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Aseptic Meningitis

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Aseptic Meningitis

  • Definition
  1. Clinical findings consistent with Meningitis, but with negative CSF Culture
  • Epidemiology
  1. Aseptic Meningitis accounts for 96% of pediatric cases with Leukocytosis on CSF
  2. Incidence
    1. Infants (<1 year): 70 per 100,000
    2. Children (age 1 to 14): 5.2 per 100,000
    3. Adults: 7.6 per 100,000
    4. Martin (2016) Lancet Infect Dis 16(11): 1279-87 [PubMed]
    5. Kupila (2006) Neurology 66(10: 75-80 [PubMed]
  • Causes
  1. Most common in children
    1. Enterovirus or Arbovirus (summer, fall)
    2. Herpes Simplex Virus (HSV)
    3. Borrelia Burgdorferi (Lyme Disease)
  2. Most common in adults
    1. Enterovirus
    2. Herpes Simplex Virus (HSV)
    3. Varicella-Zoster Virus (VZV)
  3. Common viral infections causing Aseptic Meningitis
    1. Enterovirus (85% of Viral Meningitis)
      1. Echovirus (esp. children)
      2. Coxsackievirus (type A which causes hand, foot and mouth, and Type B)
      3. Polio Virus
    2. Arbovirus (Arthopod-borne viruses such as St. Louis Encephalitis virus, West Nile Virus)
    3. Herpes Viruses (esp. HSV 2, but also HSV 1, EBV, CMV, VZV)
    4. Acute Retroviral Syndrome (HIV Infection)
    5. Lymphocytic choriomeningitis virus (rodent-borne arena virus)
    6. Mumps
    7. Less common causes include Adenovirus, Measles, Rubella
  4. Bacteria causing Aseptic Meningitis (culture negative)
    1. Epidural or subdural Brain Abscess
    2. Partially treated Meningitis
    3. Leptospira
    4. Borrelia Burgdorferi (Lyme Disease)
    5. Mycobacterium tuberculosis (Tuberculous Meningitis)
    6. Less common: Syphilis, Chlamydia, Ehrlichiosis, Rocky Mountain Spotted Fever, Mycoplasma, Brucella
  5. Other causes of Aseptic Meningitis
    1. Cryptococcal Meningitis (Advanced HIV Infection or AIDS)
    2. Fungal Meningitis (Coccidioides, Histoplasma)
    3. Medications (esp. Ibuprofen, but also other NSAIDs, TMP-SMZ, pyridium, Azathioprine)
    4. Malignancy (e.g. Leukemia, Lymphoma, metastatic cancer)
    5. Autoimmune Conditions (Sarcoidosis, Behcet's Disease)
  • Symptoms
  1. Fever
  2. Headache
  3. Stiff neck
  4. Photophobia
  • Differential Diagnosis
  1. Bacterial Meningitis
    1. Often indistinguishable without Lumbar Puncture and CSF Culture
    2. Additional findings (e.g. Parotitis in mumps) may suggest cause
  2. Encephalitis (e.g. HSV Encephalitis, West Nile Virus, St. Louis Encephalitis)
    1. Abnormal brain function distinguishes Encephalitis from Meningitis
    2. Altered behavior, personality, Level of Consciousness, speech, movement or weakness
    3. Seizures may occur with either Meningitis or Encephalitis
  • Management
  1. See Meningitis
  2. See Bacterial Meningitis Management
    1. Empiric antibiotics for Meningitis if diagnosis unclear
  • References
  1. Johnson in Hirsch (2012) Aseptic Meningitis, UpToDate, Wolters-Kluwer, accessed 4/9/2016
  2. Wan in Roos (2015) Viral Meningitis, EMedicine, Medscape, accessed 4/9/2016
  3. Bamberger (2010) Am Fam Physician 82(12): 1491-8 [PubMed]
  4. Mount (2017) Am Fam Physician 96(5): 314-22 [PubMed]