User:Bennytheslp/sandbox

I'll be focusing on the 'causes' section of the laryngitis article. I recently found a source by Wood et al (2016) that has quite a bit of data on the various causes of laryngitis. Currently, the section is divided into two parts on infectious and non-infectious causes which does not contain much content other than just listing several leading factors of laryngitis. I'll work on making this section a little more informative while being accessible at the same time.

Causes

Laryngitis can be infectious as well as noninfectious in origin. The resulting inflammation of the vocal folds results in a distortion of 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, polyps, or hard and thick lumps (nodules) on the vocal cords.^[4]

Acute

Infectious

o Viral

• Most acute cases of laryngitis are caused by viral infections, the most common of which tend to be rhinovirus, influenza virus, parainfluenza virus, adenovirus,  coronavirus, and RSV. In patients who have a compromised immune system, other viruses such as herpes, HIV and coxsackievirus may also be potential causes.

o   Bacterial

• This is another major cause of acute laryngitis, and may develop in conjunction with or due to a viral infection. Common bacterial strains are; group A streptococcus, streptococcus pneumoniae, C. diphtheriae, M. catarrhalis, haemophilus influenzae, bordetella pertussis, bacillus anthracis, and M. tuberculosis. In developing countries, more unusual bacterial causes may occur such as mycobacterial and syphilitic, though these may occur in developed nations as well.

o   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), and Cryptococcus and Coccidioides.

Noninfectious

o   Trauma

Often due to excessive use of the vocal folds such as excessive yelling, screaming, singing. Though this often results in damage to the outer layers of the vocal folds, the subsequent healing may lead to changes in the physiology of the folds. Another potential cause of inflammation may be overuse of the vocal cords.^{[5][6][7][8][9]} Laryngeal trauma, including iatrogenic (caused by endotracheal intubation), can also result in inflammation of the vocal cords.

Chronic

Disease Processes

o   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.

o   Laryngopharyngeal reflux

• One possible explanation of chronic laryngitis is that inflammation is caused by gastro-oesophageal reflux which causes subsequent irritation of the vocal folds.

Autoimmune disorders

o   Rheumatoid arthritis

• Approximately between 30-75% of persons with rheumatoid arthritis report symptoms of laryngitis.

o   Granulomatous disease (sarcoidosis)

• Symptoms of laryngitis are present in only 0.5-5% of patients that 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.

Other causes

• Excessive or chronic coughing, smoking, or alcohol consumption