Parotitis pathophysiology

Overview
Parotitis is an inflammatory disorder of the salivary gland, or sialadenitis. It is most commonly infectious in etiology but can be autoimmune or neoplastic.

Pathophysiology
Parotitis is a disease that occurs in debilitated patients. Dehydration and decreased salivary flow/stasis are the main risk factors for ascending infection through Stenson’s duct to the gland. Postoperative patients who are dehydrated and NPO with little salivary stimulation are at particular risk with an incidence estimated at 1 in 1000. Debilitating medical conditions such as Diabetes mellitus, renal failure, HIV and Sjögrens’s syndrome are risk factors.

Patients with Anorexia, Bulimia, CF or those with salivary ductal dilation are also at risk. Ductal dilation is found in those with high intraoral pressure such as trumpet players and glass blowers. Medications with anticholinergic properties or diuretic effects

The most common bacterial cause is S. aureus. S. pneumonia, S. pyogenes and H. influenza are also common. Less commonly gram negative rods (GNR) as well as anaerobes are found. M. tuberculosis and T. pallidum have also been reported but are usually associated with chronic, painless infection.

Viral etiologies include paramyxovirus (particularly Mumps), influenza, parainfluenza, echovirus and coxsackie. Cytomegalovirus (CMV) and adenovirus have been implicated in HIV patients.

Nonbacterial causes include Wegener’s granulomatosis and lymphoma. Cat-scratch and actinomycosis should be considered if the patient fails to respond to standard therapy. This predispose to parotitis.