious agent or
malignancy is detected.
42Surgical lung biopsy Thoracoscopy-Guided and
open lung biopsy
- Surgical lung biopsy remains the gold standard
for diagnosis. It is, however, by no means always
definitive the size of specimens, site of
biopsy, expertise of pathologists and
interobserver differences among pathologists are
factors that may preclude a conclusive diagnosis. - The site of the biopsy should be chosen on the
basis of HRCT findings and ideally be at the
interface of involved and less involved lung
tissue. - A biopsy of more than one site in the lung is
more helpful.
43Diagnostic approach to suspected ILD
44American Journal of Respiratory Cell and
Molecular Biology VOL.29, 2003
45Items
- Definition
- Epidemiology
- Classification
- Pathogenesis
- Diagnosis
- Treatment
- Final comments
46Treatment
- The therapeutic regimen used for patients with
ILD needs to be tailored to the patient and the
disease process (disease-specific intervention). - Avoidance of the offending agent or its
environment. - The use of corticosteroids, alone or in
combination with immunosuppressives
(azathioprine, cyclophosphamide) is currently
recommended for most patients with chronic
fibrotic lung disorders. - However the clinical response is variable and
unpredictable, some ILDs generally have a better
prognosis and response more favorably than do
others.
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48 Other measures
- Plasmapheresis is indicated in intractable and
severe cases of alveolar hemorrhage syndrome
resistant to corticosteroids and
immunosuppressives. - Supplemental oxygen is indicated to maintain
adequate oxygen saturation. - Unless contraindicated, all patients should
receive pneumococcal and periodic influenza
vaccinations. - Other supportive measures such as rehabilitation
are indicated in appropriate patients. - Lung transplantation is a viable surgical option
for selected patients who don't respond to
currently available therapeutic regimens.
49Items
- Definition
- Epidemiology
- Classification
- Pathogenesis
- Diagnosis
- Treatment
- Final comments
50 Final Comments
- The interstitial lung diseases are a fascinating
collection of lung diseases that occur at any age
group and may develop as a consequence of an
extraordinarily broad collection of systemic
diseases. - The importance of a careful history and physical
examination cannot be overstated, and may obviate
many expensive diagnostic tests. - The diagnosis and management of interstitial lung
diseases often requires active discussion and
collaboration between the clinician, surgeon,
pathologist and radiologist.
51 THANKS