Viral encephalitis causes
Template:Encephalitis Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editors-In-Chief: Priyamvada Singh, MBBS [2]
Overview
Encephalitis is an acute inflammation of the brain, commonly caused by a viral infection. Sometimes, encephalitis can result from a bacterial infection, such as bacterial meningitis, or it may be a complication of other infectious diseases like rabies (viral) or syphilis (bacterial). Certain parasitic or protozoal infestations, such as toxoplasmosis, malaria, or primary amoebic meningoencephalitis, can also cause encephalitis in people with compromised immune systems. Additionally, fungal, and autoimmune disorders can also produce encephalitis
Causes
Life Threatening Causes
Common Causes
Encephalitis is a rare condition. It occurs more often in the first year of life and decreases with age. The very young and the elderly are more likely to have a severe case. Encephalitis is most often caused by a viral infection. The virus causes inflammation of brain tissue. The brain tissue swells (cerebral edema), which may destroy nerve cells, cause bleeding in the brain (intracerebral hemorrhage), and brain damage. Many types of viruses may cause it. Exposure to viruses can occur through:
- Breathing in respiratory droplets from an infected person
- Contaminated food or drink
- Mosquito, tick, and other insect bites
- Skin contact
Different viruses will occur in different locations. Many cases will tend to cluster in a certain season. Encephalitis caused by the herpes simplex virus is the leading cause of more severe cases in all ages, including newborns. A number of viruses for which there is now a vaccine may also cause encephalitis. These include:
Other viruses that cause encephalitis include:
- Adenovirus
- Coxsackievirus
- Cytomegalovirus
- Eastern Equine Encephalitis Virus
- Echovirus
- West Nile virus
Causes by Organ System
| Cardiovascular | No underlying causes |
| Chemical / poisoning | No underlying causes |
| Dermatologic | No underlying causes |
| Drug Side Effect | No underlying causes |
| Ear Nose Throat | No underlying causes |
| Endocrine | No underlying causes |
| Environmental | No underlying causes |
| Gastroenterologic | No underlying causes |
| Genetic | No underlying causes |
| Hematologic | Vasculitic Neuropathy |
| Iatrogenic | No underlying causes |
| Infectious Disease | Botulism, diphtheria, lyme disease, poliomyelitis, CMV, paresis caused by West Nile fever |
| Musculoskeletal / Ortho | No underlying causes |
| Neurologic | Cauda equina syndrome, conus medullaris, chronic inflammatory demyelinating polyneuropathy, myasthenia gravis, multiple sclerosis, acute myelopathies with chronic back pain and sphincter dysfunction |
| Nutritional / Metabolic | Metabolic myopathies, nutritional neuropathy, |
| Obstetric/Gynecologic | No underlying causes |
| Oncologic | No underlying causes |
| Opthalmologic | No underlying causes |
| Overdose / Toxicity | Heavy metal toxicity, poisonings with organophosphate, poison hemlock, thallium, or arsenic |
| Psychiatric | No underlying causes |
| Pulmonary | No underlying causes |
| Renal / Electrolyte | No underlying causes |
| Rheum / Immune / Allergy | No underlying causes |
| Sexual | No underlying causes |
| Trauma | No underlying causes |
| Urologic | No underlying causes |
| Miscellaneous | Porphyria |