Week 4

Question 1

What are the three major types of non-small cell lung carcinoma and how do they differ in terms of association with smoking and pathological characteristics?

Answer 1

Adenocarcinoma – most common cause of lung cancer overall and by far the most common cause in non-smokers; characterized by round gland formation as well as columnar cells and the presence of mucin; frequently carry mutations in EGFR and/or KRAS; may be central or peripheral

Squamous Cell Carcinoma – almost always associated with smoking; typically central and cystic; like other squamous cell carcinomas, characterized by keratinization and intracellular bridges/desmosomes

Large Cell Carcinoma – “wastebasket” category for poorly differentiated tumors that do not fit into any other category

Question 2

What are potential management options for a patient with allergic rhinitis?

Answer 2

1. Avoidance measures – staying away from the culprit allergen; first line approach
2. Medications – nasal steroids (most effective), nasal antihistamines, oral antihistamines, leukotriene inhibitors, oral decongestants, and mast cell stabilizers
3. Immunotherapy – consists of allergy shots and tablets; injections can dramatically reduce symptoms to many allergens

Question 3

What is the mechanism through which obstructive sleep apnea may lead to pulmonary hypertension?

Answer 3

Reduced ventilation leads to decreased alveolar oxygen content; this induces pulmonary vasoconstriction (in contrast to other blood vessels, pulmonary vessels constrict in response to hypoxia); this increases pulmonary vascular resistance, leading to pulmonary hypertension .

Question 4

What are different forms of positive airway pressure therapy in patients with OSA? How do they differ?

Answer 4

Continuous positive airway pressure (CPAP) – provides positive pressure during both inspiration and expiration; pressure is constant and is set to a value above the critical opening pressure of the airway (Pcrit)

Bi-level positive airway pressure (BiPAP) – provides positive pressure during both inspiration and expiration, but the pressure is higher during inspiration

Automatic positive airway pressure (AutoPAP) – actively measures Pcrit and adjusts the supplied pressure to match it; supplies the lowest amount of pressure needed to open the airway