Primary-care providers (PCPs) see a wide variety of tumors and diseases that originate in the salivary glands, of which the three major are the parotid, submandibular and sublingual. Hundreds of additional minor salivary glands within the mouth can also develop pathology.
Salivary gland pathology can be classified broadly as inflammatory and infectious swellings, traumatic disorders, and benign and malignant tumors. Additionally, systemic disorders can involve the salivary glands. Each of these entities has a unique clinical presentation, and proper identification is critical to providing the correct and most efficient course of treatment.
Inflammatory and infectious swellings
Inflammatory and infectious swellings present acutely and are often painful enlargements of the salivary glands. Sialoliths and granulomatous diseases are inflammatory conditions that cause enlargement and pain but do not have an infectious etiology.
Typically found in the submandibular gland, sialolithiasis is the most common cause of salivary gland enlargement. It results from the formation of a stone within salivary ducts. It is thought that the long path of the submandibular duct and its thicker mucoid secretions may be responsible for the increased frequency of sialoliths in this location.
Radiographic examination will usually show an opaque mass in the duct if the stone is well calcified. The stone blocks salivary flow out of the gland, causing pain and swelling, especially before or during mealtime. If the stone is located near the duct orifice, clinicians will typically be able to feel a hard mass beneath the oral mucosa.
Small sialoliths can sometimes be removed by gentle massage, sialogogues, moist heat or increased fluid intake. Treating larger inaccessible stones involves complete removal, usually by cannulation and dilation of the duct.
Although the stone is not infectious, the backup of salivary flow predisposes the gland to secondary bacterial infection, which causes fever, redness and purulent discharge. This is why treatment includes antibiotics. Occasionally, more aggressive treatment — including complete gland removal — is needed if the stone does not resolve or continues to recur.
Infectious causes of salivary gland enlargement include mumps, parotitis and HIV lymphadenitis. Acute suppurative parotitis presents with painful parotid swelling, fever, redness and purulent discharge from Stensen’s duct.
Parotitis is attributable to a retrograde infection of the gland, usually bacterial in nature. This condition is typically seen in immunocompromised patients or subsequent to receiving a general anesthetic during a surgical procedure, especially abdominal surgery. Parotitis is thought to arise when a patient is given atropine intraoperatively after having had nothing to eat or drink, which decreases salivary flow and makes it easier for the bacteria to invade the gland.
The most common pathogens associated with acute bacterial parotitis are Staphylococcus aureus and anaerobic bacteria. Samples for culture and sensitivity testing can be obtained by milking the gland to obtain the purulent material. Therapy includes hydration and parenteral antimicrobial therapy.
Once an abscess has formed, surgical drainage is required. Swellings and cysts of the salivary glands may also be associated with HIV infection and such granulomatous diseases as sarcoidosis and tuberculosis. For example, patients with HIV may demonstrate bilateral lymphoepithelial cysts.
Chronic nonspecific sialadenitis is a lower grade salivary inflammation that usually involves one or both parotid glands. The etiology is not definitively known; it is most likely multifactorial and includes decreased salivation, stasis, and an ascending retrograde duct infection.
Sialadenitis is also thought to be caused by obstruction of one of the salivary ducts from either a stone or external radiation. The patient will complain of pain and such symptoms as fever and malaise. Fortunately, the swelling is self-limiting and typically resolves with anti-staphylococcal antibiotic therapy and increased fluid intake. Refractory cases are treated with surgical resection after failure of antimicrobial therapy.
Mumps, an acute infectious inflammation of the parotid gland, is an acute contagious viral infection typically seen in childhood. True mumps is caused by the mumps paramyxovirus, but a similar clinical disease can also be seen with coxsackievirus A and echovirus.
Mumps typically causes bilateral inflammation of the parotid glands (parotitis), but it can occur unilaterally. Fever, headache, painful testicular swelling (orchitis) and a rash may occur as well. The symptoms are generally not severe in children. This disease is self-limiting, so such palliative treatment as analgesics, antipyretics and fluid intake are appropriate. Isolation from other nonimmune individuals will prevent further spread. Although serious, sterility from orchitis is a rare complication of mumps.
Noninfectious inflammatory disorders can also cause enlargement of the salivary glands. These include the systemic diseases sarcoidosis and Sjögren’s syndrome. Sarcoidosis can cause swelling of the parotid gland and sometimes facial-nerve palsy.
Heerfordt’s uveoparotitis is a manifestation of sarcoidosis that occurs when the lacrimal gland, uveal tract and parotid gland are involved. An autoimmune disease caused by anti-SS-A and anti-SS-B antibodies, Sjögren’s syndrome presents as xerostomia, dry eyes, and bilateral swelling of the major salivary glands. Sjögren’s syndrome is often associated with such other autoimmune diseases as rheumatoid arthritis.
The most common traumatic salivary disorder encountered by PCPs is a mucocele. Other disorders include a ranula (Figure 1) and a salivary duct cyst. A mucocele, also known as a mucous extravasation phenomenon or a mucous retention cyst, is not a true cyst because it lacks an epithelial lining. It is a submucosal cystic swelling of a gland-bearing area commonly found in children and young adults. It is thought to arise following the rupture of a salivary gland duct.
Mucoceles typically present on the lower lip as a dome-shaped and fluctuant mucosal swelling. Some mucoceles may be only 1 to 2 mm in diameter, but most measure between 5 and 10 mm. Mucoceles are painless swellings and are frequently recurrent.