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biology

Pharyngitis

Pharyngitis is a biology 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 Pharyngitis rather than just read about it. In short: Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever.

Pharyngitis — main illustration
Pharyngitis — illustration

Key takeaways

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

Reference excerpt

Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoarse voice. Symptoms usually last 3–5 days, but can be longer depending on cause. Complications can include sinusitis and acute otitis media. Pharyngitis is a type of upper respiratory tract infection. Most cases are caused by a viral infection. Strep throat, a bacterial infection, is the cause in about 25% of children and 10% of adults. Uncommon causes include other bacteria such as gonococcus, fungi, irritants such as smoke, allergies, and gastroesophageal reflux disease. Specific testing is not recommended in people who have clear symptoms of a viral infection, such as a cold. Otherwise, a rapid antigen detection test or throat swab is recommended. PCR testing has become common as it is as good as taking a throat swab but gives a faster result. Other conditions that can produce similar symptoms include epiglottitis, thyroiditis, retropharyngeal abscess, and occasionally heart disease. NSAIDs, such as ibuprofen, can be used to help with the pain. Numbing medication, such as topical lidocaine, may also help. Strep throat is typically treated with antibiotics, such as either penicillin or amoxicillin. It is unclear whether steroids are useful in acute pharyngitis, other than possibly in severe cases. A recent (2020) review found that when used in combination with antibiotics, they moderately reduced pain and the likelihood of resolution. About 7.5% of people have a sore throat in any 3-month period. Two or three episodes in a year are not uncommon. This resulted in 15 million physician visits in the United States in 2007. Pharyngitis is the most common cause of a sore throat. The word comes from the Greek word pharynx meaning "throat" and the suffix -itis meaning "inflammation".

Classification

Pharyngitis is a type of inflammation caused by an upper respiratory tract infection. It may be classified as acute or chronic. Acute pharyngitis may be catarrhal, purulent, or ulcerative, depending on the causative agent and the immune capacity of the affected individual. Chronic pharyngitis may be catarrhal, hypertrophic, or atrophic. Tonsillitis is a subtype of pharyngitis. If the inflammation includes both the tonsils and other parts of the throat, it may be called pharyngotonsillitis or tonsillopharyngitis. Another subclassification is nasopharyngitis (the common cold). Clergyman's sore throat or clergyman's throat is an archaic term formerly used for chronic pharyngitis associated with overuse of the voice as in public speaking. It was sometimes called dysphonia clericorum or chronic folliculitis sore throat.

Cause Most cases are due to an infectious organism acquired from close contact with an infected individual.

Viral

These comprise about 40–80% of all infectious cases and can be a feature of many different types of viral infections.

Adenovirus is the most common of the viral causes. Typically, the degree of neck lymph node enlargement is modest, and the throat often does not appear red, although it is painful. The family Orthomyxoviridae which causes influenza presents with rapid-onset high temperature, headache, and generalized ache. A sore throat may be associated. Infectious mononucleosis ("glandular fever") is caused by the Epstein–Barr virus. This may cause significant lymph-node swelling and an exudative tonsillitis with marked redness and swelling of the throat. The heterophile test can be used if this is suspected. Herpes simplex virus can cause multiple mouth ulcers. Measles Common cold: rhinovirus, coronavirus, respiratory syncytial virus, and parainfluenza virus can cause infection of the throat, ear, and lungs, causing standard cold-like symptoms and often pain.

Bacterial Several bacteria can infect the human throat. The most common is group A streptococcus (Streptococcus pyogenes), but others include Streptococcus pneumoniae, Haemophilus influenzae, Bordetella pertussis, Bacillus anthracis, Corynebacterium diphtheriae, Neisseria gonorrhoeae, Chlamydophila pneumoniae, Mycoplasma pneumoniae, and Fusobacterium necrophorum.

Streptococcal pharyngitis

Streptococcal pharyngitis or strep throat is caused by a group A beta-hemolytic streptococcus (GAS). It is the most common bacterial cause of cases of pharyngitis (15–30%). Common symptoms include fever, sore throat, and large lymph nodes. It is a contagious infection that is spread by close contact with an infected individual. A definitive diagnosis is made based on the results of a throat culture. Antibiotics are useful to both prevent complications (such as rheumatic fever) and speed recovery.

Fusobacterium necrophorum Fusobacterium necrophorum is a normal inhabitant of the oropharyngeal flora and can occasionally create a peritonsillar abscess. In one out of 400 untreated cases, Lemierre's syndrome occurs.

Diphtheria Diphtheria is a potentially life-threatening upper respiratory infection caused by Corynebacterium diphtheriae, which has been largely eradicated in developed nations since the introduction of childhood vaccination programs, but is still reported in the Third World. Antibiotics are effective in the early stages, but recovery is generally slow.

Others A few other causes are rare, but possibly fatal, and include parapharyngeal space infections: peritonsillar abscess ("quinsy abscess"), submandibular space infection (Ludwig's angina), and epiglottitis.

Fungal Some cases of pharyngitis are caused by fungal infection, such as Candida albicans, causing oral thrush.

Noninfectious Pharyngitis may also be caused by mechanical, chemical, or thermal irritation, for example, cold air or acid reflux. Some medications may produce pharyngitis, such as pramipexole and antipsychotics.

Diagnosis

Differentiating a viral and a bacterial cause of a sore throat based on symptoms alone is difficult. Thus, a throat swab often is done to rule out a bacterial cause. The modified Centor criteria may be used to determine the management of people with pharyngitis. Based on five clinical criteria, it indicates the probability of a streptococcal infection. One point is given for each of the criteria:

… excerpt ends here. Continue reading the full article.

Illustrations

Pharyngitis illustration
Pharyngitis: A normal throat
A normal throat
Pharyngitis: Exudative pharyngitis in a person with infectious mononucleosis
Exudative pharyngitis in a person with infectious mononucleosis
Pharyngitis: A case of strep throat
A case of strep throat
Pharyngitis: Throat swab
Throat swab

Worked examples

Example 1 — a first encounter with Pharyngitis

Start with the simplest possible case. Write down what Pharyngitis claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Pharyngitis 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 Pharyngitis 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 Pharyngitis

In research
Pharyngitis appears in biology 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 Pharyngitis 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
Pharyngitis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Gastrointestinal tract disorders, Infectious diseases, Inflammations, so understanding it makes those chapters shorter.
In everyday life
Look for Pharyngitis 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.

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How to study Pharyngitis in 20 minutes

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

Frequently asked questions

What is Pharyngitis in simple terms?

Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever.

Why does Pharyngitis matter?

Because it connects several biology 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 Pharyngitis?

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 Pharyngitis.

Tags

  • Gastrointestinal tract disorders
  • Infectious diseases
  • Inflammations
  • Otorhinolaryngology
  • Pharynx disorders

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