10. Pulmonary Flashcards
What structures traverse the diaphragm, and at what vertebral levels do they pass through?
8: IVC
10: esophagus, vagus nerve
12: aorta, thoracic duct, azygos vein
What histological change takes place in the trachea of a smoker?
metaplasia (ciliated columnar –> squamous)
What cell type proliferates during lung damage?
type 2 pneumocytes
What amniotic fluid measurement is indicative of fetal lung maturity?
lecithin-sphingomyelin ratio >2
a young woman has infertility, recurrent URIs, and dextrocardia. Which of her protein is defective?
dynein
If a lung collapses, what happens to the intrathoracic volume?
Intrathoracic volume increases due to unopposed chest wall expansion
What gene mutation can cause primary pulmonary HTN?
BMPR-2 gene
What are some of the secondary causes of pulmonary HTN?
- COPD
- sleep apnea
- frequent thromboembolism
- mitral stenosis
- Left-to-right shunts
What are some of the treatment options available for pulmonary HTN? (4)
- Bosentan
- Prostacyclin analogs
- Sildenefil (phosphodiesterase inhibitors)
- Nifedipine
What is the MoA of bosentan?
competitively antagonizes at the endothelin-1-receptor (decreasing pulmonary vascular resistance)
Which form of hemoglobin A has a high affinity for oxygen? Which has a low affinity for oxygen?
R form (relaxed) - high affinity T form (taut) - low affinity
What substances tend to shift the oxygen-hemoglobin dissociation curve to the right? (5)
Does this favor oxygen loading or unloading?
- CO2
- acidosis
- elevated 2,3-DPG
- exercise
- increased temperature
- favor oxygen unloading
What is the treatment for methemoglobinemia?
methylene blue + vit C
What is the normal value for the A-a gradient?
10-15 mmHg
What might an elevated A-a gradient indicate? (5)
- high FiO2
- shunting of blood
- pulmonary fibrosis
- V/Q mismatch
- advanced age
What changes occur in the oxygen content and saturation in anemia?
- PaO2 normal
- O2 sat normal
- Total O2 content low
What is the V/Q at the apex of the lung? At the base of the lung?
apex: V/Q > 1
base: V/Q
What is the V/Q during airway obstruction? during blood flow obstruction?
airway obstruction: towards 0 (shunt)
blood flow obstruction: towards infinity
How is CO2 transported from the tissues to the lungs? (3)
- Bicarbonate
- Bound to Hgb as carbaminohemoglobin
- Dissolved in blood
How do CO2 levels in circulation change during exercise?
- no change in PaCO2
- increase in venous CO2
How does the body compensate for hypoxia at high altitudes? (6)
- increase ventilation (acute and chronic)
- increase renal excretion of bicarb
- increase number of mitochondria
- increase EPO
- increase RBC mass
- increase 2,3-BPG (right-shift of curve –> unloading of O2)
At what positive G-force does visual “black-out” occur? Why does this occur?
- 4-6G
- due to force of pooling blood in abdomen and legs
- insufficient pumping of blood to brain
What physiologically is taking place in decompression sickness?
- as pressure decreases (by re-surfacing), dissolved nitrogen gas comes out of solution
- leads to formation of bubbles that can occlude blood vessels
By what physiological mechanism does acute mountain sickness cause acute cerebral edema and acute pulmonary edema?
- cerebral edema: hypoxia induced vasodilation
- pulmonary edema: local vasoconstriction –> forces fluid out of capillaries
A patient suffers a stroke after incurring multiple long bone fractures in a skiing accident. What caused the infarct?
fat embolus
- via PFO or via pre-capillary AV shunt in the lungs
What are the hallmark characteristics of obstructive lung disease on PFT?
- increased total lung volume
- decreased FVC, FEV1
- FEV1/FVC
What are the hallmark characteristics of restrictive lung disease on PFTs?
- decreased total lung volume
- decreased FVC, FEV1
- normal or slightly elevated FEV1/FVC ratio
What is the Reid index?
= (thickness of glands layer) / (thickness of bronchial wall)
How does emphysema caused by smoking differ from the emphysema caused by alpha1-antitrypsin deficiency?
smoking: centriacinar
- also, more often in upper lungs
a1: panacinar
- more often in lower lungs
What asthma medication is the inhaled tx of choice for chronic asthma?
inhaled steroids
What asthma medication is the inhaled tx of choice for acute exacerbations?
albuterol (short acting B2 agonist)
What asthma medication has narrow therapeutic index, drug of last resort?
theophylline
What asthma medication blocks conversion of arachidonic acid to leukotriene?
zileuton
What asthma medication inhibits mast cell release of mediators, used for ppx only?
cromolyn
What asthma medication is the inhaled tx that blocks muscarinic receptors?
ipratropium, tiotropium
What asthma medication is inhaled long-acting B2 agonist?
salmetrol
What asthma medication blocks leukotriene receptors?
montelukast, zafirlukast
Which medications, if taken long term, can result in rebound nasal congestion?
alpha-adrenergic agonists (pseudoephedrine, phenylephrine)
A preterm infant has difficulty breathing. An x-ray reveals diffuse air space and interstitial opacities, with air bronchograms. What is the diagnosis and what could have prevented this condition?
neonatal resp. distress syndrome
- prevent with maternal steroids given 24-48 hrs prior to delivery
A lung biopsy from a plumber shows elongated structures with clubbed ends in tissue. What is the diagnosis, and what is he at increased risk for?
Asbestosis
- at increased risk for lung cancer, laryngeal cancer, mesothelioma
What is elevated in the serum of pts with sarcoidosis? (2)
ACE inhibitors
hypercalcemia (due to excess vit D via macrophages)
What do pts with silicosis need to be worried about? (2)
- increased susceptibility to TB
- increased risk for bronchogenic carcinoma
A patient develops bronchogenic lung cancer but has never smoked. He is a coal miner. Exposure to what substances has put him at risk for developing lung cancer? (2)
- Radon
- Silica
What are the 4 most common locations of lung cancer metastasis?
- brain
- bone
- liver
- adrenal gland
Common cause of pneumonia in immunocompromised pts
PCP
Can cause an interstitial pneumonia in bird handlers
Chlamydia psittaci
Often the cause of pneumonia in a pt with a history of exposure to bats and bat droppings
Histoplasma
Often the cause of pneumonia in a pt who has recently visited South California, New Mexico, or West Texas
Coccidioides
Pneumonia associated with “currant jelly” sputum
Klebsiella
Associated with pneumonia acquired from air conditioners
Legionella pneumophila
Most common cause of pneumonia in children 1 yo or younger
RSV
Most common cause of pneumonia in the neonate (birth-28 days)
GBS or E. coli
What infectious agent causes wool-sorter’s disease (a life threatening pneumonia)
Bacillus anthracis
Common pneumonia in ventilator pts and those with cystic fibrosis (2)
Pseudomonas, MRSA
What infectious agent causes pontiac fever
Legionella pneumophila
