Sialadenitis & Parotitis

Detailed Overview

Acute bacterial sialadenitis (suppurative sialadenitis) usually occurs in elderly, debilitated, or dehydrated patients where salivary stasis allows retrograde ascent of oral bacteria (Staphylococcus aureus) up the salivary duct. Viral parotitis is classically caused by the Mumps virus. Chronic sialadenitis often stems from recurrent obstructions by salivary stones (sialoliths), primarily in the submandibular duct (Wharton's duct) due to its tortuous, uphill course and alkaline, mucin-rich saliva. Autoimmune parotitis is a hallmark of Sjogren syndrome.

Epidemiology & Demographics

Bacterial sialadenitis predominantly affects elderly or post-operative dehydrated patients. Sialolithiasis affects 1% of the adult population, most commonly between 30-60 years of age. Submandibular stones are 4 times more common than parotid stones.

Etiological Mechanism

Acute bacterial is overwhelmingly Staphylococcus aureus. Viral is Mumps paramyxovirus, though HIV and Coxsackievirus are implicated. Obstructive is caused by calcium phosphate stones. Autoimmune involves lymphocytic infiltration in Sjogren syndrome.

Primary Causes

Staphylococcus aureus infection

Sialolithiasis (Salivary Stones)

Mumps Virus

Dehydration and Salivary Stasis

• Dehydration: Reduced salivary flow (xerostomia) allows bacteria to ascend the ducts.
• Anticholinergic Medications: Drugs like diphenhydramine or TCAs dry out oral secretions, promoting stasis.
• Poor Oral Hygiene: High oral bacterial load increases risk of ascending infection.

In acute bacterial sialadenitis, decreased salivary flow compromises the mechanical flushing and antimicrobial properties of saliva (lysozyme, IgA). Commensal oral flora ascends the Stensen (parotid) or Wharton (submandibular) duct, causing acute suppurative inflammation, microabscess formation, and purulent discharge. In sialolithiasis, calcium salts deposit around a nidus of desquamated cells or mucus, forming a calculus. The stone partially or totally occludes the duct, leading to saliva backing up during meals (mealtime syndrome), increasing intraparenchymal pressure, causing intense pain, and eventually leading to chronic glandular fibrosis and acinar atrophy.

Characteristic Clinical Presentation

• Colicky 'Mealtime' Pain: Sudden, severe pain and swelling of the gland that occurs precisely when smelling or eating food (classic for sialolithiasis).
• Glandular Swelling: Erythematous, indurated, and exquisitely tender swelling over the angle of the jaw or under the chin.
• Foul Taste: Due to purulent exudate draining into the mouth.

Physical Examination Signs

• Purulent Duct Discharge
• Palpable Stone

• Deep Neck Space Abscess: Infection spreading beyond the parotid fascia into the parapharyngeal space, risking airway compromise.
• Chronic Sclerosing Sialadenitis: Fibrotic destruction of the gland from recurrent infections (Kuttner tumor).

Diagnostic Criteria & Guidelines

Largely a clinical diagnosis based on history and physical exam (expression of pus). Imaging is required to identify stones or rule out abscess formation.

Differential Diagnosis

• Salivary Gland Neoplasm (Pleomorphic Adenoma)
• Dental Abscess
• Cervical Lymphadenitis

Laboratory Tests & Biomarkers

• Complete Blood Count: Leukocytosis with a left shift in acute suppurative bacterial infection.
• Pus Culture: Gram stain and culture of ductal discharge typically grows S. aureus.

Imaging Modalities & Findings

• CT Neck with Contrast:
• High-Resolution Ultrasound:

• Acute Simple Sialadenitis
  Inflammation and pain without abscess formation.
• Suppurative Sialadenitis with Abscess
  Collection of pus within the fascial capsule of the gland, risking deep space neck infection.

Second-Line & Adjunctive Therapy

For unresponsive infection or formed abscess: Surgical Incision and Drainage of the gland. For recurrent stones: Sialendoscopy (minimally invasive endoscopic basket retrieval of the stone) or lithotripsy.

Surgical & Procedural Management

Sialadenectomy (surgical excision of the entire submandibular or parotid gland) is reserved for severe chronic refractory sialadenitis or intractable giant stones. Parotidectomy carries a high risk of Facial Nerve (CN VII) injury.

Recommended Lifestyle Changes

• Stay highly hydrated (drink 2-3 liters of water daily).
• Maintain meticulous oral hygiene.
• Use sour candies or lemon juice to regularly stimulate salivary flow.

Patient Counseling & Advice

Advise patients to frequently massage the gland from back to front toward the mouth to promote drainage and prevent stasis. Warn about the signs of spreading neck infection (difficulty breathing or swallowing).

Follow-Up & Monitoring Schedule

Clinical re-evaluation in 48-72 hours to ensure antibiotic response and rule out abscess formation.

Preventive Strategies

Hydration and avoidance of anticholinergic medications in susceptible populations.

Excellent with prompt antibiotic therapy and hydration. Obstructive sialadenitis tends to recur unless the underlying stone is completely removed.