II. Epidemiology
- Age: under 30 years (90%)
- Peaks in late summer
III. Etiology: Common
- Coxsackie virus
- Echovirus
IV. Causes
- Most common in children
- Enterovirus or Arbovirus (summer, fall)
- Herpes Simplex Virus (HSV)
- Most common in adults
- Enterovirus
- Herpes Simplex Virus (HSV, typically HSV 2)
- 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
- HSV1 (typically causes HSV Encephalitis instead of Meningitis)
- HSV2 Meningitis (Mollaret Meningitis) - most common of herpes virus Meningitis
- Causes primary and secondary recurrent lymphocytic Meningitis
- Epstein Barr Virus (Mononucleosis)
- Cytomegalovirus
- Varicella Zoster Virus
- 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)
V. Symptoms
VI. Signs
- Fever (maximum 38-40 degrees Celsius)
- Meningeal Irritation
- Rash (Coxsackie or Echovirus)
-
Herpangina (Coxsackie Virus)
- Painful Vesicles at posterior third of oropharynx
VII. Differential Diagnosis
-
Aseptic Meningitis
- Includes Viral Meningitis, fungal Meningitis, malignancy, Autoimmune Conditions, medications
-
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. Labs: Cerebrospinal Fluid (CSF)
- CSF White Blood Cells: 10-100 (75% Lymphs)
- CSF Protein Normal
-
CSF Glucose Normal
- May be reduced in Mumps and HSV
- CSF Culture Negative
IX. Course
- Fever typically resolves in 3-5 days
- CSF Leukocytes increased for weeks
X. Management
- Symptomatic Therapy
- See Meningitis
- See Bacterial Meningitis Management
- Empiric Antibiotics for Meningitis if diagnosis unclear
XI. 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]