出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/01/21 18:41:28」(JST)
Nosebleed | |
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Classification and external resources | |
ICD-10 | R04.0 |
ICD-9 | 784.7 |
DiseasesDB | 18327 |
MedlinePlus | 003106 |
eMedicine | emerg/806 ent/701, ped/1618 |
MeSH | C08.460.261 |
Epistaxis (from Greek: επιστάζω (epistazo) to bleed from the nose: επί (epi) - "above", "over" + στάζω (stazo) - "to drip [from the nostrils]") or a nosebleed is the relatively common occurrence of hemorrhage from the nose, usually noticed when the blood drains out through the nostrils. There are two types: anterior (the most common), and posterior (less common, more likely to require medical attention). Sometimes in more severe cases, the blood can come up the nasolacrimal duct and out from the eye. Fresh blood and clotted blood can also flow down into the stomach and cause nausea and vomiting.[citation needed] It is rarely fatal, accounting for only 4 of the 2.4 million deaths in the U.S. in 1999.[1]
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The causes of nosebleeds can generally be divided into two categories, local and systemic factors, although a significant number of nosebleeds occur with no obvious cause.
Nosebleeds are due to the rupture of a blood vessel within the richly perfused nasal mucosa. Rupture may be spontaneous or initiated by trauma. Nosebleeds are reported in up to 60% of the population with peak incidences in those under the age of ten and over the age of 50 and appear to occur in males more than females.[4] An increase in blood pressure (e.g. due to general hypertension) tends to increase the duration of spontaneous epistaxis.[5] Anticoagulant medication and disorders of blood clotting can promote and prolong bleeding. Spontaneous epistaxis is more common in the elderly as the nasal mucosa (lining) becomes dry and thin and blood pressure tends to be higher. The elderly are also more prone to prolonged nose bleeds as their blood vessels are less able to constrict and control the bleeding.
The vast majority of nose bleeds occur in the anterior (front) part of the nose from the nasal septum. This area is richly endowed with blood vessels (Kiesselbach's plexus). This region is also known as Little's area. Bleeding farther back in the nose is known as a posterior bleed and is usually due to bleeding from Woodruff's plexus, a venous plexus situated in the posterior part of inferior meatus.[6] Posterior bleeds are often prolonged and difficult to control. They can be associated with bleeding from both nostrils and with a greater flow of blood into the mouth.[7]
The flow of blood normally stops when the blood clots, which may be encouraged by direct pressure applied by pinching the soft fleshy part of the nose. This applies pressure to Little's area (Kiesselbach's area), the source of the majority of nose bleeds and promotes clotting. Pressure should be firm and be applied for at least five minutes and up to 20 minutes; tilting the head forward will help decrease the chance of nausea and airway obstruction.[4] Swallowing excess blood can irritate the stomach and cause vomiting.
The local application of a vasoconstrictive agent has been shown to reduce the bleeding time in benign cases of epistaxis. The drugs oxymetazoline or phenylephrine are widely available in over-the-counter nasal sprays for the treatment of allergic rhinitis, and may be used for this purpose.[8]
If these simple measures do not work then medical intervention may be needed to stop bleeding. In the first instance this can take the form of chemical cautery of any bleeding vessels or packing of the nose with ribbon gauze or an absorbent dressing (called anterior nasal packing). Such procedures are best carried out by a medical professional. Chemical cauterisation is most commonly conducted using local application of silver nitrate compound to any visible bleeding vessel. This is a painful procedure and the nasal mucosa should be anaesthetised first, preferably with the addition of topical adrenaline to further reduce bleeding. If bleeding is still uncontrolled or no focal bleeding point is visible then the nasal cavity should be packed with a sterile dressing, which by applying pressure to the nasal mucosa will tamponade the bleeding point. Ongoing bleeding despite good nasal packing is a surgical emergency and can be treated by endoscopic evaluation of the nasal cavity under general anaesthesia to identify an elusive bleeding point or to directly ligate (tie off) the blood vessels supplying the nose. These blood vessels include the sphenopalatine, anterior and posterior ethmoidal arteries. More rarely the maxillary or a branch of the external carotid artery can be ligated. The bleeding can also be stopped by intra-arterial embolization using a catheter placed in the groin and threaded up the aorta to the bleeding vessel by an interventional radiologist. Continued bleeding may be an indication of more serious underlying conditions.[9]
The utility of local cooling of the head and neck is controversial.[10] Some state that applying ice to the nose or forehead is not useful.[11][12] Others feel that it may promote vasoconstriction of the nasal blood vessels and thus be useful.[13]
Application of a topical antibiotic ointment to the nasal mucosa has been shown to be an effective treatment for recurrent epistaxis.[14] One study found it to be as effective as nasal cautery in the prevention of recurrent epistaxis in patients without active bleeding at the time of treatment - both had a success rate of approximately 50 percent.[15]
Nosebleeds are rarely dangerous unless prolonged and heavy. However, in posterior bleeds, a great deal of blood may be swallowed and therefore the amount of blood lost can be underestimated. Recurrent nosebleeds may cause anemia due to iron deficiency.
In the visual language of Japanese comics (manga) and animation (anime), a sudden, violent nosebleed indicates that the bleeding person is sexually aroused.[16][17] This is based on a Japanese folk belief according to which nosebleeds are signs of sexual excitement.[18] (Interestingly, the nose is now known to contain erectile tissue which may become engorged during sexual arousal: honeymoon rhinitis is a condition in which nasal stuffiness or sneezing accompanies sexual thoughts or activities.[19])
In the Philippines, the word "nosebleed" is an expression for when one encounters something that is intellectually challenging. The term usually will come up amongst Filipinos when they encounter something difficult like examinations, interviews, solving complex mathematical problems, or reading things that contain technical or unfamiliar words.
In American usage, the nosebleed section or nosebleed seats are common slang for seating at sporting or other spectator events that are the highest up and farthest away from the desired event to be seen. The reference alludes to the propensity for nasal hemorrhage at high altitudes, usually owing to lower barometric pressure. Rarely, the term might be used to reference areas in clubs where mosh pits happen frequently, as the violence of mosh pits is known to cause various blunt force traumas, including nosebleeds.
In Finnish language, "begging for a nosebleed" is commonly used in abstract meaning to describe self-destructive behaviour, for example ignoring safety procedures or deliberately aggravating stronger parties.[20]
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リンク元 | 「nose bleed」 |
関連記事 | 「nasal」 |
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