Parotitis

Inflammation of the parotid gland, encompassing a range of infective, inflammatory, autoimmune and obstructive causes. The clinical task is to determine which category applies, since the presentations overlap while the management diverges completely.

Relevant anatomy

The parotid gland occupies the space between the mandibular ramus and the mastoid, extending into the retromandibular fossa and the parapharyngeal space through the stylomandibular tunnel, which is why a deep lobe lesion presents as a parapharyngeal mass with medial tonsillar displacement.

It is enclosed in a dense unyielding parotid fascia derived from the investing layer of deep cervical fascia, which is why inflammation is intensely painful and why an abscess may not fluctuate. The facial nerve divides the gland into a superficial and a deep lobe, an artificial surgical rather than anatomical division.

Stensen duct runs across masseter, turns medially at its anterior border, pierces buccinator and opens opposite the second upper molar.

Uniquely among the salivary glands, the parotid contains intraglandular lymph nodes, because it is the last of the major glands to become encapsulated during development and lymphatic tissue becomes trapped within it. This explains intraparotid lymphadenopathy, lymphoepithelial lesions in HIV, and lymphomatous involvement.

Classification of causes

Acute infective:

• Viral: mumps virus, which remains the commonest cause of acute parotitis worldwide in unvaccinated populations, and also parainfluenza, influenza, coxsackievirus, echovirus, Epstein Barr virus, cytomegalovirus, adenovirus and HIV.
• Bacterial: acute suppurative parotitis, as described under acute bacterial sialadenitis, predominantly Staphylococcus aureus.

Chronic and recurrent:

• Juvenile recurrent parotitis.
• Chronic recurrent parotitis in adults, associated with ductal ectasia and sialectasis.
• Sialolithiasis with obstruction.
• Ductal stricture.

Autoimmune and granulomatous:

• Sjögren syndrome.
• Sarcoidosis, including Heerfordt syndrome with uveoparotid fever.
• IgG4 related disease.
• Granulomatosis with polyangiitis.

Infiltrative and neoplastic:

• HIV associated benign lymphoepithelial cysts.
• Lymphoma, both primary and in the context of Sjögren syndrome, which carries a 15 to 20 fold increased risk of mucosa associated lymphoid tissue lymphoma.
• Salivary gland neoplasms presenting with secondary inflammation.

Non inflammatory enlargement, that is sialadenosis:

• Diabetes mellitus, alcoholism, bulimia nervosa, malnutrition, acromegaly, hypothyroidism, and drugs. This is bilateral, painless, soft and non inflammatory, and it is frequently misdiagnosed and treated with antibiotics.

Miscellaneous:

• Pneumoparotid from insufflation of air up Stensen duct in wind instrument players, glass blowers and self inducers, producing crepitant swelling.
• Radiation induced.
• Radioiodine induced, in patients treated for thyroid carcinoma.
• Anaesthesia mumps, a transient postoperative parotid swelling.

Mumps

• Incubation of 16 to 18 days, with a prodrome of fever, headache, malaise and myalgia.
• Bilateral parotid swelling in around 70 percent, though it is often sequential with one side swelling several days after the other.
• Swelling that lifts the ear lobe upward and outward and obliterates the angle of the mandible.
• Erythematous, oedematous duct orifice without purulent discharge, which is the key distinction from bacterial parotitis.
• Trismus and pain on chewing.
• Infectivity from 2 days before to 5 days after the onset of swelling, which determines the isolation period.
• Complications: orchitis in 20 to 30 percent of postpubertal males, usually unilateral, with subfertility rather than sterility as the consequence; oophoritis; aseptic meningitis in up to 10 percent; encephalitis; pancreatitis; and sensorineural hearing loss, which is usually unilateral, sudden and permanent, and which is one of the historical justifications for vaccination.

Bacterial suppurative parotitis

Rapid onset unilateral painful erythematous swelling with purulent discharge from Stensen duct, fever, and risk factors of dehydration and reduced salivary flow.

Sjögren syndrome

• Bilateral recurrent or persistent parotid enlargement.
• Xerostomia with difficulty swallowing dry food, need to sip water while eating, altered taste, rampant dental caries and oral candidiasis.
• Xerophthalmia with a gritty sensation, and keratoconjunctivitis sicca.
• Fatigue, arthralgia and Raynaud phenomenon.
• Primary, or secondary to rheumatoid arthritis, systemic lupus erythematosus or systemic sclerosis.

HIV associated parotid disease

Bilateral, painless, cystic enlargement from benign lymphoepithelial cysts, often with generalised lymphadenopathy. This may be the presenting feature of HIV infection, and every patient with bilateral cystic parotid enlargement requires HIV testing.

Sarcoidosis

Bilateral firm painless enlargement, with Heerfordt syndrome comprising parotid enlargement, anterior uveitis, facial nerve palsy and fever.

Red flags in any parotid swelling

• Facial nerve weakness, which in the absence of an obvious abscess or Heerfordt syndrome indicates malignancy until proven otherwise. This is the single most important sign in parotid disease.
• A hard, fixed mass, skin tethering or ulceration.
• Cervical lymphadenopathy.
• Pain, which is more common in malignant than benign tumours.
• Rapid growth.
• A parapharyngeal mass with medial tonsillar displacement, indicating deep lobe disease.
• Weight loss and night sweats.

• Full history including vaccination status, sexual history and risk factors for HIV, medication, alcohol, eating disorder history, sicca symptoms, systemic symptoms and the timing relative to meals.
• Examine the gland, the duct orifice with milking to assess the character of expressed saliva, the facial nerve in all branches, the oral cavity, the oropharynx including the parapharyngeal wall, and the neck.
• Ultrasound as the first line imaging investigation, which distinguishes diffuse parenchymal disease from a discrete mass, identifies calculi, abscess and cysts, assesses intraparotid nodes, and guides fine needle aspiration.
• Fine needle aspiration cytology of any discrete mass, which is safe, does not seed tumour, and provides the diagnosis in the majority. Core biopsy is used where cytology is inconclusive, particularly for lymphoma where architecture is required.
• Magnetic resonance imaging for any mass, which is the modality of choice for parotid neoplasm, assessing deep lobe extension, parapharyngeal involvement, perineural spread along the facial nerve, and the relationship to the retromandibular vein as a surrogate for the facial nerve plane.
• Contrast enhanced computed tomography for abscess, calculi and deep space infection.
• Sialography and magnetic resonance sialography for ductal anatomy, contraindicated in acute infection.
• Sialendoscopy for obstructive and recurrent disease.
• Mumps immunoglobulin M serology and buccal swab polymerase chain reaction.
• HIV testing in every patient with bilateral cystic parotid enlargement, and in recurrent or unexplained disease.
• Anti Ro and anti La antibodies, antinuclear antibody, rheumatoid factor, erythrocyte sedimentation rate, immunoglobulins and serum protein electrophoresis where Sjögren syndrome is suspected. Schirmer test and ocular staining score with ophthalmology input. Labial minor salivary gland biopsy showing focal lymphocytic sialadenitis with a focus score of 1 or more per 4 mm squared.
• Serum angiotensin converting enzyme, calcium and chest imaging for sarcoidosis, with tissue confirmation.
• Serum IgG4 and histology with IgG4 positive plasma cell counts for IgG4 related disease.
• Glucose, HbA1c, liver function and thyroid function.
• Amylase, which is raised in mumps and pancreatitis, though it is non specific.

Treatment is dictated entirely by the cause.

Mumps

• Supportive: rest, hydration, analgesia with paracetamol and a nonsteroidal anti inflammatory drug, soft diet and avoidance of sour foods which provoke pain.
• Isolation for 5 days from the onset of swelling.
• Notification to public health, since mumps is a notifiable disease in most jurisdictions and outbreak control depends on it.
• Manage complications: scrotal support, analgesia and bed rest for orchitis, with corticosteroid used by some though without clear evidence of benefit for fertility; admission for meningitis and encephalitis; audiological assessment where hearing loss is reported, with urgent corticosteroid treatment as for sudden sensorineural hearing loss.
• Vaccination with measles mumps rubella vaccine for prevention, and catch up vaccination for contacts and for the unvaccinated population. Explain that mumps in a vaccinated individual occurs but is milder, and that waning immunity in young adults accounts for outbreaks in university populations.

Acute suppurative parotitis

Managed as described under acute bacterial sialadenitis: aggressive rehydration, sialogogues, massage, oral hygiene, antistaphylococcal and antianaerobic antibiotics, and drainage of any abscess with blunt dissection parallel to the facial nerve branches.

Chronic and recurrent parotitis

• Hydration, sialogogues, massage and oral hygiene as maintenance.
• Antibiotics for acute exacerbations.
• Sialendoscopy with ductal irrigation, dilation of strictures and instillation of corticosteroid, which is effective and which has substantially reduced the need for gland excision.
• Botulinum toxin injection into the gland to reduce secretion in refractory recurrent disease.
• Tympanic neurectomy, dividing Jacobson nerve in the middle ear to interrupt the parasympathetic secretomotor supply.
• Duct ligation, which produces gland atrophy.
• Superficial or total parotidectomy as a last resort for a non functioning gland with intractable symptoms, accepting the risks of facial nerve injury and Frey syndrome.

Juvenile recurrent parotitis

Conservative management with hydration, massage, sialogogues and antibiotics for acute episodes. Sialendoscopy with irrigation and steroid instillation reduces the frequency of episodes and is now first line interventional treatment. Most cases resolve at puberty. Test for HIV and Sjögren syndrome.

Sjögren syndrome

• Refer to rheumatology.
• Symptomatic management of xerostomia: frequent sips of water, saliva substitutes and gels, sugar free chewing gum, avoidance of caffeine, alcohol and smoking.
• Pilocarpine 5 mg three or four times daily, or cevimeline 30 mg three times daily, where residual gland function exists. Contraindicated in asthma, chronic obstructive pulmonary disease, bradycardia, narrow angle glaucoma and uncontrolled cardiac disease. Adverse effects are sweating, flushing, nausea and urinary frequency.
• Aggressive preventive dental care with high fluoride toothpaste, fluoride varnish, and regular dental review, since rampant caries is a major and avoidable morbidity.
• Treat oral candidiasis, which is frequent in the dry mouth.
• Ocular management with lubricants, ciclosporin drops and punctal plugs, under ophthalmology.
• Hydroxychloroquine for arthralgia and fatigue, with systemic immunosuppression and rituximab for extraglandular disease.
• Surveillance for lymphoma, since the risk is 15 to 20 fold increased. Persistent unilateral gland enlargement, a new mass, a fall in immunoglobulin levels, a monoclonal band, cryoglobulinaemia, low C4, persistent lymphadenopathy and splenomegaly are the warning features, and any of these requires imaging and biopsy.

HIV associated parotid disease

• Antiretroviral therapy, which is the definitive treatment and which frequently produces regression of the lesions.
• Repeated aspiration of symptomatic cysts, with sclerotherapy in selected cases.
• Radiotherapy at low dose in refractory disease, though it is used less now that antiretroviral therapy is effective.
• Parotidectomy is generally avoided.
• Biopsy any dominant or growing lesion to exclude lymphoma and Kaposi sarcoma.

Sarcoidosis

Systemic or intralesional corticosteroid, with steroid sparing immunosuppression for persistent disease, under respiratory or rheumatology care. Facial palsy in Heerfordt syndrome usually recovers with corticosteroid.

IgG4 related disease

Prednisolone 0.6 mg/kg daily with a taper, and rituximab for relapsing disease, under specialist care.

Sialadenosis

• Treat the underlying condition: glycaemic control in diabetes, alcohol cessation, nutritional rehabilitation, and eating disorder management with psychiatric and dietetic involvement in bulimia.
• Explain that no antibiotic or surgical treatment is required, since these patients are frequently subjected to repeated antibiotic courses.
• The swelling frequently improves with treatment of the cause, though slowly.
• Bulimia related enlargement improves over months of abstinence from purging.

Pneumoparotid

Behaviour modification, avoidance of the causative activity where possible, and antibiotics for secondary infection. Persistent cases occasionally require duct ligation or parotidectomy.

Follow up

Ultrasound at 6 to 8 weeks after any acute episode to exclude an underlying stone, stricture or mass. Persistent unilateral enlargement after treatment of any inflammatory condition requires imaging and tissue, since a neoplasm may be masked by, or coexist with, inflammatory disease. Lifelong surveillance in Sjögren syndrome for lymphoma.