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A bronchodilator or broncholytic is a substance that dilates the bronchi and bronchioles, decreasing resistance in the respiratory airway and increasing airflow to the lungs. Bronchodilators may be originating naturally within the body, or they may be medications administered for the treatment of breathing difficulties, usually in the form of inhalers. They are most useful in obstructive lung diseases, of which asthma and chronic obstructive pulmonary disease are the most common conditions. Although this remains somewhat controversial, they might be useful in bronchiolitis and bronchiectasis. They are often prescribed but of unproven significance in restrictive lung diseases.
Salbutamol, also known as albuterol and sold under the brand name Ventolin among others, is a medication that opens up the medium and large airways in the lungs. It is a short-acting β2 adrenergic receptor agonist which works by causing relaxation of airway smooth muscle. It is used to treat asthma, including asthma attacks, exercise-induced bronchoconstriction, and chronic obstructive pulmonary disease (COPD). It may also be used to treat high blood potassium levels. Salbutamol is usually used with an inhaler or nebulizer, but it is also available in a pill, liquid, and intravenous solution. Onset of action of the inhaled version is typically within 15 minutes and lasts for two to six hours.
Spirometry is the most common of the pulmonary function tests (PFTs). It measures lung function, specifically the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled. Spirometry is helpful in assessing breathing patterns that identify conditions such as asthma, pulmonary fibrosis, cystic fibrosis, and COPD. It is also helpful as part of a system of health surveillance, in which breathing patterns are measured over time.
Bronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath.
Methacholine, also known as Acetyl-β-methylcholine, is a synthetic choline ester that acts as a non-selective muscarinic receptor agonist in the parasympathetic nervous system.
A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed, or airflow velocity within the respiratory tree must be heightened. Wheezing is commonly experienced by persons with a lung disease; the most common cause of recurrent wheezing is asthma, though it can also be a symptom of lung cancer, congestive heart failure, and certain types of heart diseases.
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.
Exercise-induced asthma, or E.I.A., occurs when the airways narrow as a result of exercise. The preferred term for this condition is exercise-induced bronchoconstriction (EIB). While exercise does not cause asthma, it is frequently an asthma trigger.
Reactive airway disease (RAD) is an informal label that physicians apply to patients with symptoms similar to those of asthma. An exact definition of the condition does not exist. Individuals who are typically labeled as having RAD generally have a history of wheezing, coughing, dyspnea, and production of sputum that may or may not be caused by asthma. Symptoms may also include, but are not limited to, coughing, shortness of breath, excess mucus in the bronchial tube, swollen mucous membrane in the bronchial tube, and/or hypersensitive bronchial tubes. Physicians most commonly label patients with RAD when they are hesitant about formally diagnosing a patient with asthma, which is most prevalent in the pediatric setting. While some physicians may use RAD and asthma synonymously, there is controversy over this usage.
Levosalbutamol, also known as levalbuterol, is a short-acting β2 adrenergic receptor agonist used in the treatment of asthma and chronic obstructive pulmonary disease (COPD). Evidence does not show that levosalbutamol works better than salbutamol; thus there may not be sufficient justification for prescribing it.
Bronchial thermoplasty is a treatment for severe asthma approved by the FDA in 2010 involving the delivery of controlled, therapeutic radiofrequency energy to the airway wall, thus heating the tissue and reducing the amount of smooth muscle present in the airway wall. This reduces the capacity of the immune system to cause bronchoconstriction through nitric oxide signalling, which is the main root cause of asthma symptoms. Bronchial thermoplasty is normally used to treat patients with severe persistent asthma who do not respond well to typical pharmacotherapy regimens. Through a standard bronchoscopy procedure, a small flexible tube is advanced into the airway, via mouth or nose, to mildly heat the airway walls. This treatment has been shown to result in acute epithelial destruction with regeneration observed in the epithelium, blood vessels, mucosa and nerves; however, airway smooth muscle has demonstrated almost no capacity for regeneration, and it is instead replaced with connective tissue. The treatment has been shown in prospective studies to be safe and effective with duration up to five years. Bronchial thermoplasty is indicated for the treatment of severe persistent asthma in patients 18 years and older whose asthma is not well controlled with inhaled corticosteroids and long acting beta agonists as per GINA guidelines.
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.
Pulmonary function testing (PFT) is a complete evaluation of the respiratory system including patient history, physical examinations, and tests of pulmonary function. The primary purpose of pulmonary function testing is to identify the severity of pulmonary impairment. Pulmonary function testing has diagnostic and therapeutic roles and helps clinicians answer some general questions about patients with lung disease. PFTs are normally performed by a pulmonary function technician, respiratory therapist, respiratory physiologist, physiotherapist, pulmonologist, or general practitioner.
Vocal cord dysfunction (VCD) is a pathology affecting the vocal folds characterized by full or partial vocal fold closure causing difficulty and distress during respiration, especially during inhalation.
Bronchial hyperresponsiveness is a state characterised by easily triggered bronchospasm.
Eosinophilic bronchitis (EB) is a type of airway inflammation due to excessive mast cell recruitment and activation in the superficial airways as opposed to the smooth muscles of the airways as seen in asthma. It often results in a chronic cough. Lung function tests are usually normal. Inhaled corticosteroids are often an effective treatment.
The post bronchodilator test, also commonly referred to as a reversibility test, is a test that utilizes spirometry to assess possible reversibility of bronchoconstriction in diseases such as asthma.
β2-adrenoceptor agonists is a group of drugs that act selectively on β2-receptors in the lungs causing bronchodilation. β2-agonists are used to treat asthma and COPD, diseases that cause obstruction in the airways. Prior to their discovery, the non-selective beta-agonist isoprenaline was used. The aim of the drug development through the years has been to minimise side effects, achieve selectivity and longer duration of action. The mechanism of action is well understood and has facilitated the development. The structure of the binding site and the nature of the binding is also well known, as is the structure activity relationship.
Chronic cough is long-term coughing, sometimes defined as more than several weeks or months. The term can be used to describe the different causes related to coughing, the three main ones being upper airway cough syndrome, asthma and gastroesophageal reflux disease. It occurs in the upper airway of the respiratory system. Generally, a cough lasts around one to two weeks; however, chronic cough can persist for an extended period of time defined as six weeks or longer. People with chronic cough often experience more than one cause present. Due to the nature of the syndrome, the treatments used are similar; however, there are a subsequent number of treatments available, and the clinical management of the patients remains a challenge.
Asthma triggers are factors or stimuli that provoke the exacerbation of asthma symptoms or increase the degree of airflow disruption, which can lead to an asthma attack. An asthma attack is characterized by an obstruction of the airway, hypersecretion of mucus and bronchoconstriction due to the contraction of smooth muscles around the respiratory tract. Its symptoms include a wide range of manifestations such as breathlessness, coughing, a tight chest and wheezing.
