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What Is Paroxysmal Nocturnal Dyspnea (PND)?

Medically Reviewed by Melinda Ratini, DO, MS on May 27, 2021

You go to sleep. After a few hours, you wake up breathless and feeling like you’re suffocating. You sit upright and gasp for breath, and the feeling vanishes. If you’ve had this experience, you may have paroxysmal nocturnal dyspnea, or PND.

Why Is it Called PND?

Paroxysmal means that the symptoms come on quickly and pass just as quickly. Nocturnal means that symptoms occur at night, and dyspnea is the medical term for breathing difficulties.

What Happens During PND?

PND is a feeling of suffocation when you’re not engaging in any strenuous activity ⁠— like when you’re sleeping ⁠— and it can be a sign of heart failure. However, dyspnea is not always related to the heart, so talk to your doctor to get an appropriate and accurate diagnosis.

Some patients may experience bronchospasm, or a narrowing and obstruction of the respiratory airway similar to asthma.

You don’t always feel relief immediately after you sit upright. Your body can take half an hour, or more, to normalize.

Other symptoms include:

  • Suddenly waking up with a cough or wheezing
  • Having a faster than usual heart rate
  • Feeling the need to open the window to get more air
  • Sleep anxiety
  • Insomnia

What Causes It?

‌PND is caused by the failure of the left ventricle. When this happens, it is unable to pump as much blood as the right ventricle, which is functioning normally. As a result, you experience pulmonary congestion, a condition in which fluid fills the lungs.

The condition occurs in patients with left and right ventricular heart failure and increased pulmonary fluid pressure. People with medical factors that can cause airway resistance, such as asthma, COPD, and congestive heart failure, are at risk.

It is also thought that decreased responsiveness in the part of your brain responsible for respiration during sleep is a contributing factor. PND episodes are also associated with the normally-occurring decrease in your heart’s fight-or-flight response that happens when you fall asleep.

Other causes include:

  • Respiratory muscle dysfunction
  • Decreased respiratory muscle strength
  • Decreased endurance
  • Reduced blood flow through the heart
  • Increased carbon dioxide production
  • Complications from high blood pressure

It’s believed that fluid accumulation in the lining of the airways causes the shortness of breath during an episode of PND.‌‌‌

Although the causes are well understood, the exact factors that trigger a PND episode are still unknown.

‌‌‌What it’s like to have PND

PND can be a terrifying condition. Patients report that, during episodes, they felt that they were going to die. If you’ve never previously experienced symptoms of heart failure, it can be made even worse, because you don’t know what’s happening in the moment. And, of course, you experience sleep loss.

Diagnosis of PND

Make a point of keeping track of your symptoms and the ways that they affect your life. You may want to start keeping a diary with details of PND attacks and how you manage your symptoms.

Your doctor may run tests to establish the cause of your PND. You might receive a chest CT scan, chest x-rays, a heart MRI, or other diagnostic tests.

Treatment for PND

In many cases, PND is a symptom of worsening heart failure. Your doctor may prescribe common treatments for heart failure, like beta-blockers or diuretics.

Your doctor may schedule surgery to repair birth defects or other problems, especially with your heart valves. The surgery will be an attempt to improve your heart’s performance and reduce your chances of sudden death.

If, in rare cases, your doctor can’t find a treatment option for you, you may need a heart transplant.

Lifestyle changes that improve heart health may be helpful. Some good heart-healthy habits are.

  • Quitting smoking
  • Eating a low-fat diet that contains lots of fruits, whole grains, vegetables, and lean proteins, while cutting back on your total salt intake
  • Limiting your alcohol consumption
  • Getting regular exercise
  • Managing your stress

Show Sources

SOURCES:

American Heart Association: “Medications Used to Treat Heart Failure.”

Britannica: “Ventricular dysfunction in heart failure.”

Circulation: “2013 ACCF/AHA Guideline for the Management of Heart Failure: Executive Summary.”

Chest Journal: “Paroxysmal Nocturnal Dyspnea.”

C.S. Mott Children’s Hospital: “Heart Failure Symptoms.”

Journal of Circulation and Heart Failure: “Healthy Lifestyle and Risk of Heart Failure: An Ounce of Prevention Well Worth the Effort.”

Medscape: “Heart Failure Clinical Presentation.”

Mukerji, V. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition., Butterworth Publishers, 1990.

University of Rochester Medical Center: “Lung Cancer: Managing Shortness of Breath.”

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