Respi 3 Flashcards
How do you reduce the risk of HIV-1 perinatal transmission in pregnant mothers?
Give pregnant women Antiretroviral therapy. ART should be continued so long as the mother is breastfeeding.
How do patients w/ COPD (and smoke) develop polycythemia?
Chronic bronchitis decreases airway diameter, and emphysema allows for insufficient contact b/w alveolar capillaries and airspaces. Hypoxia is sensed by renal cortical cells, w/c produce EPO in response.
How does lung adenoCA look histologically?
It consists of well-differentiated dysplastic columnar cells that may or may not secrete intracellular mucin. A preinvasive lesion would grow along intact alveolar septa. Mucinous types would produce watery sputum (bronchorrhea).
What B cell antigens would be lacking in the circulation in Bruton agammaglobulinemia? What infections would patients w/ this condition be susceptible to?
In Bruton, pre-B cells (CD19, CD20) fail to develop into mature B cells, so patients would no B cells and absence of all antibody types. They’d be susceptible to pyogenic bacteria, enteroviruses, and Giardia lamblia.
How does LHF contribute to dec. lung compliance?
LHF can increase hydrostatic pressure in pulmo circulation, causing transudation of fluid into the lung interstitium. This causes a distortion (swelling) of the tissue, increasing its resistance to movement and its inability to distend during inspiration (dyspnea).
What is the Reid index?
Reid index describes the ration of thickness of the mucous gland layer o the thickness of the bronchial wall b/w the epithelium and the cartilage. It measures mucous gland enlargement and bronchial wall thickening in Chronic bronchitis.
How are Tidal volume and RR affected when pulmonary elastic resistance is increased? When airflow resistance is increased?
> Inc. elastic resistance: work of breathing minimized w/ inc. RR and dec. TV (rapid, shallow breaths).
Inc. airflow resistance: work of breathing minimized w/ dec. RR and inc. TV (slow, deep breaths).
How is minute ventilation (TV x RR) important in regards to work of breathing?
Adequate minute ventilation maintains oxygenation of CO2 excretion. To prevent fatigue, TV and RR are optimized by the respi centers to minimize the work of breathing.
How are patients w/ sepsis and pulmonary infections at risk of developing ARDS?
Cytokines are released into the circulation in response to infection, activating the pulmo epithelium and provoking and inflammatory response mediated by neutrophils. This leads to capillary damage and fluid and protein leakage into the alveolar space. Hypoxia worsens, and respi failure may develop.
How do patients w/ Pulmonary embolism develop hypoxemia and respiratory alkalosis?
PE can cause hypoperfusion, w/c redistributes blood flow to better ventilated alveoli (V/Q mismatch). The ensuing hypoxemia is because the highly oxygenated lung can’t absorb extra O2 to compensate for the poorly oxygenated parts. This induces hyperventilation, causing hypocapnia and respiratory alkalosis.
How do you determine if Respiratory acidosis is Acute or Chronic?
Kidneys have delayed compensation for inc. PCO2 in the body (takes 3-5 days).
>Acute: dec. pH, inc. pO2, normal HCO3 (less than 30).
>Chronic: dec. pH, inc. pO2, inc. HCO3 (> 30)
What is the MOA of Ipratropium?
Anticholinergic, derivative of Atropine.
Blocks ACh action at Muscarinic receptors, preventing bronchoconstriction.
Dec. Parasympathetic stimulation of tracheobronchial submucosal glands.
How do you differentiate Sarcoidosis from other interstitial lung diseases?
Sarcoid granulomas can produce ACE and active vit D, so patients have inc. ACE and hypercalcemia. The CD4/CD8 ratio in bronchoalveolar lavage fluid is high in sarcoidosis due to accumulated CD4+ cells.
What are the neutrophil chemotactic agents? (4)
LTB4 is the most potent.
5-HETE (leukotriene precursor).
C5a, IL-8.
What is the MOA of Cromolyn?
Cromolyn inhibits mast cell degranulation. Since it doesn’t influence bronchoconstriction directly, it’s used to prevent acute attacks rather than treat acute exacerbations (prophylactic). It’s 2nd line for allergic rhinitis and bronchial asthma.
