Science Fair Project Encyclopedia
A nosebleed, medically known as epistaxis, is the relatively common occurence of hemorrhage (bleeding) from the nose, usually noticed when it drains out through the nostrils. There are two types: anterior (the most common), and posterior (less common, but more severe).
There are several causes for the nosebleed including trauma (such as hitting the nose), fracture (broken nose), altitude, anticoagulant (anti-clotting) medication, excessively dry air, excessive nosepicking among children, allergic rhinitis and high blood pressure among the elderly. Some rare diseases that may cause nosebleeds are Wegener's granulomatosis and hereditary hemorrhagic telangiectasia (HHT, Rendu-Osler-Weber disease); sarcoidosis, when it involves the nose, has been reported to cause nosebleeds.
Both the frequency of spontaneous epistaxis and the length and severity of bleeding can be increased by anticoagulants. These may include prescription medications such as warfarin or aspirin as well as herbal supplements such as ginkgo. Cultures with a diet rich in fish sources that include high levels of omega-3 fatty acids (especially the Inuit) have also been observed to experience a higher incidence of nosebleeds.
All nosebleeds are due to tears in the mucosal lining and the many small blood vessels it contains. Fragility or injury may cause the tears, while inflammation, coagulation problems and other disorders may make the injury harder to repair.
The flow of blood normally stops when the blood clots, which may be encouraged by direct pressure. Medical opinion is divided on whether the best position to apply pressure is the bridge of the nose or the fleshy part. It is also undecided as to whether it is better to tilt the head forward during this procedure (to drain the blood and prevent it from flowing down the throat and into the stomach) or backward (to minimize the volume of blood in the nose).
If techniques such as pressure, ice on the bridge of the nose, application of a vasoconstrictor, etc. don't work, a nasal tampon such as a rhinorocket is usually the next step. The nasal tampon stops the bleeding by applying pressure from inside of the nose and is usually kept in for 1-3 days.
Persistent epistaxis is an indication for urgent medical consultation. Nasal packing, cryotherapy, electrocautery or application of trichloracetic acid are options that may be used in severe epistaxis.
It is uncommon to exsanguinate (die from bleeding) through nosebleeds. Nevertheless, severe protracted nosebleeds may cause anemia due to iron deficiency.
Nosebleeds in fiction
In anime and manga, it is very common to see sexually aroused male characters getting brutal nosebleeds. This does not occur in real life, but is based on Japanese old wives' tales, which say that getting too sexually excited leads to a nosebleed. Attila the Hun is reputed to have died of a nosebleed after his wedding.
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details