5 ILD Flashcards
WHat is the definition of interstitial lung disease
A large group of pulmonary disorders, most of which cause progressive scarring of lung tissue surrounding the alveoli
Causes: Idiopathic Autoimmune Exposure to hazardous material Drugs
Generally an irreversible process and cumbersome to treat
Drugs that can cause interstitial lung disease
Amiodarone Propranolol Nitrofurantoin Methotrexate Rituximab
Pathophysiology of ILD
A process of fibrosis and inflammation - not infectious
Alveolar epithelium damage —> Type II alveolar epithelial cells proliferate to repair damage —> Repair process leads to fibrosis and scarring —> Lung stiffens, ability to transport O2 diminishes —> Hypoxemia or hypercapnia
SSx of ILD
Progressive dyspnea on exertion
Persistent non-productive cough
WHeezing and chest pain are uncommon
Extrapulmonary symptoms: May be suggestive of a connective tissue disease; MSK pain, weakness, joint pain or swelling, fevers, dry eyes/mouth (related to underlying conditions)
ILDs that can be acute
Acute idiopathic interstitial PNA
Eosinophilic pneumonitis
Hypersensitivity pneumonitis
Cryptogenic organizing pneumonitis
ILDs that can be subacute (weeks to months)
Sarcoidosis
Alveolar hemorrhage
Cryptogenic organizing pneumonia
Connective tissue disease (SLE, polymyositis)
ILDs that can be chronic (months to years)
IPF
Sarcoidosis
Pulmonary langerhans cell histocytosis
Chronic hypersensitivity pneumonitis
Physical exam findings in ILD
CRACKLES (usually at the bases; Velcro sounding)
Inspiratory squeaks (high pitched rhonchi)
Cor pulmonale - present in middle or late stages
Cyanosis - uncommon, indicates advanced disease
Digital clubbing - advanced disease
Extrapulmonary manifestations with different diseases (erythema nodusum in sarcoidosis, cottron’s papules in dermatomyositis)
Gottron’s papules are also known as …
“Mechanics Hands”
Gold standard for diagnosing ILD
Tissue biopsy
Multiple diagnostics available but HRCT offers highest yield as it is non-invasive
Dx may take a long period to make confirmatory Dx
CXR findings suggestive of ILD
Reticular “netlike” (most common), modular, or mixed (reticulonodular) opacities —> Honeycombing (small cystic spaces)
Ground glass appearance often an early finding (nonspecific)
CXR finding that indicates a poor prognosis for ILD
Honeycombing
Test with a greater diagnostic accuracy than CXR for ILD
High Resolution Computed Tomography (HRCT)
Distribution of disease within the lung and pattern of disease both apparent
Comparison to old CT - interval progression of disease
What sorts of serologic studies do we do in ILD?
ANA and Rheumatoid Factor to rule out subclinical autoimmune disease, possible Anti-SS-DNA for SLE
If pulmonary hemorrhage or suspicious systemic symptoms, evaluate for vasculitis (Antineutrophil cytoplasmic antibodies (ANCA)
Sed rate and CRP are markers of inflammation but they are nonspecific and generally not helpful in ILD
Most ILDs are associated with a ___________ pattern on PFTs
Restrictive
Decreased TLC, decreased flow rates (FEV1 and FVC) but changes proportional to dismissed lung volumes to FEV1/FVC ratio is normal or increased
What do you do next if PFTs show restrictive or normal pattern?
Obtain DLCO
If DLCO low, consistent with ILD (may be only finding in early disease)
What do arterial blood gases look like in ILD?
Resting blood gas may be normal, or may show hypoxemia (low PaO2) or respiratory alkalosis (low PaCO2)
Despite normal resting blood gas, severe exercise or sleep induced hypoxemia may be present
May need to perform exercise testing with serial ABGs
What is bronchoalveolar lavage and when do we perform it?
Minor extension of bronchoscopy, allows sampling from distal airways and alveoli
Cell counts: WBC differential (can help narrow Dx)
Cultures: ID typical/atypical infection
Cytology: ID malignancy
Evaluate source of hemoptysis
NOT typically performed with HRCT findings c/w IPF
Gold standard for Dx of ILD
Lung Biopsy
Indications:
Specifying Dx
Atypical or rapidly progressing HRCT findings or progressive disease
Unexplained extrapulmonary manifestations
Excluding neoplasm or infection that can mimic ILD
ID a more treatable process than originally suspected
Predict likelihood of response to therapy
When is lung biopsy CONTRAINDICATED?
Honeycombing on imaging, as prognosis is poor and biopsy won’t change management at this point
Different types of lung biopsy
Transbronchial biopsy (via bronchoscopy) - helpful for central locations
Surgical biopsy - done under general anesthesia with one lung ventilation, allowing for larger sample, especially on periphery
Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA)
Types of surgical biopsy
Video assisted thoracoscopic surgery (VATS) - two small incisions to the lateral chest wall, associated with less morbidity
Thoracotomy - 5-6 cm incision required
When is endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) indicated?
Special bronchoscope used to evaluate hilar and mediastinal lymph nodes
Done under general anesthesia
Can be done in conjunction with transbronchial lung biopsy but need to pass different scope
Especially useful if SARCOIDOSIS suspected
Most common interstitial lung disease
Idiopathic Pulmonary FIbrosis
Age >50 (generally between 50-85)
Males > Females (5:1)
Histopathology referred to as “Usual Interstitial Pneumonia”
Genetic predisposition
Poor prognosis (2-5 year survival from time of diagnosis)
