Laryngitis

Key takeaways

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

Reference excerpt

Laryngitis is inflammation of the larynx (voice box). The primary symptom is loss of some vocal function, ranging from hoarse voice to no voice at all. Laryngitis can be caused by overuse of the vocal chords, or by other inflammation, trauma, or infection. The accompanying symptoms depend on the primary cause. Typically, these last under 2 weeks.

Signs and symptoms The primary symptom of laryngitis is a hoarse voice or aphonia, when there is no sound at all. Because laryngitis can have various causes, other signs and symptoms may vary. They can include:

Dry or sore throat Coughing (both a causal factor and a symptom of laryngitis) Frequent throat clearing Increased saliva production Dysphagia (difficulty swallowing) Sensation of swelling in the area of the larynx (discomfort in the front of the neck) Globus pharyngeus (feeling as if there were a lump in the throat) Cold or flu-like symptoms (which, like a cough, may also be a causal factor for laryngitis) Swollen lymph nodes in the throat, chest, or face Fever General muscle pain (myalgia) Shortness of breath, predominantly in children

Voice quality Aside from a hoarse-sounding voice, changes to pitch and volume may occur with laryngitis. Speakers may experience a lower or higher pitch than normal, depending on whether their vocal folds are swollen or stiff. They may also have breathier voices, as more air flows through the space between the vocal folds (the glottis), quieter volume, and a reduced range.

Causes Laryngitis is categorized as acute if it lasts less than 3 weeks and chronic if symptoms last more than 3 weeks. Acute cases usually occur as part of a viral upper respiratory tract infection, other infections, and trauma such as from coughing or other causes. Chronic cases may occur due to smoking, tuberculosis, allergies, acid reflux, rheumatoid arthritis, or sarcoidosis. The underlying mechanism involves irritation of the vocal cords.

Laryngitis can be infectious as well as noninfectious in origin. The resulting inflammation of the vocal folds distorts the sound produced there. It normally develops in response to either an infection, trauma to the vocal folds, or allergies. Chronic laryngitis may also be caused by more severe problems, such as nerve damage, sores, and polyps, or hard and thick lumps (nodules) on the vocal cords.

Acute

Viral Viral infections cause most cases of acute laryngitis, the most common of which tend to be rhinovirus, influenza virus, parainfluenza virus, adenovirus, coronavirus, and respiratory syncytial virus (RSV). In patients who have a compromised immune system, other viruses such as herpes and human immunodeficiency virus (HIV) may also be potential causes.

Bacterial This is another major cause of acute laryngitis. It may develop in conjunction with or due to a bacterial infection. Common bacterial strains are group A streptococcus, Streptococcus pneumoniae, Corynebacterium diphtheriae, Moraxella catarrhalis, Haemophilus influenzae, Bordetella pertussis, Bacillus anthracis,, and Mycobacterium tuberculosis. In developing countries, more unusual bacterial cases may occur, such as mycobacterial and syphilitic, though these may occur in developed nations as well.

Fungal Laryngitis caused by fungal infection is common but not frequently diagnosed, according to a review by BMJ, and can account for up to 10% of acute laryngitis cases. Patients with both functioning and impaired immune systems can develop fungal laryngitis, which may develop as a result of recent antibiotic or inhaled corticosteroids use. Certain strains of fungi that may cause laryngitis include, Histoplasma, Blastomyces, Candida (especially in immunocompromised persons), Cryptococcus, and Coccidioides.

Trauma Trauma is often due to excessive use of the vocal folds, such as by yelling, screaming, or singing. Though this often results in damage to the outer layers of the vocal folds, the subsequent healing process may change the physiology of the folds. Another potential cause of inflammation may be overuse of the vocal cords. Laryngeal trauma, including iatrogenic (caused by endotracheal intubation), can also result in inflammation of the vocal cords.

Chronic

Allergies Findings are unclear as to whether asthma may cause symptoms commonly associated with laryngitis. Some researchers have posited that allergic causes of laryngitis are often misdiagnosed as being the result of acid reflux.

Reflux One possible explanation of chronic laryngitis is that inflammation is caused by gastroesophageal reflux, which causes subsequent irritation of the vocal folds.

Autoimmune disorders Approximately 30 and 75% of persons with rheumatoid arthritis report symptoms of laryngitis. Symptoms of laryngitis are present in only 0.5–5% of people who have sarcoidosis. According to a meta-analysis by Silva et al. (2007), this disease is often an uncommon cause of laryngeal symptoms and is frequently misdiagnosed as another voice disorder.

Diagnosis Laryngitis is generally more common in women than men, as women's vocal cords are thinner and thus more prone to damage. Concerning signs that may require further investigation include stridor, history of radiation therapy to the neck, trouble swallowing, duration of more than 3 weeks, and a history of smoking. If concerning signs are present. The vocal cords should be examined via laryngoscopy. Other conditions that can produce similar symptoms include epiglottitis, croup, inhaling a foreign body, and laryngeal cancer. Diagnosis of different forms of acute laryngitis includes:

Laryngitis following trauma: This form of laryngitis is usually identified by obtaining a case history providing information on previous phono-traumatic experiences, internal trauma caused by recent procedures, as well as any previous neck injuries. Acute viral laryngitis: This form of laryngitis is characterized by lower vocal pitch as well as hoarseness. The symptoms in this form of laryngitis are usually present for less than 1 week, however they can persist for 3–4 weeks. This form of laryngitis might also be accompanied by upper respiratory tract symptoms such as sore throat, odynophagia, rhinorrhea, dyspnea, postnasal discharge, and congestion. Fungal laryngitis: A biopsy and culture of an abnormal lesion may help confirm fungal laryngitis.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Laryngitis

Start with the simplest possible case. Write down what Laryngitis 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 Laryngitis 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 Laryngitis 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 Laryngitis

In research: Laryngitis 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 Laryngitis 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: Laryngitis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Acute upper respiratory infections, Human throat, Human voice, so understanding it makes those chapters shorter.
In everyday life: Look for Laryngitis 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.

How to study Laryngitis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Laryngitis 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 Laryngitis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Laryngitis in simple terms?

Laryngitis is inflammation of the larynx (voice box). The primary symptom is loss of some vocal function, ranging from hoarse voice to no voice at all.

Why does Laryngitis 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 Laryngitis?

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 Laryngitis.