Cough
Encyclopedia
A cough is a sudden and often repetitively occurring reflex which helps to clear the large breathing passages from secretions, irritants, foreign particles and microbes. The cough reflex
consists of three phases: an inhalation
, a forced exhalation
against a closed glottis
, and a violent release of air from the lungs following opening of the glottis, usually accompanied by a distinctive sound. Coughing can happen voluntarily as well as involuntarily.
Frequent coughing usually indicates the presence of a disease. Many virus
es and bacteria
benefit evolutionarily by causing the host
to cough, which helps to spread the disease to new hosts. Most of the time, coughing is caused by a respiratory tract infection
but can be triggered by choking, smoking
, air pollution
, asthma
, gastroesophageal reflux disease
, post-nasal drip
, chronic bronchitis
, lung tumors, heart failure and medications such as ACE inhibitor
s.
Treatment should target the cause; for example, smoking cessation
or discontinuing ACE inhibitors. Some people may be worried about serious illnesses, and reassurance may suffice. Cough suppressants such as codeine
or dextromethorphan
are frequently prescribed, but have been demonstrated to have little effect. Other treatment options may target airway inflammation
or may promote mucus expectoration. As it is a natural protective reflex, suppressing the cough reflex might have damaging effects, especially if the cough is productive.
(of sudden onset) if it is present less than three weeks, subacute if it is present between three and eight weeks, and chronic
when lasting longer than eight weeks. A cough can be non-productive (dry) or productive (when sputum
is coughed up). It may occur only at night (then called nocturnal cough), during both night and day, or just during the day.
A number of characteristic coughs exist. While these have not been found to be diagnostically useful in adults, they are of use in children. A barky cough is part of the common presentation of croup
, while a staccato cough has been classically described with chlamydia
pneumonia
.
. In adults with a chronic cough, i.e. a cough longer than 8 weeks, more than 90% of cases are due to post-nasal drip
, asthma
, eosinophilic bronchitis
, and gastroesophageal reflux disease
. The causes of chronic cough are similar in children with the addition of bacterial bronchitis
.
, pneumonia
, pertussis
, or tuberculosis
. In the vast majority of cases, acute coughs, i.e. coughs shorter than 3 weeks, are due to the common cold. In people with a normal chest X-ray, tuberculosis is a rare finding. Pertussis is increasingly being recognised as a cause of troublesome coughing in adults.
After a viral infection has cleared, the person may be left with a postinfectious cough. This typically is a dry, non-productive cough that produces no phlegm. Symptoms may include a tightness in the chest, and a tickle in the lungs. This cough may often persist for weeks after an illness. The cause of the cough may be inflammation similar to that observed in repetitive stress disorders such as carpal tunnel. The repetition of coughing produces inflammation which produces discomfort, which in turn produces more coughing creating a closed loop. Postinfectious cough typically does not respond to conventional cough treatments. Treatment consists of any anti-inflammatory medicine to treat the inflammation, and a cough suppressant to reduce frequency of the cough until inflammation clears. Inflammation may increase sensitivity to other existing issues such as allergies, and treatment of other causes of coughs (such as use of an air purifier or allergy medicines) may help speed recovery. A bronchodilator, which helps open up the airways, may also help treat this type of cough.
and reversibility), this is termed cough-variant asthma. Two related conditions are atopic cough and eosinophilic bronchitis. Atopic cough occurs in individuals with a family history
of atopy
, abundant eosinophils in the sputum, but with normal airway function and responsiveness. Eosinophilic bronchitis is also characterized by eosinophils in the sputum, without airway hyperresponsiveness or an atopic background. This condition responds to treatment with corticosteroids. Cough can also worsen in an acute exacerbation of chronic obstructive pulmonary disease
.
Asthma is a common cause of chronic cough in adults and children. Coughing may be the only symptom the person has from their asthma, or asthma symptoms may also include wheezing, shortness of breath, and a tight feeling in their chest. Depending on how severe the asthma is it can be treated with bronchodilators (medicine which causes the airways to open up) or inhaled steroids. Treatment of the asthma should make the cough go away.
Chronic bronchitis
is defined clinically as a persistent cough that produces sputum (phlegm) and mucus, for at least three months in two consecutive years. Chronic bronchitis is often the cause of “smoker’s cough.” The tobacco causes inflammation, secretion of mucus into the airway, and difficulty clearing that mucus out of the airways. Coughing helps clear those secretions out. May be treated by quitting smoking. May also be caused by Pneumoconiosis and long-term fume inhalation.
should be considered. This occurs when acidic contents of the stomach come back up into the esophagus. Symptoms usually associated with GERD include heartburn, sour taste in the mouth, or a feeling of acid reflux in the chest, although, more than half of the people with cough from GERD don’t have any other symptoms. An esophageal pH monitor can confirm the diagnosis of GERD. Sometimes GERD can complicate respiratory ailments related to cough, such as asthma or bronchitis. The treatment involves anti-acid medications and lifestyle changes with surgery indicated in cases not manageable with conservative measures.
including tobacco smoke, particulate matter, irritant gases, and dampness in the home.
The human health effects of poor air quality are far reaching, but principally affect the body's respiratory system and the cardiovascular system. Individual reactions to air pollutants depend on the type of pollutant a person is exposed to, the degree of exposure, the individual's health status and genetics. People who exercise outdoors, for example, on hot, smoggy days increase their exposure to pollutants in the air.
can sometimes be suspected, for example if the cough started suddenly when the patient was eating. Rarely, sutures left behind inside the airway branches can cause coughing. A cough can be triggered by dryness from mouth breathing
or recurrent aspiration of food into the windpipe
in people with swallowing difficulties
.
and quinapril
. There are cases of "cough of unknown origin" who had resolution with stopping the drug.
, cystic fibrosis
, interstitial lung diseases and sarcoidosis
. Coughing can also be triggered by benign or malignant lung tumor
s or mediastinal masses. Through irritation of the nerve, diseases of the external auditory canal (wax, for example) can also cause cough. Cardiovascular diseases associated with cough are heart failure, pulmonary infarction and aortic aneurysm. Nocturnal cough is associated with heart failure, as the heart does not compensate for the increased volume shift to the pulmonary circulation, in turn causing pulmonary edema
and resultant cough. Other causes of nocturnal cough include asthma
, post-nasal drip
and gastroesophageal reflux disease
(GERD). Another cause of cough occurring preferentially in supine position
is recurrent aspiration.
Coughing may also be used for social reasons, such as the coughing before giving a speech. Cough may also be psychogenic, which is different from habit coughing and tic coughing. Coughing may occur in tic disorder
s such as Tourette syndrome
, although it should be distinguished from throat-clearing in this disorder.
Given its irritant nature to mammal tissues, capsaicin
is widely used to determine the cough threshold and as a tussive stimulant in clinical research of cough suppressants. Capsaicin is what makes chilli peppers spicy, and might explain why workers in factories with these vegetables can develop a cough.
Coughing is not always involuntary, and can be used in social situations. Coughing can be used to attract attention, release internal psychological tension, or become a maladaptive displacement behavior. It is believed that the frequency of such coughing increases in environments vulnerable to psychological tension and social conflict. In such environments, coughing may become one of many displacement
behaviors and/or defense mechanisms.
in healthy individuals which is influenced by psychological factors. The cough reflex is initiated by stimulation of two different classes of afferent nerve
s, namely the myelin
ated rapidly adapting receptors, and nonmyelinated C-fibers
with endings in the lung
s. However it is not certain that the stimulation of nonmyelinated C-fibers
leads to cough with a reflex
as it's meant in physiology
(with its own five components): this stimulation may cause mast cell
s degranulation
(through an asso-assonic reflex) and edema
which may work as a stimulus for rapidly adapting receptors.
.
supported by little evidence and thus not recommended by the American Academy of Pediatrics
.
A trial of antibiotics or inhaled corticosteroids may be tried in children with a chronic cough in an attempt to treat protracted bacterial bronchitis or asthma
respectively.
or chronic. Acute complications include cough syncope (fainting spells due to decreased blood flow to the brain when coughs are prolonged and forceful), insomnia
, cough-induced vomiting
, rupture of bleb
s causing spontaneous pneumothorax (although this still remains to be proven), subconjunctival hemorrhage
or "red eye
", coughing defecation
and in women with a prolapse
d uterus
, cough urination
. Chronic complications are common and include abdominal or pelvic hernia
s, fatigue fracture
s of lower ribs and costochondritis
.
in the United States.
Cough reflex
The cough reflex has both sensory and motor components. Pulmonary irritant receptors in the epithelium of the respiratory tract are sensitive to both mechanical and chemical stimuli...
consists of three phases: an inhalation
Inhalation
Inhalation is the movement of air from the external environment, through the air ways, and into the alveoli....
, a forced exhalation
Exhalation
Exhalation is the movement of air out of the bronchial tubes, through the airways, to the external environment during breathing....
against a closed glottis
Glottis
The glottis is defined as the combination of the vocal folds and the space in between the folds .-Function:...
, and a violent release of air from the lungs following opening of the glottis, usually accompanied by a distinctive sound. Coughing can happen voluntarily as well as involuntarily.
Frequent coughing usually indicates the presence of a disease. Many virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es and bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
benefit evolutionarily by causing the host
Host (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
to cough, which helps to spread the disease to new hosts. Most of the time, coughing is caused by a respiratory tract infection
Respiratory tract infection
Respiratory tract infection refers to any of a number of infectious diseases involving the respiratory tract. An infection of this type is normally further classified as an upper respiratory tract infection or a lower respiratory tract infection...
but can be triggered by choking, smoking
Smoking
Smoking is a practice in which a substance, most commonly tobacco or cannabis, is burned and the smoke is tasted or inhaled. This is primarily practised as a route of administration for recreational drug use, as combustion releases the active substances in drugs such as nicotine and makes them...
, air pollution
Air pollution
Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....
, asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
, gastroesophageal reflux disease
Gastroesophageal reflux disease
Gastroesophageal reflux disease , gastro-oesophageal reflux disease , gastric reflux disease, or acid reflux disease is chronic symptoms or mucosal damage caused by stomach acid coming up from the stomach into the esophagus...
, post-nasal drip
Post-nasal drip
Post-nasal drip , also known as Upper Airway Cough Syndrome , occurs when excessive mucus is produced by the nasal mucosa. The excess mucus accumulates in the throat or back of the nose...
, chronic bronchitis
Chronic bronchitis
Chronic bronchitis is a chronic inflammation of the bronchi in the lungs. It is generally considered one of the two forms of chronic obstructive pulmonary disease...
, lung tumors, heart failure and medications such as ACE inhibitor
ACE inhibitor
ACE inhibitors or angiotensin-converting enzyme inhibitors are a group of drugs used primarily for the treatment of hypertension and congestive heart failure...
s.
Treatment should target the cause; for example, smoking cessation
Smoking cessation
Smoking cessation is the process of discontinuing the practice of inhaling a smoked substance. This article focuses exclusively on cessation of tobacco smoking; however, the methods described may apply to cessation of smoking other substances that can be difficult to stop using due to the...
or discontinuing ACE inhibitors. Some people may be worried about serious illnesses, and reassurance may suffice. Cough suppressants such as codeine
Codeine
Codeine or 3-methylmorphine is an opiate used for its analgesic, antitussive, and antidiarrheal properties...
or dextromethorphan
Dextromethorphan
Dextromethorphan is an antitussive drug. It is one of the active ingredients in many over-the-counter cold and cough medicines, such as Robitussin, NyQuil, Dimetapp, Vicks, Coricidin, Delsym, and others, including generic labels. Dextromethorphan has also found other uses in medicine, ranging...
are frequently prescribed, but have been demonstrated to have little effect. Other treatment options may target airway inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
or may promote mucus expectoration. As it is a natural protective reflex, suppressing the cough reflex might have damaging effects, especially if the cough is productive.
Classification
A cough can be classified by its duration, character, quality, and timing. The duration can be either acuteAcute (medicine)
In medicine, an acute disease is a disease with either or both of:# a rapid onset, as in acute infection# a short course ....
(of sudden onset) if it is present less than three weeks, subacute if it is present between three and eight weeks, and chronic
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
when lasting longer than eight weeks. A cough can be non-productive (dry) or productive (when sputum
Sputum
Sputum is mucus that is coughed up from the lower airways. It is usually used for microbiological investigations of respiratory infections....
is coughed up). It may occur only at night (then called nocturnal cough), during both night and day, or just during the day.
A number of characteristic coughs exist. While these have not been found to be diagnostically useful in adults, they are of use in children. A barky cough is part of the common presentation of croup
Croup
Croup is a respiratory condition that is usually triggered by an acute viral infection of the upper airway. The infection leads to swelling inside the throat, which interferes with normal breathing and produces the classical symptoms of a "barking" cough, stridor, and hoarseness...
, while a staccato cough has been classically described with chlamydia
Chlamydia trachomatis
Chlamydia trachomatis, an obligate intracellular human pathogen, is one of three bacterial species in the genus Chlamydia. C. trachomatis is a Gram-negative bacteria, therefore its cell wall components retain the counter-stain safranin and appear pink under a light microscope.The inclusion bodies...
pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
.
Differential diagnosis
A cough in children may be either a normal physiological reflex or due to an underlying cause. In healthy children it may be normal in the absence of any disease to cough ten times a day. The most common cause of an acute or subacute cough is a viral respiratory tract infectionRespiratory tract infection
Respiratory tract infection refers to any of a number of infectious diseases involving the respiratory tract. An infection of this type is normally further classified as an upper respiratory tract infection or a lower respiratory tract infection...
. In adults with a chronic cough, i.e. a cough longer than 8 weeks, more than 90% of cases are due to post-nasal drip
Post-nasal drip
Post-nasal drip , also known as Upper Airway Cough Syndrome , occurs when excessive mucus is produced by the nasal mucosa. The excess mucus accumulates in the throat or back of the nose...
, asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
, eosinophilic bronchitis
Eosinophilic bronchitis
Eosinophilic bronchitis 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...
, and gastroesophageal reflux disease
Gastroesophageal reflux disease
Gastroesophageal reflux disease , gastro-oesophageal reflux disease , gastric reflux disease, or acid reflux disease is chronic symptoms or mucosal damage caused by stomach acid coming up from the stomach into the esophagus...
. The causes of chronic cough are similar in children with the addition of bacterial bronchitis
Bronchitis
Acute bronchitis is an inflammation of the large bronchi in the lungs that is usually caused by viruses or bacteria and may last several days or weeks. Characteristic symptoms include cough, sputum production, and shortness of breath and wheezing related to the obstruction of the inflamed airways...
.
Infections
A cough can be the result of a respiratory tract infection such as the common coldCommon cold
The common cold is a viral infectious disease of the upper respiratory system, caused primarily by rhinoviruses and coronaviruses. Common symptoms include a cough, sore throat, runny nose, and fever...
, pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
, pertussis
Pertussis
Pertussis, also known as whooping cough , is a highly contagious bacterial disease caused by Bordetella pertussis. Symptoms are initially mild, and then develop into severe coughing fits, which produce the namesake high-pitched "whoop" sound in infected babies and children when they inhale air...
, or tuberculosis
Tuberculosis
Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...
. In the vast majority of cases, acute coughs, i.e. coughs shorter than 3 weeks, are due to the common cold. In people with a normal chest X-ray, tuberculosis is a rare finding. Pertussis is increasingly being recognised as a cause of troublesome coughing in adults.
After a viral infection has cleared, the person may be left with a postinfectious cough. This typically is a dry, non-productive cough that produces no phlegm. Symptoms may include a tightness in the chest, and a tickle in the lungs. This cough may often persist for weeks after an illness. The cause of the cough may be inflammation similar to that observed in repetitive stress disorders such as carpal tunnel. The repetition of coughing produces inflammation which produces discomfort, which in turn produces more coughing creating a closed loop. Postinfectious cough typically does not respond to conventional cough treatments. Treatment consists of any anti-inflammatory medicine to treat the inflammation, and a cough suppressant to reduce frequency of the cough until inflammation clears. Inflammation may increase sensitivity to other existing issues such as allergies, and treatment of other causes of coughs (such as use of an air purifier or allergy medicines) may help speed recovery. A bronchodilator, which helps open up the airways, may also help treat this type of cough.
Reactive airway disease
When coughing is the only complaint of a person who meets the criteria for asthma (bronchial hyperresponsivenessBronchial hyperresponsiveness
Bronchial hyperresponsiveness is a state characterised by easily triggered bronchospasm ....
and reversibility), this is termed cough-variant asthma. Two related conditions are atopic cough and eosinophilic bronchitis. Atopic cough occurs in individuals with a family history
Family history
Family history is the systematic narrative and research of past events relating to a specific family, or specific families.- Introduction :...
of atopy
Atopy
Atopy or atopic syndrome is a predisposition toward developing certain allergic hypersensitivity reactions.Atopy may have a hereditary component, although contact with the allergen must occur before the hypersensitivity reaction can develop ....
, abundant eosinophils in the sputum, but with normal airway function and responsiveness. Eosinophilic bronchitis is also characterized by eosinophils in the sputum, without airway hyperresponsiveness or an atopic background. This condition responds to treatment with corticosteroids. Cough can also worsen in an acute exacerbation of chronic obstructive pulmonary disease
Acute exacerbation of chronic obstructive pulmonary disease
An acute exacerbation of COPD is a sudden worsening of COPD symptoms that typically lasts for several days. It may be triggered by an infection with bacteria or viruses or by environmental pollutants...
.
Asthma is a common cause of chronic cough in adults and children. Coughing may be the only symptom the person has from their asthma, or asthma symptoms may also include wheezing, shortness of breath, and a tight feeling in their chest. Depending on how severe the asthma is it can be treated with bronchodilators (medicine which causes the airways to open up) or inhaled steroids. Treatment of the asthma should make the cough go away.
Chronic bronchitis
Chronic bronchitis
Chronic bronchitis is a chronic inflammation of the bronchi in the lungs. It is generally considered one of the two forms of chronic obstructive pulmonary disease...
is defined clinically as a persistent cough that produces sputum (phlegm) and mucus, for at least three months in two consecutive years. Chronic bronchitis is often the cause of “smoker’s cough.” The tobacco causes inflammation, secretion of mucus into the airway, and difficulty clearing that mucus out of the airways. Coughing helps clear those secretions out. May be treated by quitting smoking. May also be caused by Pneumoconiosis and long-term fume inhalation.
Gastroesophageal reflux
In people with unexplained cough, gastroesophageal reflux diseaseGastroesophageal reflux disease
Gastroesophageal reflux disease , gastro-oesophageal reflux disease , gastric reflux disease, or acid reflux disease is chronic symptoms or mucosal damage caused by stomach acid coming up from the stomach into the esophagus...
should be considered. This occurs when acidic contents of the stomach come back up into the esophagus. Symptoms usually associated with GERD include heartburn, sour taste in the mouth, or a feeling of acid reflux in the chest, although, more than half of the people with cough from GERD don’t have any other symptoms. An esophageal pH monitor can confirm the diagnosis of GERD. Sometimes GERD can complicate respiratory ailments related to cough, such as asthma or bronchitis. The treatment involves anti-acid medications and lifestyle changes with surgery indicated in cases not manageable with conservative measures.
Air pollution
Coughing may be caused by air pollutionAir pollution
Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....
including tobacco smoke, particulate matter, irritant gases, and dampness in the home.
The human health effects of poor air quality are far reaching, but principally affect the body's respiratory system and the cardiovascular system. Individual reactions to air pollutants depend on the type of pollutant a person is exposed to, the degree of exposure, the individual's health status and genetics. People who exercise outdoors, for example, on hot, smoggy days increase their exposure to pollutants in the air.
Foreign body
A foreign bodyForeign body
A foreign body is any object originating outside the body. In machinery, it can mean any unwanted intruding object.Most references to foreign bodies involve propulsion through natural orifices into hollow organs....
can sometimes be suspected, for example if the cough started suddenly when the patient was eating. Rarely, sutures left behind inside the airway branches can cause coughing. A cough can be triggered by dryness from mouth breathing
Mouth breathing
Mouth breathing refers to the state of inhaling and exhaling through the mouth.A healthy individual normally breathes through the nose while resting or doing light exercise, and breathes simultaneously through both the nose and mouth during vigorous aerobic exercise, in order to supply sufficient...
or recurrent aspiration of food into the windpipe
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...
in people with swallowing difficulties
Dysphagia
Dysphagia is the medical term for the symptom of difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, the term is sometimes used as a condition in its own right. Sufferers are sometimes unaware of their dysphagia....
.
ACE inhibitor
Angiotensin-converting enzyme inhibitors are drugs used in diabetics, heart disease, and high blood pressure. In 10-25% of the people who take it, it can cause them to have a cough as a side effect. Stopping the drug is the only way to make the cough go away. Such medicines for hypertension are very common in use such as ramiprilRamipril
Ramipril is an angiotensin-converting enzyme inhibitor, used to treat high blood pressure and congestive heart failure.-Mechanism of action:ACE inhibitors lower the...
and quinapril
Quinapril
Quinapril is an angiotensin-converting enzyme inhibitor used in the treatment of hypertension and congestive heart failure.-Pharmacology:Quinapril is a prodrug...
. There are cases of "cough of unknown origin" who had resolution with stopping the drug.
Psychogenic cough
A psychogenic cough ("habit cough" or "tic cough") may be the cause in the absence of a physical problem. In these instances emotional and psychological problems are suspected. However, other illnesses have to be ruled out before a firm diagnosis of psychogenic cough is made. Psychogenic cough is thought to be more common in children than in adults. A possible scenario: psychogenic cough develops in a child who has a chronically ill brother or sister.Other
Cough may also be caused by conditions affecting the lung tissue such as bronchiectasisBronchiectasis
Bronchiectasis is a disease state defined by localized, irreversible dilation of part of the bronchial tree caused by destruction of the muscle and elastic tissue. It is classified as an obstructive lung disease, along with emphysema, bronchitis, asthma, and cystic fibrosis...
, cystic fibrosis
Cystic fibrosis
Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
, interstitial lung diseases and sarcoidosis
Sarcoidosis
Sarcoidosis , also called sarcoid, Besnier-Boeck disease or Besnier-Boeck-Schaumann disease, is a disease in which abnormal collections of chronic inflammatory cells form as nodules in multiple organs. The cause of sarcoidosis is unknown...
. Coughing can also be triggered by benign or malignant lung tumor
Lung cancer
Lung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. If left untreated, this growth can spread beyond the lung in a process called metastasis into nearby tissue and, eventually, into other parts of the body. Most cancers that start in lung, known as primary...
s or mediastinal masses. Through irritation of the nerve, diseases of the external auditory canal (wax, for example) can also cause cough. Cardiovascular diseases associated with cough are heart failure, pulmonary infarction and aortic aneurysm. Nocturnal cough is associated with heart failure, as the heart does not compensate for the increased volume shift to the pulmonary circulation, in turn causing pulmonary edema
Pulmonary edema
Pulmonary edema , or oedema , is fluid accumulation in the air spaces and parenchyma of the lungs. It leads to impaired gas exchange and may cause respiratory failure...
and resultant cough. Other causes of nocturnal cough include asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
, post-nasal drip
Post-nasal drip
Post-nasal drip , also known as Upper Airway Cough Syndrome , occurs when excessive mucus is produced by the nasal mucosa. The excess mucus accumulates in the throat or back of the nose...
and gastroesophageal reflux disease
Gastroesophageal reflux disease
Gastroesophageal reflux disease , gastro-oesophageal reflux disease , gastric reflux disease, or acid reflux disease is chronic symptoms or mucosal damage caused by stomach acid coming up from the stomach into the esophagus...
(GERD). Another cause of cough occurring preferentially in supine position
Supine position
The supine position is a position of the body: lying down with the face up, as opposed to the prone position, which is face down, sometimes with the hands behind the head or neck. When used in surgical procedures, it allows access to the peritoneal, thoracic and pericardial regions; as well as the...
is recurrent aspiration.
Coughing may also be used for social reasons, such as the coughing before giving a speech. Cough may also be psychogenic, which is different from habit coughing and tic coughing. Coughing may occur in tic disorder
Tic disorder
Tic disorders are defined in the Diagnostic and Statistical Manual of Mental Disorders based on type and duration of tics...
s such as Tourette syndrome
Tourette syndrome
Tourette syndrome is an inherited neuropsychiatric disorder with onset in childhood, characterized by multiple physical tics and at least one vocal tic; these tics characteristically wax and wane...
, although it should be distinguished from throat-clearing in this disorder.
Given its irritant nature to mammal tissues, capsaicin
Capsaicin
Capsaicin 2CHCH=CH4CONHCH2C6H3-4--3- ) is the active component of chili peppers, which are plants belonging to the genus Capsicum. It is an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact...
is widely used to determine the cough threshold and as a tussive stimulant in clinical research of cough suppressants. Capsaicin is what makes chilli peppers spicy, and might explain why workers in factories with these vegetables can develop a cough.
Coughing is not always involuntary, and can be used in social situations. Coughing can be used to attract attention, release internal psychological tension, or become a maladaptive displacement behavior. It is believed that the frequency of such coughing increases in environments vulnerable to psychological tension and social conflict. In such environments, coughing may become one of many displacement
Displacement (psychology)
In Freudian psychology, displacement is an unconscious defense mechanism whereby the mind redirects effects from an object felt to be dangerous or unacceptable to an object felt to be safe or acceptable...
behaviors and/or defense mechanisms.
Pathophysiology
A cough is a protective reflexReflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...
in healthy individuals which is influenced by psychological factors. The cough reflex is initiated by stimulation of two different classes of afferent nerve
Afferent nerve
In the nervous system, afferent neurons , carry nerve impulses from receptors or sense organs towards the central nervous system. This term can also be used to describe relative connections between structures. Afferent neurons communicate with specialized interneurons...
s, namely the myelin
Myelin
Myelin is a dielectric material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system. Myelin is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination...
ated rapidly adapting receptors, and nonmyelinated C-fibers
Group C nerve fiber
-Location:C fibers are found in the peripheral nerves of the somatic sensory system. They are afferent fibers, conveying input signals from the periphery to the central nervous system.-Structure:...
with endings in the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s. However it is not certain that the stimulation of nonmyelinated C-fibers
Group C nerve fiber
-Location:C fibers are found in the peripheral nerves of the somatic sensory system. They are afferent fibers, conveying input signals from the periphery to the central nervous system.-Structure:...
leads to cough with a reflex
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...
as it's meant in physiology
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
(with its own five components): this stimulation may cause mast cell
Mast cell
A mast cell is a resident cell of several types of tissues and contains many granules rich in histamine and heparin...
s degranulation
Degranulation
Degranulation is a cellular process that releases antimicrobial cytotoxic molecules from secretory vesicles called granules found inside some cells...
(through an asso-assonic reflex) and edema
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
which may work as a stimulus for rapidly adapting receptors.
Diagnostic approach
The determination of the cause of a cough usually begins by determining if it is specific or nonspecific in nature. A specific cough is one associated with other symptoms and further workup is dependent on these symptoms while a non specific cough occurs without other signs and symptoms. Further workup may include labs, x rays, and spirometrySpirometry
Spirometry is the most common of the pulmonary function tests , measuring lung function, specifically the measurement of the amount and/or speed of air that can be inhaled and exhaled...
.
Treatment
The treatment of a cough in children is based on the underlying cause with the use of cough medicineCough medicine
A cough medicine is a medicinal drug used in an attempt to treat coughing and related conditions. For dry coughs, treatment with cough suppressants may be attempted to suppress the body's urge to cough...
supported by little evidence and thus not recommended by the American Academy of Pediatrics
American Academy of Pediatrics
The American Academy of Pediatrics is the major professional association of pediatricians in the United States. The AAP was founded in 1930 by 35 pediatricians to address pediatric healthcare standards. It currently has 60,000 members in primary care and sub-specialist areas...
.
A trial of antibiotics or inhaled corticosteroids may be tried in children with a chronic cough in an attempt to treat protracted bacterial bronchitis or asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
respectively.
Complications
The complications of coughing can be classified as either acuteAcute (medicine)
In medicine, an acute disease is a disease with either or both of:# a rapid onset, as in acute infection# a short course ....
or chronic. Acute complications include cough syncope (fainting spells due to decreased blood flow to the brain when coughs are prolonged and forceful), insomnia
Insomnia
Insomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
, cough-induced vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
, rupture of bleb
Bleb (medicine)
In medicine, a bleb is a large blister filled with serous fluid. Blebs can form in a number of tissues due to different pathologies, including frostbitten tissues, and as a cause of spontaneous pneumothorax. In the lungs, a bleb is a collection of air within the layers of the visceral pleura...
s causing spontaneous pneumothorax (although this still remains to be proven), subconjunctival hemorrhage
Subconjunctival hemorrhage
thumb|right|250px| A stress induced subconjunctival hemorrhage in the left eye one week after hemorrhaging. Same hemorrhage four weeks after hemorrhaging. Some of the blood in the [[sclera]] has turned yellow, like a bruise....
or "red eye
Red eye (medicine)
In medicine, red eye is a non-specific term to describe an eye that appears red due to illness, injury, or some other condition. Conjunctivitis and subconjunctival hemorrhage are two forms of a red eye....
", coughing defecation
Defecation
Defecation is the final act of digestion by which organisms eliminate solid, semisolid or liquid waste material from the digestive tract via the anus. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum...
and in women with a prolapse
Prolapse
Prolapse literally means "to fall out of place", from the Latin prolabi meaning "to fall out". In medicine, prolapse is a condition where organs, such as the uterus, fall down or slip out of place. It is used for organs protruding through the vagina or the rectum or for the misalignment of the...
d uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
, cough urination
Urination
Urination, also known as micturition, voiding, peeing, weeing, pissing, and more rarely, emiction, is the ejection of urine from the urinary bladder through the urethra to the outside of the body. In healthy humans the process of urination is under voluntary control...
. Chronic complications are common and include abdominal or pelvic hernia
Hernia
A hernia is the protrusion of an organ or the fascia of an organ through the wall of the cavity that normally contains it. A hiatal hernia occurs when the stomach protrudes into the mediastinum through the esophageal opening in the diaphragm....
s, fatigue fracture
Fracture
A fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures , or to crystals or crystalline materials, such as gemstones or metal...
s of lower ribs and costochondritis
Tietze's syndrome
Tietze syndrome is a benign inflammation of one or more of the costal cartilages. It was first described in 1921 by the German surgeon Alexander Tietze .Though thought to be the same conditions, Tietze syndrome is not the same as costochondritis...
.
Epidemiology
A cough is the most common reason for visiting a primary care physicianPrimary care physician
A primary care physician, or PCP, is a physician/medical doctor who provides both the first contact for a person with an undiagnosed health concern as well as continuing care of varied medical conditions, not limited by cause, organ system, or diagnosis....
in the United States.