Lung Flashcards
What are the 3 mechanisms of impaired alveolar oxygen diffusion?
- ↓ Surface area
- ↓ driving pressure
- diffusion distance
What 3 things can cause ↓surface area mediated alveolar-capillary oxygen diffusion impairment?
- alveolar destruction (COPD/emphysema)
- loss of capillaries (embolism, pulmonary HTN)
- alveolar filling defect (fluid, pus, blood)
What 2 things can cause alveolar-capillary oxygen diffusion impairment by ↓ driving pressure?
- bronchiole obstruction (asthma)
- alveolar filling defect (pneumonia)
What can cause alveolar-capillary oxygen diffusion impairment by ↑ diffusion distance?
wide alveolar capillary space (fibrosis, edema)
How does emphysema/COPD cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
alveolar destruction → ↓ surface area
How does a PE or pulmonary HTN cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
loss of capillaries → ↓ surface area
How does fluid, pus or blood cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
alveolar filling defect → ↓ surface area
How does asthma cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
bronchiole obstruction (inflammation) → ↓ driving pressure
How does pneumonia cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
alveolar filling defect→ ↓ driving pressure
How does fibrosis or edema cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
wide alveolar-capillary distance → ↑ diffusion distance
What is the MC pulmonary ssx?
dyspnea!
This spirometry reading, FEV1/FVC ratio < 70%, is dx of which type of lung dz?
obstructive
Is it possible to determine restrictive lung dz physiology from spirometry tests?
NO!! Need to do lung volume tests
subepithelial collagen deposition leading to ↑ bronchial wall thickness
severe asthma
Main inflammatory mediators of asthma
eosinophils
Airway inflammation is primarily mediated by CD4(+) T-cells and eosinophils in which airway dz?
asthma
Airway inflammation is primarily mediated by CD8(+) T-cells and M∅/ PMNs in which airway dz?
COPD
What are the 2 things necessary to dx COPD?
- evidence of airflow obstruction (FEV1/FVC < 70%)
- clinical ssx (cough, sputum prdn., or dyspnea)
2 useful tests (other than spirometry) used to dx asthma
- methacholine challenge test
- peak flow variation
What are the 4 pathologic locations restrictive thoracic disorders can occur?
- pleural cavity
- interstitium (lung parenchyma)
- Neuromuscular
- Thoracic/Extrathoracic
How are the timing of clinical ssx different b/w asthma and COPD?
- asthma: intermittent and variable
- COPD: persistent and progressive worsening
How does a patients cough differ b/w asthma and COPD?
- asthma: nocturnal cough or on exertion
- COPD: morning cough w/ sputum
What are the 2 broad categories of COPD? What are their characteristic pathologic findings?
- chronic bronchitis: inflammation & excess mucus d/t hyperplasia of mucous glands
- emphysema: breakdown of alveolar membranes
Compare the prevelance and mortality trends of asthma and COPD
- asthma: ↑prevelance, ↓mortality
- COPD: ↑prevelance, ↑mortality
How can asthma be fatal?
mucous plugs
How is the clinical dx of chronic bronchitis COPD defined?
presence of chronic productive cough for 3 months in each of 2 successive years in a patient in whom other causes of chronic cough have been excluded
What is the most significant pathologic feature of asthmatic bronchial airways?
reduced airway lumen area
What is a normal A-a gradient?
10
What can ↑ fremitus on lung exam indicate?
lung consolidation (e.g. pneumonia)
What are 3 things ↓ fremitus on lung physical exam indicate?
- pneumothorax
- pleural effusion
- emphysema
What is the normal percussive tone of the lung heard on physical exam?
resonant- air filled tissues produce a higher resonant tone
Give a pathologic example that can cause dullness to percussion on lung physical exam
lobar pneumonia
Give 2 pathologic example that can cause a hyperresonant sound to percussion on lung physical exam
- emphysema
- pneumothorax
What is stridor?
inspiratory wheeze
What are 3 criteria that factor into the 4 COPD classifications by GOLD criteria?
- classification of airway flow obstruction (1,2,3,4)
- symptoms measured by mMRC (0-1, ≥2) or CAT (< 10, >10) score
- exacerbation hx (0, 1, ≥2)
Which medication used alone (monotherapy) is contraindicated in COPD pts. ? How can it be used?
inhaled corticosteroids (ICS)
-used in combination w/ long acting β-agonist (LABA)
Which medication used alone (monotherapy) is contraindicated in asthma pts. ?
long acting β-agonists
What factor is key in the tx of COPD?
smoking cessation
What class of drugs are the cornerstone of asthma therapy?
inhaled corticosteroids
Which values are expected to be low on a lung volumes test in a patient w/ restrictive lung dz?
- RV
- FRC (RV + ERV)
- TLC (IRV + TV + ERV + RV)
In what lung dz might you see respiratory acidosis? Why?
COPD→ obstructive, can’t get air out →CO2 can’t get out either
What are 3 radiographic findings found in patients w/ COPD?
- hyperinflation
- ↑ retrosternal airspace
- bullae
When is tx w/ supplemental oxygen indicated in COPD patients?
if they have baseline, exercise, or sleep related pO2 < 55 OR SpO2 ≤ 88% or ≤ 89% w/ evidence of cor pulmonale
How is compliance of the lung altered in obstructive vs. restrictive lung dz?
obstructive: ↑compliance
restrictive: ↓compliance
How does long term lung damage in asthma patients occur (3 steps)? At what stage of asthma does this begin to happen?
acute response →chronic inflammation →airway remodeling =
long-term damage
-occurs even in mild asthma!
What is the purpose of a metacholine challenge test in asthma patients?
to determine Rx dose (highly sensitive) → use muscarinic agonist → determine dose @ which FEV1 ↓20%
What is the pathophysiology of airway remodeling in asthma?
cell proliferation and ↑ECM
What are 3 non-pharmalogical tx for COPD?
- oxygen therapy
- vaccination
- pulmonary rehab
What are 2 types of drugs that can be used to tx COPD exacerbations?
- Roflumilast (PDE-4 inhibitor)→ use in combo w/ LABA
- Azithromycin (Abx)
What type of procedure can an asthma patient have done if they are not responding to Rx?
bronchialthermoplasty → ↓ airway mm.
What are the 4 classifications of asthma patients (+ ssx and FEV1) used for tx?
- mild-intermittent
(FEV1 >80%, exacerbations ≤ 1-2x/wk + nighttime ssx ≤ 1-2x/mo.)
- mild-persistant
(FEV1 > 80%, exacerbations > 2x/wk + nighttime ssx > 2x/mo.)
- moderate-persistant
(FEV1 > 60%, exacerbations > 2x/wk + nighttime ssx > 1x/wk.)
- severe-persistant
(FEV1 < 60%, frequent exacerbations & nighttime ssx)
What are the 4 broad categories of restrictive thoracic disorders?
- pleural
- insterstitial (lung parenchyma)
- neuromuscular
- thoracic/extrathoracic
What are 3 types of pleural restrictive lung dzs?
- pneumothorax (spontaneous, trauma, tension)
- effusion (transudate, exudate)
- asbestosis
parietal/visceral pleura contain pain fiber innervation
parietal
visceral = NO PAIN
What are 3 broad reasons pleural fluid can accumulate?
- changes in hydrostatic forces (= transudation)
- ↑ leak across capillaries (=exudation)
- ↓ flow through lymphatic stoma
What is the protein content and cellularity of transudate vs exudate:
- transudate: poor protein, low cell counts
- exudate: protein rich, cellular
bilateral hilar lymphadenopathy (CXR/CT) w/ non-caseating granulomas (path)
sarcoid mediated ILD
CXR/CT: upper lobe nodules w/ egg shell calcification of LNs
Pathology: birefringent particles
environmental ILD d/t silicosis
How does asbestos exposure affect smokers?
↑ risk of malignancy
- clinical presentation: hemoptysis
- CXR: cavitary lesions
- c-ANCA
Wegener’s granulomatosis
In what types of jobs might you be exposed to silica?
- sandblasting
- foundry work
Lower lobe predominant fibrotic changes
idiopathic pulmonary fibrosis (dx of exclusion)
insidious onset of SOB and dry cough
interstitial lung dz
What is the tx for tension pneumothorax? When should you start tx?
- 100% O2 + pleural decompression
- MUST START IMMEDIATELY!! (i.e. don’t wait for CXR results)
pleural calcified plaques
asbestosis
What are LIGHT’s criteria for establishing an exudative pleural effusion?
need ≥ 1 of any of the criteria (if not → transudate)
- pleural fluid : serum total protein > 0.5
- pleural fluid : serum LDH > 0.6
- pleural fluid LDH > 2/3 upper limit of normal serum LDH
What is the gold standard clinical test for PE? When should you consider using this test?
pulmonary angiogram (however rarely done anymore) → consider using in patients w/ (-) or indeterminante non-invasive tests AND there is no plausible competing dx
CXR: pleural based wedge shaped density (Hampton’s Hump)
PE (however, it’s rarely seen)
Describe the Well’s criteria for pretest probability assessment of PE:
- 3 pts = DVT ssx, PE highest on ddx
- 1.5 pts = HR > 100, surgery hx w/in 4 wks, > 3 days immobile, hx of VTE
- 1 pt = hemoptysis, malignancy
score ≥ 4 pts → PE likely → spiral CT angiogram
What are the defining criteria (2) of pulmonary HTN?
- resting mean pulmonary arterial pressure ≥ 25mmHg (measured via R. heart catheterization)
- normal pulmonary capillary wedge or left atrial pressure (≤ 15mmHg)
inactivating mutation in BMPR2 gene (normally inhibits vascular SM proliferation)
pulmonary arterial hypertention
MCC of pulmonary HTN
pHTN d/t left-heart dz
What are the 5 WHO classification groups for pHTN?
- pulmonary arterial HTN (PAH) (idopathic or BMPR2 mut.)
- PH d/t left ♥︎ dz (MC) (systolic/diastolic, valvular)
- PH d/t lung dz or hypoxia (COPD or obstruction sleep apnea)
- Chronic thromboembolic PH
- Miscellaneous/ multifactorial
What 3 pathogenic processes cause narrowing in PAH?
- Vasoconstriction (↑endothelin, ↓prostacyclin, ↓NO)
- SM proliferation
- Thrombosis
ssx: unexplained dyspnea, syncope
PE: accentuated P2, RV heave
Pathology: plexiform lesions
PAH
Which 3 tests should you do for an initial evaluation for dx of PAH?
-ECG
-CXR
-Echocardiogram
List the findings consistent w/ PAH for each of the following tests:
- ECG
- CXR
- Echocardiogram
-ECG: RVH, right axis deviation
-CXR: prominent vasculature in the hilum
-Echocardiogram: (est. of PA systolic pressure) → presesence of conditions that contribute to PH (e.g. valvular ♥︎ dz, LV systolic dysfunc., impaired diastolic func. etc.)
“Gold Standard” for dx of PAH (and differentiation from other causes of PH)
right ♥︎ cardiac catheterization
Which 3 signs of right sided HF are predictors of poor survival for patients w/ PAH?
- high right atrial pressure
- low cardiac index
- High BNP levels in the blood
What is the natural hx (survival w/o tx) of patients w/ idiopathic PAH?
50% die w/in 3 years
What are 3 specific drug classes used for tx of PAH?
- PDE-5 inhibitors (↑NO)
- Endothelin receptor antagonists (vasodilation)
- Prostanoids
Define apnea and hypopnea:
- apnea: air flow stops ≥ 10s
- hypopnea: reduction in airflow for 10s
What are the 3 classifications of Obstructive sleep apnea (OSA)?
- Mild: 5-15 apnea + hypopnea / hr
- Moderate: 16-30 apnea + hypopnea /hr
- Severe: > 30 apnea + hypopnea/ hr
How is obstructive sleep apnea diagnosed?
polysomnogram (sleep study)
Define obstructive sleep apnea
air flow stops ≥ 10s → complete blockage of the airway despite efforts to breathe
Tx of choice for OSA
CPAP→ functions as an air splint → effective in 90%
What are 4 non-pharmacological (not CPAP) tx for OSA?
- avoid alcohol
- avoid sleep deprivation
- lose weight
- positional therapy (avoid supine sleep position)
Define central sleep apnea
air flow stops ≥10s w/ absence of respiratory effort (aka CNS doesn’t realize you’re not breathing)
Which CVDzs are assoc. w/ OSA and CSA?
- OSA: HTN
- CSA: CHF
Cheyne-strokes (crescendo-decrescendo respiratory pattern)
CSA + CHF
What is the peak age range for OSA in children? What physiologic even does this time period coincide with?
ages 2-7 → coincides w/ peak lymphoid hyperplasia (tonsils)
Define Sudden Infant Death Syndrome (SIDS)
unexplained death of infant after autopsy, death scene examination and clinical review (dx of exclusion)
1 prevention of SIDS
supine sleeping (‘back to sleep campaign’)
What are some signs and ssx of sleep disordered breathing?
- excessing daytime sleepiness
- unrefreshing sleep
- snoring
- witnessed apneas
- HTN
- CHF
- excessive/ redundant pharyngeal tissue
What is the common pathophysiology of mycobacterial and fungal pneumonias?
intracellular pathogens of macorphages→ granulomas
What is the ddx (4) of upper lobe infiltrate and adjacent hilar adenopathy?
- lung cancer
- mycobacterial dz (e.g. TB or no-TB mycobacteria)
- Fungi (histo, blasto, coccidio)- acute phase
- sarcoidosis
Endemic mycoses of the Ohio and Mississippi River valley areas
histoplasmosis
What are the 4 broad clinical spectrums of histoplasmosis (based on time course and location of dz)
- acute localized
- acute diffuse
- chronic
- disseminated
Both acute and chronic histoplasmosis are upper/lower lobe predominant
upper
How does acute localized pulmonary histo look on CXR?
localized pulmonary infiltrate w/ accompanying hilar adenopathy
How does chronic pulmonary histo look on CXR?
cavitary (mimics TB and non-RB mycobacteria)
In acute/chronic pulmonary histo, the organism can be isolated in the sputum
chronic
How is histoplasmosis typically contracted?
bird or bat droppings (in Ohio/Mississippi river valley area)
Which pt. pop. gets chronic histo? What about disseminated histo?
- chronic: peeps w/ pre-existing lung dz
- disseminated: immunocomprimised
Which drug ↑ your risk of contracting disseminated histo?
TNF inhibitor
Pathology: silver stain → helmet morphology
histoplasmosis
broad-based budding yeast
blastomycosis
Co-infx w/ what dz greatly escalates progression from latent → active TB infx?
HIV
What is the key distinction of TB from all other chronic pneumonias?
TB transmission is person-to-person ONLY
Tissue destruction w/ TB infx is primarily d/t what?
host’s inflammatory response
Pathophysiology of latent TB infx:
both w/in m∅s and extracellularly → caseous granulomas
no clinical signs or ssx
Pathophysiology of active TB infx:
chronic, progressive dz primarily in lungs
What are the dx criteria for a latent TB infx (for both TB skin test and new INFƔ release assay)?
TB skin test (TST):
- (-) CXR &
- (+) TST ≥ 10 mm OR
- (+) TST 5-10mm if they have HIV, are immunosuppressed, or have close contact to person w/ active TB
- ≥ 15 mm in very low TB incidence areas
INFƔ release assay (IGRA) (replacing TST → more specific + unaffected by BCG vaccine):
- (-) CXR & (+) IGRA
What is the duration of tx for latent and active TB?
active: 6 mo
latent: 9 mo
Which type of lung cancer has a high prevelance of paraneoplastic syndromes?
small cell lung cancer
- ACTH → Cushing’s
- ADH → SIADH
MC type of lung cancer
adenocarcinoma
What are the 5 stages of lung cancer? What are they corresponding tx strategies?
Stage 0 : carcinoma in situ- early form
Stage 1: localized → surgery
Stage 2: early, locally advanced → surgery + adjuvant chemo
Stage 3: Late, locally advanced → (3a) neoadjuvant chemoXRT +/- surgery
Stage 4: metastasized → (3B + 4) palliative chemo + hospice
Who should you be screeing for lung cancer w/ an annual low-dose CT?
- age: 55-75
- (+) smoking hx of 30 pack-years OR
- exsmokers who quit smoking < 15 years ago
When does normal pleural space have a negative pressure?
- during inhalation → “breathing sucks”
- @ FRC
When does normal pleural space have a positive pressure?
w/ active exhalation or valsalva
early hospice intervention improves/deminishes median survial, patient and family satisfaction in stage IV lung cancer?
improves
What is the caveat of the fixed < 70 % FEV1/FVC ration for obstructive lung dz?
- underdx in the young peeps
- overdx in the old peeps
FEV1/FVC naturally ↓ w/ age
↓ FVC suggests restrictive/obstructive lung physiology
restrictive→ need lung volumes to confirm restrictive pathology
How is ‘air-trapping’ defined (via lung volumes) in obstructive lung dz?
air trapping = ↑RV > 120% of predicted value
How is ‘hyperinflation’ defined (via lung volumes) in obstruction lung dz?
hyperinflation = TLC > 120% predicted
What are 2 exam findings indicitive of lung hyperinflation found in COPD patients?
- hyperresonance
- distant breath sounds
What are 3 exam findings evident of airflow obstruction found in COPD patients?
- prolonged expiratory phase
- ↓ breath sounds
- wheezing
List the 4 stages by GOLD criteria of COPD and their corresponding FEV1 values
I: Mild → FEV1 ≥ 80%
II: Moderate → 50-80%
III: severe → 30-50%
IV: very severe → < 30% (or FEV1 < 50% + respiratory failure)
MCC of transudative pleural effusion
LV ♥︎ failure
classic finding on PE: crackles at lung bases (velcro rales)
idiopathic pulmonary fibrosis
