7. The Mouth

7.3. Clinical issues of the Mouth

Dental and periodontal infections are very common and represent major public health issues in a global scale. They are covered in chapter 15 Dental Disease and Treatment. A number of other relevant health conditions can manifest themselves in the oral cavity and the main ones are discussed below.

Herpetic Gingivostomatitis

Infections by herpes simplex virus type 1 (HSV-1) frequently manifest as oral herpes, also called acute herpes labialis and characterized by cold sores on the lips, mouth, or gums. HSV-1 can also cause acute herpetic gingivostomatitis, a condition that results in ulcers of the mucous membranes inside the mouth. Herpetic gingivostomatitis is normally self-limiting except in immunocompromised patients. Like oral herpes, the infection is generally diagnosed through clinical examination, but cultures or biopsies may be obtained if other signs or symptoms suggest the possibility of a different causative agent. If treatment is needed, mouthwashes or antiviral medications such as acyclovir, famciclovir, or valacyclovir may be used.

Figure 1. (a) This cold sore is caused by infection with herpes simplex virus type 1 (HSV-1). (b) HSV-1 can also cause acute herpetic gingivostomatitis. (credit b: modification of work by Klaus D. Peter). More details.

Oral Thrush

The yeast Candida is part of the normal human microbiota, but overgrowths, especially of Candida albicans, can lead to infections in several parts of the body. When Candida infection develops in the oral cavity, it is called oral thrush. Oral thrush is most common in infants because they do not yet have well developed immune systems and have not acquired the robust normal microbiota that keeps Candida in check in adults. Oral thrush is also common in immunodeficient patients and is a common infection in patients with AIDS.

Oral thrush is characterized by the appearance of white patches and pseudomembranes in the mouth and can be associated with bleeding. The infection may be treated topically with nystatin or clotrimazole oral suspensions, although systemic treatment is sometimes needed. In serious cases, systemic azoles such as fluconazole or itraconazole (for strains resistant to fluconazole), may be used. Amphotericin B can also be used if the infection is severe or if the Candida species is azole-resistant.

Figure 2. Candida in the mouth is called thrush. It often appears as white patches. (credit: modification of work by Centers for Disease Control and Prevention). More Details.

Mumps

The viral disease mumps is an infection of the parotid glands, the largest of the three pairs of salivary glands. The causative agent is mumps virus (MuV), a paramyxovirus with an envelope that has hemagglutinin and neuraminidase spikes. A fusion protein located on the surface of the envelope helps to fuse the viral envelope to the host cell plasma membrane.

Mumps virus is transmitted through respiratory droplets or through contact with contaminated saliva, making it quite contagious so that it can lead easily to epidemics. It causes fever, muscle pain, headache, pain with chewing, loss of appetite, fatigue, and weakness. There is swelling of the salivary glands and associated pain. The virus can enter the bloodstream (viremia), allowing it to spread to the organs and the central nervous system. The infection ranges from subclinical cases to cases with serious complications, such as encephalitis, meningitis, and deafness. Inflammation of the pancreas, testes, ovaries, and breasts may also occur and cause permanent damage to those organs; despite these complications, a mumps infection rarely cause sterility.

Mumps can be recognized based on clinical signs and symptoms, and a diagnosis can be confirmed with laboratory testing. The virus can be identified using culture or molecular techniques such as RT-PCR. Serologic tests are also available, especially enzyme immunoassays that detect antibodies. There is no specific treatment for mumps, so supportive therapies are used. The most effective way to avoid infection is through vaccination. Although mumps used to be a common childhood disease, it is now rare in the United States due to vaccination with the measles, mumps, and rubella (MMR) vaccine.

Figure 3. This child shows the characteristic parotid swelling associated with mumps. (credit: modification of work by Centers for Disease Control and Prevention). More Detail.

Oral cancer

Also known as mouth cancer, oral cancer is a type of head and neck cancer and is any cancerous tissue growth located in the oral cavity. It may arise as a primary lesion originating in any of the tissues in the mouth, by metastasis from a distant site of origin, or by extension from a neighboring anatomic structure, such as the nasal cavity. It may involve multiple tissues (teratoma), salivary glands (adenocarcinoma), tonsils (lymphoma), melanocytes (melanoma), keratinocytes (squamous cell carcinomas), or skin stem cells (basal cell carcinoma). The most common form is squamous cell carcinoma involving the tongue, the floor of the mouth, cheek lining, gingiva (gums), lips, or palate (roof of the mouth). In 2013 oral cancer resulted in 135,000 deaths up from 84,000 deaths in 1990. In the United States, fewer than 63% of the patients survive more than 5 years after diagnosis.

Figure 4. Oral cancer on the side of the tongue, a common site along with the floor of the mouth. More details.

Symptoms

In its early stages, it can go unnoticed. It can be painless with slight physical changes. Early symptoms can include persistent red or white patches, a non-healing ulcer, progressive swelling or enlargement, unusual surface changes, sudden tooth mobility without apparent cause, unusual oral bleeding or epitaxis and prolonged hoarseness.

Late stage symptoms can include thickened skin, tingling or dysesthesia of the tongue or lips, airway obstruction, chronic middle ear infections, pain in the ears, locked jaws, eating disorders, cervical lymphadenopathy, persistent pain or referred pain and altered vision.

Causes

Around 75 percent of oral cancers are linked to modifiable behaviors such as tobacco use and excessive alcohol consumption. Infection with human papillomavirus (HPV), particularly type 16 (there are over 180 types), is a another risk factor for oral cancer. Other factors include poor oral hygiene, irritation caused by ill-fitting dentures and other rough surfaces on the teeth, poor nutrition, and some chronic infections. If oral cancer is diagnosed in its earliest stages, treatment is generally effective.

Figure 5. Histopathologic appearance of a well differentiated squamous cell carcinoma specimen. Hematoxylin-eosin stain. More details.

Contents

Oral cancer often presents as a non-healing ulcer (shows no sign of healing after 2 weeks). In the US, oral cancer accounts for about 8 percent of all malignant growths. Men are affected twice as often as women, particularly men older than 40.

Management

Surgical removal of the tumor is usually recommended if the tumor is small enough, and if surgery is likely to result in a functionally satisfactory result. Radiation therapy with or without chemotherapy is often used in conjunction with surgery, or as the definitive radical treatment, especially if the tumor is inoperable.

Following treatment, rehabilitation may be necessary to improve movement, chewing, swallowing, and speech. Speech and language pathologists may be involved at this stage.

Summary

Several health conditions manifest themselves in tissues of the mouth. Oral herpes is a viral infection that commonly causes cold sores and ulcers. Oral thrush is caused by the yeast Candida and commonly affects infants and people with weakened immune systems forming white patches on the oral mucosa. Oral cancer can originate in salivary glands, tonsils and skin cells, having alcohol and tobacco as the main risk factors. Periodontal disease and caries are discussed in chapter 15.

Key terms

Oral herpes, herpetic gingivostomatitis, oral thrush, mumps, oral cancer, carcinoma

Figure credits

Figure 1 by OpenStax College - Microbiology, Connexions Web site. https://cnx.org/contents/5CvTdmJL@4.11:ryt9cF1D@8, CC BY 4.0, https://commons.wikimedia.org/wiki/File:Herpes_labialis_-_opryszczka_wargowa.jpg

Figure 2 by OpenStax College - Microbiology, Connexions Web site. https://cnx.org/contents/5CvTdmJL@4.11:ryt9cF1D@8, CC BY 4.0, https://commons.wikimedia.org/wiki/File:Oral_thrush_Aphthae_Candida_albicans._PHIL_1217_lores.jpg

Figure 3 by OpenStax College - Microbiology, Connexions Web site. https://cnx.org/contents/5CvTdmJL@4.11:ryt9cF1D@8, CC BY 4.0, https://commons.wikimedia.org/wiki/File:Mumps_PHIL_130_lores.jpg

Figure 4 by Welleschik - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/wiki/File:ZungenCa2a.jpg

Figure 5 by No machine-readable author provided. KGH assumed (based on copyright claims). - No machine-readable source provided. Own work assumed (based on copyright claims)., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=486166

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