General Information
The
function of the salivary glands is to secrete
saliva. Saliva is important for the preparation
of food prior to swallowing. Additionally,
saliva contains an enzyme (salivary amylase) to
aid in digestion. Lastly, saliva contains
immunoglobulins that help to maintain oral
hygiene. The stimulus for salivation includes
seeing or thinking about food and eating.
The
major salivary glands consists of the paired
parotid glands, submandibular glands, and
sublingual glands. The parotid and
submandibular glands each have a long duct that
empties saliva into the mouth. In addition to
these major salivary glands, there are an
estimated 10,000 minor salivary glands
throughout the mouth. These glands empty
directly into the oral lining.
The
consistency of saliva varies depending on the
gland that produced it. The saliva from the
parotid gland is watery in nature. The saliva
from the submandibular glands is thicker and
more like mucous in nature. The saliva from the
minor salivary glands lie somewhere between
these two extremes.
Xerostomia
Dry
mouth (or xerostomia) can have many different
causes. Chief among these are chronic illness,
medications, radiation therapy to the head and
neck, autoimmune disorders (Sjogren's syndrome,
sarcoidosis) and dehydration. Identifying this
underlying cause is the most important step
toward treatment. Most patients manage this
condition by constantly sipping water to help
keep the oral membranes moisturized and to
maintain oral health. Some patients find that a
medication, like Evoxac, can help produce
additional saliva.
Ptyalism
The
condition of overproduction of saliva is called
ptyalism. The causes of ptyalism can include
medications, disorders of oral or pharyngeal
motor function, chronic illness or pregnancy.
Identifying the underlying cause is important in
order to treat it properly. Medications can
sometimes be used to help minimize saliva
production.
Sialoadenitis
Infections and inflammation of the salivary
glands is called sialoadenitis. The symptoms of
this condition include swelling of the gland,
pain in the gland, fever, foul taste in the
mouth, and difficulty opening the mouth or
chewing. Sialoadenitis can be caused by viral,
bacterial or auto-immune causes. Mumps is an
example of a viral sialoadenitis; it is rarely
seen in the US do to widespread vaccination.
Bacterial infection of the salivary glands
usually follows a period of dehydration or in
association with stone formation (sialolithiasis).
Prevention of salivary flow or very thick saliva
blocks up the duct. The bacteria within the
mouth are then able to establish an infection.
Antibiotics, either oral or intravenous, usually
resolves these bacterial infections. Abscess
formation is a rare complication of these
bacterial infections and requires surgical
incision and drainage.
Auto-immune disorders, such as Sjogren's
syndrome or sarcoidosis, produce inflammation of
the gland without bacterial infection. Patients
with these disorders are best managed in
consultation with rheumatologists.
Repeated infection and inflammation of the gland
can produce narrowing and scarring of the
salivary ducts, precipitating further infection
and inflammation. When this pattern occurs
chronically, then
surgery
to remove the affected gland might be
considered.
Sialolithiasis
Production of stones in the salivary glands is
called sialolithiasis. The mucoid nature of the
saliva, the long duct, and the tortuous course
of the duct from the submandibular gland makes
stone production more likely from this gland
than from any gland. These stones are
concretions of the mucoid saliva, and these
stones are not calcified as might be found in
kidney stones.
Generally, small stones will pass
spontaneously. Slightly larger stones might
need dilation of the duct in order to pass.
Very large stones might not be able to pass and
might require
surgical removal of the
gland.
Salivary Gland Tumors
Both
benign and malignant tumors occur in the
salivary glands. Benign tumors are more common
than malignant tumors in the parotid gland.
Malignant tumors are more common in the
submandibular gland and minor salivary gland.
The tumors require careful evaluation prior to
surgical excision. CT scan, MRI scan and fine
needle aspirate might be required as part of the
evaluation. Ultimately, a final pathologic
diagnosis requires
surgical excision of the
gland.
