Pulmonology Flashcards
What protein mutation is associated with cystic fibrosis?
Abnormal posttranslational processing of CFTR, a transmembrane protein which prevents it from reaching the cell surface. This protein is thus absent in the apical membrane of affected epithelial cells.
What is the mechanism of action of echinocandid antifungals?
To block glucan synthesis.
Name two echinocandid antifungals.
Capsofungin and echinocandin.
What is 1,3-beta-D-glucan?
A polysaccharide component of the fungal cell wall.
What is the difference in mechanism of action between echinocandin antifungals and polyene and azole antifungals?
Polyene and azole antifungals target the fungal cell membrane; echinocandins suppress synthesis of the fungal cell wall.
What species is Capsofungin effective against? Ineffective?
Affective: Candida, Aspergillus; Ineffective: Cryptococcus neoformans, limited activity against Mucor and Rhizopus.
What is the mechanism of action of Amphotericin B?
Polyene antifungal that binds ergosterol in the fungal cell membrane to lead to pore formation and cell lysis.
What is the mechanism of itraconazole?
Azole antifungal that inhibits ergosterol synthesis
What is terbinafine used to treat?
Dermatophytosis
What is the mechanism of action of terbinafine?
It inhibits the fungal enzyme squalene-2,3-epoxidase resulting in decreased synthesis of ergosterol.
What is the mechanism of action of Griseofulvin?
Enters fungal cells, binds microtubules, inhibits mitosis. It is effective only against dermatophyte fungi.
What is the mechanism of action of flucytosine?
Inhibits synthesis of DNA and RNA in fungal cells. It is used synergistically with amphotericin B, especially to treat cryptococcal meningitis.
Assuming a normal rate of metabolic CO2 production, hypocapnia implies what state?
Alveolar hyperventillation.
What is the main indicator of total alveolar ventilation?
Arterial PaCO2.
What may cause alveolar hyperventilation?
V/Q mismatch that causes decreased O2 and CO2 exchange (ex pneumonia, PE)
What central changes occur due to hypoxemia?
Elevated respiratory drive causing excessive CO2 excretion by the lungs and resulting in hypocapnia.
Name four causes of alveolar hypoventillation.
Upper airway obstruction, reduced ventillatory drive, respiratory muscle fatigue, decreased chest wall compliance.
What is the histological presentation of asbestosis?
Localized pleural thickening with calcification, espeically of the posterolateral mid-lung zones and diaphragm.
How does asbestosis manifest radiographically?
Linear interstitial densities in the lower lobes.
How does silicosis present histologically?
Nodular densities and eggshell calcifications.
How does berylliosis present histologically?
Nodular infiltrates, enlarged lymph nodes, non-caseating granulomas (similar to sarcoidosis).
How does hypersensitivity pneumonitis due to inhalation of organic dusts present on chest xray?
Diffuse nodular interstitial infiltrates on xray
When does the trachea deviate towards the opacified lung on xray?
With volume loss- atelectasis
When does the trachea deviate away from the opacified lung on xray?
Large pleural effusion