Flow-Volume Loop
- Variable Extrathoracic Upper Airway Obstruction: adversely affects predominantly inspiratory flow (as inspiratory negative intraluminal pressures exacerbate the inspiratory airway narrowing, while expiratory positive intraluminal pressures splints the obstruction open)
- Example: vocal cord paralysis -> inspiratory stridor with no expiratory obstruction
- Variable Intrathoracic Upper Airway Obstruction: adversely affects predominantly expiratory flow (as inspiratory negative pressures decrease the inspiratory airway narrowing, while expiratory positive intrapleural pressures exacerbate the airway obstruction)
- Example: tracheomalacia -> expiratory worsening of airway obstruction
- Fixed Upper Airway Obstruction: adversely affects both inspiratory and expiratory flows
Spirometry
- xxx
Lung Volumes
- xxx
Diffusion Capacity for Carbon Monoxide (DLCO)
Increased DLCO
Etiology
- Diffuse Alveolar Hemorrhage (DAH) (see Diffuse Alveolar Hemorrhage, [[Diffuse Alveolar Hemorrhage]])
- Asthma (see Asthma, [[Asthma]]): due to increased pulm capillary blood volume
Decreased DLCO
Etiology
- Obstructive Lung Diseases (see Obstructive Lung Disease, [[Obstructive Lung Disease]])
- Chronic Obstructive Pulmonary Disease (COPD) (see Chronic Obstructive Pulmonary Disease, [[Chronic Obstructive Pulmonary Disease]])
- Restrictive Lung Diseases
- Interstitial Lung Disease (ILD) (see Interstitial Lung Disease, [[Interstitial Lung Disease]])
- Pulmonary Vascular Disease
- Chronic Thromboembolic Pulmonary Hypertension (CTEPH) (see Chronic Thromboembolic Pulmonary Hypertension, [[Chronic Thromboembolic Pulmonary Hypertension]])
- Idiopathic Pulmonary Arterial Hypertension (IPAH) (see Idiopathic Pulmonary Arterial Hypertension, [[Idiopathic Pulmonary Arterial Hypertension]])
- Other
- Anemia (see Anemia, [[Anemia]])
Restriction
Etiology -> P-A-I-N-T-O-P-P-M
Pleural Disease
- Examples
- Fibrothorax (see Fibrothorax, [[Fibrothorax]])
- Large Pleural Effusion (see Pleural Effusion-Exudate, [[Pleural Effusion-Exudate]])
- PFT Features
- Variable lung volumes
Alveolar Filling Process
- Examples
- Cardiogenic Pulmonary Edema (CHF) (see Congestive Heart Failure, [[Congestive Heart Failure]])
- Pulmonary Alveolar Proteinosis (PAP) (see Pulmonary Alveolar Proteinosis, [[Pulmonary Alveolar Proteinosis]])
- PFT Features
- Proportional decrease in TLC, FRC, RV, and VC
Interstitial Lung Disease (ILD)
- Examples
- Idiopathic Pulmonary Fibrosis (IPF) (see Idiopathic Pulmonary Fibrosis, [[Idiopathic Pulmonary Fibrosis]])
- Hypersensitivity Pneumonitis (HP) see Hypersensitivity Pneumonitis, [[Hypersensitivity Pneumonitis]])
- PFT Features
- Decreased TLC
- Decreased FRC
- Decreased VC
- Small decrease in RV
Neuromuscular Disease
- Examples
- Amyotrophic Lateral Sclerosis (ALS) (see Amyotrophic Lateral Sclerosis, [[Amyotrophic Lateral Sclerosis]])
- Bilateral Diaphragmatic Paralysis (see Bilateral Diaphragmatic Paralysis, [[Bilateral Diaphragmatic Paralysis]])
- Guillain-Barre Syndrome (GBS) (see Guillain-Barre Syndrome, [[Guillain-Barre Syndrome]])
- Muscular Dystrophy
- Myasthenia Gravis (see Myasthenia Gravis, [[Myasthenia Gravis]])
- Poliomyelitis (see Poliomyelitis, [[Poliomyelitis]])
- PFT Features
- Decreased TLC in pure inspiratory weakness, but not in pure expiratory muscle weakness (this is one of the cases where restriction can be diagnosed in setting of a normal TLC)
- No change in FRC in cases with both inspiratory and expiratory muscle weakness
Thoracic Cage Abnormality
- Examples
- Ankylosing Spondylitis (see Ankylosing Spondylitis, [[Ankylosing Spondylitis]]): due to costovertebral spondylosis
- Ascites (see Ascites, [[Ascites]])
- Kyphoscoliosis (see Kyphoscoliosis, [[Kyphoscoliosis]])
- Polydermatomyositis (see Polydermatomyositis, [[Polydermatomyositis]]): extensive soft tissue chest wall calcification
- Pregnancy (see Pregnancy, [[Pregnancy]])
- Scleroderma (see Scleroderma, [[Scleroderma]]): skin tightness over chest may restrict thoracic cage expansion
- PFT Features
- Decreased TLC
- Decrease in VC
- Small decrease in FRC (normal-slightly increased in Ankylosing Spondylitis cases with restricted thoracic cage expansion)
Obesity
- PFT Features
- xxxx
Pulmonary Hypertension
- Associated Disorders
- Chronic Thromboembolic Pulmonary Hypertension (CTEPH) (see Chronic Thromboembolic Pulmonary Hypertension, [[Chronic Thromboembolic Pulmonary Hypertension]]): restrictive PFT’S are seen in 20% of cases
- Pulmonary Hypertension (see Pulmonary Hypertension, [[Pulmonary Hypertension]])
- PFT Features
- Generally mild restriction
Poor Cooperation
- PFT Features
- xxxx
Miscellaneous
- Beta Thalassemia Major (see Thalassemias, [[Thalassemias]]): restriction may occur (for unclear reasons)
- Pulmonary function test (PFT) defects correct with transfusion and do not correlate with the iron burden, blood counts, or degree of hemolysis
References
- xxx