Pulm question in NBME4

[dendrites]

---

Members don't see this ad.

Can someone explain this question to me:

57 y/o woman with a 2 year history of progressive productive cough of yellow sputum daily. 40 year smoking history. O2sat=90%, PE: decreased breath sounds in all fields and rhonci at lung bases. Expiratory phase is prolonged. ECG= sinus tach with P pulmonale

PFTS: FEV1 greater than 80% of predicted. FEV1:FVC ratio 70% of predicted. DLCO: greater than 60%.

Most likely diagnosis??
Chronic bronchitis, emphysema, CF, Kartageners, post nasal drip

They made it seem like chronic bronchitis from the description but I picked emphysema because I know that has a high DLCO. Not sure which answer is correct. Also, why is the FEV1 greater than 80% predicted?? I thought it was supposed to be decreased in COPD?

 

[ipizzy]

DLCO is *decreased* in emphysema (due to destruction of alveoli --> less CO2 exchange) but is normal in chronic bronchitis. Everything about this case points towards chronic bronchitis!

Yes, her FEV1 is technically in the normal range (80-120%) but she's at the lower end of normal. If you look at her FEV1/FVC ratio, she's actually not obstructed that badly (definition of obstructive is <70% and she's right on the border). I'd take the low-normal FEV1 and the borderline obstructive FEV1/FVC ratio as indicators of early COPD. Taken with the signs/symptoms and her relatively preserved DLCO, you eliminate emphysema and diagnose her with chronic bronchitis.

 

[link2swim06]

Can someone explain this question to me:

57 y/o woman with a 2 year history of progressive productive cough of yellow sputum daily. 40 year smoking history. O2sat=90%, PE: decreased breath sounds in all fields and rhonci at lung bases. Expiratory phase is prolonged. ECG= sinus tach with P pulmonale

PFTS: FEV1 greater than 80% of predicted. FEV1:FVC ratio 70% of predicted. DLCO: greater than 60%.

Most likely diagnosis??
Chronic bronchitis, emphysema, CF, Kartageners, post nasal drip

They made it seem like chronic bronchitis from the description but I picked emphysema because I know that has a high DLCO. Not sure which answer is correct. Also, why is the FEV1 greater than 80% predicted?? I thought it was supposed to be decreased in COPD?

Chronic Bronchitis is what I'd choose. Classic description. Obstructive pattern. Should be straight forward if you consider the whole question.

Also I don't think emphysema has a normal DLCO.

 

[StrangerX]

ipizzy is correct. I will however add that chronic bronchitis patients tend to desaturate earlier in the disease course and have higher CO2 levels (blue bloaters) vs. emphysema patients (pink puffers) who, while they may desaturate they tend to do so later (and so are pink) and tend to have lower/normal CO2 levels. This is because while gas exchange is indeed impaired, they have increased clearance of CO2 via increased ventilation. I believe this relates to differences in how the CNS interprets the ABGs of pink puffers vs. blue bloaters.

 

[dendrites]

Sorry, you are right. Emphysema has a low DLCO.

Which diseases have a high DLCO?

 

[link2swim06]

Sorry, you are right. Emphysema has a low DLCO.

Which diseases have a high DLCO?

I want to say asthma does...maybe polycythemia too?

 

[drk]

Asthma does.