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