Paroxysmal nocturnal dyspnoea

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Paroxysmal nocturnal dyspnoea
Specialty Pulmonology

Paroxysmal nocturnal dyspnea or paroxysmal nocturnal dyspnoea (PND) is an attack of severe shortness of breath and coughing that generally occurs at night. [1] It usually awakens the person from sleep, and may be quite frightening. [2] PND, as well as simple orthopnea, may be relieved by sitting upright at the side of the bed with legs dangling, as symptoms typically occur when the person is recumbent, or lying down. [3]

Contents

Risk Factors

Since paroxysmal nocturnal dyspnea occurs mainly because of heart or lung problems, common risk factors include those that affect the function of the heart and lungs. Risk factors for cardiac diseases include high blood pressure, high cholesterol, diabetes, obesity, and a lifestyle lacking exercise and a healthy diet. Risk factors for lung diseases include tobacco use, including second hand smoke, pollution, exposure to hazardous fumes, and allergens. [4]

Mechanism

PND can be explained by mechanisms similar to those of orthopnea and typical dyspnea. When a person is recumbent, or is lying down, blood is redistributed from the lower extremities and abdominal cavity (splanchnic circulation) to the lungs. [5] Failure to accommodate this redistribution results in decreased vital capacity and pulmonary compliance, further causing the shortness of breath experienced in PND. In addition to the redistribution of blood in the body, most cases of dyspnea are accompanied by an increase in the overall work of breathing, often caused by abnormal pulmonary mechanisms. [5]

The perception of dyspnea is theorized to be a complicated connection between peripheral receptors, neural pathways, and the central nervous system. [5] Receptors in the chest wall and central airways, as well receptors in the respiratory center of the central nervous system, produce an increased requirement for ventilation which is not matched by respiratory output, resulting in the conscious recognition of dyspnea. [5] Respiratory muscles and vagal afferent neural pathways relay information from the chest wall/airways to the central nervous system, facilitating the presentation of dyspnea. [4]

In people with underlying congestive heart failure, this redistribution may overload the pulmonary circulation, causing increased pulmonary congestion. In congestive heart failure, left ventricular dysfunction will also increase pulmonary congestion, so further congestion caused by the redistribution of blood volume upon laying down will worsen any dyspnea. [5]

Other theories exist for why PND occurs, especially in those where PND only occurs while sleeping. Theories include decreased responsiveness of the respiratory center in the brain and decreased adrenergic activity in the myocardium during sleep. [3]

Diagnosis

Paroxysmal nocturnal dyspnea is a serious medical symptom that can develop into worsening conditions. Many tests can be done in order to evaluate the cause of paroxysmal nocturnal dyspnea. Because it is commonly associated with heart failure, tests that may be run mainly focus on measuring the function and capability of the heart. Common tests may include an echocardiography, cardiac magnetic resonance imaging (MRI), coronary artery angiogram, chest x-ray or chest CT scan, blood tests, physical exams, or a myocardial biopsy. The diagnostic workup will vary depending on the suspected cause. [6] For example, for people who enter the emergency room with shortness of breath, a diagnosis is achieved through a physical examination, electrocardiography, chest radiograph, and if necessary, a serum BNP level. [7]

As a subjective symptom self-reported by people, dyspnea is difficult to characterize since its severity cannot be measured. Dyspnea can come in many forms, but it is commonly known as shortness of breath or having difficulty breathing. People presenting with dyspnea usually show signs of rapid and shallow breathing, use of their respiratory accessory muscles, and may have underlying conditions causing the dyspnea, such as cardiac or pulmonary diseases. [5] With paroxysmal nocturnal dyspnea specifically, it is felt while sleeping and causes a person to wake up after about 1 to 2 hours of sleep. [3]

More serious forms of dyspnea can be identified through accompanying findings, such as low blood pressure, decreased respiratory rate, altered mental status, hypoxia, cyanosis, stridor, or unstable arrhythmias. [4] When these symptoms accompany PND, it is typically a red flag that something more serious is causing the dyspnea presentation and should be evaluated further. [4]

Paroxysmal nocturnal dyspnea is a common symptom of several heart conditions such as heart failure with preserved ejection fraction, in addition to asthma, chronic obstructive pulmonary disease, and sleep apnea. [8] Other symptoms that may be seen alongside paroxysmal nocturnal dyspnea are weakness, orthopnea, edema, fatigue, and dyspnea. [9]

Differential Diagnoses

Dyspnea affects about 25% of people in the ambulatory care setting and is a common symptom of many underlying conditions. [9] Dyspnea is a subjective symptom, meaning it can only be expressed by the person experiencing it, and it is imperative in diagnosis to distinguish it from other breathing problems. [5] Dyspnea is typically the sensation of feeling short of breath and should not be confused with rapid breathing (tachypnea), excessive breathing (hyperpnea) or hyperventilation. [5] Once dyspnea is properly identified, it is important to differentiate between acute and chronic dyspnea, typically through a detailed physical exam and observation of the person's breathing patterns. [9] The most common causes of dyspnea are cardiac (cardiac asthma) [10] and pulmonary conditions, like congestive heart failure with preserved ejection fraction, COPD, or pneumonia. [9] Less commonly, some cases of dyspnea can be attributed to neuromuscular diseases of the chest wall or anxiety. [5] When distinguishing PND from typical dyspnea, it is important to identify common characteristics of PND. Some important criteria to identify are temporal characteristics (i.e., acute or chronic onset, intermittent or persistent symptoms), situational characteristics (i.e., symptoms at rest, upon exertion, upon different body positions, or upon special exposures), and pathogenic characteristics (i.e., physiologic or mental conditions). [9] PND typically presents at night during sleep, especially while the person is laying down, distinguishing PND from typical dyspnea. [3]

Treatment

Treatment for paroxysmal nocturnal dyspnea depends on the underlying cause. If the underlying cause is heart failure with preserved ejection fraction (HFpEF, when part of the heart does not fill properly with blood), treatments can include diuretics, beta blockers, and ACE inhibitors. [9] Another potential underlying cause of PND is central sleep apnea (CSA) with Cheyne-Stokes Breathing (CSB), for which the treatment recommended by the American Academy of Sleep Medicine is continuous positive airway pressure (CPAP) and nocturnal home oxygen therapy (HOT). [11]

The shortness of breath sensation felt from PND can typically be relieved by maintaining an upright position while sleeping. [3]

Potential Underlying CauseTreatment
central sleep apnea with Cheyne-Strokes breathingcontinuous positive airway pressure (CPAP)
heart failure with preserved ejection fraction (HFpEF)diuretics, beta blockers, ACE inhibitors

Epidemiology

While a small source of data exists on the prevalence of PND, a large pool of data exists on the epidemiology of dyspnea in general. Reports show that 7.4% of people reporting to the emergency room identify dyspnea as one of their symptoms, with 1-4% of people identifying dyspnea as their primary concern. [9] Dyspnea is often the cause of situational changes in a person's environment or activity. For example, 10% of people complain of dyspnea while walking on flat ground to their primary care provider (PCP), [9] while 25% of people complain of dyspnea upon more intense exertion (i.e. climbing stairs or a hill) to their PCP. [9] Of these people seeing a PCP, 1-4% see their provider for dyspnea specifically. [9] After identifying the cause of dyspnea, most people continue on to see a specialist to manage dyspnea presentation and address underlying conditions. Roughly 15-50% of people who are regularly seen by a cardiologist are seen in regard to dyspnea symptoms, [9] while just under 60% of people regularly see a pneumonologist in regard to their dyspnea. [9]

Additionally, there have been epidemiological studies performed on central sleep apnea in heart failure. Central sleep apnea in heart failure's epidemiology is relevant, as sleep apnea and heart failure have both been associated in people with paroxysmal nocturnal dyspnea. [12] According to the study, researchers were able to conclude that ~70% of people with heart failure had breathing disorders while they slept, while half of that ~70% also experienced central sleep apnea with Cheyne Stokes respiration (CSA-CSR). [12] Atrial fibrillation, the male gender, an age greater than 60, and awake PaCO2 being less than or equal to 38 mm Hg were all risk factors associated with CSA-CSR.

Special Populations

Pregnancy

In people who are pregnant, the presence of paroxysmal nocturnal dyspnea is abnormal. Further investigation and diagnostic tests should be done in order to prevent harm to the fetus and to the mother. [13]

Hypereosinophilic Syndrome (HES)

Hypereosinophilic syndrome is a combination of rare complications that are explained by an increased amount of serum and persistent tissue eosinophilia. [14] An uncommon disorder that is known to be associated with Hypereosinophilic Syndrome is Löffler endocarditis.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Shortness of breath</span> Feeling of difficulty breathing

Shortness of breath (SOB), known as dyspnea or dyspnoea, is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity", and recommends evaluating dyspnea by assessing the intensity of its distinct sensations, the degree of distress and discomfort involved, and its burden or impact on the patient's activities of daily living. Distinct sensations include effort/work to breathe, chest tightness or pain, and "air hunger". The tripod position is often assumed to be a sign.

<span class="mw-page-title-main">Heart failure</span> Failure of the heart to provide sufficient blood flow

Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to fill with and pump blood.

<span class="mw-page-title-main">Obesity hypoventilation syndrome</span> Condition in which severely overweight people fail to breathe rapidly or deeply enough

Obesity hypoventilation syndrome (OHS) is a condition in which severely overweight people fail to breathe rapidly or deeply enough, resulting in low oxygen levels and high blood carbon dioxide (CO2) levels. The syndrome is often associated with obstructive sleep apnea (OSA), which causes periods of absent or reduced breathing in sleep, resulting in many partial awakenings during the night and sleepiness during the day. The disease puts strain on the heart, which may lead to heart failure and leg swelling.

<span class="mw-page-title-main">Pleurisy</span> Disease of the lungs

Pleurisy, also known as pleuritis, is inflammation of the membranes that surround the lungs and line the chest cavity (pleurae). This can result in a sharp chest pain while breathing. Occasionally the pain may be a constant dull ache. Other symptoms may include shortness of breath, cough, fever, or weight loss, depending on the underlying cause. Pleurisy can be caused by a variety of conditions, including viral or bacterial infections, autoimmune disorders, and pulmonary embolism.

<span class="mw-page-title-main">Pulmonary heart disease</span> Medical condition

Pulmonary heart disease, also known as cor pulmonale, is the enlargement and failure of the right ventricle of the heart as a response to increased vascular resistance or high blood pressure in the lungs.

<span class="mw-page-title-main">Pulmonary edema</span> Fluid accumulation in the tissue and air spaces of the lungs

Pulmonary edema, also known as pulmonary congestion, is excessive fluid accumulation in the tissue or air spaces of the lungs. This leads to impaired gas exchange, most often leading to shortness of breath (dyspnea) which can progress to hypoxemia and respiratory failure. Pulmonary edema has multiple causes and is traditionally classified as cardiogenic or noncardiogenic.

<span class="mw-page-title-main">Hypercapnia</span> Abnormally high tissue carbon dioxide levels

Hypercapnia (from the Greek hyper = "above" or "too much" and kapnos = "smoke"), also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood. Carbon dioxide is a gaseous product of the body's metabolism and is normally expelled through the lungs. Carbon dioxide may accumulate in any condition that causes hypoventilation, a reduction of alveolar ventilation (the clearance of air from the small sacs of the lung where gas exchange takes place) as well as resulting from inhalation of CO2. Inability of the lungs to clear carbon dioxide, or inhalation of elevated levels of CO2, leads to respiratory acidosis. Eventually the body compensates for the raised acidity by retaining alkali in the kidneys, a process known as "metabolic compensation".

Orthopnea or orthopnoea is shortness of breath (dyspnea) that occurs when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair. It is commonly seen as a late manifestation of heart failure, resulting from fluid redistribution into the central circulation, causing an increase in pulmonary capillary pressure and causing difficulty in breathing. It is also seen in cases of abdominal obesity or pulmonary disease. Orthopnea is the opposite of platypnea, shortness of breath that worsens when sitting or standing upright.

<span class="mw-page-title-main">Cheyne–Stokes respiration</span> Abnormal breathing pattern

Cheyne–Stokes respiration is an abnormal pattern of breathing characterized by progressively deeper, and sometimes faster, breathing followed by a gradual decrease that results in a temporary stop in breathing called an apnea. The pattern repeats, with each cycle usually taking 30 seconds to 2 minutes. It is an oscillation of ventilation between apnea and hyperpnea with a crescendo-diminuendo pattern, and is associated with changing serum partial pressures of oxygen and carbon dioxide.

<span class="mw-page-title-main">Generalized hypoxia</span> Medical condition of oxygen deprivation

Generalized hypoxia is a medical condition in which the tissues of the body are deprived of the necessary levels of oxygen due to an insufficient supply of oxygen, which may be due to the composition or pressure of the breathing gas, decreased lung ventilation, or respiratory disease, any of which may cause a lower than normal oxygen content in the arterial blood, and consequently a reduced supply of oxygen to all tissues perfused by the arterial blood. This usage is in contradistinction to localized hypoxia, in which only an associated group of tissues, usually with a common blood supply, are affected, usually due to an insufficient or reduced blood supply to those tissues. Generalized hypoxia is also used as a synonym for hypoxic hypoxia This is not to be confused with hypoxemia, which refers to low levels of oxygen in the blood, although the two conditions often occur simultaneously, since a decrease in blood oxygen typically corresponds to a decrease in oxygen in the surrounding tissue. However, hypoxia may be present without hypoxemia, and vice versa, as in the case of infarction. Several other classes of medical hypoxia exist.

<span class="mw-page-title-main">Valvular heart disease</span> Disease in the valves of the heart

Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart. These conditions occur largely as a consequence of aging, but may also be the result of congenital (inborn) abnormalities or specific disease or physiologic processes including rheumatic heart disease and pregnancy.

<span class="mw-page-title-main">Hypoxemia</span> Abnormally low level of oxygen in the blood

Hypoxemia is an abnormally low level of oxygen in the blood. More specifically, it is oxygen deficiency in arterial blood. Hypoxemia has many causes, and often causes hypoxia as the blood is not supplying enough oxygen to the tissues of the body.

Eosinophilic pneumonia is a disease in which an eosinophil, a type of white blood cell, accumulates in the lungs. These cells cause disruption of the normal air spaces (alveoli) where oxygen is extracted from the atmosphere. Several different kinds of eosinophilic pneumonia exist and can occur in any age group. The most common symptoms include cough, fever, difficulty breathing, and sweating at night. Eosinophilic pneumonia is diagnosed by a combination of characteristic symptoms, findings on a physical examination by a health provider, and the results of blood tests and X-rays. Prognosis is excellent once most eosinophilic pneumonia is recognized and treatment with corticosteroids is begun.

Cardiac asthma is the medical condition of intermittent wheezing, coughing, and shortness of breath that is associated with underlying congestive heart failure (CHF). Symptoms of cardiac asthma are related to the heart's inability to effectively and efficiently pump blood in a CHF patient. This can lead to accumulation of fluid in and around the lungs, disrupting the lung's ability to oxygenate blood.

Trepopnea is dyspnea that is sensed while lying on one side but not on the other. It results from disease of one lung, one major bronchus, or chronic congestive heart failure that affects only a side of breathing. Patients with trepopnea in most lung diseases prefer to lie and sleep on the opposite side of the diseased lung, as the gravitation increases perfusion of the lower lung. Increased perfusion in diseased lung would increase shunting and hypoxemia, resulting in worsening shortness of breath when lying on the affected lung. To maximize function of the healthier lung and to relieve dyspnea, the patient is best to lie on the side of the healthier lung, so that it receives adequate perfusion. Patients with chronic heart failure prefer to lie mostly on the right side, to enable a better blood return, whereby cardiac output is augmented. One exception is pleural effusion, in which the patients experience less dyspnea when lying on the side of the pleural effusion, instead of the healthy lung.

Wilson–Mikity syndrome, a form of chronic lung disease (CLD) that exists only in premature infants, leads to progressive or immediate development of respiratory distress. This rare condition affects low birth babies and is characterized by rapid development of lung emphysema after birth, requiring prolonged ventilation and oxygen supplementation. It is closely related to bronchopulmonary dysplasia (BPD), differing mainly in the lack of prior ventilatory support. All the initial patients described with Wilson–Mikity syndrome were very low birth weight infants that had no history of mechanical ventilation, yet developed a syndrome that clinically resembled BPD. Upon the death of some of these infants, autopsies showed histologic changes similar to those seen in BPD.

Central sleep apnea (CSA) or central sleep apnea syndrome (CSAS) is a sleep-related disorder in which the effort to breathe is diminished or absent, typically for 10 to 30 seconds either intermittently or in cycles, and is usually associated with a reduction in blood oxygen saturation. CSA is usually due to an instability in the body's feedback mechanisms that control respiration. Central sleep apnea can also be an indicator of Arnold–Chiari malformation.

<span class="mw-page-title-main">Pathophysiology of heart failure</span>

The main pathophysiology of heart failure is a reduction in the efficiency of the heart muscle, through damage or overloading. As such, it can be caused by a wide number of conditions, including myocardial infarction, hypertension and cardiac amyloidosis. Over time these increases in workload will produce changes to the heart itself:

<span class="mw-page-title-main">Ventilation–perfusion coupling</span> Relationship between respiratory and cardiovascular processes

Ventilation-perfusion coupling is the relationship between ventilation and perfusion processes, which take place in the respiratory system and the cardiovascular system. Ventilation is the movement of gas during breathing, and perfusion is the process of pulmonary blood circulation, which delivers oxygen to body tissues. Anatomically, the lung structure, alveolar organization, and alveolar capillaries contribute to the physiological mechanism of ventilation and perfusion. Ventilation-perfusion coupling maintains a constant ventilation/perfusion ratio near 0.8 on average, while the regional variation exists within the lungs due to gravity. When the ratio gets above or below 0.8, it is considered abnormal ventilation-perfusion coupling, also known as a ventilation–perfusion mismatch. Lung diseases, cardiac shunts, and smoking can cause a ventilation-perfusion mismatch that results in significant symptoms and diseases, which can be treated through treatments like bronchodilators and oxygen therapy.

References

  1. ↑ Charles Pollak; Michael J. Thorpy; Jan Yager (2009). The Encyclopedia of Sleep and Sleep Disorders. Infobase Publishing. pp. 170–. ISBN   978-1-4381-2577-0 . Retrieved 16 December 2012.
  2. ↑ Lippincott Williams & Wilkins (2007). Nursing: Interpreting signs & symptoms. Lippincott Williams & Wilkins. pp. 469–. ISBN   978-1-58255-668-0 . Retrieved 16 December 2012.
  3. 1 2 3 4 5 Mukerji, bVaskar (1990). "Dyspnea, Orthopnea, and Paroxysmal Nocturnal Dyspnea". In Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.). Clinical Methods: The; History, Physical, and Laboratory Examinations (3r uy5u5u5u5d ed.). Butterworths. ISBN   0-407-02853-6. PMID   21250057 . Retrieved 2009-03-14.
  4. 1 2 3 4 Coccia, Cecilia B. I.; Palkowski, Gregori H.; Schweitzer, Beverley; Motsohi, Tshepo; Ntusi, Ntobeko (2015). "Dyspnoea: Pathophysiology and a clinical approach". South African Medical Journal. 106 (1): 32–36. doi: 10.7196/SAMJ.2016.v106i1.10324 . hdl: 11427/34942 . ISSN   2078-5135. PMID   26933707.
  5. 1 2 3 4 5 6 7 8 9 Bass, John B. (1990), Walker, H. Kenneth; Hall, W. Dallas; Hurst, J. Willis (eds.), "Dyspnea", Clinical Methods: The History, Physical, and Laboratory Examinations (3rd ed.), Boston: Butterworths, ISBN   978-0-409-90077-4, PMID   21250198 , retrieved 2021-07-27
  6. ↑ Yancy, Clyde W.; Jessup, Mariell; Bozkurt, Biykem; Butler, Javed; Casey, Donald E.; Drazner, Mark H.; Fonarow, Gregg C.; Geraci, Stephen A.; Horwich, Tamara; Januzzi, James L.; Johnson, Maryl R. (2013). "2013 ACCF/AHA Guideline for the Management of Heart Failure: Executive Summary". Circulation. 128 (16): 1810–1852. doi: 10.1161/CIR.0b013e31829e8807 . PMID   23741057.
  7. ↑ Wang, Charlie S.; FitzGerald, J. Mark; Schulzer, Michael; Mak, Edwin; Ayas, Najib T. (2005). "Does this dyspneic patient in the emergency department have congestive heart failure?". JAMA. 294 (15): 1944–1956. doi:10.1001/jama.294.15.1944. ISSN   1538-3598. PMID   16234501.
  8. ↑ Yayan, Josef; Rasche, Kurt (2016), Pokorski, Mieczyslaw (ed.), "Asthma and COPD: Similarities and Differences in the Pathophysiology, Diagnosis and Therapy", Respiratory Medicine and Science, Advances in Experimental Medicine and Biology, vol. 910, Cham: Springer International Publishing, pp. 31–38, doi:10.1007/5584_2015_206, ISBN   978-3-319-30659-9, PMID   26820733 , retrieved 2021-07-29
  9. 1 2 3 4 5 6 7 8 9 10 11 12 Berliner, Dominik; Schneider, Nils; Welte, Tobias; Bauersachs, Johann (2016). "The Differential Diagnosis of Dyspnea". Deutsches Ärzteblatt International. 113 (49): 834–845. doi:10.3238/arztebl.2016.0834. ISSN   1866-0452. PMC   5247680 . PMID   28098068.
  10. ↑ Harrison’s principles of internal medicine
  11. ↑ Terziyski, K.; Draganova, A. (2018), Islam, Md. Shahidul (ed.), "Central Sleep Apnea with Cheyne-Stokes Breathing in Heart Failure – from Research to Clinical Practice and Beyond", Heart Failure: From Research to Clinical Practice: Volume 3, Advances in Experimental Medicine and Biology, vol. 1067, Cham: Springer International Publishing, pp. 327–351, doi:10.1007/5584_2018_146, ISBN   978-3-319-78280-5, PMID   29411336 , retrieved 2021-07-27
  12. 1 2 Naughton, Matthew T. (2016). "Epidemiology of central sleep apnoea in heart failure". International Journal of Cardiology. 206: S4–S7. doi:10.1016/j.ijcard.2016.02.125. ISSN   0167-5273. PMID   26948168.
  13. ↑ Villablanca, Amparo C. (2015). "Heart disease during pregnancy". Postgraduate Medicine. 104 (4): 183–192. doi:10.3810/pgm.1998.10.460. PMID   9793564.
  14. ↑ "Hypereosinophilic syndrome | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program". rarediseases.info.nih.gov. Retrieved 2021-08-04.
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