science

Nosebleed

Nosebleed is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Nosebleed rather than just read about it. In short: A nosebleed, also known medically as epistaxis, is bleeding from the nasal cavity caused by rupture of small blood vessels in the nasal mucosa. Most cases are minor and stop spontaneously with simple first-aid or medical care.

Key takeaways

Nosebleed belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Nosebleed to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Nosebleed from memory before moving on to harder problems.

Reference excerpt

A nosebleed, also known medically as epistaxis, is bleeding from the nasal cavity caused by rupture of small blood vessels in the nasal mucosa. Most cases are minor and stop spontaneously with simple first-aid or medical care. In some cases, blood may flow down into the stomach, and cause nausea and vomiting. In more severe cases, blood may come out of both nostrils. Rarely, bleeding may be so significant that low blood pressure occurs. Blood may also be forced to flow up and through the nasolacrimal duct and out of the eye, producing bloody tears. Risk factors include trauma; especially from nosepicking, blood thinners, high blood pressure, alcoholism, seasonal allergies, dry weather, and inhaled corticosteroids. There are two types: anterior, which is more common; and posterior, which is less common but more serious. Anterior nosebleeds generally occur from Kiesselbach's plexus while posterior bleeds generally occur from the sphenopalatine artery or Woodruff's plexus. The diagnosis is by direct observation. Although nosebleeds can appear dramatic, they are rarely life-threatening; most resolve without medical intervention, but posterior or severe bleeds may require urgent care. Prevention may include the use of petroleum jelly in the nose. Initially, treatment is generally the application of pressure for at least thirty minutes over the lower half of the nose. If this is not sufficient, nasal packing may be used. Tranexamic acid may also be helpful. If bleeding episodes continue, endoscopy is recommended. About 60% of people have a nosebleed at some point in their life. About 10% of nosebleeds are serious. Approximately 6% of patients will seek medical attention for epistaxis. Nosebleeds are rarely fatal, accounting for only 4 of the 2.4 million deaths in the U.S. in 1999. Nosebleeds most commonly affect those younger than 10 and older than 50.

Cause

Nosebleeds can occur due to a variety of reasons. Some of the most common causes include trauma from nose picking, blunt trauma (such as a motor vehicle accident), or insertion of a foreign object (more likely in children). Low relative humidity (such as in centrally heated buildings), respiratory tract infections, chronic sinusitis, rhinitis or environmental irritants can cause inflammation and thinning of the tissue in the nose, leading to a greater likelihood of bleeding from the nose. Most causes of nose bleeding are self-limiting and do not require medical attention. However, if nosebleeds are recurrent or do not respond to home therapies, an underlying cause may need to be investigated. Some rarer causes are listed below: Coagulopathy

Thrombocytopenia (thrombotic thrombocytopenic purpura, idiopathic thrombocytopenic purpura) Von Willebrand's disease Hemophilia Leukemia HIV Chronic liver disease—cirrhosis causes deficiency of factor II, VII, IX,& X Dietary

Sulfur dioxide (sulphur dioxide) E220 (as a food preservative used particularly in wines and dried fruits) Sulphites as food preservatives Salicylates naturally occurring in some fruits and vegetables Inflammatory

Granulomatosis with polyangiitis Systemic lupus erythematosus Medications/Drugs

Anticoagulation (warfarin, heparin, aspirin, etc.) Insufflated drugs (particularly cocaine) Nasal sprays (particularly prolonged or improper use of nasal steroids) Neoplastic

Squamous cell carcinoma Adenoid cystic carcinoma Melanoma Nasopharyngeal carcinoma Nasopharyngeal angiofibroma Nosebleeds can be a sign of cancer in the sinus area, which is rare, or tumors starting at the base of the brain, such as meningioma. Due to the sensitive location, nosebleeds caused by tumors are typically associated with other symptoms, such as hearing or vision problems. Traumatic

Anatomical deformities (e.g. septal spurs) Blunt trauma (usually a sharp blow to the face such as a punch, sometimes accompanying a nasal fracture) Foreign bodies (such as fingers during nose-picking) Digital trauma (nose picking) Middle ear barotrauma (such as from descent in aircraft or ascent in scuba diving) Nasal bone fracture Septal fracture/perforation Intranasal tumors (e.g. Nasopharyngeal carcinoma or nasopharyngeal angiofibroma) Nasal cannula O2 (tending to dry the olfactory mucosa) Nasal sprays (particularly prolonged or improper use of nasal steroids) Surgery (e.g. septoplasty and functional endoscopic sinus surgery) Leech infestation Nasal bleeds may be due to fracture of facial bones, namely maxilla and zygoma. Vascular

Hereditary hemorrhagic telangiectasia (Osler–Weber–Rendu disease) Angioma Aneurysm of the carotid artery

Pathophysiology

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Nosebleed

Start with the simplest possible case. Write down what Nosebleed claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Nosebleed before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Nosebleed ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Nosebleed

In research: Nosebleed appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Nosebleed in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Nosebleed is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bleeding, First aid, Nose disorders, so understanding it makes those chapters shorter.
In everyday life: Look for Nosebleed outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Nosebleed in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Nosebleed means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Nosebleed out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Nosebleed in simple terms?

Why does Nosebleed matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Nosebleed?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Nosebleed.