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Airway obstruction | |
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Specialty | Pulmonology |
Airway obstruction is a blockage of respiration in the airway that hinders the free flow of air. Airway obstructions can occur either in the upper airway or lower airway. The upper airway consists of the nose, throat, and larynx. The lower airway comprises the trachea, bronchi, and bronchioles. [1] [ page needed ]
Airway obstruction is a life-threatening condition and requires urgent attention. [2]
The causes of upper airway obstructions can be acute or chronic. Acute causes of upper airway obstruction include foreign body aspiration, blunt trauma to the neck, infection, and swelling due to allergies or other inflammatory conditions. [3] In children, viral infections such as croup or epiglottitis are frequent causes. [4] Adults are more likely to experience obstruction from enlargement of the tonsils or vocal cord paralysis. [3] Obstructive sleep apnea is the most common chronic cause of upper airway obstruction. [2]
Stridor is a high-pitched sound which occurs during breathing and is associated with obstruction at the level of the larynx. Difficulty swallowing and changes in voice are common symptoms. [3] If there is total obstruction, severe respiratory distress or cyanosis due to hypoxia (lack of oxygen in the blood) can occur. [2]
With acute upper airway obstruction, respiratory distress can rapidly lead to respiratory failure without appropriate management [2] necessitating urgent and comprehensive assessment of ABCs (airway, breathing, and circulation). [1]
Imaging studies, including x-rays and CT scans, can aid diagnosis and quickly assess the obstruction's extent. [2] For children, ultrasound or MRI are preferred as they do not involve radiation. [5] Flexible laryngoscopy or bronchoscopy can directly visualize the airway. [2]
Treatment depends on how severe the patient's condition is and the cause of the obstruction. If the patient is choking on a foreign body, the Heimlich maneuver can be used. More invasive methods, such as intubation, may be necessary to secure the airway. In severe cases, intubation may be difficult and a cricothyrotomy or tracheostomy may be necessary. [2] [6]
Infections typically cause obstruction by swelling and are usually treated with antibiotics or corticosteroids to reduce inflammation. [1] For causes like tumors or abscesses, surgical removal may be required. [2]
With prompt treatment, outcomes are usually favorable. This is especially true for reversible conditions, like foreign body aspiration. [2] Chronic conditions, like vocal cord paralysis and sleep apnea, [7] may need ongoing care. If managed well, they usually have good outcomes.
Untreated or prolonged upper airway obstruction can cause severe, life-threatening complications.
Lower airway obstruction is mainly caused by increased resistance in the bronchioles, usually due to a decreased radius of the bronchioles. This typically occurs due to constriction and inflammation of the bronchioles that reduces the air inhaled in each breath. This restriction is worsened by mucus production and airway remodeling in chronic conditions. [1] [ page needed ] Diseases that cause lower airway obstruction are called obstructive lung diseases. [10] Examples include chronic obstructive pulmonary disease (COPD), asthma, and bronchitis. [11]
Patients often experience wheezing, shortness of breath, and a chronic cough. A wheeze is a coarse, whistling sound in the airways during breathing. Worsening symptoms may include increased mucus production and reduced exercise tolerance. [11]
Spirometry that measures the FEV1/FVC ratio, is the gold standard for diagnosing lower airway obstruction. A decreased ratio indicates obstruction. [12]
Chest X-rays can help exclude alternative diagnoses or include other comorbidities. CT images can provide more insight into any possible structural abnormalities. [11]
Treatment of lower airway obstruction includes:
Severe cases may need hospitalization and mechanical ventilation to help support breathing by keeping the airways open. [9] [ page needed ]
Prognosis depends on the severity and cause of the obstruction. With early diagnosis and treatment, conditions like asthma often have a good outcome. But, chronic diseases like COPD are progressive, requiring ongoing management. [11]
Complications of lower airway obstruction, often from chronic diseases, include:
Hypoxia is a condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level. Hypoxia may be classified as either generalized, affecting the whole body, or local, affecting a region of the body. Although hypoxia is often a pathological condition, variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise.
Sleep apnea is a sleep-related breathing disorder in which repetitive pauses in breathing, periods of shallow breathing, or collapse of the upper airway during sleep results in poor ventilation and sleep disruption. Each pause in breathing can last for a few seconds to a few minutes and often occurs many times a night. A choking or snorting sound may occur as breathing resumes. Common symptoms include daytime sleepiness, snoring, and non restorative sleep despite adequate sleep time. Because the disorder disrupts normal sleep, those affected may experience sleepiness or feel tired during the day. It is often a chronic condition.
The respiratory tract is the subdivision of the respiratory system involved with the process of conducting air to the alveoli for the purposes of gas exchange in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa.
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.
Positive airway pressure (PAP) is a mode of respiratory ventilation used in the treatment of sleep apnea. PAP ventilation is also commonly used for those who are critically ill in hospital with respiratory failure, in newborn infants (neonates), and for the prevention and treatment of atelectasis in patients with difficulty taking deep breaths. In these patients, PAP ventilation can prevent the need for tracheal intubation, or allow earlier extubation. Sometimes patients with neuromuscular diseases use this variety of ventilation as well. CPAP is an acronym for "continuous positive airway pressure", which was developed by Dr. George Gregory and colleagues in the neonatal intensive care unit at the University of California, San Francisco. A variation of the PAP system was developed by Professor Colin Sullivan at Royal Prince Alfred Hospital in Sydney, Australia, in 1981.
Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release (degranulation) of substances from mast cells or basophils under the influence of anaphylatoxins. It causes difficulty in breathing which ranges from mild to severe.
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.
Upper airway resistance syndrome (UARS) is a sleep disorder characterized by the narrowing of the airway that can cause disruptions to sleep. The symptoms include unrefreshing sleep, fatigue, sleepiness, chronic insomnia, and difficulty concentrating. UARS can be diagnosed by polysomnograms capable of detecting Respiratory Effort-related Arousals. It can be treated with lifestyle changes, functional orthodontics, surgery, mandibular repositioning devices or CPAP therapy. UARS is considered a variant of sleep apnea, although some scientists and doctors believe it to be a distinct disorder.
Atelectasis is the partial collapse or closure of a lung resulting in reduced or absence in gas exchange. It is usually unilateral, affecting part or all of one lung. It is a condition where the alveoli are deflated down to little or no volume, as distinct from pulmonary consolidation, in which they are filled with liquid. It is often referred to informally as a collapsed lung, although more accurately it usually involves only a partial collapse, and that ambiguous term is also informally used for a fully collapsed lung caused by a pneumothorax.
Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway leading to reduced or absent breathing during sleep. These episodes are termed "apneas" with complete or near-complete cessation of breathing, or "hypopneas" when the reduction in breathing is partial. In either case, a fall in blood oxygen saturation, a disruption in sleep, or both, may result. A high frequency of apneas or hypopneas during sleep may interfere with the quality of sleep, which – in combination with disturbances in blood oxygenation – is thought to contribute to negative consequences to health and quality of life. The terms obstructive sleep apnea syndrome (OSAS) or obstructive sleep apnea–hypopnea syndrome (OSAHS) may be used to refer to OSA when it is associated with symptoms during the daytime.
Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, the nerves and muscles of respiration. Respiratory diseases range from mild and self-limiting, such as the common cold, influenza, and pharyngitis to life-threatening diseases such as bacterial pneumonia, pulmonary embolism, tuberculosis, acute asthma, lung cancer, and severe acute respiratory syndromes, such as COVID-19. Respiratory diseases can be classified in many different ways, including by the organ or tissue involved, by the type and pattern of associated signs and symptoms, or by the cause of the disease.
Hypopnea is overly shallow breathing or an abnormally low respiratory rate. Hypopnea is typically defined by a decreased amount of air movement into the lungs and can cause hypoxemia It commonly is due to partial obstruction of the upper airway, but can also have neurological origins in central sleep apnea.
Obstructive lung disease is a category of respiratory disease characterized by airway obstruction. Many obstructive diseases of the lung result from narrowing (obstruction) of the smaller bronchi and larger bronchioles, often because of excessive contraction of the smooth muscle itself. It is generally characterized by inflamed and easily collapsible airways, obstruction to airflow, problems exhaling, and frequent medical clinic visits and hospitalizations. Types of obstructive lung disease include asthma, bronchiectasis, bronchitis and chronic obstructive pulmonary disease (COPD). Although COPD shares similar characteristics with all other obstructive lung diseases, such as the signs of coughing and wheezing, they are distinct conditions in terms of disease onset, frequency of symptoms, and reversibility of airway obstruction. Cystic fibrosis is also sometimes included in obstructive pulmonary disease.
Restrictive lung diseases are a category of extrapulmonary, pleural, or parenchymal respiratory diseases that restrict lung expansion, resulting in a decreased lung volume, an increased work of breathing, and inadequate ventilation and/or oxygenation. Pulmonary function test demonstrates a decrease in the forced vital capacity.
Diffuse panbronchiolitis (DPB) is an inflammatory lung disease of unknown cause. It is a severe, progressive form of bronchiolitis, an inflammatory condition of the bronchioles. The term diffuse signifies that lesions appear throughout both lungs, while panbronchiolitis refers to inflammation found in all layers of the respiratory bronchioles. DPB causes severe inflammation and nodule-like lesions of terminal bronchioles, chronic sinusitis, and intense coughing with large amounts of sputum production.
An acute exacerbation of chronic obstructive pulmonary disease, or acute exacerbations of chronic bronchitis (AECB), is a sudden worsening of chronic obstructive pulmonary disease (COPD) symptoms including shortness of breath, quantity and color of phlegm that typically lasts for several days.
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.
Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by chronic respiratory symptoms and airflow limitation. GOLD 2024 defined COPD as a heterogeneous lung condition characterized by chronic respiratory symptoms due to abnormalities of the airways and/or alveoli (emphysema) that cause persistent, often progressive, airflow obstruction.
Emphysema is any air-filled enlargement in the body's tissues. Most commonly emphysema refers to the permanent enlargement of air spaces (alveoli) in the lungs, and is also known as pulmonary emphysema.
Ventilation–perfusion coupling is the relationship between ventilation and perfusion in the respiratory and cardiovascular systems. Ventilation is the movement of air in and out of the lungs during breathing. Perfusion is the process of pulmonary blood circulation, which reoxygenates blood, allowing it to transport oxygen to body tissues. Lung structure, alveolar organization, and alveolar capillaries contribute to the physiological mechanism of ventilation and perfusion.