March 17 - Pulmonary Flashcards
Four stages of lobar pneumonia: timing, macro and micro findings
- Congestion: Seen in first 24 hours. Macro: red, heavy, boggy lobe. Micro: vasodilation, exudate full of bacteria
- Red hepatization: Seen in days 2-3. Macro: red and firm. Micro: exudate with red cells, PMNs, fibrin.
- Gray hepatization: Seen in days 4-6. Macro: grey-brown firm lobe. Micro: disintegrated RBCs, exudate with PMNs and fibrin.
- Resolution: Enzymatic digestion of exuate. Return to normal
Three pneumonia types
Bronchopulmonary: patchy inflammation of multiple lobules
Interstitial: inflammatoyr infiltrate of aveolar walls
Lobar: involves entire lobe of lung
Three ways to diagnose CF
- Increased sweat chloride (can be normal in mild disease.)
- Nasal potential difference measurements (more negative than normal)
- Genetic testing for CFTR mutations
Pathophysiology of CF in respiratory and gastric glands
Normal: CFTR increases Na+ and water content by secreting Cl-. Na+ stays extracellular for charge balance rather than being reabsorbed by ENAC channels.
CF: CFTR is impaired. Cl- can’t be secreted so Na+ reabsortpin is increased through the ENAC channels. Water follows resulting in viscous mucus.
Pathophysiology of CF in sweat glands
Normal: CFTR reabsorbs Cl-. Na+ follows through ENAC channels. Low salt content in sweat
CF: CFTR can’t reabsorb Cl- so high Cl- in sweat. Na+ follows for charge balance resulting in salty sweat
Nystatin
Polyene that inhibits ergosterol similar to amphotericin B. Given as swish and swallow agent for thrush (not absorbed in stomach)
Histoplasma vs coccidioides vs cryptococcus in clinical specimens
Histoplasma: Oval or round yeasts within macrophages
Coccidioides: large thick walled spherules containing endospores
Cryptococcus: Extracellular encapsulated yeast
Clearance of respiratory contaminants
Airways through the terminal bronchioles: mucociliary system
Distal to terminal bronchioles: alveolar macrophages
Airway anatomy: cartilate, goblet cells, epithelium types, smooth muscle, gas exchange
Cartilage: Present in trachea and bronchi
Goblet cells: Present in trachea and bronchi
Pseudostratified ciliated columnar epithelium: Trachea through terminal bronchioles
Cuboidal epithelium: Respiratory bronchioles
Simple squamous epithelium: Aveoli
Smooth muscle: Present through terminal bronchioles (in the conducting airways)
Gas exchange: respiratory bronchioles and aveoli; through the terminal bronchioles is conducting zone
Basis of ESR
Fibrinogen, an acute phase reactant, causes erythrocytes to form stacks that sediment faster. TNF-alpha, IL-1, and IL-6 stimulate production of acute phase reactants by liver, stimulating the systemic inflammatory response.
Airway resistence
Highest in medium sized bronchi, then drops dramatically as airways branch more
Elastin structure
Mostly nonpolar amino acids with proline and lysine like collagen but unlike collagen, not hydroxylated. Lysine deaminated, allowsing for desmoline cross links to form which gives elastin its rubber like properties
Aspiraiton pneumonia: locations
Supine: posterior segment of RUL, superior segment of RLL
Upright: basilar segments of lower lobes
Chediak-higashi presentation
Oculocutaneous albinism
Pyogenic infections
Neurologic dysfunction
Wiskott Aldrich syndrome: presentaiton and cause
Presentation: recurrent infections that worsen with age, easy bleeding, eczema
Cause: abnormal cytoskeleton, B and T cell dysfunction
Polyribosyl-ribitol-phosphate (PRP)
component of H flu capsule, immunogenic
Nocardiasis: cause, presentation, transmission
Cause: infection with Nocardia - branching gram pos rod that is partially acid fast
Transmission: spore inhalation or skin inoculation. Bacteria present in soil
Presentation: Pneumonia, brain abscess in elderly/immunocompromised
Listeria vs nocardia
Both gram pos rods. Listeria has tumbling motility; nocardai has branching filaments.
Listeria causes meningoencephalitis but not pulmonary disease. Nocardia causes pulmonary disease and brain abscess
Hamartoma: imaging and path
Most common benign lung tumor. Contains mature hyaline cartilage, fat, smooth muscle lined by respiratory epihtlieum. Coin shaped lesion on imaging.
Distinguishing between alpha hemolytic strep
Strep pneumo: optochin sens, bile soluble
Viridans strep: optochin resistance, bile insoluble
Bacteria asociated with hyponatremia
Legionella
Fungus associated with cave exploration
histoplasma
Langerhans giant cells
Multiple nuclei in horseshoe chape. Nonspecific finding in granulomatous inflammation. Form of activated macrophages
DHR flow cytometry
Alternative method to diagnose CGD. In CGD see absence of green fluorescence.
Intercostal vessels and nerve location
In subcostal groove on the lower border of the rib
Cord factor
TB virulence factor responsible for serpentine growth pattern. Inactivates PMNs, damages mitochondria, causes release of TNF
Actinomycosis
Caused by gram pos anaerobe that colonizes mouth, colon, vagina. Disruption of mucosa can cause systemic infection. Aspiration can cause pulmonary actinomyces. Bacteria has filamentous branching pattern and sulfur granules
Obesity - PFTs
Greatest change is decrease in ERV
RV is relatively unchanged
Complication of inhaled corticosteroids
Deposition of steroid in oral cavity leading to oral candidiasis. Can prevent with a spacer and oral rinsing
Accenutated second heart sound
indicative of pulmonary artery hypertension
Regulation of breathing: three receptors
1) Central chemoreceptors: predominantly sense pH. Located in medulla. H+ can’t cross BBB but CO2 can, so primarily sense PaCO2.
2) Peripheral chemoreceptors. Located in carotid and aortic bodies. Primarily sense and respond to PaO2. Also can sense PaCO2/pH.
3) Pulmonary stretch receptors. C fibers in lungs and airways. Protect against lung hyperinflation through regulation of duration of inspiration based on lung distension.
Varenicline
Drug used for smoking cessation. Partial agonist at nicotinic ACh receptor in CNS that mediates nicotine dependence. Competes with nicotine and prevents it from binding. Mildly stimulates receptor, decreases withdrawal symptoms,
Treatment of lung abscesses and diagnosis
Diagnosis - see air fluid levels on imaging
Most often caused by aspiration pneumonia which is often mixed anaerobe/aerobe infection. So need to cover for both. Clindamycin a good option. MEtronidazole covers anaerobes but not aerobes. Cipro covers aerobes, not anaerobes
Functional residual capcity and intrapleural pressure
Point at which positive alveolar transmural pressure is equal to the negative chest wall pressure. Airway pressure is zero. Intrapleural pressure is negative, around -5cm H2O. Will decrease to around -7.5 during inspiration.
Zones of lung
Zone 1: Alvolear pressure is greater than areterial and venous. Vessels collapsed and there is no flow. Seen at apex of lung. V greater than Q.
Zone 2: Arterial pressure higher than alveolar, but alveolar higher than venous. Pulsatile flow when arterial pressure is increased during systole. Seen in upper regions of lung. V=Q.
Zone 3: Arterial and venous pressure higher than alveolar pressure. Continuous blood flow with squished alveoli. Seen in lower lung regions. V less than Q.
Hypoxic vasoconstriction occurs in zone 3 to increase blood flow going to zone 2, increasing size of zone 2 and decreasing size of zone 1. When take a deep breath such as during excercise, open up some of zone 3 and increase amt of lung being used.
Cheyne stokes breathing
Seen in advanced CHF at night due to chronic hyperventilaion with hypocapnea. During sleep, CO2 falls below threshold. This is sensed by central chemoreceptors which decrease respiratory drive leading to apnea. The mechanism overshoots so that CO2 goes above threshold and the patient goes back to hyperventilation. Occurs cyclically.
Vimentin
Intermediate filament. Marker of sarcoma,
Complication of untreated OSA
Pulmonary HTN and cor pulmonale
Pulmonary vascular resistance: how it varies with lung volume
Increased lung volume such as during inspiration causes alveolar expansion which stretches interstitial alveolar BVs, increasing resistance.
Decreased lung volumes such as during expiration narrows vessels by decreasing radial traction, also increasing resistance.
Sweet spot is at FRC - when PVR is lowest. Increases above and below FRC.
Risks of secondhand smoke exposure to child
Sudden infant death syndrome
Otitis media
Pulmonary infections
Asthma
Bosentan: MOA and use
Endothelin receptor antagonist. Blocks endothelin’s vasoconstrictive effects resulting in vasodilation. Used to treat PAH.
Indomethacin MOA
Nonspecific cyclooxygenase inhibitor.
Coal miners pneumoconiosis
Upper lung nodules on imaging. Carbon gets into alveoli, macrophages take it up and cause massive fibrosis because can’t “kill” it. Black shrunken lung grossly, Associated with RA.
Silicosis
Seen in silica miners and sandblasters. Impairs phagolysosome formation in macrophages, increasing risk for TB infection. Fibrotic nodules in upper lobe.
Beryllium pneumoconiosis
Seen in miners and aerospace workers. Resembles sarcoidosis: noncaseating granulomas in lung, hilar nodes, and other organs. Increased risk for lung cancer.
ARDS pathophysiology and presentation, risk factor, treatment, complication
Pathophys: Damage to alveolar-capillary interface causes leak of protein rich fluid, which forms hyaline membranes along the air sacs. This thickens the diffusion barrier resulting in hypoxemia and cyanosis. In addition, the membranes are sticky, increasing surface tension and causing collapse of the lung.
Presentation: SOB, hypoxemia, and diffuse white out on CXR
Risk factor: acute pancreatitis
Treatment with PEEP
Complication of recovery is interstitial fibrosis.
Forms of lung transplant rejection
Hyperacute: vessel spasm, DIC, and ischemia
Acute: vascular damage, perivascular and peribronchial infiltrates
Chronic: bronchiolitis obliterans with inflammation of small bronchioles. Presents with dyspnea, cough, weezing
MAC: population, prophylaxis, distinction from TB
- seen with CD4+ count less than 50
- prophylax with azithromycin
- distinguished from TB by growth at high temps (optimal at 41 degrees C)
Vit A deficiency in CF
Can lead to squamous metaplasia in the pancreas. Vitamin A and retinoic acid required for maintenance of specialized epithelia
Abscess formation in lung
Neutrophils and macrophages release lysosomal enzymes that destroy tissue, setting stage for abscess formation
Monteleukast: MOA and USe
Leukotriene receptor inhibitor that doesn’t inhibit leukotriene production. Used for asthma, esp good for aspirin-induced asthma
Zileuton: MOA and USe
MOA: Inhibits 5-lipoxygenase, preventing leukotriene synthesis
Use: Asthma
Theophylline: MOA and USE
MOA: inhibits phosphodiesterase, increasing cAMP and cuasing bronchodilation
Use: Asthma
Congenital diaphragmatic hernia: pathophys and presentation
Pathophys: gailure of diaphragm to close and form properly, resulting in herniation of bowel into the thorax. Results in underdevelopment of lungs and pulmonary vasculature and can push mediastinal structures to contralateral side. 90% of time on the left.
Presentaiton: Bowel sounds in lung zone. Heart sounds heard better on right side. Lack of lung sounds on left. Respiratory distress. Scaphoid abdomen. Pulm HTN
Distinguishing causes of atypical pneumonia on sputum
Chlamydia pnuemonia has cytoplasmic inclusions, mycoplasma does not
Treatment of pseudomonas
Three cephalosporins effective: cefoperazone, ceftazidime, cefepime
TB drug that causes drug-induced lupus
INH
Ethambutol MOA
inhibits arabinosyl transferase
Change in lung during strenuous exercise
Oxygen fails to equilibrate and becomes diffusion limited
CF most common mutation
Defective ER processing
Amphotericin toxicity
Fever and chills, hypotension, nephrotoxicity, QT prolongation, arrhythmia
