L77-L80 Pulmonary Flashcards
What three concerns can be detected by PFTs and what technique is used?
- Obstruction - Spirometry
- Restriction - Lung Volume Determination
- Diffusion Defect - Diffusion Capacity Measurement
How are the measurements taken in spirometry reported?
- Flow-Volume Loop
2. Volume-Time Curve
What data points can be garnered from the Flow-Volume Loop?
Total Lung Capacity (TLC) Residual Volume (RV)
What data points can be garnered from the Volume-Time Curve?
Forced Expiratory Volume in 1 Second (FEV1)
Forced Vital Capacity (FVC)
What happens to the Flow-Volume Loop in obstruction?
Scooped Loop appearance - less flow at any given moment due to narrowed airways
What happens to the Volume-Time Curve in obstruction?
Delayed raise in the curve
How is obstruction defined numerically?
Reduced ratio of FEV1:FVC
Normal: >0.8 (age 20-39), >0.7 (age 60-80)
What determines the severity of an obstruction?
FEV1 % predicted value
What determines the reversibility of an obstruction?
FEV1 increases by 200 mL and 12% with a bronchodilator
What determines hyperreactivity in obstruction?
FEV1 decreases by 20% in response to methacholine (bronchoconstrictor)
Discuss the difference between lower and upper airway obstruction.
Lower: airflow is relatively normal at high lung volumes; obstruction worsens during exhalation, results in gradually decreasing airflow
Upper: airflow is reduced even at high lung volumes (when bronchioles should be maximally open)
What is the difference between fixed and variable upper airway obstructions?
Fixed: intra-thoracic pressure changes do NOT affect the degree of obstruction (both loops are flat); obstruction may be either intra- or -extra-thoracic
Variable: intra-thoracic pressure changes do affect the degree of obstruction (one loop is flat, one is normal)
What happens to intrathoracic pressure upon inspiration? Expiration?
Inspiration: lowers
Expiration: raises
Which part of the Flow-Volume loop is affected in an extra-thoracic obstruction? Intra-thoracic obstruction?
Extra-thoracic: inspiratory limb affected
Intra-thoracic: expiratory limb affected
What are the three lung volumes important in restrictive disease?
- TLC
- RV
- FRC
What determines TLC?
Elastic recoil
What determines FRC?
Balance between elastic recoil of the lung (in) and the chest wall (out)
What is RV?
Volume of gas trapped due to airway closure at the end of forced expiration
What does a decreased TLC indicate?
Restrictive process (interstitial lung disease, chest wall disease, neuromuscular disease)
What does an increased TLC indicate?
Hyperinflation (loss of elastic recoil, emphysema)
What does an increased RV indicate?
Gas trapping (any obstructive process)
What are the three categories of restrictive lung disease?
- Interstitial lung disease
- Chest wall disease
- Neuromuscular disease
What is the primary problem in interstitial lung disease and how do we measure it?
Increased lung elastic recoil
Decreased TLC
What is the primary problem in chest wall disease and how do we measure it?
Decreased chest wall elastic recoil
Decreased TLC
What happens to various volumes in obesity?
Reduced chest wall recoil
Mild obesity - reduced FRC
Severe obesity - reduced TLC
What happens to lung volumes in neuromuscular disease?
Decreased TLC
Increased RV
Normal FRC
Prove by measuring strength of inspiratory and expiratory force
How is diffusion capacity measured?
Inhale known [CO], which diffuses easily across alveolar and capillary membranes and binds easily with Hgb
Measure exhaled [CO]
DL = [CO inhaled] - [CO exhaled]
What is a normal DL CO?
25 mL/min/mmHg
What are causes of reduced DL CO?
Loss of alveoli (emphysema and interstitial lung disease), loss of blood flow to alveoli (pulmonary HTN), anemia
What are causes of increased DL CO?
Alveolar hemorrhage, CHF, polycythemia
Suspect ___ when DL CO is low but spirometry, lung volumes, and Hgb are normal.
Pulmonary HTN
If FEV1:FVC Ratio is <0.70, think ___.
Obstruction
If TLC is < 80% predicted, think ___.
Restriction
If DLCO is <80% predicted, think ___.
Diffusion defect
If PFT’s are normal, what is not ruled out?
Asthma or mixed defects
What causes obstructive sleep apnea?
Upper airway obstruction; thoracic effort maintained
What causes central sleep apnea?
Failure of the brain to initiate respiration; thoracic effort interrupted
What happens in obesity-hypoventilation syndrome?
Obstructive sleep apnea + hypoventilation when awake
How is sleep apnea diagnosed?
Polysomnography (sleep study)
What is the apnea-hypopnea index (AHI)?
Combined number of 10-second episodes per hour of apnea and hypopnea (partial reduction in airflow)
What are risk factors for obstructive sleep apnea?
- Obesity
- Neck circumference (>17”)
- HTN
- Males
- Increasing age
- Smoking
- Retrognathia
What are risk factors for central sleep apnea?
- CHF
2. CNS disease
What are consequences of fragmented sleep in apnea?
- Daytime hypersomnolence (measure with Epworth sleepiness scale)
- Intellectual impairment
What are consequences of repeated episodes of hypoxia in apnea?
- Pulmonary HTN
2. Polycythemia
Why are their cardiovascular effects of sleep apnea?
Breathing stops, saturation levels drop and are sensed by carotid bodies, SNS activated, repeated cycle
What is lead-time bias?
Diagnosis of disease is made earlier in the screened group, resulting in an apparent increase in survival time, although the time of death is the same in both groups
What is length-time bias?
The probability of detecting disease is related to the growth rate of the tumor. Aggressive, rapidly growing tumors have a short potential screening period. Unless screening tests are repeated frequently, patients with aggressive tumors are more likely to present with symptoms. More slowly growing tumors have a longer potential screening period and are more likely to be detected when asymptomatic. As a result, a higher proportion of “indolent” tumors is found in the screened group, causing an apparent improvement in survival.
What is overdiagnosis bias?
Extreme form of length-time bias; detection of indolent tumors in the screened group produces apparent increases in # of cases.
What are the current USPSTF guidelines for lung cancer screening?
B recommendation - annual screening with low-dose CT in adults 55-80 y/o who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years. Stop screening once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery.
What are the three broad etiologies of dyspnea?
- Cardiac
- Pulmonary
- Other (renal, anemia, neuromuscular)
Obstruction involves increased ___ and ___ lungs. Restriction involves abnormal ___ and ___ lungs.
Airway resistance; large
Elastic recoil; small
Compare the lung sounds heard in obstruction vs. restriction.
Obstruction: wheezing
Restriction: crackles
How is asthma treated, broadly?
- Relievers (PRN, bronchodilators)
2. Controllers (regular, anti-inflammatory)
What are the first line “relievers” for asthma treatment?
- Albuterol
- Pirbuterol
(Beta agonists)
What are the second line “relievers” for asthma treatment?
- Levalbuterol (beta-agonist)
2. Ipratropium (anti-cholinergic)
What are the first line “controllers” for asthma treatment?
Inhaled corticosteroids (beclomethasone, budesonide, ciclesonide, fluticasone, mometasone)
What are common and rare side effects of inhaled corticosteroids?
- Oral-pharyngeal (candida)
- HPA axis suppression
- Bone problems
- Cataracts
What are the second line “controllers” for asthma treatment?
In addition to inhaled corticosteroids:
- Long-acting beta-agonists (Salmeterol, Formoterol)
- Anti-leukotrienes (Montelukast, Zafirlukast, Zileutin)
What are some less common treatments for asthma?
- Cromolyn (mast cell stabilizer)
- Theophylline
- Anti-cholinergics
- Omalizumab
What is the last resort for asthma treatment?
Chronic oral steroids
What are the 3 most common causes of chronic cough?
- Cough-variant asthma
- Post-nasal drip
- GERD
What is Reactive Airway Dysfunction Syndrome?
“Big bang” exposure leading to asthma (no prior asthma), treated with steroids
What is Samter’s triad?
Syndrome caused by aspirin sensitivity:
- Asthma
- Nasal polyposis
- ASA sensitivity
How is aspirin sensitivity treated?
Anti-leukotrienes
What is Allergic Bronchopulmonary Aspergillosis (ABPA)?
Asthma with central bronchiectasis, migratory pulmonary infiltrates, peripheral eosinophilia, high IgE to Aspergillus
What is the key feature of emphysema?
Permanent distention of the distal air spaces with destruction of alveolar septa
What is the key feature of chronic bronchitis?
Excessive sputum production
How does COPD present?
Insidious onset of dyspnea and cough with minimal day to day variability
What is seen on PFT’s with COPD?
- Obstruction with minimal bronchodilator response
- Hyperinflation
- Reduced diffusing capacity
What is the medication treatment for COPD?
- Short-acting bronchodilators (anti-cholinergics, beta-agonists, combination)
- Long-acting bronchodilators (anti-cholinergics, beta-agonists)
- Other: corticosteroids, azithromycin, theophylline
What is the staging and treatment of COPD Stage 0?
“At risk”
Normal spirometry
Smoking cessation
What is the staging and treatment of COPD Stage 1?
“Mild COPD”
FEV1/FVC <0.70, but normal FEV1
Short-acting bronchodilators
What is the staging and treatment of COPD Stage 2?
“Moderate COPD”
FEV1 50-80% predicted
Long-acting bronchodilator
What is the staging and treatment of COPD Stage 3?
“Moderately severe COPD”
FEV1 30-50% predicted
Maybe add inhaled corticosteroids
What is the staging and treatment of COPD Stage 4?
“Severe COPD”
FEV1 <30% predicted
Maybe methylxanthines
What is the only thing that can prolong life in COPD?
Long-term oxygen therapy (only works in patients who are hypoxic)
Check ___ levels in all patients with COPD.
Alpha-1-anti-trypsin
What is the primary pathology of bronchiectasis?
Permanent abnormal dilation of the bronchi
What is Cole’s vicious cycle of inflammation?
- Bacterial colonization
- Neutrophil inflammation (proteases)
- Airway destruction and distortion (bronchiectasis)
- Abnormal mucus clearance
Repeat
What are the bacteria commonly seen in bronchiectasis?
GN: P. aeruginosa, H. influenzae, M. catarrhalis
GP
NTM
What are the symptoms of bronchiectasis?
- SOB/DOE
2. Daily copious sputum production
What is seen on PFT in Bronchiectasis?
Obstruction
What is seen CXR/CT in Bronchiectasis?
- Signet ring sign - internal diameter of the bronchus is larger than that of its accompanying vessel
- Tram tracking - bronchus fails to taper in the periphery of the chest
What is the treatment for bronchiectasis?
- Airway clearance therapy (CPT, 7% hypertonic saline, bronchodilators)
- Antibiotic therapy (suppressive vs. eradication)
- Anti-inflammatory therapy (inhaled corticosteroids, macrolides)
What are the main interstitial lung diseases?
- Sarcoid
- Hypersensitivity pneumonitis
- Idiopathic pulmonary fibrosis
- TB
- Fungal
- Aspiration/Asbestosis
- Connective tissue diseases/Cancer
- Eosinophilic Granuloma
- Drugs (amiodarone, nitrofurantoin, bleomycin)
- Pneumoconioses
How does interstitial lung disease present?
Dyspnea and cough
What are the signs of interstitial lung disease?
Crackles, small lungs, +/- clubbing
What is seen on CXR in interstitial lung disease?
Reduced volumes
Interstitial markings
What is seen on PFT in interstitial lung disease?
Decreased TLC
What are the treatments for IPF?
Pirfenidone and Nintedanib
Normally, the pleural space contains less than ___ of fluid.
10 mL
What is a pleural effusion?
Excess pleural fluid accumulation
Which part of the pleura is innervated?
Parietal
Discuss the arterial and venous supply of the visceral pleura.
Arterial: bronchial and pulmonary arteries
Venous: through pulmonary veins to LA
Discuss the arterial and venous supply of the parietal pleura.
Arterial: aortic intercostals
Venous: through IVC to RA
What does primary left heart failure cause?
Pulmonary edema, pleural effusions, and/or both
What does pulmonary arterial HTN cause?
Cor pulmonale, no pulmonary edema or effusions
What creates the sub-atmospheric pleural pressure?
Elastic recoil of the lung pulling in and elastic recoil of the chest wall pulling out
What can cause an increase in the filtration coefficient, leading to excess pleural fluid formation?
Infection, inflammation, cancer
What can cause an increase in the capillary hydrostatic pressure, leading to excess pleural fluid formation?
LV failure
What can cause an decrease in the pleural hydrostatic pressure, leading to excess pleural fluid formation?
Atelectasis
What can cause an decrease in the capillary osmotic pressure, leading to excess pleural fluid formation?
Nephrotic syndrome, cirrhosis, malnutrition
What are some symptoms of pleural effusions?
Asymptomatic
Pain
Dyspnea
Respiratory failure
What are some signs of pleural effusions?
Dullness to percussion
Decreased breath sounds
Tactile fremitus
Egophony
What are some CXR findings of pleural effusions?
- Blunting of the angle
- Meniscus
- White-out + shift of mediastinum away
- Lateral decubitus layering
- Loculations (adhesion between parietal and visceral pleura, creates a trapped chamber of fluid)
What are the Light’s Criteria for exudates?
- Total pleural protein/Total serum protein >0.5, or
- Pleural LDH/Serum LDH >0.6, or
- Pleural LDH >200 (or 2/3 upper normal)
What are the Revised Criteria for exudates?
- Pleural LDH > 200 (or 2/3 upper normal), or
2. Pleural cholesterol >45
What is on the differential for transudative effusions?
- CHF
- Cirrhosis
- Nephrotic syndrome
- Atelectasis
- Hypothyroidism
- PE (15%)
- Peritoneal dialysis
What is on the differential for exudative effusions?
- Cancer
- Infections (empyema)
- Parapneumonic effusions
- PE (85%)
- Connective tissue diseases
- Esophageal rupture
- Drug-induced disease (hydralazine)
- Post-MI
- Post-pericardiotomy
- Uremia
- Asbestos
- Meig’s syndrome (ovarian cancer with malignant effusions)
- Yellow nail syndrome
- Hemothorax
- Chylothorax (ruptured thoracic duct)
What else can be tested in the pleural fluid?
pH - normally slightly higher than serum due to active HCO3 transport; low pH may be seen in infection, malignancy, and esophageal rupture
Glucose - low in RA, B, cancer, empyema
Lots of PMNs on CBC indicate what in pleural effusion? Lots of lymphocytes?
Acute infection
TB or fungus
Elevated adenosine deaminase (ADA) is indicative of ___.
TB
Elevated amylase is indicative of ___ or ___.
Pancreatitis and/or esophageal rupture
Pattern: exudative, lymphocytic, <5% mesothelial cells, +ADA
TB
Pattern: exudative, lymphocytic, RBC’s, +/- low pH/glucose, large
Malignant effusion
Pattern: small, unilateral, exudative, +/- bloody
PE 85% of the time
Pattern: left-sided, low pH, high amylase
Esophageal rupture
Pattern: bloody, +/- associated with pneumothoraces/hemoptysis
Endometriosis
Pattern: underlying cirrhosis, transudative, R>L sided, rapid re-accumulation
Hepatic effusions
Pattern: milky effusions
- Chylothorax (triglycerides >110)
- Pseudochylothorax (triglycerides >100 and cholesterol >200)
- Empyema
What can be used to treat loculations?
Thrombolytics
What is air in the pleural space?
PT
What happens in a PT?
Air enters the pleural space until Ppl = Patm, lung collapses inward, and chest wall expands
What are signs of a PT?
Unilateral hyperinflation
Decreased breath sounds
Tactile fremitus
Hyperresonance
What is seen on CXR in a PT?
Hyperlucent lung fields
Lack of lung markings
Thin white pleural line
Shift of mediastinum (tension)