Lymphadenitis

Basics

Description

  • Lymph nodes are inflamed causing enlargement and tenderness
    • Become engorged with lymphocytes and macrophages
    • May be infected
  • Classified by location and acuity of node enlargement
    • Acute regional
      • Infection in distal extremity may result in adenitis proximally
      • Acute suppurative lymphadenitis may occur after pharyngeal or skin infection
    • Causes of chronic regional and systemic lymphadenitis are mentioned in this chapter, but are more fully discussed in disease-specific chapters

Etiology

  • Cervical:
    • Viral: common, usually bilateral adenitis
      • Epstein–Barr virus (EBV)
      • Cytomegalo virus (CMV)
      • Adenovirus (or other causes of upper respiratory infection)
    • Bacterial: Common, either bilateral or unilateral, more likely to be suppurative
      • Skin origin: Staphylococcus aureus: Both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA), group A β-hemolytic Streptococcus
        • Staph risk factors discussed below
      • Pharyngeal origin: Group A β-hemolytic Streptococcus
      • Periodontal origin: Group A β-hemolytic Streptococcus and anaerobes
      • Mycobacterium tuberculosis, atypical mycobacterium – uncommon; subclinical course
      • Bartonella henselae: Cat-scratch disease; subclinical course
  • Axillary:
    • Streptococcus pyogenes (group A β-hemolytic Streptococcus)
      • Fever, axillary pain, and acute lymphedema of arms and chest, without features of cellulitis or lymphangitis; ipsilateral pleural effusion may be present; primary source arm or hand
    • Skin origin: S. aureus and group A β-hemolytic Streptococcus
    • B. henselae: Cat-scratch disease
      • Most common lymph node region affected, subclinical course
  • Inguinal:
    • Skin origin: Usually unilateral
      • S. aureus: Both MSSA and MRSA, group A β-hemolytic Streptococcus
      • Sexually transmitted disease: Can be unilateral or bilateral
      • Syphilis (primary and secondary)
      • Lymphogranuloma venereum (LGV) – Chlamydia trachomatis
      • Chancroid
      • Primary genital herpes
    • B. henselae: Cat-scratch disease
      • Usually unilateral, subclinical course
    • Yersinia pestis: Bubonic plague:
      • Exposure to fleas from rodents or rabbits in western U.S.
      • Seen in hunters, backpackers, rural workers
  • S. aureus risk factors
    • Staph (MSSA and MRSA) more common in suppurative adenitis and/or abscess formation
    • Risk factors for Staph infection (MSSA and MRSA):
      • Recent hospital or long-term care admission
      • Recent surgery
      • Children
      • Soldiers
      • Incarcerated persons
      • Athletes in contact sports
      • Injection drug use
      • Men who have sex with men
      • Dialysis treatments and catheters
      • History of penetrating trauma
    • Additional risk factors for MRSA infection:
      • Prior MRSA infection
      • MRSA colonization
      • Area of high MRSA incidence, close contact with MRSA patient
  • Systemic lymphadenitis/lymphadenopathy:
    • HIV
    • EBV, CMV
    • Toxoplasmosis, acute
    • Miliary tuberculosis
    • Secondary syphilis
    • Leptospirosis

Pediatric Considerations
  • Acute unilateral cervical suppurative lymphadenitis:
    • Most common at age <6 yr
    • Group A Streptococcus, S. aureus, and anaerobes are most common causes
    • Source is pharyngeal or scalp
    • Acute torticollis possible

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