What Is Paroxysmal Nocturnal Dyspnea?

Paroxysmal nocturnal dyspnea, or PND, is a symptom of heart failure. It is characterized by being awakened during sleep with severe shortness of breath (dyspnea), gasping for air, coughing, and feeling the need to sit up, stand up, and/or open a window for air, all of which may help improve breathing after a few minutes. PND is caused by the buildup of fluid around the lungs that impairs pulmonary (lung) function.

Symptoms of Paroxysmal Nocturnal Dyspnea

People with PND experience classic nighttime episodes such as:

• Sudden awakening at night with breathlessness, often after only one or two hours of sleep
• Severe anxiety provoked by a feeling of suffocation or shortness of breath
• Sitting bolt upright suddenly during sleep in an attempt to take in more air
• Feeling short of breath for 30 minutes or longer upon sudden nighttime awakening

Causes

Most cardiologists use the term "PND" specifically in reference to those experiencing breathlessness as a result of congestive heart failure. It most commonly occurs in people experiencing shortness of breath with exertion, or shortness of breath when lying down (orthopnea). 

People who experience orthopnea usually have at least some swelling (edema) in their feet and legs, which, in heart failure, usually indicates fluid overload.

In people who have heart failure, lying down can cause significant fluid shifts in the body. Fluid tends to shift from the tissues into the plasma, which increases the plasma volume.

Further, fluid that has pooled in the legs or abdomen during the day due to gravity tends to move to the lungs when lying down.​ In normal individuals, fluid shifts have little effect, but in people with heart failure, the additional volume cannot be pumped out by the left ventricle because of disease, causing shortness of breath as fluid accumulates in the chest. 

Strictly speaking, “paroxysmal nocturnal dyspnea” means “sudden-onset shortness of breath at night,” and as such it can be applied to any medical condition that may produce dyspnea during sleep. These include:

• Sleep apnea
• Asthma
• Pulmonary embolus (a blood clot in the pulmonary artery that leads to the lungs)
• Diastolic heart failure, caused by stiffening of one of the ventricles (chambers) of the heart
• Acute cardiac ischemia (insufficient blood flow to the heart)

Diagnosis

If you experience symptoms but have not been diagnosed with a heart condition, your doctor is likely to order one of several tests to see the condition of the heart and measure heart function. These might include:

• Blood tests
• Bronchoscopy
• Chest CT scan
• Chest X-ray
• Coronary artery angiogram
• Echocardiogram, or a cardiac ultrasound
• Stress tests
• A cardiac MRI
• A myocardial biopsy 

People with heart failure who develop PND may soon develop more severe, acute heart failure. They require aggressive therapy right away to prevent a severe, possibly life-threatening, episode of heart failure.

Treatment

If the cause of PND is heart failure, it will require lifelong management through a combination of medications and lifestyle choices. Sometimes, surgery may be required to repair a heart valve or a device may be inserted which helps the heart to contract properly. With such treatments, heart failure can improve, and the heart sometimes becomes stronger.

A wide array of medications are given to treat heart failure, and therefore this condition. They include diuretics, anti-hypertensives, and cardiac medications, including beta blockers and ACE inhibitors:

Diuretics

• Lasix (furosemide)
• Bumex (bumetanide)
• Demadex (torsemide)
• Diuril (chlorothiazide)
• Esidrix, Hydrodiuril (hydrochlorothiazide or HCTZ)
• Lozol (indapamide)
• Metolazone (zaroxolyn)
• Triamterene (dyrenium)

Angiotensin-Converting Enzyme (ACE) Inhibitors

• Capoten (captopril)
• Vasotec (enalapril)
• Monopril (fosinopril)
• Prinivil, Zestril (lisinopril )
• Aceon (perindopril)
• Accupril (quinapril)
• Altace (ramipril)
• Mavik (trandolapril)

Angiotensin II Receptor Blockers (or Inhibitors)

• Atacand (candesartan)
• Losartan (cozaar)
• Valsartan (diovan)

Beta Blockers

• Zebeta (bisoprolol)
• Toprol XL (metoprolol succinate)
• Coreg (carvedilol)

Aldosterone Antagonists

• Aldactone (spironolactone)
• Inspra (eplerenone)

Hydralazine and isosorbide dinitrate (specifically benefits African-Americans with heart failure)

• Bidil (hydralazine and isosorbide dinitrate) (combination drug)

Lifestyle Modifications

In many cases, heart function can be improved simply by proper diet, regular exercise, and healthy living.  You can manage heart disease:

• If you smoke, quit.
• Maintain a healthy weight.
• Eat a low-fat diet with plenty of fruits, vegetables, whole grains, and lean proteins.
• Avoid trans fats.
• Cut back on salt.
• Limit alcohol and fluids. 
• Stay physically active. (Check with your doctor first about the right exercise program.)
• Take steps to manage stress.

While you may need to change many aspects of your life to address the underlying causes of PND, you can also sleep easier by raising your head by using more pillows to keep your chest elevated and help prevent fluid from shifting to your chest and surrounding your lungs.

Surgery and Devices

Depending on the severity of your heart failure, surgery or a medical device may be necessary. Your doctor may propose:

• Coronary bypass surgery 
• Heart valve repair or replacement 
• Implantable cardioverter-defibrillators (ICDs), similar to a pacemaker
• A pacemaker, otherwise known as cardiac resynchronization therapy (CRT), or biventricular pacing
• A ventricular assist devices (VADs), also known as a mechanical circulatory support device
• A heart transplant, if surgery or medications don't help

A Word From Verywell

It’s not up to you to figure out whether your acute dyspnea at night is due to heart failure or to some other cause. It’s up to your doctor. What you need to know is that PND always indicates that a serious medical problem is going on. Whatever the cause turns out to be, you need to get medical help right away if you experience this symptom.