Discussion of interesting or befuddling cases related to pulmonary and critical care medicine.
Wednesday, October 12, 2005
PFT dilemna
What causes severe obstruction (40%)with no post-bronch reversibility, and a normal DLCO (80%) in a non-smoker? Here are some extra things: her PFT's on and off Advair were not changed. Her CXR:
No I meant what causes that obstructive picture with *NORMAL* DLCO? Most of the things on your list would have a decreased DLCO except for #1 but her inspiratory loop was perfectly round.
To address each of your excellent points of what diagnoses may fit with those PFT values: 1. COPD with chronic bronchitis but she is a nonsmoker and doesn't have a productive cough. 2. chronic asthma with airway-remodeling yes this could be a possibility. 3. HP - this is usually restricitive and the DLCO would go down, especially for with this degree of abnormality in pulmonary mechanics. More history: On exam she truly did have wheezing.
I like JCH's list. How old is she? I seem to see a lot of older non-smoker women who have had untreated "mild" asthma with rare wheezing that come in with airway remodelling and fixed obstruction (JCH' #5).
You indicate HP is usually restrictive with a low DLCO. I agree. It usually is.
However, there is literature indicating the HP can be manifest by PURE OBSTRUCTION.
Lalancette M et al. ARRD 1993; 148(1):216-21
In fact HRCT can look like emphysema. Granted, this above article speaks of Farmer's lung, but I believe that it is probably applicable to all forms of HP.
Before you chalk this up to IBO or chronic asthma with airway remodeling, I would urge you to get a HRCT.
10 comments - CLICK HERE to read & add your own!:
1) Large airway obstruction
2) COPD (possibly alpha-1) in a non-smoker with extensive second-hand smoke
3) idiopathic bronchiolitis obliterans
4) infectious bronchiolitis
5) chronic asthma with airway-remodeling/subepithelial fibrosis
6) ABPA
7) Churg-Strauss
8) Sarcoidosis
I'm sure there are more, many of which I've never heard of...I'll leave those for Carlos.
No I meant what causes that obstructive picture with *NORMAL* DLCO? Most of the things on your list would have a decreased DLCO except for #1 but her inspiratory loop was perfectly round.
Actually, most things on my list, especially #5,6,7, and 8, could have a normal DLCO.
Add to the list:
1. Hypersensitivity pneumonitis
2. COPD with mostly a chronic bronchitis component
A high resolution CT of the chest could help distinguish between some of these...
To address each of your excellent points of what diagnoses may fit with those PFT values:
1. COPD with chronic bronchitis but she is a nonsmoker and doesn't have a productive cough.
2. chronic asthma with airway-remodeling yes this could be a possibility.
3. HP - this is usually restricitive and the DLCO would go down, especially for with this degree of abnormality in pulmonary mechanics.
More history: On exam she truly did have wheezing.
I like JCH's list. How old is she? I seem to see a lot of older non-smoker women who have had untreated "mild" asthma with rare wheezing that come in with airway remodelling and fixed obstruction (JCH' #5).
I like the remodeling diagnosis too and that's what I'm going with in this patient.
BNP is normal. EF 55%, but CXR is as above.
There was no response in FEV1 with or without ADVAIR.
You indicate HP is usually restrictive with a low DLCO. I agree. It usually is.
However, there is literature indicating the HP can be manifest by PURE OBSTRUCTION.
Lalancette M et al. ARRD 1993; 148(1):216-21
In fact HRCT can look like emphysema. Granted, this above article speaks of Farmer's lung, but I believe that it is probably applicable to all forms of HP.
Before you chalk this up to IBO or chronic asthma with airway remodeling, I would urge you to get a HRCT.
Just my 2 cents.
JJ, would you get a HRCT already?
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