What is the etiology of parotitis?

Etiology of Parotitis

Parotitis is primarily caused by viral or bacterial infections, with predisposing factors including dehydration, decreased salivary flow, and immunocompromised states. 1, 2

Infectious Causes

Viral Etiologies

• Paramyxovirus (mumps) - historically the most common viral cause 2
• Epstein-Barr virus - often associated with infectious mononucleosis 3
• Other viral agents: coxsackievirus, influenza A, parainfluenza viruses, cytomegalovirus, and herpes simplex virus 3, 2

Bacterial Etiologies

• Staphylococcus aureus - most common bacterial pathogen, accounting for approximately 80% of bacterial cases 4, 1
• Streptococcus species - including Group A, C, and G streptococci 3, 1
• Anaerobic bacteria:
  • Peptostreptococcus species 2
  • Bacteroides species 2
  • Pigmented Porphyromonas and Prevotella species 1, 2
  • Fusobacterium species 1
• Gram-negative organisms (more common in hospitalized patients):
  • Escherichia coli 1
  • Pseudomonas aeruginosa 1
  • Klebsiella pneumoniae 1
• Less common bacterial causes:
  • Mycobacterium tuberculosis (rare) 1
  • Atypical mycobacteria 1
  • Haemophilus influenzae 1
  • Salmonella species 1
  • Eikenella corrodens 1

Predisposing Factors

Reduced Salivary Flow

• Dehydration - particularly in elderly or debilitated patients 1, 2
• Medications that reduce salivation (anticholinergics, antihistamines, diuretics) 2
• Sjögren syndrome - autoimmune condition causing chronic suppurative parotitis 4
• Other autoimmune conditions (e.g., rheumatoid arthritis) 4

Mechanical Factors

• Salivary duct obstruction 5
• Sialolithiasis (salivary stones) 2
• Duct malformations (particularly in juvenile recurrent parotitis) 6

Host Factors

• Malnutrition 2
• Immunosuppression 1, 2
• Advanced age 4
• Oral neoplasms 2
• Post-surgical or post-radiation changes 3

Clinical Patterns

Acute Suppurative Parotitis

• Characterized by sudden onset of pain, swelling, and purulent discharge 1
• Often associated with dehydration and poor oral hygiene 1, 2
• Commonly caused by bacterial infection, particularly S. aureus 1

Chronic Recurrent Parotitis

• Characterized by repeated episodes of painful swelling 5, 6
• Two main forms:
  • Juvenile form - often self-limiting as patients grow up (90% of cases) 6
  • Adult form - typically associated with ductal strictures or stenoses 6
• May be associated with autoimmune conditions like Sjögren syndrome 4

Diagnostic Considerations

• Differentiate local primary parotid infection from systemic infection 2
• Consider non-infectious causes such as autoimmune conditions 4
• Evaluate for obstructive versus non-obstructive disease 5, 6
• In cases of purulent discharge, cultures should be obtained for both aerobic and anaerobic bacteria 1, 2
• Beta-lactamase-producing organisms can be isolated in approximately 75% of patients 2

Prevention and Management

• Maintain adequate hydration 1, 2
• Ensure good oral hygiene 1
• Early and appropriate antimicrobial therapy for bacterial infections 1, 2
• Conservative approaches for chronic cases: gland massage, sialagogues, local heat application 4, 6
• Surgical drainage may be required for abscess formation 1
• Sialendoscopy with duct rinsing and corticosteroid instillation for recurrent cases 6
• Total parotidectomy as last resort for severe chronic cases 5, 6