Phlegm

For the humor in ancient medicine, see Humorism. For the British artist, see Phlegm (artist).

Phlegm /ˈflɛm/ (Greek: φλέγμα "inflammation, humour caused by heat") is a liquid secreted by the mucous membranes of mammals. Its definition is limited to the mucus produced by the respiratory system, excluding that from the nasal passages, and particularly that which is expelled by coughing (sputum). Phlegm is in essence a water-based gel consisting of glycoproteins, immunoglobulins, lipids and other substances. Its composition varies depending on climate, genetics, and state of the immune system. Its color can vary from transparent to pale or dark yellow and green, from light to dark brown, and even to dark grey depending on the constituents.

Distinction between mucus and phlegm

Contrary to popular misconception and misuse, mucus and phlegm are not always the same.

Mucus

Mucus is a normal protective layering around the airway, eye, nasal turbinate, and urogenital tract. Mucus is an adhesive viscoelastic gel produced in the airway by submucosal glands and goblet cells and is principally water. It also contains high-molecular weight mucous glycoproteins that form linear polymers.

Phlegm

Phlegm is more related to disease than is mucus. Phlegm is a secretion in the airway during disease and inflammation. Phlegm usually contains mucus with bacteria, debris, and sloughed-off inflammatory cells. Once phlegm has been expectorated by a cough it becomes sputum.[1]

Excessive phlegm creation

There are multiple factors that can contribute to an excess of phlegm in the throat or larynx.

Phlegm and humourism

Main article: humourism

Humourism is an ancient theory that the human body is filled with four basic substances, called the four humours, which are held in balance when a person is healthy. It is closely related to the ancient theory of the four elements and states that all diseases and disabilities result from an excess or deficit in black bile, yellow bile, phlegm, and blood. Hippocrates, an ancient Greek medical doctor, is credited for this theory, about 400 BC. It influenced medical thinking for more than 2,000 years, until finally discredited in the 1800s.

Phlegm was thought to be associated with apathetic behaviour; this old belief is preserved in the word "phlegmatic". This adjective always refers to behaviour, and is pronounced differently, giving full weight to the "g": not /ˈflɛmatɪk/ but /flɛgˈmatɪk/.[16] To have "phlegm" traditionally meant to have stamina and to be unswayed by emotion. Sir William Osler’s 1889 Aequanimitas discusses the imperturbability or calmness in a storm required of physicians. "'Imperturbability means coolness and presence of mind under all circumstances, calmness amid storm, clearness of judgment in moments of grave peril, immobility, impassiveness, or, to use an old and expressive word, phlegm." This was his farewell speech at the University of Pennsylvania in 1889 before becoming Physician-in-Chief at the recently founded Johns Hopkins Hospital in Baltimore, Maryland. This is from "Celebrating the Contributions of William Osler" in the Alan Mason Chesney Medical Archives of the Johns Hopkins Medical Institutions."

The phlegm of Humourism is far from the same thing as phlegm as it is defined today. Nobel laureate Charles Richet MD, when describing humorism's "phlegm or pituitary secretion" in 1910 asked rhetorically, "this strange liquid, which is the cause of tumours, of chlorosis, of rheumatism, and cacochymia - where is it? Who will ever see it? Who has ever seen it? What can we say of this fanciful classification of humours into four groups, of which two are absolutely imaginary?"[17]

Illnesses related to phlegm

Phlegm may be a carrier of larvae of intestinal parasites (see hookworm). Bloody sputum can be a symptom of serious disease (such as tuberculosis), but can also be a relatively benign symptom of a minor disease (such as bronchitis). In the latter case, the sputum is normally lightly streaked with blood. Coughing up any significant quantity of blood is always a serious medical condition, and any person who experiences this should seek medical attention.

References

  1. Rubin, Bruce (January 2010). "The Role of Mucus in Cough Research". Lung. 188 Suppl 1: S69–72. doi:10.1007/s00408-009-9198-7. PMID 19936981.
  2. "Influence of Abusive Vocal Habits, Hydration, Mastication, and Sleep in the Occurrence of Vocal Symptoms in Teachers". Journal of Voice 24: 86–92. doi:10.1016/j.jvoice.2008.06.001. Retrieved 2013-03-25.
  3. Archived October 9, 2010, at the Wayback Machine.
  4. "Singers, Let's Prevent Vocal Problems!". Voiceteacher.com. 1987-08-01. Retrieved 2013-03-25.
  5. "Vocal Survival Techniques For Singers Who Abuse And Overuse Their Voices". Ent-consult.com. Retrieved 2013-03-25.
  6. "Voice & Swallowing Center - Voice Disorders". Entandallergy.com. Retrieved 2013-03-25.
  7. Davies, Shela, "Sound Advice: Your guide to a strong, clear, easy voice"
  8. http://www.sciencemag.org/content/172/3984/741.full.pdf
  9. "Symptoms of cough and shortness of breath among occasional young adult smokers". Ntr.oxfordjournals.org. Retrieved 2013-03-25.
  10. "Brigham Young University Sign-in Service". Web.ebscohost.com.erl.lib.byu.edu. Retrieved 2013-03-25.
  11. "Bronchitis". Umm.edu. 2012-12-03. Retrieved 2013-03-25.
  12. "Asthma". Netdoctor.co.uk. Retrieved 2013-03-25.
  13. "Brigham Young University Sign-in Service". Web.ebscohost.com.erl.lib.byu.edu. Retrieved 2013-03-25.
  14. <http://www.oed.com/view/Entry/142540>; accessed 27 May 2012.
  15. Charles Richet, MD, Professor of Physiology, University of Paris. Ancient Humorism and Modern Humorism. Delivered at the International Congress of Physiology held in Vienna, September 27th to 30th 1910, as reported on page 921 of the British Medical Journal of October 1, 1910 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2336103/pdf/brmedj07876-0001.pdf

Further reading

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