Paroxysmal Nocturnal Dyspnea: Overview and More

Paroxysmal nocturnal dyspnea, or PND, is a distressing symptom often caused by heart failure.

A person with PND will suddenly awaken in the night with severe shortness of breath (dyspnea) and coughing, gasping for air, and feeling compelled to assume an upright posture. A person with PND may sit or stand to breathe more easily, and feel a need to open a window for air. Breathlessness generally improves after a few minutes, but even once symptoms abate, it may be impossible to return to sleep, due to the anxiety that this frightening symptom provokes.

These nighttime episodes occur as a result of decreased pulmonary function as fluid builds up around the lungs. Some doctors use the term PND to refer to nighttime breathlessness that can occur as a result of conditions like sleep apnea, while cardiologists often use the term only in reference to congestive heart failure.

Symptoms

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 after sleep, in an attempt to take in more air
• Feeling short of breath for 30 minutes or longer upon sudden nighttime awakening

When PND occurs in those with heart failure, it is always a dangerous sign indicating that a person’s heart failure is becoming substantially worse. Anyone experiencing PND needs to contact his or her doctor right away, even if the symptoms resolve quickly.

Causes

Strictly speaking, “paroxysmal nocturnal dyspnea” really just 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
• Diastolic heart failure 
• Acute cardiac ischemia 

However, most cardiologists use the term 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 PND 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 to go to sleep can cause significant fluid shifts in the body. Fluid tends to shift from the tissues into the plasma, which increases the plasma volume.

Further, some excess fluid, that gravity has “pooled” in the legs or the abdomen during the day, moves from the lower parts of the body when the person lies down to the lungs.​ These fluid shifts cause shortness of breath as soon as the person with heart failure lies down. This immediate fluid shift produces breathlessness while lying down.

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.

Medications

Some medications used to treat heart failure include but are not limited to:

• Angiotensin-converting enzyme (ACE) inhibitors, that widen blood vessels to lower blood pressure, improve blood flow and decrease the workload on the heart. Examples include enalapril (Vasotec), lisinopril (Zestril) and captopril (Capoten).
• Beta blockers, that slow the heart rate and reduce blood pressure. Examples include carvedilol (Coreg), metoprolol (Lopressor) and bisoprolol (Zebeta).
• Diuretics, which keep fluid from collecting in your body by causing you to urinate more frequently. Furosemide (Lasix), also decreases fluid in your lungs, helping you to breathe more easily.
• Inotropes, which are used intravenously in people with severe heart failure to improve heart function and maintain blood pressure.
• Digoxin or digitalis, (Lanoxin), which boosts the strength of heart muscle contractions.

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

Lifestyle Modifications

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

• Stop smoking
• 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 )
• Reduce stress

Coping

While you may need to change many aspects of your life to address the underlying causes of PND, there are small things you can do to sleep easier.

People with PND quickly learn to elevate the head of their beds, which has the effect of keeping their chests elevated. This prevents fluid from moving up to their lungs. (This is also why doctors usually ask their patients with heart failure how many pillows they use at night — it’s a rough estimate of the degree of orthopnea that person is experiencing.)

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.