At a Glance
Paroxysmal nocturnal dyspnea (PND) is sudden shortness of breath that wakes a person from sleep, often forcing them to sit or stand up to breathe more easily. It's usually a symptom of another health issue, like heart failure or lung disease, and should be evaluated by a doctor to identify and treat the underlying cause.
Sleep apnea, a sleep-related breathing disorder, may cause a sleeper to wake up during the night gasping for air. This symptom may be difficult for some people to distinguish from paroxysmal nocturnal dyspnea, another medical symptom that involves waking up at night gasping for air.
Understanding the difference between gasping related to sleep apnea and gasping related to paroxysmal nocturnal dyspnea is important, because paroxysmal nocturnal dyspnea can indicate a serious heart problem. Below, we explore what paroxysmal nocturnal dyspnea is, how it differs from sleep apnea, its causes, and potential treatments.
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What Is Paroxysmal Nocturnal Dyspnea?
Paroxysmal means a sudden symptom, while nocturnal means at night, and dyspnea means trouble breathing. Thus, paroxysmal nocturnal dyspnea, sometimes called PND, refers to a type of breathing difficulty that occurs while a person is lying down. Usually, PND happens all of a sudden and wakes a person up from sleeping.
Paroxysmal Nocturnal Dyspnea vs. Sleep Apnea
Sleep apnea is a sleep-related breathing disorder that causes repeated periods of disrupted breathing during sleep, while paroxysmal nocturnal dyspnea is a symptom that involves sudden shortness of breath while lying down. Both issues can cause a person to wake up during the night, gasping for air.
In sleep apnea, a person may gasp for air following a period of not breathing. When a sleeper's repeated lapses in breathing are primarily caused by an airway obstruction, the disorder is called obstructive sleep apnea (OSA). When the repeated lapses in breathing are caused by the brain failing to signal breathing muscles, it's called central sleep apnea (CSA).
Paroxysmal nocturnal dyspnea is a symptom, rather than a disorder itself. Often, it results from another underlying health problem.
Paroxysmal Nocturnal Dyspnea vs. Orthopnea
Orthopnea describes shortness of breath that develops while a person is lying down and stops when they sit or stand up. Paroxysmal nocturnal dyspnea is a severe type of orthopnea that occurs suddenly during sleep, causing a person to wake up gasping for breath and feeling like they cannot breathe well. Both paroxysmal nocturnal dyspnea and orthopnea fall under the umbrella of dyspnea, which is a medical term for difficulty breathing or shortness of breath.
Symptoms of Paroxysmal Nocturnal Dyspnea
A person experiencing paroxysmal nocturnal dyspnea may experience the following symptoms:
- Suddenly waking up from sleep, often within an hour or two of falling asleep
- Gasping for breath
- A sensation of shortness of breath or difficulty breathing
- A feeling of fear or terror
- The need to sit or stand up to resolve symptoms
Because of the unpleasantness of paroxysmal nocturnal dyspnea, people who experience this type of shortness of breath may find themselves wanting to sleep with their head and upper body propped up. However, this isn’t an adequate treatment for the symptom, and it’s important to see a doctor.
The personal experience of paroxysmal nocturnal dyspnea can differ from person to person. One person may describe the symptom as shortness of breath, while others may say they can't catch their breath, they feel like they're suffocating, or breathing feels difficult.
Paroxysmal Nocturnal Dyspnea Causes
Paroxysmal nocturnal dyspnea can stem from different causes.
- Heart transplant rejection: If the body of a person who received a heart transplant begins to reject the new heart, PND may be a symptom.
- Heart failure: A person who has congestive heart failure, or is in the days or weeks before fully developing heart failure, may wake up at night with PND. Shortness of breath becomes more likely as a person with heart failure lies down, because there's more blood flow to the heart in this position.
- Chronic obstructive pulmonary disease (COPD): This progressive, inflammatory lung disease is characterized by obstructed airflow, which can cause PND.
- Obesity: While obesity doesn't directly cause PND, it can worsen PND or the disorders that make PND more likely. Fat around the abdomen in particular can exacerbate PND, by adding pressure to the abdominal area.
- Pregnancy: Some people experience shortness of breath, including PND, during pregnancy. This may be from the pregnancy alone, or the result of a heart issue that developed during pregnancy. If the shortness of breath stems from a heart issue, it may continue after childbirth.
- Central sleep apnea (CSA): Although sleep apnea doesn't usually cause PND, it can in certain cases. People with a type of central sleep apnea that involves a breathing pattern called Cheyne-Stokes breathing may experience PND after a lapse in breathing during sleep. This usually occurs in people who have both central sleep apnea and heart failure.
- Drug and alcohol misuse: Using the recreational drug cocaine can lead to heart issues and related symptoms, including PND. Similarly, consuming unhealthy amounts of alcohol can cause heart issues that present as PND.
- Heart tumors: Tumors in the heart can block blood flow and, as a result, cause PND.
How Paroxysmal Nocturnal Dyspnea Is Diagnosed
A doctor evaluating a person with paroxysmal nocturnal dyspnea generally begins by asking questions about symptoms. They may ask if a person has difficulty breathing. If the answer is yes, they’ll want to understand the details of how long ago the difficult breathing episodes began, when they occur, how often they occur, how long they last, and how severe they are.
Once the doctor feels like they understand the nature of a person's shortness of breath, they may ask about other potential symptoms that can be related to breathing difficulties. For example, they may ask if a person has ever experienced chest pain, rapid or unusual heart rate, coughing, or wheezing. They may ask questions about a person's other medical conditions, medications, and if they smoke. These types of questions can help determine which underlying disorders may or may not be present and contributing to the breathing difficulties.
Often, a doctor conducts a physical exam of patients experiencing breathing difficulties, including paroxysmal nocturnal dyspnea. They may listen to the heart, listen to the lungs during breathing, and check the legs for swelling. A doctor is also likely to order tests related to heart and lung function, which may include blood tests, chest X-rays, electrocardiography (ECG), breathing tests, or more detailed imaging, like computed tomography (CT) scans of the chest.
Treating Paroxysmal Nocturnal Dyspnea
Doctors treat paroxysmal nocturnal dyspnea by treating the underlying disorder causing this nighttime shortness of breath. Most often, PND is caused by heart failure, another heart condition, or a chronic lung disorder, like COPD.
In an emergency situation in which a person's shortness of breath has caused hypoventilation and low blood oxygen levels or is resulting from fluid in the lungs (pulmonary edema), a doctor may give supplemental oxygen. Morphine may also be given to help a person calm down and reduce discomfort. If a life-threatening situation is occurring, a person may be given mechanical ventilation for breathing.
When to Talk to Your Doctor
If you wake up at night gasping for air, talk to your doctor immediately. Whether your gasping is paroxysmal nocturnal dyspnea or a symptom of sleep apnea, it's important to determine the underlying cause and treat any disorders you may have. Sleep apnea and the underlying causes of PND share similar risk factors, so you cannot figure out which one you have on your own without a doctor's formal evaluation.
If you’re experiencing confusion or changes to your consciousness in addition to shortness of breath during the night, go to an emergency room for immediate treatment.
Medical Disclaimer: This content is for informational purposes and does not constitute medical advice. Please consult a health care provider prior to starting a new treatment or making changes to your treatment plan.
Written by
Tochukwu Ikpeze, MD, Contributing WriterTochukwu grew up in New York and has a passion for creative and scientific writing. Tochukwu holds an undergraduate degree in Biology and Psychology, a Master’s degree in Biomedical Science, and a Medical Degree as well. In his free time, Tochukwu enjoys reading, learning, exploring various topics pertaining to the human condition and conveying that information to the public through writing.
Reviewed by
Gerard J. Meskill, MD, FAASM, Medical ReviewerDr. Gerard J. Meskill is a neurologist and sleep medicine physician specializing in the diagnosis and treatment of sleep disorders, including narcolepsy, obstructive sleep apnea, and insomnia. He is board-certified in both neurology and sleep medicine and has extensive experience helping patients manage complex sleep conditions and disorders of excessive daytime sleepiness.
