Approach to sialadenitis

Symptoms and causes

Acute suppurative sialadenitis: Acute suppurative sialadenitis is inflammation of the salivary glands caused by bacterial infection. It most commonly involves the parotid glands although less commonly it can affect the submandibular glands.⁴ Acute suppurative sialadenitis can present in both children and adults.⁵

Acute suppurative sialadenitis most commonly affects men aged 50 to 70, with an incidence of 0.173 cases per 10,000 people.² It most often presents with a combination of swelling, tenderness, and induration in affected glands, frequently accompanied by a purulent discharge from their respective ducts.^2,5 Staphylococcus aureus is the most common bacterial cause, while Streptococcus species and Haemophilus influenzae are other causes.⁶

Salivary stasis is one of the main precipitating factors of acute suppurative sialadenitis.^2,7 This can be caused by medications or sialolithiasis.² Salivary stasis is associated with dehydration and common medications, including tricyclic antidepressants, antipsychotics, benzodiazepines, anticholinergics, β-blockers, and antihistamines.^5,8 The stasis leads to bacterial overgrowth and inflammation.² Sialolithiasis is the most common obstructive salivary gland disease, responsible for approximately 50% of cases.^1,6 Sialolithiasis involves formation of calculi in the ductal systems of the salivary glands and primarily affects the submandibular glands (80% to 90% of cases).^1,5,9 Sialolithiasis tends to peak in incidence between the ages of 30 and 70 with no sex predilection.⁵ The tendency of sialolithiasis to affect the submandibular duct is due to the duct’s length and its antigravitational flow, as well as due to saliva being more alkaline, being higher in mucus content, and having a higher concentration of calcium phosphate.⁴ Although calculi affecting the parotid and submandibular glands are similar in chemical composition, 90% of submandibular calculi are radiopaque whereas a similar percentage of parotid calculi are radiolucent when imaged with standard facial x-ray scans.^4,10 Patients with sialolithiasis frequently present with swelling and pain after eating and a history of recurrent acute suppurative sialadenitis.² The calculus may be palpable upon physical examination, and massage of the affected gland may produce a decreased amount of saliva that is cloudier than normal.² Chronic inflammation of the glands due to the presence of calculi can result in atrophy of the gland accompanied by a decrease in secretory function and potentially fibrosis.⁵ Complications of sialolithiasis include acute suppurative sialadenitis, stricture, and ductal ectasia.²

Other risk factors for acute suppurative sialadenitis include diabetes mellitus, HIV infection, poor oral hygiene, and chronic xerostomia.⁵

Viral sialadenitis: Viral infections are a cause of acute nonsuppurative sialadenitis. The viral infection that most frequently involves the salivary glands is mumps, which primarily affects the parotid glands and generally presents with bilateral swelling and tenderness.² In Canada, mumps primarily affects individuals between the ages of 15 and 39.¹¹ Between 2011 and 2013, the average annual incidence of mumps in Canada was 0.4 cases per 100,000 persons.¹² Other viruses that may affect the salivary glands include HIV, hepatitis C, influenza, cytomegalovirus, and coxsackieviruses.^2,13

Chronic sialadenitis: Chronic sialadenitis is characterized by recurrent episodes of pain and swelling of the salivary glands. Causes include salivary stasis, bacterial infections, neoplastic processes, and autoimmune disorders.⁴ As with acute suppurative sialadenitis, salivary stasis is thought to play a key role in the onset of inflammation.¹⁴

Juvenile recurrent parotitis is a rare disease found in children aged 3 to 5 years that is characterized by several acute, nonsuppurative flare-ups per year, but will spontaneously resolve as the child ages.¹⁵

The primary autoimmune disease associated with sialadenitis is Sjögren syndrome, a condition characterized by hypofunction of the salivary and lacrimal glands.^16,17 Patients with Sjögren syndrome often present with concerns of dry eyes and mouth.

Chronic sclerosing sialadenitis, which primarily affects the submandibular glands and presents as firm swelling around the affected gland, can be quite difficult to differentiate histologically from a neoplastic process.^18,19

Sialadenosis is a nonspecific, noninflammatory, and nonneoplastic enlargement of the salivary glands, primarily affecting the parotid glands.^2,10 The condition is associated with changes to secretory and parenchymal components of the glands and generally presents with bilateral nonpainful enlargement.^2,5 The condition occurs most frequently in adults between the ages of 30 and 70 with no sex predilection.² Sialadenosis is often associated with underlying metabolic conditions such as alcohol use disorder and liver dysfunction.²⁰

Red flags. Complications of acute suppurative sialadenitis are uncommon, but in some cases they can be life threatening. These complications can include abscess formation and extension into the deep spaces of the neck, and respiratory obstruction. Ludwig angina, which is a rapidly progressive bilateral cellulitis of the submandibular space, can also originate from infection of the salivary glands.²¹ It typically presents with fever, weakness, fatigue, prominent edema of the neck and submandibular tissues, and trismus, and can progress to substantial airway obstruction.²¹ In cases where acute suppurative sialadenitis is not responsive to conservative treatments such as broad-spectrum or culture-directed antibiotic therapy, imaging should be ordered to rule out an abscess.²

Neoplastic processes of the salivary glands usually present as a painless mass in the gland. Parotid masses tend to be benign (about 80%) whereas submandibular and sublingual masses tend to be malignant (50% to 80%).² Regardless of the site, the presentation of a neoplastic mass differs from the presentation of sialadenitis as it generally does not fluctuate, is not affected by eating, and is a well-circumscribed mass. All salivary gland masses deserve workup as if they are neoplastic, including imaging (ultrasound scan as first line), biopsy, and referral for surgical management. Clinical signs that may indicate a malignant process include facial paresis, pain, fixation of the mass to underlying tissue, and palpable neck lymphadenopathy.² The most common malignancies of the salivary glands are mucoepidermoid carcinoma and adenoid cystic carcinoma. Metastatic cutaneous squamous cell carcinoma to the parotid gland is the most common malignant process found within the parotid glands.³ A patient with a history of cutaneous squamous cell carcinoma and a parotid mass needs urgent workup. The most common benign tumours include pleomorphic adenoma and Warthin tumour.¹ Smoking has been identified in the literature as being associated with the development of Warthin tumour.²²

Gradual nontender enlargement of the major salivary glands with associated xerostomia may be suggestive of HIV infection–associated salivary gland disease.²³ Given that the presentation of HIV infection–associated salivary gland disease is similar to that of other viral causes and to that of more chronic causes, viral serology is indicated to direct management.⁷

Diagnostic workup. History and physical examination play key roles in determining the cause of a patient’s sialadenitis. Salient points to be assessed are whether the presentation was acute or chronic, changes in the size of the glands, presence of pain or fever, and the patient’s medication history.

An inspection of the head and neck region in patients with suspected sialadenitis is essential in the diagnostic workup. First, confirm a stable airway. Signs of a compromised airway should prompt urgent management. Next, inspect the salivary glands for erythema, warmth, swelling, and asymmetry. Palpate for the presence of a discrete mass to rule out a neoplasm.^2,8 Inspect the oral cavity for masses, lesions, and swelling. Massage the glands to assess for purulent drainage from the salivary ducts.²⁴ The parotid glands drain via the parotid duct (also known as the Stensen duct), which is a small punctum seen at the level of the second maxillary molar (Figure 2).²⁵ The submandibular glands (also historically known as submaxillary glands) drain via the submandibular duct (also historically known as the submaxillary duct), which is on the floor of the mouth directly lateral to the frenulum of the tongue. Examining cranial nerves 7 and 12 is important, as cranial nerve deficits may indicate the presence of a malignancy or a complication of infection.

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Figure 2.

Dissection showing salivary glands of the right side

Laboratory workup: Generally laboratory workup is not needed for diagnosis of sialadenitis. In cases of persistent xerostomia where Sjögren syndrome may be suspected, positive serologic test results for anti-SSA (also known as anti-Ro) antibodies indicate an autoimmune process.²⁶ If there are concerns of abscess, blood cultures and a complete blood count could be performed.

Imaging: While a thorough history and physical examination may be sufficient to diagnose sialadenitis, imaging is often necessary to diagnose sialolithiasis and is always indicated when a palpable mass is present. Ultrasound is the primary imaging method employed as it can detect stones and diffuse any focal lesions within the parotid glands.²⁷ Computed tomography and magnetic resonance imaging can be useful for diagnosing sialolithiasis, neoplasms, or abscesses.^27,28

Management

Prevention: Patient education on good oral hygiene and maintaining adequate hydration can help prevent both the onset and recurrences of sialadenitis.⁸

Acute infection: Management of acute suppurative sialadenitis can be readily remembered with the acronym MASHH, which stands for glandular massage, antibiotics, sialagogues, heat, and hydration.⁴ The recommended massage technique involves placing 2 fingers on the body of the gland and then applying gentle pressure while sweeping in the direction of the duct.²⁹ Empiric antibiotic treatment should begin promptly and should seek to target Gram-positive bacteria and anaerobes until therapy can be further refined based on findings of the culture.^2,7 In the outpatient setting, a combination of 875 mg of amoxicillin and 125 mg of clavulanate orally twice a day will provide adequate coverage. If no improvement is seen or the patient’s condition worsens, the patient will require treatment in an inpatient setting where a combination of 2 g of ampicillin and 1 g of sulbactam intravenously every 6 hours is the recommended first-line treatment. Given the absence of established guidelines, duration of treatment is based on the severity of the infection and its response to therapy. Sialagogues such as sugar-free chewing gum or hard candies can stimulate salivary production and flow and prevent further salivary stasis. Acute exacerbations of chronic inflammatory sialadenitis should be treated in the same way as acute suppurative sialadenitis, where anti-inflammatory medications such as ibuprofen, diclofenac, and naproxen can be added to decrease swelling.^2,7 Viral causes of sialadenitis should be treated primarily with supportive care along with other measures to address the underlying virus (eg, antiretroviral therapy in cases of HIV-related salivary gland disease).^1,2

Surgical intervention: In certain cases where conservative management does not suffice or will not address the underlying problem, surgical intervention is required. In cases where the patient has an unstable airway, steps should be taken to secure the airway surgically or with intubation. In cases of acute suppurative sialadenitis where abscesses are formed, surgical drainage is required.² When the underlying cause is sialolithiasis, the stone should be extracted. This can be done via ductal dilation or by making a small incision in the duct to extract the stone. More recently, sialendoscopy has become a viable treatment option. This technique uses small endoscopes placed in the salivary duct that can be used to dilate the duct and remove the calculus.² In cases of chronic sialadenitis that are unresponsive to conservative management or sialendoscopy, surgical intervention is generally used. This can range from minor operations including calculus removal and ductal ligation to complete excision of the gland.^2,30 Most cases of neoplastic processes in the salivary glands are treated surgically to remove the mass, prevent metastasis, and preserve the function of surrounding structures.²