Pulm Random Facts Flashcards
Relationship of the pulmonary artery to the bronchus at each lung hilm
RALS= Right anterior; left superior
What goes through the diaphragm at T12?
Aorta, thoracic duct, and azygos vein
What is the functional residual capacity?
Volume of gas in lungs after normal expiration (residual volume plus expiratory reserve volume)
How to calculate physiologic dead space?
Tidal volume * (Paco2-Peco2)/Paco2; Paco2= arterial Pco2; Peco2=expired air Pco2
What decreases pulmonary compliance?
Pulmonary fibrosis, pneumonia, pulmonary edema
What increases pulmonary compliance?
Emphysema, normal aging
What shifts the hemoglobin dissociation curve to the right?
Increased Cl, H+, CO2, 2,3-BPG, and temperature
What is familial erythrocytosis?
A beta-globulin mutation that results in reduced binding of 2,3-BPG
How to remember which is ferrous and which is ferric?
Just the two of us: ferroUS is Fe2+
How much oxygen can 1 g of hemoglobin bind?
1.34 mL
Which gases are perfusion limited?
O2 (normal health), CO2, N20
Which gases are diffusion limited?
O2 (emphysema, fibrosis), CO.
How do you calculate the pulmonary vascular resistance?
[P(pulm artery)-P(L atrium)]/cardiac output
What is the alveolar gas equation?
PAo2=PIo2-(PaCO2/R); R is the respiratory quotient=CO2 produced/O2 consumed
What can cause an A-a gradient?
V/Q mismatch, diffusion limitation (eg. fibrosis), right to left shunt
What is the normal V/Q ratio at the apex and base of the lungs?
V/Q at apex=3 (wasted ventilation); V/Q=0.6 (wasted perfusion); BUT both ventilation and perfusion are greater at the base of the lung than at the apex
Pressures in the apex of the lung
PA> Pa > Pv
Pressures in zone 2 of the lung
Pa >PA> Pv
Pressures in zone 3 (base) of the lung
Pa >Pv > PA
What is the Bohr effect?
Increased Pco2 causes increased H+, which causes decreased hemoglobin affinity for O2 causing oxygen unloading
What is the Haldane effect?
Increasing Po2 causes increased binding of O2 o Hb causing release of H+ and CO2
Where does CO2 bind to hemoglobin
At the N-terminus of globin (NOT to heme)
What happens in the kidney in response to high altitude?
Increased renal excretion of HCO3- to compensate for respiratory alkalosis (can augment with acetazolamide)
Which bacteria may be superimposed on viral rhino sinusitis?
S. pneumo, H. flu, M. catarrhalis
Where do life-threatening nose bleeds occur?
Posterior segment (sphenopalatine artery, a branch of maxillary artery)
Classic triad of fat emboli?
Hypoxemia, neurologic abnormalities, petechial rash
Multifocal ischemic necrosis of bone
Caisson disease, chronic form of air emboli.
What are Charcot-Leyden crystals?
Eosinophilic, hexagonal, double-pointed, need-like crystals form from breakdown of eosinophils in sputum, associated with asthma
What are Curschmann spirals?
Shed epithelium forms whorled mucus plugs (associated with asthma)
What is bronchiectasis?
Chronic necrotizing infection of bronchi causes permanently dilated airways, purulent sputum, recurrent infections, hemoptysis
Which drugs can cause interstitial lung diseases?
Bleomycin, amiodarone, methotrexate, busulfan
What do you see in hypersensitivity pneumonitis
Mixed type III/IV hypersensitivity, predominance of CD8+ cells, often seen in farmers and those exposed to birds
What is Caplan syndrome?
Rheumatoid arthritis and pneumoconioses with intrapulmonary nodules
What is anthracosis
Asymptomatic condition found in many urban dwellers exposed to sooty air
“Eggshell” calcification of hillier lymph nodes
Silicosis
What do you see on histology in silicosis
Birefringent silica particles surrounded by fibrous tissue
What is silicosis associated with?
Foundries, sandlasting, mine
What is the relationship between silicosis and TB
Silica may disrupt phagolysosomes and impair macrophages, increasing susceptibility to TB
What does therapeutic O2 in neonates predispose to?
Retinopathy of prematurity, intraventricular hemorrhage, bronchopulmonary dysplasia
What is idiopathic PAH often due to?
An inactivating mutation in BMPR2 gene (which normally inhibits vascular smooth muscle proliferation)
What are Light’s criteria:
Exudate if 2 of 3: Effusion protein/serum protein ratio >0.5, effusion LDH/serum LDH >0.6; Effusion LDH > 2/3 the upper limit of the reference range
What are lung abscesses often caused by?
Anaerobes (eg. Bacteroides, Fusoacterium, Peptostreptococcus) or S. pneumo
“Cough productive of foul-smelling sputum”
Abscess
Tumor cells with long, slender microvilli and abundant tonofilaments
Mesothelioma
What is the immunohistochemical marker for mesothelioma
Pancytokeratin
Where does lung cancer metastasize to?
Adrenals, brain, bone (pathologic fracture), liver (jaundice, hepatomegaly)
Tx of small cell lung cancer
Chemotherapy (Inoperable!!)
Lung cancer that’s chromogranin A +
Small cell or bronchial carcinoid tumor
What does small cell carcinoma stain positive for?
Chromogranin A, neural cell adhesion molecule (NCAM), neuron-specific enolase, and synpatophysis
What does CXR show in bronchioloalverolar subtype of adenocarcinoma of the lung?
Hazy infiltrates similar to pneumonia because it grows along alveolar septa causing apparent “thickening” of the walls. This type has an excellent prognosis.
Which type of lung tumor can secrete beta-HCG?
Large cell carcinoma. Also has pleomorphic giant cells and a poor prognosis.
What is chlorpheniramine
First generation H1 blocker
What is hydroxyzine
First generation H1 blocker
What is loratadine
Second generation H1 blocker
What is fexofenadine
2nd gen H1 blocker
What is desloratadina
2nd gen H1 blocker
What is dimenhydrinate
1st gen H1 blocker
MOA of N-acetylcysteine for expectoration
Loosens mucus plugs by disrupting disulfide bonds
MOA of dextromethorphan
Antagonizes NMDA glutamate receptors. Synthetic codeine analog
MOA of bosentan
Endothelia receptor antagonist to decrease pulmonary vascular resistance. Hepatotoxic (monitor LFTs)
What can PDE5 inhibitors be used for other than erectile dysfunction
Pulmonary HTN
MOA of epoprostenol, iloprost
Prostacyclin (PGI2) analogs with direct vasodilatory effects on pulmonary and systemic arterial vascular beds. Inhibit platelet aggregation
MOA of ipratropium
Muscarinic antagonist, competitively blocks muscarinic receptors, preventing bronchoconstriction
MOA of montelukast and zafirlukast
Block leukotriene receptors (CysLT1).
What are montelukast and zafirlukast especially good for?
Aspirin-induced asthma
MOA of zileuton
5-lipoxygenase pathway inhibitor. Blocks conversion of arachidonic acid to leukotrienes. Hepatotoxic
What is omalizumab?
Monoclonal anti-IgE antibody. Binds mostly unbound serum IgE and blocks binding to Fc-epsilon-RI. Used in allergic asthma resistant to inhaled steroids and long-acting beta2-agonists
What type of drug is theophylline?
Methylxanthine
MOA of theophylline
Likely causes bronchodilation by inhibiting phosphodiesterase causing increased cAMP levels due to decreased cAMP hydrolysis. Also blocks actions of adenosine (which cause bronchoconstriction)
Toxicity of theophylline
Seizures and tachyarrhythmias
MOA of methacholine
Muscarinic receptor (M3) agonist.
MOA of magnesium in an acute asthma flare-up
Inhibits Ca influx into airway smooth muscle
