Salivary glands
Inflammatory
Sialadenitis-infectious

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Minor changes: 26 October 2020

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PubMed Search: Sialadenitis[TI] salivary[TI]

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Cite this page: Ely KA. Sialadenitis-infectious. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/salivaryglandssialadenitis.html. Accessed October 26th, 2020.
Definition / general
  • Infection / inflammation of the salivary glands of either bacterial (acute suppurative sialadenitis) or viral origin
    • Paramyxovirus (mumps) is the best known cause of viral sialadenitis
Essential features
  • Acute suppurative sialadenitis
    • Results from ascending bacterial contamination from the oral cavity in a setting of impaired salivary flow
    • Staphylococcus aureus is the most common cause
    • Usually affects parotid of either preterm infants or the elderly
  • Viral sialadenitis
    • Causative agents include paramyxovirus (mumps), cytomegalovirus, coxsackievirus, herpes simplex virus, influenza A, parainfluenza and adenovirus
    • Viral sialadenitis due to mumps
      • Occurs mainly in those less than 15 years old (85%)
      • Affects the parotid bilaterally with epididymo-orchitis occurring in 20 - 30% of postpubertal males (Am J Hyg 1959;69:91)
      • Peaks in late winter / early spring for those in temperate climates
Terminology
  • Acute suppurative sialadenitis is also known as acute sialadenitis or bacterial sialadenitis
  • Viral sialadenitis (mumps)
ICD coding
  • ICD-10: K11.20 - Sialoadenitis, unspecified
  • ICD-10: K11.21 - Acute sialoadenitis
Epidemiology
  • Acute suppurative sialadenitis is most common in preterm infants and the elderly (J Craniofac Surg 2003;14:37)
    • Predisposing factors include dehydration, obstruction (sialolithiasis), malnourishment, immunosuppression, chronic illness, certain medications (i.e. anticholinergics) and diabetes mellitus (Am Fam Physician 2014;89:882)
  • Viral sialadenitis caused by mumps peaks in late winter / early spring for those in temperate climates
    • 85% occur in those less than 15 years old
    • Risk factors include compromised immunity, international travel and lack of vaccination (StatPearls: Mumps [Accessed 1 September 2020])
    • While immunization has reduced the frequency paramyxovirus (mumps), there were 150 outbreaks and 9,000 cases in the United States between 2015 and 2017 (JAMA 2019;322:1022)
Sites
  • Both affect the parotid; however, mumps is typically bilateral
    • Parotid is more prone to acute suppurative sialadenitis because serous saliva is less able to protect against bacterial infection than the mucoid rich content of saliva from the sublingual and submandibular glands (Oral Maxillofac Surg Clin North Am 2009;21:353)
Pathophysiology
  • Mumps is caused by the single stranded RNA paramyxovirus and humans are the only natural hosts (Int J Environ Res Public Health 2020;17:1686)
    • Highly contagious and transmitted by droplet infection from respiratory secretions
Etiology
  • Acute suppurative sialadenitis is due to retrograde bacterial contamination from the oral cavity in a setting of impaired salivary flow
    • Staphylococcus aureus is the most common cause; Streptococcal species and Haemophilus influenza are also common (Ann Surg 1962;156:251)
  • Viral sialadenitis results from systemic infection by a virus rather than direct infection (Otolaryngol Clin North Am 2014;47:763)
Clinical features
  • Patients present with tender enlargement of the salivary glands
    • Epididymo-orchitis occurs in 20 - 30% of postpubertal males affected by mumps (Am J Hyg 1959;69:91)
Diagnosis
  • Diagnosis of mumps is made on symptoms and physical exam and is supported by serology or reverse transcription PCR (RT-PCR) (J Virol Methods 2020;277:113817)
Case reports
Treatment
  • Acute suppurative sialadenitis is managed by antimicrobial therapy based on culture result with surgical drainage if abscess develops
  • Mumps is self limited
Microscopic (histologic) description
  • Diagnoses of both acute suppurative and viral sialadenitis are usually reached on clinical grounds, although rarely biopsied
    • Acute suppurative sialadenitis is associated with edema, hyperemia and acute inflammation
    • Viral sialadenitis shows diffuse interstitial edema, intense hyperemia and a dense lymphohistiocytic infiltrate (Am J Pathol 1949;25:1105)
Sample pathology report
  • Parotid, right, biopsy:
    • Acute suppurative sialadenitis (see comment)
    • Comment: There is edema, hyperemia, bacteria and increased numbers of neutrophils. Neutrophils surround and infiltrate ducts and focally is associated with duct destruction. If clinically indicated, correlation with culture results would be helpful in directing appropriate antibiotic therapy.
Differential diagnosis
  • Diagnosis of infectious sialadenitis is usually made clinically and thus microscopic evaluation is rare
    • Cytomegalovirus:
      • Intranuclear "owl’s eye" viral inclusions in ducts and acini
      • Lacks acute inflammation
    • Tuberculosis:
      • Usually within an intraparotid or periparotid lymph node
      • Necrotizing granulomas
      • Acid fast bacilli on Ziehl-Nielson stain
      • Lacks acute inflammation
Board review style question #1
What is the most common bacterial cause of acute suppurative sialadenitis?

  1. Actinomyces
  2. Escherichia coli
  3. Haemophilus influenzae
  4. Peptostreptococcus species
  5. Staphylococcus aureus
Board review answer #1
E. Staphylococcus aureus

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Reference: Sialadenitis-infectious
Board review style question #2
Acute suppurative sialadenitis most often affects the

  1. Minor salivary glands
  2. Parotid gland
  3. Sublingual gland
  4. Submandibular gland
Board review answer #2
B. Parotid gland

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Reference: Sialadenitis-infectious
Board review style question #3
Which of the following is true about mumps?

  1. Has been eradicated since the introduction of the mumps vaccine
  2. Is caused by double stranded DNA paramyxovirus
  3. Most commonly presents as epididymo-orchitis
  4. Usually affects those less than 15 years old
Board review answer #3
D. Usually affects those less than 15 years old

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Reference: Sialadenitis-infectious
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