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Methacholine Challenge Test
A bronchial challenge test is a medical test used to assist in the diagnosis of asthma. The patient breathes in nebulized methacholine or histamine. Thus the test may also be called a methacholine challenge test or histamine challenge test respectively. Both drugs provoke bronchoconstriction, or narrowing of the airways. Whereas histamine causes nasal and bronchial mucus secretion and bronchoconstriction via the H1 receptor, methacholine utilizes the M3 receptor for bronchoconstriction. The degree of narrowing can then be quantified by spirometry. People with pre-existing airway hyperreactivity, such as asthmatics, will react to lower doses of drug. Sometimes, to assess the reversibility of a particular condition, a bronchodilator is administered to counteract the effects of the bronchoconstrictor before repeating the spirometry tests. This is commonly referred to as a ''reversibility test'', or a ''post bronchodilator test'' (post BD), and may help in distinguishing asthma fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Test
A medical test is a medical procedure performed to detect, diagnose, or monitor diseases, disease processes, susceptibility, or to determine a course of treatment. Medical tests such as, physical and visual exams, diagnostic imaging, genetic testing, chemical and cellular analysis, relating to clinical chemistry and molecular diagnostics, are typically performed in a medical setting. Types of tests By purpose Medical tests can be classified by their purposes, the most common of which are diagnosis, screening and evaluation. Diagnostic A diagnostic test is a procedure performed to confirm or determine the presence of disease in an individual suspected of having a disease, usually following the report of symptoms, or based on other medical test results. This includes posthumous diagnosis. Examples of such tests are: * Using nuclear medicine to examine a patient suspected of having a lymphoma. * Measuring the blood sugar in a person suspected of having diabetes mellitus after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronchial Hyperresponsiveness
Bronchial hyperresponsiveness (or other combinations with airway or hyperreactivity, BH used as a general abbreviation) is a state characterised by easily triggered bronchospasm (contraction of the bronchioles or small airways). Bronchial hyperresponsiveness can be assessed with a bronchial challenge test. This most often uses products like methacholine or histamine. These chemicals trigger bronchospasm in normal individuals as well, but people with bronchial hyperresponsiveness have a lower threshold. Bronchial hyperresponsiveness is a hallmark of asthma but also occurs frequently in people with chronic obstructive pulmonary disease (COPD). In the Lung Health Study, bronchial hyperresponsiveness was present in approximately two-thirds of patients with non-severe COPD, and this predicted lung function decline independently of other factors. In asthma it tends to be reversible with bronchodilator A bronchodilator or broncholytic (although the latter occasionally includes secretory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Tests
A medical test is a medical procedure performed to detect, diagnose, or monitor diseases, disease processes, susceptibility, or to determine a course of treatment. Medical tests such as, physical and visual exams, diagnostic imaging, genetic testing, chemical and cellular analysis, relating to clinical chemistry and molecular diagnostics, are typically performed in a medical setting. Types of tests By purpose Medical tests can be classified by their purposes, the most common of which are diagnosis, screening and evaluation. Diagnostic A diagnostic test is a procedure performed to confirm or determine the presence of disease in an individual suspected of having a disease, usually following the report of symptoms, or based on other medical test results. This includes posthumous diagnosis. Examples of such tests are: * Using nuclear medicine to examine a patient suspected of having a lymphoma. * Measuring the blood sugar in a person suspected of having diabetes mellitus after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DLCO
DLCO or TLCO ( diffusing capacity or transfer factor of the lung for carbon monoxide (CO),) is the extent to which oxygen passes from the air sacs of the lungs into the blood. Commonly, it refers to the test used to determine this parameter. It was introduced in 1909. Mechanism This test involves measuring the partial pressure difference between inspired and expired carbon monoxide. It relies on the strong affinity and large absorption capacity of red blood cells for carbon monoxide and thus demonstrates gas uptake by the capillaries that are less dependent on cardiac output. The measurement of DLCO is affected by atmospheric pressure and/or altitude and correction factors can be calculated using the method recommended by the American Thoracic Society. Expected DLCO is also affected by the amount of hemoglobin, carboxyhemoglobin, age and sex. The correction for hemoglobin is based on the method of Cotes as recommended by the American Thoracic Society. DLCO vs TLCO Generally DLCO i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronic Obstructive Pulmonary Disease
Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by long-term respiratory symptoms and airflow limitation. The main symptoms include shortness of breath and a cough, which may or may not produce mucus. COPD progressively worsens, with everyday activities such as walking or dressing becoming difficult. While COPD is incurable, it is preventable and treatable. The two most common conditions of COPD are emphysema and chronic bronchitis and they have been the two classic COPD phenotypes. Emphysema is defined as enlarged airspaces ( alveoli) whose walls have broken down resulting in permanent damage to the lung tissue. Chronic bronchitis is defined as a productive cough that is present for at least three months each year for two years. Both of these conditions can exist without airflow limitation when they are not classed as COPD. Emphysema is just one of the structural abnormalities that can limit airflow and can exist without ai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post Bronchodilator Test
The post bronchodilator test (Post BD), 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. Indications This procedure is indicated in the diagnosis and follow-up of asthma, and in the differentiation between asthma and COPD. Procedure An initial spirometry is performed to assess the patient's native respiratory status. You will be asked to take a deep breath and then blow into the mouthpiece of the spirometer as hard as you can. This is a baseline measurement. A dose of bronchodilator medication is administered by means of inhaler or nebulizer (such as 400mcg of salbutamol (also known as albuterol)). You will wait about 15 minutes and then the spirometry is repeated.{{Cite web, title = Bronchodilator Reversibility Testing - Online Medical Encyclopedia - University of Rochester Medical Center, url = https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronchodilator
A bronchodilator or broncholytic (although the latter occasionally includes secretory inhibition as well) 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. Bronchodilators are either short-acting or long-acting. Short-acting medications provide quick or "rescue" relief from acute bronchoconstriction. Long-acting bronchodilators help to control and prevent symptoms. The three types of pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asthmatics
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. These may occur a few times a day or a few times per week. Depending on the person, asthma symptoms may become worse at night or with exercise. Asthma is thought to be caused by a combination of genetic and environmental factors. Environmental factors include exposure to air pollution and allergens. Other potential triggers include medications such as aspirin and beta blockers. Diagnosis is usually based on the pattern of symptoms, response to therapy over time, and spirometry lung function testing. Asthma is classified according to the frequency of symptoms, forced expiratory volume in one second (FEV1), and peak expiratory flow rate. It may also be classified as atopic or non-atopic, wher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirometry
Spirometry (meaning ''the measuring of breath'') 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. Spirometry generates pneumotachographs, which are charts that plot the volume and flow of air coming in and out of the lungs from one inhalation and one exhalation. Indications Spirometry is indicated for the following reasons: * to diagnose or manage asthma * to detect respiratory disease in patients presenting with symptoms of breathlessness, and to distinguish respiratory from cardiac disease as the cause * to measure bronchial responsiveness in patients suspected of having asthma * to diagnose and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagnosis
Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine " cause and effect". In systems engineering and computer science, it is typically used to determine the causes of symptoms, mitigations, and solutions. Computer science and networking * Bayesian networks * Complex event processing * Diagnosis (artificial intelligence) * Event correlation * Fault management * Fault tree analysis * Grey problem * RPR Problem Diagnosis * Remote diagnostics * Root cause analysis * Troubleshooting * Unified Diagnostic Services Mathematics and logic * Bayesian probability * Block Hackam's dictum * Occam's razor * Regression diagnostics * Sutton's law copy right remover block Medicine * Medical diagnosis * Molecular diagnostics Methods * CDR Computerized Assessment System * Computer-assisted diagnosis * Differential diagnosis * Medical di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M3 Receptor
The muscarinic acetylcholine receptor, also known as cholinergic/acetylcholine receptor M3, or the muscarinic 3, is a muscarinic acetylcholine receptor encoded by the human gene CHRM3. The M3 muscarinic receptors are located at many places in the body, e.g., smooth muscles, the endocrine glands, the exocrine glands, lungs, pancreas and the brain. In the CNS, they induce emesis. Muscarinic M3 receptors are expressed in regions of the brain that regulate insulin homeostasis, such as the hypothalamus and dorsal vagal complex of the brainstem. These receptors are highly expressed on pancreatic beta cells and are critical regulators of glucose homoestasis by modulating insulin secretion. In general, they cause smooth muscle contraction and increased glandular secretions. They are unresponsive to PTX and CTX. Mechanism Like the M1 muscarinic receptor, M3 receptors are coupled to G proteins of class Gq, which upregulate phospholipase C and, therefore, inositol trisphosphate and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
H1 Receptor
The H1 receptor is a histamine receptor belonging to the family of rhodopsin-like G-protein-coupled receptors. This receptor is activated by the biogenic amine histamine. It is expressed in smooth muscles, on vascular endothelial cells, in the heart, and in the central nervous system. The H1 receptor is linked to an intracellular G-protein (Gq) that activates phospholipase C and the inositol triphosphate (IP3) signalling pathway. Antihistamines, which act on this receptor, are used as anti-allergy drugs. The crystal structure of the receptor has been determined (shown on the right/below) and used to discover new histamine H1 receptor ligands in structure-based virtual screening studies. Function The expression of NF-κB, the transcription factor that regulates inflammatory processes, is promoted by the constitutive activity of the H1 receptor as well as by agonists that bind at the receptor. H1-antihistamines have been shown to attenuate NF-κB expression and mitigate certain in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
