Restrictive Lung Disease Flashcards
Physiologic abnormalities in restrictive lung disease
TLC AND FRC < 80
Decreased compliance (stiffer lungs OR restricted motion of the chest wall)
P-V curve is flatter and shifted downward (reflecting lower compliance & decreased lung volumes)
FEV1/FVC often normal or slightly elevated
3 mechanisms that lead to restrictive physiology
- Increased thickness of lung interstitium (ILD)
- Increased lung water (interstitial/alveolar edema)
- Increased alveolar surface tension (RDSI, ARDS, pulmonary edema)
Differentiation of restrictive disease vs. physiology
P-V curve slope is reduced in restrictive lung disease but preserved in restrictive physiology (with lower TLC)
DLCO/VA is reduced in restrictive disease but preserved in restrictive physiology
PFT pattern of mixed lung disease
Reduced lung volumes (decreased TLC, FRC)
Reduced air flow (decreased FEV1/FVC)
Diagnostic approach to interstitial lung disease
Clinical
Radiographic (high resolution CT)
Pathologic (surgical lung biopsy)
Known causes of ILD
Autoimmune (RA, lupus, scleroderma)
Exposure to inorganic dusts (silica, asbestos)
Exposure to organic molecules (birds, mold)
Drug effects (chemo, radiation)
Familial
Sarcoidosis & Chronic Beryllium Disease - Pathology
Systemic, granulomatous inflammation disorders of unknown (Sarcoid) or known (CBD) etiology
Characterized by the presence of well-formed, non-necrotizing granulomas surrounded by collagen deposition; often follow lymphatic distribution
Sarcoidosis - Treatment
Usually none
Sometimes corticosteroids or methotrexate to treat/prevent progressive organ involvement
Idiopathic pulmonary fibrosis (IPF) - Definition
Idiopathic, scarring lung disease with a pattern of lung injury consistent with usual interstitial pneumonia (UIP)
Usual Interstitial Pneumonia (UIP)
Most common pattern if ILD
Patchy, heterogenous fibrosis of the septa by collagen; usually worse in lower lobes
Fibroblastic foci - compact collections of fibroblasts within the alveolar septae, bulging out into the airspaces
Honeycomb cystic change - formation of mucus-filled cysts surrounded by thick, fibrotic walls
IPF - Radiographic findings
Peripheral and basilar predominant reticulation and bronchiectasis
Idiopathic Nonspecific Interstitial Pneumonia (NSIP)
Uniform, homogenous inflammation (cellular type) or fibrosis (fibrotic type); cellular type is steroid-responsive
Lack of fibroblastic foci and honeycombing
Clinical characteristics of IPF vs. NSIP
NSIP is more likely to affect younger females, is more responsive to anti-inflammatory treatment, and has a better prognosis
Cryptogenic organizing pneumonia
Noninfectious pneumonia - may be idiopathic, secondary to drugs HP, or aspiration
Path shows organizing pneumonia with plugs of granulation tissue
Steroid responsive
Pulmonary manifestatiosn of ALS
Dysphagia - risk of aspiration pneumonia
Restrictive physiology due to respiratory muscle weakness
Hypoventilation - elevated PCO2
Pulmonary manifestations of Rheumatoid Arthritis
Rheumatoid effusion - exudative with increased protein and > 3,000 WBCs
Pleuritis
Lung nodules
Pulmonary hypertension (2/2 vasculitis)
Goodpasture Syndrome
Caused by auto-antibodies directed against pulmonary and glomerular basement membrane proteins
Associated with diffuse alveolar hemorrhage, resulting in restrictive disease (due to alveolar destruction)
Pulmonary manifestations of Sickle Cell Disease
Acute Chest Syndrome Infection (2/2 spleen auto-infarct) Bone marrow emboli (2/2 bone marrow auto-infarct) Lung infarction (2/2 in-situ thrombosis) Pulmonary edema Pulmonary HTN
Acute pneumonia - Pathology
Characterized by an accumulation of neutrophils, macrophages, and fibrin within air spaces
Eosinophilic pneumonia - Pathology
Characterized by an accumulation of eosinophils, macrophages, and fibrin within air spaces
Organizing pneumonia (AKA BOOP, COP) - pathology
Fibroblast plugs filling airspaces - usually in a “patchy” pattern; some fibrin deposition within air spaces
Reversible, steroid responsive
Respiratory bronchiolitis
Characterized by the presence of brown pigmented macrophages inside airspaces surrounding the respiratory bronchiole; air spaces farther away from the airway are usually spared
Smokig-related disease; macrophages are trying to clear the cigarette smoke particles but end up leading to air space destruction
Diffuse alveolar damage (DAD) - pathology
Presence of fibrin ribbons (“hyaline membranes”) caked over the alveolar membranes; alveolar space are sealed off from gas exchange
This pattern is characteristic of ARDS and Respiratory Distress Syndrome of the Infant
Diffuse alveolar hemorrhage - Pathology
Presence of blood and iron-containing macrophages within the air spaces; may be associated with capillaritis (neutrophils attacking the capillaries of the alveolar septa)
Hypersensitivity Pneumonia (HP) - Pathology
Response to foreign antigens (birds, mold) characterized by:
Airway-centered chronic inflammation (lymphocytes and activated macrophages)
Non-necrotizing granulomas
Organizing pneumonia
Causes of acute consolidation on CXR
HEAP
Hemorrhage
Edema
Alveolar Protein
Pneumonia
Hypersensitivity Pneumonitis
Presents acutely with flu-like respiratory illness occurring after acute, high dose antigen exposure
Chronic Beryllium Disease (CBD)
A chronic, granulomatous lung disease pathologically indistinguishable from sarcoid
Treatment: Inhaled or oral steroids
Coal Workers’ Pneumoconiosis (Black Lung) - Diagnosis
Imaging shows small, rounded, nodular opacities present in the upper lobes
Silicosis
Upper lobe predominant nodular interstitial lung disease; may progress to involve architectural distortion and volume loss (complicated silicosis)
Asbestosis
Bilateral fibrosis affecting the lower lung zones preferentially
Non-malignant asbestos-related lung diseases
Asbestos pleural effusion
Pleural thickening/calcification
Rounded atelectasis
Asbestosis
Malignant asbestos-related lung diseases (2)
Lung cancer - all histologic types
Mesothelioma
5 ILDs associated with environmental exposure
Asbestos-related lung disease Silicosis Coal Miner's Pneumoconiosis (Black Lung) Chronic Beryllium Disease Hypersensitivity Pneumonitis
Risk groups for asbestos exposure
Construction workers
Boilermakers
Shipyard and dock workers
Automechanics who do brake work
Risk groups for silicosis
Workers who blast, cut, or grind hard rock
Sandblasters
Foundry workers
Stone-washed jean manufacturers
Risk groups for Chronic Beryllium Disease
Beryllium is a lightweight metal used in aerospace engineering and high tech electronics
Aerospace workers, airplane mechanics, air traffic controllers, etc. are all at higher risk
Triggers of Hypersensitivity Pneumonitis
Animal proteins (birds) Microbial aerosols (fungi, hot tubs and indoor pools, humidifiers)
