Thursday, May 04, 2006

Myopathy and decreased DLCO

An outside question, posed here for any comments. Doug/Jeff H: maybe Fernando can address?


I am a41 yr old female dx'd with a probable mitochondrial myopathy. My muscle bx showed increased lipid drops. An EMG showed a myopathic trend. Testing for MG was negative. My pft's revealed fev1 77% of predicted, fev1/fvc 74%. Diffusing capacity at 69% of predicted- last one was 68%--DL/CO/VA of 5.45. MVV was 31% of predicted and negative inspiratory force was -10.
HRCT showed minimal bilateral basilar scarring vs interstitial changes. Echo showed left atrial enlargement,decreased lt ventricular systolic function,trace mitral and aortic regurgitation, ef of 45% (was >55% in 1999).

DO you think the decreased diffusion should be followed upon or is it because of the neuromuscular disease process going on? My pulmo said I have mild asthma but the muscle weakness is a bigger problem. Any suggestions would be appreciated.

Chest xray showed...normal except for degeneartive changes in the thoracic spine
My other PmHx is SF hashimoto&'s on synthroid. My ANA-1:640 speckled pattern
aldolase 7.1(1.2-7.6) ck 56.

18 comments - CLICK HERE to read & add your own!:

Baleeiro said...

I am also curious to see what JCH / DA will think.
I don't see a lot of mitochondrial myopathies anymore but that alone should not account for the low DLCO (neither should asthma).
It seems that othe processes are at play here (i.e. abnormal ECHO, interstitial changes with +ANA, etc.) and I would probably try and investigate it further.

Jennings said...

Actually, I think you can get an isolated DLCO with a myopathy. In fact the very first case ever posted was of a patient with isolated DLCO (with dyspnea). http://pulmonaryroundtable.blogspot.com/2005/05/isolated-dlco.html After extensive w/u I referred to Fernando and the impression is that it may in fact be myopathy (not definitive yet)

Anonymous said...

Though does the DLCO/VA normalize if there is only a myopathy?

Linda said...

I wanted to add that I also have dyspnea and tachycardia with minimal exertion- hr up to 180 with pvc's verified by an event monitor/ Also have dyspnea-like I can't get a deep breath in. ( I posted the original question)

Jeff H said...

Very interesting. Although some findings support neuromuscular weakness here (decreased NIF, decreased MVV, the EMG/nerve conduction), there are several complicating features that I think argue against the diagnosis at this time.

First: given the history of Hashimoto's thyroiditis and current thyroid supplementation, it is critical to exclude current hyper or hypothyroidism.

Second: The elevated ANA suggests that there may be an ongoing autoimmune process--these may cause small vessel vasculitides and neurologic manifestations, and myositis, although I would expect to see some evidence of this on the muscle biopsy.

Third: The echocardiographic findings are definitely concerning, as is the tachycardia with exertion. Collectively, they suggest that a cardiomyopathy may be present, and I agree that this needs to be further investigated.

Fourth: The decreased DlCO would not be typical for mitochondrial myopathy, although the point by Jennings is well taken and we certainly cannot exclude myopathy based solely on this. I'm presuming that the hemoglobin/hematocrit is normal (although I would not be surprised if an anemia is present.) What did the rest of the pulmonary function studies show (i.e. total lung capacity and residual volume). Overall, I think the DlCO more likely represents either cardiac or pulmonary disease.

I would do the following now--
-verify a euthyroid state
- obtain a cardiopulmonary exercise test
- do an exercise echocardiogram to see what happens to LV function etc.
- make sure the muscle biopsy is interpreted by a pathologist with experience in myopathy.

Linda said...

I will try to explain further. My TSH is <1.0. My FVC was 3.00 (87% of predicted),a concurrent TLC of 4.98 liters (95 % of predicted.) These were done Jan 05. I am scheduled to have these repeated this month.
My cardiologist says he is not will not treat or be concerned unless my EF drops below 30%. I am not sure I am comfortable with this. I am an RN and therefore have some knowledge and would rather treat something sooner rather than later if it could prevent problems later- such as beta blockers etc.
My pulmo who I had moved away but he had placed me on a bipap of 14/4 to be used at hs. But I have had much difficulty with it. I am scheduled to see a new pulomonologist at UNC_Chapel Hill this month and am curious as to what he may think. My old pulmo explained the low dlco being related to the muscle weakness.
Thanks for you comments and look forward to further comments.

Linda said...

Also my h/h is wnl hgb 12-13.

Linda said...

I forgot to add that I have proximal weakness in my upper arms,thighs ,hips, shoulders and neck.

Jeff H said...

I think I would find a new cardiologist. Not only is there no reason to withold treatment, I think I would be looking aggresively for a cause of the decreased LV function and left atrial enlargement.

Baleeiro said...

I agree with Jeff H Re: the CHF treatment. Again, between the +ANA, decreased EF, thyroid abnormalities and interstitial changes I would not blame the low DLCO on the myopathy alone.

Linda said...

Thank you all. I think I will try and get another cardiologist. I have not had a stress echo or anything like that. Do you have any other suggestions since I am seeing a new pulmonologist this month and will try to see if he will refer me to another cardiologist at UNC?
I also have mild ankle and lower leg edema-1+ pitting. But i was told when I mentioned this to my doc that if it goes away, it is nothing to worry about.
Too bad I am not near any of your practices for another opinion!
Linda

Linda said...

Just an update. I saw the new pulmo. doc and was very impressed. My pft's yesterday revealed a restrictive process that he felt was compatible with the neuromuscular disease. My dlco remains low. He's not sure why as he said that it doesn't necessarily fit in with the myopathy. He also was concerned with the high ANA and repeated that yesterday along with some other labs. He reviewed the ct chest and he noticed the enlarged lt atrium on the ct.When I go back to see him,he is going to repeat some more specific neuromuscular pft's.I told him what my cardiologist has said about not treating until the ef was < 30%. He did not feel comfortable with that as he felt that was too low to wait for treatment.
Thank you for this great site.

Linda

Krayem said...

although cpk and aldolase levels do not fit very well, everything else suggests POLYMYOSITIS (including the CHF, the interstitial changes at the bases, proximal weakness, ANA positivity....)... evaluation by a rheumatologist should be strongly considered....

Linda said...

I recieved the results of my labs today. The aldolase,ck and esr were normal . The ANA again was postive at >1:640 speckled pattern.Not sure what is causing the ANA. I wish someone could figure it out.

Linda

Anonymous said...

linda...what is your pco2 readings. this can play a part in low dlco, and have you ever been diagnosed with polycythemia vera secondary..or anemia...perhaps you should be tested..a simple cbc can done, and if any wbc,rbc,or platets show high or low, should be repeated 2 more times and you referred to a hematolist/oncologist. good luck

Linda said...

I do not know what my pco2 is. I have never had ABG's drawn. I just had a cbc drawn and the hgb/hct were on the high side of normal and rbc slightly elevated although I don't have the #'s right in front of me. Who knows? It is so frustrating to not to be able to fit all the pieces together.

Linda said...

Just a quick follow up. I did have my echo repeated and it was better than last year with the ef of 50-55. I had a stress echo which was good except that my sat was 91 that came up to 97%. It showed poor exercise tolerance which I guess is related to the myopathy. I was very dyspneic that was much worse when I laid down for the post echo after being on the treadmill. The dyspnea gradually got better. I still have air hunger .

Anonymous said...

Linda, I am wondering if you ever found an answer. I am in a similar, though different, situation with shortness of breath with exercise, DLCO now down to 52%, muscle weakness with the suggested (not confirmed) diagnosis of myopathy, positive ANA, positive SCL-70, normal chest CT, normal echo, normal stress echo ( aside from desaturation via pulse ox. to 75%). I have had these reoccurring episodes in cold weather, stress, and pregnancy. In between I am active but not equal to peers in exercise tolerance. I am also being evaluated at UNC currently and have been to Baylor, Johns Hopkins, Stanford, and Mayo. If I had a dollar for every time a doctor tells me, "Boy, you sure are a mystery!" I might have enough money to cover all of the travel and medical expenses. Thank you for your insight.