Description

• Acute bacterial infection of a cervical lymph node
  • Often arising after a prior bacterial infection of the head or neck area
• Primarily a pediatric disease:
  • Becoming more common in adults owing to immunocompromised disease states (HIV, cancer, transplant patients)
• Any cervical node can become infected:
  • >80% of childhood cervical lymphadenitis involves the submandibular or deep cervical nodes
  • Jugulodigastric node located just below the angle of the mandible is common site
  • Cervical nodes act as the final common pathway for lymphatic drainage of all areas of the head and neck
  • Initial lymphadenopathy results after bacterial invasion of regional areas of the head and neck
  • Local lymph nodes swell secondary to hyperplasia of sinusoidal cells and infiltration of lymphocytes
  • If the infection is not contained, the bacteria enter the lymph system and proliferate (lymphadenitis)
  • Pus forms when neutrophils are incited, and an abscess develops when host defenses are unable to clear infection
  • Clinically manifests as warm, tender, swollen, erythematous node

Etiology

• ∼70% of cases are a result of group A β-hemolytic Streptococcal infection
  • 20% Staphylococcal infection
  • 10% related to viral infection or other bacteria
• Infections secondary to community-acquired MRSA (CA-MRSA) have increased in frequency
• Children have one of the highest rate of CA-MRSA colonization and invasive disease
• Mycobacteria TB:
  • Scrofula or tuberculous lymphadenitis
  • Rarely seen
  • Usually a chronic lymphadenitis in the posterior cervical nodes
  • Purified protein derivative (PPD) is usually strongly reactive
  • Treatment is nonsurgical
• Atypical mycobacteria (nontuberculous) Mycobacterium avium complex:
  • More commonly seen
  • Usually a chronic lymphadenitis in the submandibular or anterior cervical nodes
  • PPD test results are unreliable
  • Treatment is primarily surgical
• Bartonella henselae (catscratch disease):
  • Subacute lymphadenitis
  • Fever and mild systemic symptoms occur in only ∼3% of patients
  • Has indolent course but usually spontaneously resolves after 4–6 wk
• Anaerobes:
  • Consider when associated with infections of the teeth or gingiva
• Rare organisms:
  • Gram-negative bacilli
  • Yersinia pestis
  • Group B streptococcus
  • Francisella tularensis
  • Alpha-streptococcus
  • Anthrax

• One of the most common causes of a neck mass in a child
• Overall, group A Streptococcus and Staphylococcus aureus most common causes
• In neonates, group B Streptococcus and S. aureus most common
• Group B Streptococcal cellulitisadenitis syndrome:
  • Infants are usually 3–7 wk of age, male, febrile, with submandibular or facial cellulitis, and an ipsilateral otitis media
  • 94% incidence of concurrent bacteremia
• S. aureus associated with more indolent course and higher frequency of suppuration
• Viral infections generally result in bilateral lymphadenopathy

• Consider malignancy over infection in this population, especially in the absence of fever, leukocytosis, etc.
• Fixed, nontender, hard node most likely not cervical adenitis