Week 2

Question 1

What are the 3 causes of Hypoxemia with a normal A-a difference (or high PaO2/FiO2 ratio) ?

Answer 1

1. Low atmospheric pressure
2. low FiO2
3. Increased PaCO2

[2/2/21 SM159-160]

Question 2

What are the 3 causes of hypoxemia with a wide A-a difference (low P/F)?

Answer 2

1. Shunt (V/Q = 0)
2. Low V/Q (but not zero)
3. diffusion limitation

For these causes, a fall in SVO2 can markedly worsen hypoxemia

[2/2/21 SM159-160]

Question 3

What are the 4 causes of low SVO2?

Answer 3

1. Low cardiac output
2. anemia
3. hypoxemia
4. increased VO2

[2/2/21 SM159-160]

Question 4

What gene variant is responsible for > 90% of cases of CF in the US

Answer 4

delta F508, a class II (abnormal processing/maturation) variant

[2/2/21 SM158]

Question 5

What does the Sweat Test in CF measure?

Answer 5

Cl^- levels

In patients with CF, dysfunction of the CFTR channel leads to an abnormally high level of Cl- in sweat. Levels > 60 mmol/L are felt to be diagnostic of CF

[2/2/21 SM158]

Question 6

What changes in pH are expected in acute respiratory acidosis/alkalosis?

Answer 6

0.08 in the opposite direction as the change in PaCO2

[2/3/21 SM162]

Question 7

What are the two main types of metabolic alkalosis?

Answer 7

1. Cl^- responsive (vomiting, NG suctioning, over diueresis)
2. Cl^- non-responsive (mineralcorticoid excess: primary hyperaldo, exogenous steroids, etc)

[2/3/21 SM162]

Question 8

What acronym is associated with non-gap metabolic acidosis?

Answer 8

USED CARS

uretero-enterostomy with bicarb rich ostomy fluid

saline administration

endocrine disorders (eg, adrenal insufficiency)

diarrhea

carbonic anhydrase inhibitors (acetazolamide)

ammonium chloride

renal tubular acidosis

spironolactone

*bold=most common in clinical practice

[2/3/21 SM162]

Question 9

What should you consider during a delta-delta analysis?

Answer 9

If drop in HCO3 > change in AG, you have a concurrent non-gap metabolic acidosis

If drop in HCO3 < change in AG you have a concurrent metabolic alkalosis (raising HCO3 higher than would be expected)

[2/3/21 SM163]

Question 10

DDX of anion gap metabolic acidosis?

Answer 10

(MUD PILES)

methanol

uremia

diabetic ketoacidosis (or ketoacidosis from EtOH, starvation)

propylene glycol

isoniazid

lactic acidosis

ethylene glycol

salicylates

[2/3/21 SM162]

Question 11

What are the main cytokines that drive TH2 inflammation in asthma?

Answer 11

Il-4, Il-5, IL-13

[2/4/21 SM165]

Question 12

What are the pathologic hallmarks of asthma?

Answer 12

Goblet cell hyperplasia

subepithelial fibrosis

basement membrane hypertrophy

[2/4/21 SM165]

Question 13

What does an asthma diagnosis involve?

Answer 13

A clinical diagnosis based on history. Is NOT dependent on a specific finding on PFTs

[2/4/21 SM165]

Question 14

What does a COPD diagnosis involve?

Answer 14

DOES have a spirometeric component to diagnosis. Requires an FEV1/FVC < 0.7

[2/4/21 SM166]

Question 15

What are the pathologic hallmarks of COPD?

Answer 15

Emphysema

mucus hypersecretion

peribronchiolar fibrosis

[2/4/21 SM166]