Pulmonary Diseases and Conditions Flashcards
Emphysema
Obstructive lung disease (within COPD)
Destruction of the alveolar-capillary membranes distal to terminal bronchioles, resulting in dilatation of terminal air spaces, and this reduces surface area of the lung
Lose elasticity/recoil of lungs, taking you to higher FVC
EPP moves farther along airways to alveoli, causing ariway collapse
Tau (R x C) is increased so can’t count on passive exhalation anymore and have to use accessory muscles
Barrel chest, difficulty breathing out, increasing expiratory flow does NOT prevent airways from collapsing
Emphysema worse in upper lobes than in lower lobes
Examples of obstructive lung disease
Asthma
Bronchitis
Upper airway?
Examples of restrictive lung disease
Pulmonary fibrosis
Chest wall deformity
Neuromuscular weakness
Lung volumes in obstructive lung disease
TLC, FRC, RV increased
FEV1/FVC ratio is decreased (normal is 80%)
Remember: hyperinflation, air trapping
Lung volumes in restrictive lung disease
TLC, FRC, RV decreased because lungs are smaller
FEV1/FVC same or larger
Lungs are less compliant and thus more elastic
Polio
Viral disease that causes muscle weakness that leads to restrictive lung disease
Iron lung was a negative pressure ventilator to aid patients in breathing
Interstitial fibrosis
Stiff lungs
Can result in mechanical problems (alveolar hypoventilation) but also thickening can cause diffusion abnormality because of thickening of alveolar walls
On exercise PaO2 falls because of inadequate time for oxygen diffusion (this doesn’t happen very commonly)
High altitude
Lower barometric pressure, so therefore 21% O2 concentration is lower O2 pressure, so you get lower PAO2 because of altitude
Also at high altitude, CO will increase (widening pulse pressure)
Also pulmonary arteries will constrict (hypoxic pulmonary vasoconstriction)
Pulmonary embolism
Happens in people who are immobile for a long time, previously healthy, estrogen therapy, “bad cold” at onset of symptoms is actually PE, causes rapid deterioration
Pulmonary vascular resistance is increased
If no pulmonary infarction, PE can even be asymptomatic, or difficult to diagnose
Bronchiectasis
Necrotizing infection of bronchi
Dilated bronchi that have destruction of muscle and elastic tissue
Green/yellow sputum
Smokers, CF, congenital, poor ciliary motility, breathing in food particles
Obstructive lung disease
Honeycomb change
Multiple abnormal airspaces surrounded by dense collagen (pink)
Thick wall spaces
Seen in end stage pulmonary fibrosis, life expectancy only 3 years once you see honeycomb change
COPD
Chronic Obstructive Pulmonary Disease
Two components: emphysema and airway inflammation
Lungs and chest get big–barrel chest
Lungs very gray/black because of anthrocrotic pigment
Destruction of alveoli
Emphysema worse in upper lobes than lower lobes
Diseases caused by smoking
Emphysema
Chronic bronchitis
Respiratory bronchiolitis
Desquamative interstitial pneumonia
Eosinophilic granuloma
Cancer
Chronic bronchitis
Airway inflammation causes increased glands and secretions (mucous in the airway)
Interstitial lung disease (ILD)
200 different diseases with different causes but similar symptoms (inflammation and fibrosis)
Not that common
Most important is Usual Interstitial Pneumonia, usually affects lower lobe (spatially and temporally heterogeneous)
Acute Lung Injury
Adult Respiratory Distress Syndrome (see hyaline membranes: pink lining that represents necrotic epithelial cells in alveolar septae and plasma proteins deposited from leakage of capillaries)
or
Diffuse Alveolar Damage (first see edema on x-ray, then hyaline membranes 24 hours later)
Consolidation
Exudate, inflammatory cells that eventually turn white and harden
Seen in pneumonia
Virchow’s triad of things that increase the probability of thromboemboli
1) Vascular injury
2) Stasis
3) Hypercoagulable state
Note: people who have just had surgery more at risk for PE because of these 3 things
Major types of lung cancer
1) Adenocarcinoma
2) Squamous cell carcinoma
3) Small cell carcinoma (neuroendocrine/Kulchitsky cell)
4) Large cell undifferentiated carcinoma
Mesothelioma
Tumor encasing/surrounding lung
Associated with asbestos exposure (can even have secondary asbestos exposure via clothes etc as a cause)
Mechanism of damage caused by smoking
Activation of leukocytes that induce chronic inflammation and structural injury by release of enzymes and ROS’s
Inactivates anti-proteases, causing tissue destruction
D-dimer test
D-dimer is a fibrin degradation product
Used to diagnose PE
High sensitivity (people who have PE WILL have high D-dimer) but low specificity (many false positives, so people with no PE may easily still have high D-dimer)
Chronic hypercapnia/Chronic lung disease
Chronic respiratory failure causes increased PaCO2, low PaO2, acidic pH –> CO2 goes into CSF, H+ gets into kidney tubule, causes excretion of H+ and retention of HCO3- –> HCO3- actively transported out of BBB to try to reduce pH changes –> reduces H+ in CSF –> reduced stimulus for chemoreceptors to increase ventilation (bad!)
Compensated respiratory acidosis with chronic hypoxemia, hypercapnia, renal HCO3- retention, normal blood pH
Patients insensitive to chronically elevated PaCO2, so ventilation stimulated by hypoxia!
Dejor effect says: Don’t give 100% O2 to person with chronic hypercapnia because that decreases ventilation more (peripheral carotid bodies turned off!) and increases PCO2 even more
Patient develops pulmonary hypertension, edema, in response to hypoxemia which can lead to right side heart failure
Sleep apnea
Cessation of breathing for more than 10 seconds
Caused by obstruction of hypopharyngeal airway or disturbance of ventilatory control during sleep
Leads to sleep disruption, nocturnal hypoxemia, early morning hypercapnia, sleepiness during day
How can you tell if someone has diaphragm paralysis?
When they breathe in, their abdomen will be sucked INWARD
Thoraco-abdominal paradox
Have to use their accessory muscles to expand ribcage due to floppy diaphragm and this causes abdomen to be sucked in
Why is emphysema considered obstructive?
Airways collapse because less elastic recoil moves EPP closer to alveoli, so can’t get air out
