Alternative Names: Acute sialadenitis; chronic sialadenitis; sialadenosis.
Definition: Infectious or inflammatory disorders of the salivary glands.
What Is Going on in My Body? There are three major pairs of salivary glands, which would include the parotid, submandibular, and sublingual glands. Scattered throughout the mouth and pharynx are minor salivary glands, which lie just below the mucous membrane lining. The parotid glands sit just in front of the ears, whereas the submandibular and sublingual glands are under the lining of the floor of mouth tucked on the inside of the jawbone. Their normal function is to manufacture saliva, which is important to assist in swallowing in that it lubricates the mouth and throat structures, assists in digestion by beginning to break down starches, and lastly by providing an environment that is hostile for the formation of cavities in teeth.
Acute salivary gland infections rarely affect the minor salivary glands or sublingual glands. The acute conditions more typically involve the parotid and submandibular glands. During an acute inflammatory process, there is swelling of the affected gland, overlying pain, gland tenderness, fever, and on occasion difficulty opening the mouth. Often the pain is intensified with eating in that food ingestion stimulates saliva flow, which will typically cause the gland to swell and thus exacerbate the pre-existing symptoms. Acute inflammatory processes largely fall into bacterial, viral, and autoimmune states. In chronic gland disorder, the symptoms are similar, although much less intense. There is usually swelling of the affected gland with a less intense discomfort and less overlying tenderness. The gland may fluctuate in size and discomfort with eating but usually not to the degree seen with acute infectious causes.
In the inflammatory conditions, the gland is not so much a target of bacterial or viral processes but is inflamed by antibodies directed against salivary gland tissues.
What Are the Causes and Risks? Salivary glands may be infected by viruses of which mumps is the most common. Mumps is known as epidemic parotitis, but it is quite common for mumps to also affect the pancreas, gonads, and central nervous system. The mumps virus is typically transmitted by the saliva, with the initial infection involving the upper respiratory tract. The parotid gland is most frequently involved during mumps, and about three-quarters of the time both glands are affected. Mumps can also affect the inner ear and is one of the most common causes of unilateral nerve deafness.
Other viruses have been associated with acute sialadenitis. Coxsackie A virus, which causes hand, mouth, and foot disease, can generate a clinical picture similar to mumps except that the lining inside the mouth is often inflamed and is covered with numerous small ulcers. Other viruses have been associated with acute parotitis. These latter viruses are more likely to cause non-epidemic forms of acute parotitis, which more often than not involve just one major salivary gland, particularly the parotid. When these patients are examined, the affected salivary gland is often boggy and swollen, with mild to moderate tenderness. When the saliva exiting the gland is inspected, it is typically clear, as opposed to bacterial infections in which it is often discolored. As the salivary glands drain into lymph nodes in the neck, there may be some tenderness and enlargement of cervical lymph nodes. As with most viral infections, there are often other constitutional symptoms, such as fever, chills, sweats, muscle aches, joint pains, and fatigue.
Another salivary gland infection occurs from bacteria. These infections usually begin in the mouth and then ascend into the gland through its drainage system. A gland is prone to infection whenever the saliva drains less efficiently than normal, such as with dehydration and drainage pathway obstruction. Therefore, one of the most common settings for acute bacterial salivary gland infection to occur is in the dehydrated individual. This can result from simple dehydration but is most frequently seen as a result of medical therapy with diuretics and certain antidepressants and antihistamines that decrease saliva flow rates as a side effect. Although any age group can be affected by acute bacterial salivary gland infection, older individuals are more likely to suffer from it. In acute bacterial infections there is often significant, fairly sudden onset of pain and swelling, with involvement of the lymph nodes into which the affected salivary gland drains. The overlying skin may be reddened; and when the drainage is visualized coming from the affected gland duct, it is often purulent and in some cases may be absent either because a stone or extreme duct swelling is preventing any further salivary drainage. There may be a low-grade fever. The most common bacteria that causes acute bacterial sialadenitis is Staphylococcus aureus, but other bacteria have been implicated. The parotid gland is usually more affected than the submandibular gland in spite of the fact that the submandibular gland is more likely to be affected by stones. Some individuals continue to have recurrent, acute sialadenitis usually as a consequence of excessively thick saliva or a duct obstruction. Should this process become chronic, there is swelling and local pain and tenderness of the involved gland, but often without the fever associated with the more acute infection. The parotid gland is more likely to be affected in chronic bacterial sialadenitis, and as the infection continues, the drainage system becomes more dysfunctional.
There are other infectious processes which can mimic acute parotid gland infection. Around and within the parotid gland are a variety of small lymph nodes which can be involved by infectious agents, such as mycobacterium, tuberculosis, atypical mycobacterial species, brucellosis, and histoplasmosis. These infectious agents are more likely to involve the perior intraparotid lymph nodes and thus mimic an acute or chronic parotitis or even in some cases a parotid gland mass. The clinical picture can vary and manifest either as an acute process with fevers, chills, sweats, gland swelling, pain, and tenderness all the way to a more chronic manifestation characterized by enlargement, firmness, and minimal tenderness.
Systemic diseases can also affect the salivary gland. The first one is sarcoidosis, a disorder of uncertain etiology characterized by large lymph nodes noticed on a chest x-ray or subcutaneous, small, firm nodules particularly around the nose and mouth. The parotid gland can be acutely involved by sarcoidosis and when accompanied by fever and uveitis of the eye is termed Heerfordt’s syndrome (uveoparotid fever). Although it is an infrequent manifestation of sarcoidosis, usually both salivary glands, tear glands, and uvea are affected. The parotid swelling is constant with minimal pain. The salivary glands can also be attacked by the individual’s own immune system, which goes by the name of sicca or Mikulicz’s syndrome. As the immune system attacks the salivary tissue, its ability to produce saliva lessens. Therefore, these individuals often suffer from a dry mouth and dry eyes. If it is associated with another connective tissue disorder, such as rheumatoid arthritis or lupus, the term Sjogren’s syndrome is applied. The cause of the autoimmune process that leads to inflammatory sialadenitis is unclear. Typically these individuals present with bilateral parotid gland swelling, but also the submandibular and lacrimal (tear) glands can be significantly involved. Women are more likely to be affected. The involved glands are typically not swollen or tender, but should these symptoms develop, an acute superimposed secondary bacterial infection can be pre-supposed to have occurred. Typically the saliva in these individuals is clear to slightly white and is much more viscous than that from a normal individual.
The major salivary glands can be affected by a variety of other disorders and often present as asymptomatic swellings termed sialadenosis. Typically the parotids are most likely to be affected, although the submandibular glands can also be involved. Sialadenosis is associated with diabetes, hypothyroidism, pregnancy, protein deficiency states, alcoholism, side effects to certain medications, and bulimia.
Lastly, some mention must be made of benign lymphoepithelial lesion, which is an end-stage result of chronic parotid inflammation and is most typically associated with Sjogren’s syndrome, sarcoidosis, tuberculosis, gout, syphilis, lymphoma, and leukemia. In benign lymphoepithelial lesion there is usually significant white blood cell infiltration into the salivary gland tissue and the formation of large fluid-filled cysts. Benign lymphoepithelial lesion is also associated with AIDS (human immunodeficiency virus) infection.
How to Prevent the Disease: The mumps vaccine has been very effective in reducing the frequency of mumps and its sequelae. The other non-epidemic forms of parotitis are more difficult to prevent, but should an individual knowingly be infected by any of the other viruses associated with acute sialadenitis, he should be avoided. Many of the forms of parotid lymph node involvement cannot be prevented except perhaps the tuberculosis form. Individuals with active TB need to be avoided. The other disorders, such as sarcoidosis and autoimmune sialadenitis are consequent to other systemic disease entities and thus are not preventible. Also sialadenosis is a result of a systemic-wide process. Control of the underlying disease, such as diabetes or malnutrition, is the most effective means of prevention.
How Is It Diagnosed? In acute salivary gland infections it may be difficult to discern whether the process is bacterial or viral. Typically, as mentioned above, mumps is usually going to present with both parotid glands involved. Blood tests can look at the antimumps antibody, which during acute infection will be elevated. As the gland is damaged by the infection, there is release of salivary gland amylase (which helps to break down starches) into the bloodstream, and therefore, there is often an increase in blood amylase levels. Other viruses are going to be more difficult to isolate, although it may be necessary should the clinical situation warrant it. Bacterial salivary gland infections usually involve just one gland. In addition to the acute pain, tenderness, and swelling seen with acute viral infections, the main means of distinguishing a bacterial from a viral process is examination and culturing of the saliva emanating from the gland. In a viral infectious process it is typically clear, and in bacterial infections it is usually more yellow. It may be necessary, particularly if a patient is not responding to therapy, to culture the material draining from the duct opening. Patients who have involvement of the parotid lymph nodes may need to have the infected node curetted or removed to be examined microscopically, but also to be cultured to try to isolate the offending agent. In sarcoidosis, the diagnosis can be confirmed by a chest x-ray, which often shows enlarged lymph nodes between the lungs, and a Kveim skin test will be positive. Patients with active sarcoid will have elevated levels of serum calcium and angiotensin converting enzyme. Ultimately it may be necessary to biopsy the affected salivary gland or skin lesions in order to confirm the diagnosis.
In autoimmune sialadenitis, diagnosis is often made on the basis of clinical grounds and can be quite easy if the patient has a previously diagnosed autoimmune process. Should there be a need to confirm the autoimmune etiology of the sialadenitis, tests such as determining tear production rate and looking for blood levels of rheumatoid factor, elevated sedimentation rate, elevated antinuclear antigen antibodies, and antibodies to single stranded DNA (SS-A, SS-B) may be helpful. Once again, if the diagnosis is not clear, biopsy of a minor salivary gland is often confirmatory. Sialadenosis is usually diagnosed based upon the clinical appearance of enlarged, rubbery parotid and submandibular glands in the setting of a patient with a known disease process associated with sialadenosis. On occasion, biopsy of the affected gland may be necessary to establish this entity.
What Are the Long-Term Effects? With acute epidemic and non-epidemic parotitis there are usually no long-term effects upon the salivary glands. If there should be several cases of acute bacterial sialadenitis, there will probably be no long-term effects; but should repetitive, acute infections continue, then chronic bacterial sialadenitis may result. In sialadenosis, salivary flow rates and composition are usually adequate to maintain saliva function, but in individuals who suffer from autoimmune involvement of the salivary glands, there are several long-term effects, which include difficulty swallowing because of a dry mouth and throat, acute bacterial infections because of the thickened, poorly draining saliva, benign lymphoepithelial lesion formation, and dental cavities. As with any autoimmune disorder, there is an elevated risk of leukemias and lymphomas, particularly if the parotid glands are involved in the process.
Am I Putting Others at Risk? For the patient with acute viral sialadenitis, any saliva-to-saliva transmission could potentially place another at risk for the infection. It is known that HIV is excreted in saliva and tears, but it is not clear if saliva exchange places another individual at risk for HIV infection. No others are at risk in the case of acute bacterial sialadenitis, autoimmune sialadenitis, or sialadenosis.
What Are the Treatments? In the viral forms of sialadenitis the treatment is largely supportive with analgesics, increased fluid ingestion, warm compresses, and sialogogues that stimulate saliva flow (such as lemon drops). For the patient with acute bacterial sialadenitis, antistaphylococcal antibiotics are usually effective, along with increasing the patient’s hydration, adding sialogogues to stimulate saliva flow, and performing gland massage to try to flush the gland of infected bacterial material. The main form of therapy for tuberculosis is antituberculous drugs. For patients with atypical mycobacterial infections, antibiotics may be helpful, but it is usually necessary to make a small incision over the infected lymph node and scrape it out (or excise it). For the patient with a chronic bacterial infection, low-dose radiation may be useful to destroy the involved salivary tissue, and in certain extreme cases, removal of the entire gland may be required. There is really no necessity for treatment in sialadenosis other than to control the underlying disease state, and the main form of management in the autoimmune sialadenitis disorders would be non-steroidal anti-inflammatories, oral steroids, Plaquenil, saliva substitutes, and sialogogues. There has been some promising early work in electrical (galvanic) rehabilitation of salivary glands in Sjogren’s syndrome patients.
What Are the Side Effects to the Treatments? The use of sialogogues in an obstructed or acutely inflamed gland may actually temporarily increase the amount of pain. The side effects to the medications would be specific to the agent used.
What Happens After Treatment? In the acute viral and the vast majority of acute bacterial infections, the gland returns to an asymptomatic state. Certain individuals with chronic bacterial infections not responding to appropriate conservative and antibiotic measures may require either radiation or removal of the affected gland to control its symptoms.
How Do I Monitor the Disease? The bacterial and acute viral infection must be treated aggressively both with antibiotics and non-antibiotic measures respectively to limit the infection’s ability to damage the gland’s drainage system and potentially predispose it to further more difficult-to-treat infections in the future. Monitoring is really not necessary in sialadenosis. The patient with autoimmune sialadenitis needs to be aware of their increased risk for hematopoietic malignancy and should alert their physician should any rapid enlargement of any salivary gland or lymph node occur.