Interstitial lung disease
Background
- General group of diseases that involve the scarring of lung parenchyma
- Grouped together because of similar clinical, physiologic, radiographic, or pathologic findings
- Specific diseases separated into ones with known causes and idiopathic
- Treatment and prognosis differs between specific diseases
- Examples of specific diseases:
- Interstitial pneumonia
- Hypersensitivity pneumonitis
- Cryptogenic organizing pneumonia
- Acute interstitial pneumonitis
- Sarcoidosis
- Idiopathic pulmonary fibrosis
Clinical Features
- Symptoms
- +/- hemoptysis, pleuritic chest pain
- May have history of smoking, occupational exposures (asbestosis, silicosis, grain dust, bird droppings), medications that can cause pulmonary damage, connective tissue disease, IBD
- Physical exam
- Usually nonspecific
- Increased work of breathing, hypoxia
- +/- Abnormal lung sounds (classically fine, "velcro-like" crackles)
Differential Diagnosis
Pulmonary Fibrosis
- Interstitial pneumonias (acute, lymphocytic)
- Lung malignancy
- Aspiration pneumonia or pneumonitis
- Bacterial, viral, or fungal pneumonia
- Cryptogenic organizing pneumonia
- Interstitial lung disease associated with collagen vascular disease
- Drug-induced pulmonary toxicity (amiodarone, bleomycin, amphotericin B, carbamazepine, etc.)
- Eosinophilic granuloma (Histiocytosis X)
- Radiation pneumonitis
- Sarcoidosis
- Pneumoconiosis (Workplace exposure)
- Asbestosis
- Berylliosis
- Chemical worker's lung
- Coal worker's pneumoconiosis
- Silicosis
Acute dyspnea
Emergent
- Pulmonary
- Airway obstruction
- Anaphylaxis
- Angioedema
- Aspiration
- Asthma
- Cor pulmonale
- Inhalation exposure
- Noncardiogenic pulmonary edema
- Pneumonia
- Pneumocystis Pneumonia (PCP)
- Pulmonary embolism
- Pulmonary hypertension
- Tension pneumothorax
- Idiopathic pulmonary fibrosis acute exacerbation
- Cystic fibrosis exacerbation
- Cardiac
- Other Associated with Normal/↑ Respiratory Effort
- Other Associated with ↓ Respiratory Effort
Non-Emergent
- ALS
- Ascites
- Uncorrected ASD
- Congenital heart disease
- COPD exacerbation
- Fever
- Hyperventilation
- Interstitial lung disease
- Neoplasm
- Obesity
- Panic attack
- Pleural effusion
- Polymyositis
- Porphyria
- Pregnancy
- Rib fracture
- Spontaneous pneumothorax
- Thyroid Disease
- URI
Evaluation
- Definitive diagnosis of ILD rarely made in the ED
- ED workup should focus on assessing for reversible pathologies that may be causing or exacerbating symptoms (e.g. infection, PE, pulmonary hypertension, pulmonary edema, concomitant COPD exacerbation, etc.)
- VBG/ABG
- CBC, BMP
- CXR
- Consider CT chest (to rule out PE or better characterize lung parenchyma)
- +/- Infectious workup, echo as appropriate
- Inpatient/outpatient workup may include serologic studies (ANA, rheumatoid factor), PFTs, BAL, lung biopsy
Management
- Treat underlying/exacerbating factors (e.g. antimicrobials for infection, optimize volume/hemodynamics for pulmonary hypertension patients, bronchodilators for concomitant obstructive lung disease)
- Support oxygenation and ventilation
- Specific disease treatments vary, but many respond to steroids, sometimes at high doses
- See management section of idiopathic pulmonary fibrosis
Disposition
- Low threshold to admit