Viral meningitis overview
|
Viral meningitis Microchapters |
|
Diagnosis |
|
Treatment |
|
Case Studies |
|
Viral meningitis overview On the Web |
|
American Roentgen Ray Society Images of Viral meningitis overview |
|
Risk calculators and risk factors for Viral meningitis overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Ahmed Elsaiey, MBBCH [2]
Overview
Viral meningitis is a condition in which the layers lining of the brain, or meninges, become inflamed due to a viral infection. Meningitis is diagnosed on a history of characteristic symptoms and certain examination findings (e.g. Kernig's sign). Investigations should show an increase in the number of leukocytes present in the cerebrospinal fluid (CSF), obtained via lumbar puncture.
Historical Perspective
Meningitis was first discovered by the hippocrats. Wallgren described aseptic meningitis in 1924 and defined it as a disease with acute onset that had typical systematic symptoms of meningeal involvement, in association with a cerebrospinal fluid (CSF) typical of meningitis (typically with a mononuclear cell predominance). Additionally, there was absence of bacteria on stain and culture and there was no identifiable parameningeal infection.[1]
Classification
There is no specific classification to the viral meningitis. However, it may be classified based on the age into child and adult viral meningitis. It may be also according to the causative virus like enterovirus, arbovirus, mumps and herpes simplex viruses.
Pathophysiology
Viral meningitis pathophysiology differs from virus to another and depends on many factors like age, immune status and gene expression. Invasion into the meninges by a pathogen can set up a local inflammatory response. The clinical signs are due to this meningeal irritation - for example, Kernig's sign is due to pain produced by stretching of the inflamed meninges.
Causes
Viral meningitis is caused by many viruses. The most important and the most common virus group that causes meningitis is Enteroviruses group. There are other viruses cause meningitis as Arbovirus and herpes simplex virus groups but not common as the enteroviruses.[1][2][3]
Risk Factors
The viruses that cause viral meningitis are contagious. Enteroviruses, for example, are very common during the summer and early fall, and many people are exposed to them. However, most infected persons either have no symptoms or develop only a cold or rash with low-grade fever. Only a small proportion of infected persons actually develop meningitis. Therefore, if you are around someone who has viral meningitis, you have a moderate chance of becoming infected, but a very small chance of developing meningitis.
Natural History, Complications and Prognosis
Patients typically had a relatively short and benign course. Other terms sometimes included in the umbrella ‘aseptic meningitis’ (AM) are lymphocytic, viral, chemical, non-bacterial and sterile. Currently, the term AM is used to describe patients with no detectable bacterial cause after initial CSF evaluation. Unfortunately, it is often difficult to predict who will have a life-threatening disease from those who will rapidly recover without specific treatment.
Medical Therapy
Treatment is needed for fungal or mycobacterial causes of aseptic meningitis. Herpesvirus or varicella (chickenpox) virus may be treated with antiviral medicines. Treatment for noninfectious causes consists of pain medications and managing complications, if they occur. No specific treatment is available for enteroviral or most other viral forms of aseptic meningitis.
References
- ↑ Logan SA, MacMahon E (2008). "Viral meningitis". BMJ. 336 (7634): 36–40. doi:10.1136/bmj.39409.673657.AE. PMC 2174764. PMID 18174598.
- ↑ Rotbart HA (2000). "Viral meningitis". Semin Neurol. 20 (3): 277–92. doi:10.1055/s-2000-9427. PMID 11051293.
- ↑ Yi EJ, Shin YJ, Kim JH, Kim TG, Chang SY (2017). "Enterovirus 71 infection and vaccines". Clin Exp Vaccine Res. 6 (1): 4–14. doi:10.7774/cevr.2017.6.1.4. PMC 5292356. PMID 28168168.