Interstitial Lung Disease
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Contents |
More Specific Terms
- acute interstitial pneumonia
- asbestosis
- berylliosis
- bronchiolitis
- bronchiolitis obliterans with organizing pneumonia (cryptogenic organizing pneumonia, BOOP)
- coal workers' pneumoconiosis
- drug-induced interstitial lung disease
- eosinophilic pneumonia
- familial hypocalciuric hypercalcemia
- glycogen storage disease (glycogenosis)
- Hermansky-Pudlak syndrome
- hypersensitivity pneumonitis; extrinsic allergic alveolitis; pigeon breeder's lung; farmer's lung; allergic pneumonitis
- idiopathic pulmonary fibrosis (IPF); Hamman-Rich syndrome; idiopathic alveolar fibrosis (IAF); usual interstitial pneumonitis (UIP)
- lymphangioleiomyomatosis
- neurofibromatosis (von Recklinghausen's disease)
- respiratory bronchiolitis associated interstitial lung disease (desquamative interstitial pneumonia, RBILD)
- sarcoidosis
- silicosis
- tuberous sclerosis (Bourneville disease)
Introduction
- Interstitial lung diseases are a heterogenous group of disorders characterized by acute, subacute or chronic infiltration of the alveolar walls of cells, fluid & connective tissue. The alveolar & interstitial inflammation, if left untreated, may progress to fibrosis with resultant irreversible disruption of alveolar architecture & impaired gas exchange.
- Interstitial lung diseases are a heterogenous group of disorders characterized by acute, subacute or chronic infiltration of the alveolar walls of cells, fluid & connective tissue. The alveolar & interstitial inflammation, if left untreated, may progress to fibrosis with resultant irreversible disruption of alveolar architecture & impaired gas exchange.
- Reference 2 considers 'diffuse parenchymal lung disease' a more appropriate term since these diseases are NOT restricted to the pulmonary interstitium, & not all interstitial tissue is necessarily affected.
Etiology
- occupational or environmental inhalants
-
- gases, fumes
- oxygen toxicity
- chlorine gas
- ammonia
- coal worker's pneumoconiosis
- silicosis
- asbestosis
- berylliosis
- drugs
- radiation
- infections (interstitial pneumonia)
- viral, bacterial, fungal, parasites
- non-specific interstitial pneumonia
- lymphocytic interstitial pneumonia
- cardiogenic
- non- cardiogenic
- lymphangitic spread of carcinoma
- carcinoma
- lymphoma
- alveolar carcinoma
- metabolic causes
- sarcoidosis
- idiopathic pulmonary fibrosis ( cryptogenic fibrosing alveolitis)
- connective tissue disease
- pulmonary vasculitis
- pulmonary hemorrhage
- Goodpasture's syndrome
- idiopathic hemosiderosis
- eosinophilic granuloma
- alveolar proteinosis
- amyloidosis
- pulmonary veno-occlusive disease
- microlithiasis
- inherited disorders
Pathology
- varying degrees of inflammation & fibrosis
- no evidence of granulomatous or vascular disease in the pulmonary parenchyma
Clinical-manifestations
- breathlessness
- non-productive cough
- acute presentation with fever suggests BOOP, drug-induced pulmonary injury or hypersensitivity pneumonitis
- crackles
- fibrosing interstitial lung disease
- idiopathic pulmonary fibrosis
- less common in sarcoidosis
- mid- inspiratory squeaks: bronchiolitis
- signs of pulmonary hypertension
- increased intensity of P2 heart sound
- right ventricular lift
- pansystolic murmur of tricuspid regurgitation
- idiopathic pulmonary fibrosis (30%)
- uncommon in:
- bronchiolitsi obliterans
- cryptogenic organizing pneumonia
- connective tissue disease
- maculopapular exanthum
- uveitis &/or conjunctivitis
- lacrimal gland or salivary gland enlargement
- connective tissue disease
- inflammatory bowel disease
- sarcoidosis
- Behcet's syndrome
- ankylosing spondylitits
- muscle weakness or myalgias: polymyositis
- neurologic signs/symptoms
- interstitial lung diseases that can present acutely
Laboratory
- arterial blood gas: variable
- complete blood count ( CBC)
- chemistry panel ( chem7)
- erythrocyte sedimentation rate (ESR)
- serology:
- serum BNP
- urinalysis [2]
Diagnostic-procedures
-
- variable, but often restrictive pattern
- reduced DLCO
- abnormal alveolar-arterial oxygen gradient at rest or with exertion
- airflow obstruction with or without restriction suggests:
- tissue diagnosis
- fiberoptic bronchoscopy
- open lung biopsy
- obtain tissue for pathology prior to initiation of:
- echocardiogram [2] ( pulmonary artery pressure)
- exercise stress testing ( physiologic response to exercise)
Radiology
-
- variable -> bilateral infiltrates
- not predictive of specific pathologic picture
- predominantly upper lobe interstitial infiltrates
- predominantly lower lobe infiltrates
- idiopathic pulmonary fibrosis
- connective tissue disorders
- asbestosis
- chronic hypersensitivity pneumonitis
- bilateral adenopathy suggests sarcoidosis
- high resolution computed tomography ( CT) of chest
- more sensitive & specific for diagnosis of interstitial lung disease than chest X-ray
- pseudoreticulation is a false-positive finding due to atelectasis in gravity-dependent lung regions
- obtain prior to lung biopsy
Management
- serial evaluation of disease activity:
- progression of disease
- effects of therapy
- treat underlying etiology if known
- supplemental O2
- acute respiratory worsening is most often a result of infection or edema [2]
More General Terms
Additional Terms
References
- Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 253-56
- Medical Knowledge Self Assessment Program (MKSAP) 11, 15, American College of Physicians, Philadelphia 1998
- National Guideline Clearinghouse Interstitial lung disease. In: Pulmonary (acute & chronic). Work Loss Data Institute ngc-guideline: [1]
