Saliva is produced by 3 pairs of major salivary glands, and hundreds of smaller (1-2 millimeter) minor salivary glands distributed throughout the mouth and throat. The paired major salivary glands are the parotid glands, which are located in front of the ears in the upper neck, the submandibular glands, located just under the jawline on each side, and the sublingual glands, located in the mouth just under the tongue. The parotid glands drain their saliva into the mouth by a tube, or duct, that enters the mouth inside the cheek near the upper molar teeth. The submandibular and sublingual glands both drain their saliva into the mouth under the tongue in the front of the mouth. The salivary glands continuously produce saliva to lubricate the mouth, but produce a far greater amount during eating to help break down foods in the mouth and assist with swallowing. In addition, saliva is critical to maintaining healthy teeth and preventing tooth decay, and allowing foods to reach the taste buds. Diseases of the salivary glands can be categorized as disorders of saliva production, infections, and masses or tumors.
Diseases of Saliva Production
Excessive saliva production is rather uncommon. This may be caused by medications or stimulation of saliva production by dental disease. Some patients with neurological disorders affecting swallowing function may have problems swallowing their saliva, leading to excessive saliva in the mouth and even drooling despite normal saliva production. Excessive saliva production may often be controlled with medications, while difficulty swallowing saliva sometimes also requires surgery to remove saliva glands, or to relocate the salivary gland ducts further back in the mouth, thus directing saliva down the throat and reducing drooling.
Reduced saliva production, leading to the symptom of dry mouth, is somewhat more common. It is unlikely that one would experience oral dryness after removal of one or even more than one of the major salivary glands, as is sometimes performed for treatment of infections or tumors of the salivary glands. To cause significant oral dryness, a process must affect saliva production from all of the salivary glands, including the numerous minor salivary glands. This can occur due to medications, radiation given for treatment of cancers of the mouth and throat, and Sjogren's (pronounced show-gren's) syndrome, a disease in which the immune system attacks all salivary gland tissue. Commonly used medications that affect saliva production include antihistamines used to treat allergies, and diuretics (“fluid pills”) used in the treatment of high blood pressure. Radiation treatment can cause permanent scarring of all salivary tissue to which it is delivered, leading to permanent dryness of the mouth. Sjogren's syndrome is seen more commonly in patients with other diseases of the immune system, such as rheumatoid arthritis or lupus, and can also affect the lacrimal, or tear glands, causing dry eyes. Treatments for dry mouth include increasing water intake, salivary substitutes, and medications to increase saliva production.
Infections of the Salivary Glands
Infection may occur in the salivary glands due to stasis, or back-up, of saliva in one or more glands. This can be due to dehydration, or to blockage of the salivary ducts by a stone (stones can form in the salivary ducts similar to gallstones or kidney stones), cyst, or tumor within a gland. An early sign of blockage of a salivary duct is swelling of the affected gland around mealtimes. This occurs because even before one starts eating, the salivary glands receive a message from the brain to produce saliva. If a duct is blocked and this extra saliva has no way to drain out of the gland, the gland will swell. This can sometimes be painful, and if it progresses, may lead to redness of the overlying skin, and fevers or chills. This can usually be treated with antibiotics. In the case of a stone blocking a duct, sometimes the stone may be removed through the mouth under local anesthesia. If a gland proves to be a recurring source of infection, removal of the gland may become necessary. In some cases an infection may progress rapidly, and lead to formation of an abscess, or pus pocket, within the gland. Treatment for such a severe infection may require drainage of the abscess, either with a needle or surgically, and intravenous antibiotics in the hospital.
Masses or Tumors of the Salivary Glands
Masses in the salivary glands may represent cysts or solid masses. A salivary cyst usually forms in the setting of blockage of a salivary duct as discussed above. Patients infected with HIV have a high tendency of developing cysts in the parotid glands, such that a patient developing cysts in the parotid glands may need to be tested for HIV to exclude this possibility. A salivary cyst can often be treated by drawing off the fluid within it using a needle, placing a compressive dressing for several days, and using medication to reduce saliva production. Cysts may also lead to infection, which may require the involved gland to be removed surgically.
The parotid glands, unlike the other salivary glands, contain a number of lymph nodes. These may become enlarged due to infection or inflammation, as with any of the lymph nodes in the neck (the so-called “swollen glands” one develops during an upper respiratory infection). As such a mass in the parotid gland may not necessarily indicate a tumor.
Tumors of the salivary glands may be benign or malignant (cancerous). In general, the larger the salivary gland, the less likely a tumor in that gland will be cancer. Almost 80% of tumors in the parotid glands are benign, compared with only 50% of submandibular tumors and 20% of minor salivary gland tumors. Treatment of benign salivary gland tumors is by surgical removal. This can be challenging given the close proximity of each of the salivary glands to important nerves and blood vessels of the upper neck, and is best performed by a skilled otolaryngologist – head and neck surgeon. Certain types of salivary gland cancer act less aggressively (slower growth, less tendency to spread), and may be adequately treated by surgical removal of the gland alone. More aggressive tumors often require more extensive surgery, including the gland of origin, some of the surrounding structures, and some of the lymph nodes of the neck to which these tumors may spread. In addition, these tumors may also require post-operative radiation and, less commonly, chemotherapy.
Evaluation of the Salivary Glands
Assessment of diseases of the salivary glands usually begins with a thorough history and examination by an otolaryngologist - head and neck surgeon. Depending on the problem at hand, other testing may be required, including a) blood testing to evaluate for Sjogren's syndrome b) needle biopsy of a mass or tumor, or c) Xray, either CT or MRI, of the neck and salivary glands.
For a problem with the salivary glands, call 628-4368 to schedule
an appointment with Dr. DiNardo, Dr. Heller, or Dr. Reiter.
|
