CT chest and PAH

[grace77]

I am a 44 yr old female with dx of mitochondrial myopathy with resp. muscle weakness. My doctor ordered a CT Chest and I also had a muga scan.My DLCO is 62% and PFT"S show a restrictive pattern. My MIP and MEP are 18% and 21%. I had a sleep study that showed hypoventilation and elevated CO2. I was given a CPAP but am unable to tolerate it even after different masks etc. I do have a lot of shortness of breath with exertion and experience a lot of air hunger at night. Sometimes I have to get up in the middle of the night to try and relieve the air hunger and shortness of breath.
The results are as follows:
No mediastinal,hilar or axillary adenopathy. left infrahilar calcified lymph node is seen. No pericardial or pleural effusion. Main pulmonary artery  measures 3.7 cm. Lungs are hyperinflated. Mild emphysematous changes are seen. No pneumothorax. Mild bronchial wall thickening is seen. There is a cluster of nodular opacities seen in the medial left perihilar/left upper lobe region suggestive of mucus plugging. Developing pneumonitis cannot be excluded. Subsegmental atelectasis  along the left major fissure. Calcified lymph node is seen .
Impression:
1. hyperinflation with mild emphysematous changes and bronchial wall thickening. Cluster of left perihilar nodular opacities is suggestive of bronchial mucus plugging with possible developing pneumonitis. Recommend follow up ct chest in 3 mos to document resolution.
2. Pulmonary Arterial Hypertension
My questions are:
1) Is the CT chest measurement usually fairly accurate and a good tool to diagnose PH?
2)Is the echo a good diagnostic tool? I am scheduled to have an echo. My dr said even if the pressures were mildly elevated- he probably would not do any further testing.
3) What should the normal follow up be with this?
4) What does the calcified lymph node mean? What about the area of atelectasis?
5) What about the emphysema findings?
Thanks so much.

[National Jewish Health]

The most important concern for the physicians managing your respiratory problem is to secure adequate ventilation during sleep and, while both awake and asleep, to make sure that your blood is adequately oxygenated at all times.  I address that below.  

The CT measurement of the pulmonary artery size provides a reasonable estimate of the PA diameter but is not the best way to assess pulmonary pressure and pulmonary hypertension (PH).  Echocardiography, especially when technically deemed quite satisfactory does provide a fairly accurate of pressure and cardiac catheterization would be the “gold standard” for pressure determination.  Should your PA size be 1 ½-2 standard deviations above the mean for your body size it would be reasonable, given the degree of respiratory insufficiency to proceed with an ECHO and if this is elevated, proceed with other studies such as cardiac catheterization, and consideration of therapy for pulmonary hypertension.

The first consideration, however, would be to determine with some certainty if you have PH.   If you do, hypoxemia could be playing a major role in causing the PH, especially at night, and if so, supplemental oxygen would be crucial.  Given the demonstration of elevation of C02 during sleep, it is almost a certainty that, without supplemental oxygen, that you are also experiencing a significant fall in oxygen saturation to a degree that might well aggravate PH.  Even should you prove not to have PH, the nocturnal hypoxemia should be addressed, the best way being the effective use of CPAP.  I strongly suggest that you work diligently with the sleep laboratory personnel to find a way to make the CPAP tolerable.  The benefit from it could be very important.  

Further regarding oxygen desaturation (hypoxemia), it could also be responsible for the shortness of breath you experience with exertion.  If not already performed, you should have a determination of oxygen saturation with exercise.

I assume that the CPAP was prescribed not for obstructive sleep apnea, but to enhance the compromised  ventilation, secondary to respiratory muscle weakness. If that is correct, there is another, seldom considered form of ventilation  And, if after much effort you are still unable to use the CPAP, that alternative form of ventilation would be Negative Pressure Ventilation (also called Continuous negative extrathoracic pressure --CNEP).  The two main types of negative pressure ventilation are:  1) iron lung ventilators (of the type used decades ago during polio epidemics and, 2) cuirass ventilators.  The second of these is a plastic shell tightly applied to the front of the chest from neck to upper abdomen. (See the following abstract that describes the use of a cuirass ventilator, albeit in a different circumstance requiring assisted ventilation.—

You might want to share this note and abstract with your pulmonary physician. Some doctors might scoff at the suggestion of an iron lung in this day and age but, in the circumstance of fairly elastic lungs, adequate to provide gas exchange (oxygen and carbon dioxide) when provided with mechanical assistance to the respiratory muscles, each of these devices is easy to get used to and ideally suited for use during sleep.  You and your doctors might having trouble locating an iron lung or a cuirass but they are available.  Please let us know how this works-out  for you.

The calcified lymph node and the “subsegmental atelectasis” are of no consequence.  The first, simply the residual of infection sometime in the past, perhaps distant past and the second related to weakness of your respiratory muscles.

The emphysema changes are described as mild and there is a fairly good correlation between “mild” CT signs of emphysema and clinical severity of emphysema/COPD.  So, if you have emphysema, it is probably mild and should not pose a problem for you.

Good luck,

[grace77]

I am having an echo done tomorrow. Hopefully, it will be useful. I am having 1-2+ edema in my ankles and lower legs.