COUGH

A 'cough', also known as 'tussive' is a sudden, often repetitive, spasmodic contraction of the thoracic cavity, resulting in violent release of air from the lungs, and usually accompanied by a distinctive sound.
Coughing is an action the body takes to get rid of substances that are irritating the air passages. A cough is usually initiated to clear a buildup of phlegm in the trachea. Coughing can also be triggered by a bolus of food entering the trachea rather than the esophagus due to a failure of the epiglottis. Frequent or chronic coughing usually indicates the presence of a disease. Provided the patient is a non-smoker and has a normal chest X-ray, the cause of chronic cough in 93% of all patients is due to asthma, heartburn or post-nasal drip. Other causes of chronic cough include chronic bronchitis and medications such as ACE inhibitors. Coughing can happen voluntarily as well as involuntarily.

Contents

Physiology

Cause

Complications

Treatment

During injections

See also

References

External links

Physiology

A cough is a protective, primitive reflex in healthy individuals. The cough reflex is initiated by stimulation of two different classes of afferent nerves, namely the myelinated rapidly adapting receptors, and nonmyelinated C-fibers with endings in the lungs.

Cause

A persistent cough can be debilitating, socially distressing, and adversely impair quality of life.^[1] One of the more common presentations to a medical practitioner is a dry cough. The common causes of chronic dry coughing include post-nasal drip, gastroesophageal reflux disease, asthma, post viral cough and certain drugs such as beta blockers, ACE inhibitors and aspirin. If a cough lasts for more than three weeks, multiple causes are likely and symptoms will abate only when all the causes are treated will the patient be symptom free. Individuals who smoke often have a smoker's cough, a loud, hacking cough which often results in the expiration of phlegm.
Coughing may also be used for psychological or social reasons, such as the coughing before giving a speech. This is known as psychogenic, habit or tic coughing, and may increase in frequency in social situations featuring conflict.^[2]
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.

Complications

The complications of coughing can be classified as either acute 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 blebs causing spontaneous pneumothorax, subconjunctival hemorrhage or "red eye", coughing defecation and in women with a prolapsed uterus, cough urination. Chronic complications are common and include abdominal or pelvic hernias, fatigue fractures of lower ribs and costochondritis.

Treatment

Coughs can be treated with cough medicines. Dry coughs are treated with cough suppressants (antitussives) that suppress the body's urge to cough, while productive coughs (coughs that produce phlegm) are treated with expectorants that loosen mucus from the respiratory tract. Centrally acting cough suppressants, such as codeine and dextromethorphan reduce the urge to cough by inhibiting the response of the sensory endings by depolarization of the vagus nerve. A recent study indicates that, because of the presence of theobromine in chocolate, 50 grams of dark chocolate may be an effective treatment for a persistent cough.
Gargling with salt and warm water can also be helpful by cutting phlegm.

During injections

Coughing during an injection can lessen the pain of the needle stick caused by a sudden, temporary rise in pressure in the chest and spinal canal, inhibiting the pain-conducting structures of the spinal cord.^[3]

See also

★ Whooping cough

★ Kennel cough

★ Cough medicine

References

1. Theobromine inhibits sensory nerve activation and cough., Omar S. Usmani, Maria G. Belvisi, Hema J. Patel, Natascia Crispino, Mark A. Birrell, Marta Korbonits, Dezso Korbonits, and Peter J. Barnes, , , The FASEB Journal, 2005
2. (Unpublished thesis)
3. Reducing venipuncture pain by a cough trick: a randomized crossover volunteer study, , TI, Usichenko, Anesthesia and Analgesia, 2004


★ Global physiology and pathophysiology of cough: ACCP evidence-based clinical practice guidelines., McCool F, , , Chest, 2006 ''Full text''

External links

★ FamilyDoctor.org – Chronic cough: causes and cures

★ Coughing:Quick tips to help stop a coughing fit.