Sialadenitis

Sialadenitis is the inflammation of a salivary gland. The causes of sialadenitis include bacterial and viral infections, such as mumps and HIV, obstruction from stones or radiation, and autoimmune disorders such as Sjogren’s syndrome. The complications of sialadenitis include recurrence, abscess, and chronic sialadenitis. Sialadenitis must be differentiated from other diseases that can cause swelling in the salivary glands, such as sialolithiasis, human immunodeficiency virus, radiation, and systemic diseases such as, sarcoidosis, and sjögren’s syndrome. History from the patient will reveal symptoms of sialadenitis that include fever, redness of overlying skin, pain, and difficulty in opening the mouth. The diagnosis of choice is a high resolution CT scan. Sialoendoscopy can be used in the diagnosis of small stones and differentiate them from polyps. Conservative treatment is the first line of therapy in the most patients and it involves Hydration, applying moist heat, massaging the gland, duct milking, discontinuation of medication that can decrease the saliva flow, such as the TCAs (because of their anticholinergic effects). Also, antibiotics can be used in the case of superimposed infection. Preferred regimens are Dicloxacillin 500 mg q 6h PO for 7 to 10 days, or Cephalexin 500 mg q 6h PO for 7 to 10 days.

The historical perspective of sialadenitis is as follows:^[1]

• In 17th century, major salivary gland ductal system in anatomical human studies was first reported.
• In 1990, , Konigsberger et al. performed the first successful salivary endoscopy.^[2]
• In 2004, Zenk et al. reported the use of semirigid sialendoscope in different types of obstructive salivary disorders.^[3]
• In 2006, Nahlieli et al. described sialendoscopy in the management of radioiodine sialadenitis.^[4]

• There is no established system for the classification of sialadenitis, but it can be classified according to location of the stone.^[5]

• Submandibular stones can be classified further as anterior, or posterior in relation to the mandibular first molar teeth.
• Stones may be radiopaque, where they can be radiopaque or radiolucent.
• Stones may also be symptomatic or asymptomatic.

• Sialadenitis is the inflammation of a salivary gland. ^[6]
• Swelling is usually present in this condition.
• Acute sialadenitis may be caused by viral or bacterial infection^[7]
  • Parotid and submandibular glands are more involved in acute sialadenitis. Approximately 10% sialadenitis cases are related to the involvement of submandibular gland.
• Chronic sialadenitis is caused by repeated episodes of inflammation and finally it progresses in to salivary gland dysfunction.

Common causes of sialadenitis include the following:

Bacterial and viral infections:^[8]

• Mumps
• HIV
• Staph aureus
• Streptococci viridans
• Pseudomonas aeruginosa
• Escherichia coli
• Moraxella catarrhalis
• Tuberculosis^[9]

Obstruction:

• Stones
• Radiation
• Strictures
• Sarcoidosis

Autoimmune disorders:

• Sjogren’s syndrome

• Sialadenitis must be differentiated from other diseases that cause swelling in salivary glands, such as sialolithiasis, human immunodeficiency virus, radiation, and systemic diseases such as, sarcoidosis, and sjögren’s syndrome.^{[10][11][12][13][14][15][16][17]}

• The exact prevalence of submandibular sialadenitis is unclear.

• The incidence of acute sialadenitis is approximately 275 per 100,000 individuals in United Kingdom.^[18]

• Patients of all age groups may develop sialadenitis.

• Sialadenitis commonly affects older and dehydrated patients.

Common risk factors in the development of sialolithisis which can lead to sialadenitis include:^[19]

• Dehydration
• Diuretics
• Local trauma
• Sjögren’s syndrome
• Gout
• Anticholinergic medications
• Smoking
• History of nephrolithiasis
• Chronic periodontal disease
• Head and neck radiotherapy^[20]

There is insufficient evidence to recommend routine screening for sialadenitis.

• If left untreated, patients with sialadeitis may progress to develop secondary infection and chronic sialadenitis including gland atrophy.^[21]

• Common complications of sialadenitis include:^[22]
  • Recurrence
  • Abscess
  • Cellulitis

• Prognosis is generally good with fluid management and antimicrobial therapy, but edema in the gland may persist for several weeks.^[16]

Acute sialadenitis is a clinical diagnosis and presents with pain, swelling, and redness of skin.^[23]

The most common symptoms of sialadenitis include fever and pain.^[22]

• A positive history of pain, swelling, overlying skin redness, and hard lump is suggestive of sialadenitis.

• Vital signs are usually normal, but fever may be seen in sialadenititis as a complication of sialolithiasis.^[7]

Normal salivary gland is spongy.

In sialadenitis:^[24][25]

• Tenderness of the involved gland
• Palpable hard lump near the end of the involved duct or under the tongue in submandibular duct stone.
  • Stones, sometimes may be felt smooth or irregular.
• In total obstruction, no saliva is being produced from the duct.
• Erythema of the floor of the mouth
• Pus discharging from the duct
• Stone in the minor salivary glands can be felt as a small nodule
• Stones are typically rock hard and small; they may be smooth or irregular. They are most commonly felt within the ductal system.

• Cervical lymphadenitis in cases of infection.

• There are no diagnostic laboratory findings associated with sialadenitis. In the case of superimposed inflammation and infection, high ESR or leukocytosis may be seen.
• Duct discharge should be used for culture.^[26]

There are no ECG findings associated with sialadenitis.

• An x-ray is not diagnostic in sialadenitis.
• An x-ray may be helpful in the diagnosis of chronic sialadenitis. Findings on an x-ray suggestive of chronic sialadenitis include:^[27]
  • Radiopaque stones: 43-60% of the parotid stones and 80-95% of the submandibular stones are radiopaque and can be seen in x-ray.

• There are no ultrasound findings associated with acute sialadenitis.

• There are no CT scan findings associated with acute sialadenitis. However, a CT scan may be helpful in the diagnosis of complications of sialadenitis, which include abscess.^[28][23]
  • Most stones contain enough calcium, so they can be visible on non-contrast CT scan.

• The following results are seen in acute obstruction of the salivary duct due to sialadenitis after administration of contrast:
  • The gland may appear enlarged
  • Hyperdensity of gland with stranding

• In chronic sialadenitis, fat atrophy and reduction in salivary gland parenchymal volume may be seen.

Sialography is contraindicated in active infection of the involved gland.

• There are no other diagnostic studies associated with sialadenitis.

• Most cases are easily treated with conservative medical management. Acute symptoms resolve within 1 week; however, edema in the area may last for several weeks.^[29]

• Antibiotics usage in the case of superimposed infection:^[23]
  • Preferred regimen (1): Dicloxacillin 500 mg q 6h PO for 7 to 10 days.
  • Preferred regimen (2): Cephalexin 500 mg q 6h PO for 7 to 10 days.

• If the patients clinics did not change in five days of using above antibiotics, change to:
  • Preferred regimen (1): Amoxicillin/clavulanate 625 mg q 8h PO for 7 to 10 days.
  • Preferred regimen (2): Clindamycin 300 mg q 8h PO for 7 to 10 days.\

• Many cases of sialadenitis cannot be cured by using medical therapy alone; invasive, or open surgery methods can be used for salivary gland stones. The interventional methods are discussed in the sialadenitis surgery page.

• Certain individuals with chronic bacterial infections who do not respond to appropriate conservative and antibiotic measures may require either radiation or removal of the affected gland to control its symptoms.

• The mainstay of treatment for acute siladenitis is medical therapy. Surgery is not the first-line treatment option for patients with acute siladenitis. Surgery is usually reserved for patients with abscess that do not respond to medical therapy.^[23]

• Surgical resection of involved gland in chronic bacterial sialadenitis may be considered if it does not respond to medical therapy. ^[22]

For surgical intervention of sialolithiasis please click here.

• Effective measures for the primary prevention of sialadenitis include:^[19][29][23]
  • Healthy oral care regimen ( brushing teeth)
  • Increased water intake
• There are no available vaccines against sialolithiasis

Effective measures for the secondary prevention of acute sialadenitis include hygiene and repeated massaging of the gland when tenderness had subsided. ^{[22][17][1][29][30]}

• Prevention of dehydration
• Healthy oral care regimen (brushing teeth)
• Treatment of underlying disease such as Sjögren’s syndrome and gout
• Avoid anticholinergic and diuretic medications

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