Posts Tagged ‘paroxysmal nocturnal dyspnea’

orthopnea paroxysmal nocturnal dyspnea pnd www.drsvenkatesan.com

Some Infrequently asked questions in (iFAQ) in PND

Is basal rales mandatory during episodes of PND ?

Yes. Most will have. But it should be emphasised orthopnea patients rales are rare since it takes some time for lung congestion take place. If rales appear immediately after lying down it may Indicate severely compromised LV function.

PND vs Orthopnea : Which is reproducuible symptom ?

Obviously orthopnea. PND can never predict which day its going to come as there is CNS component to the circuit in triggering this. (REM sleep, Dreams etc)

How many episodes of PND can occur in one night ?

Usually one. Because PND requires time lag of atleast few hours.Usualy these patients will not sleep thereafter or the usual wake up time ensues.

Can episodes of PND be prevented ?

Since its a volume dependent pulmonary hemodynamic stress , a diuretic at dusk will prevent these episodes in many.

What is the sensitivity of PND for predicting heart disease ?

It has low sensitivity( <30% ) but 75% specificity to diagnose heart disease.

Is PND sign of advanced heart disease ?

No .It has very low sensitivity to predict severity of heart disease.

Can PND and Orthopnea occur at same patient at same time same day ?

Orhopnea has no time lag.It occurs immediately hence it is obviously more severe. Many of these patients , however do get into sleep after some time as some sort of compensation or adaptation to neural signals of dyspnea take place.

These patients later on can get into the same cycle of PND .However ,as heart disease (as in cardiomyoapthy ) worsens the pulmonary interstitium shows some reactive fibrotic changes resist water logging in lungs.

Since PND and orthopnea share close relationship in terms of pathophysiology, we cluster it together in symptomatology.However they are temporally separated in most patients in the natural history.

PND : is it an equivalent to acute heart failure ?

Yes, it can be called so (If it is due to heart disease*) . It fulfils all criteria of a cardiac failure . LV/LA filling pressure raised , forward output (Cardiac Index may still be normal ) .PND is transient, acute , left sided failure which results in acute oxygen debt for the body which is self corrected usually.

* In volume overloaded , CKD patients PND can occur

What is the relationship between RV dysfunction to PND /Orthopnea?

There is a complex fluid regulatory mechanisms in failing heart.The lung can be congested if and only if the RV function is adequate enough to flood the lungs and at the same time LV function matches it with its inadequacy resulting in persistent congestion. In other words a very high RVEDP is protective against pulmonary edema (However patient will feel the dyspneic still due to hypoxia /VP VQ etc !)

Its prudent to give importance to PND/Orthopnea with reference to balance of RV and LV function. One may recall why pericardial disease where right heart filling is impeded rarely lead to lung congestion.

Can PND be associated with Angina ?

Yes, it can but generally its not. Angina occurs due to nocturnal sub endocardial Ischemia.This combination occurs in critical Aortic valve disease.(Both AS/AR)

Is PND a cardiac emergency ?

Difficult question. Most times, no. Since its self-limiting especially if the patient knows he is going to settle with his past experience. But it can trigger dangerous events in severely compromised heart.As expected, the first episode creates much panic and invariably elicits emergency alert.

PND has sinister significance if is due to nocturnal ACS .Its a sign of ischemic LVF and requires immediate care.

Which is the most benign form of PND and Orthopnea ?

Students should know , medicine is a funny science. PND as a symptom be ap benign in some, while it denotes impending death in some others.

Benign PND : Obese men, women, in pregnancy may experience terrifying dyspnea at night when they turn around or stretch .This is due to upward movement of diaphragm encroaching lung space.

If you record mitral inflow doppler filling pattern during an episode of PND what will you find ?

Its quiet simple logic.You do yourself and find it as a learning exercise.(Please don’t make the patient suffer by doing echo at times of distress.One of your colleagues to attend to him as you simultaneously do an echo for academic purpose)

Try calculating LVEDP with various echo formulas.

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