Table Of Contents
Encephalitis
Encephalitis is an infection and inflammation of the brain parenchyma resulting in neurological dysfunction. The common causes of encephalitis are viruses (HSV, CMV, VZV, West Nile). The most common entry point is the olfactory nerves. It commonly affects the temporal lobe, presenting somewhat similar to an ischemic stroke in the temporal-parietal area. Patients may have meningeal symptoms because infection often extends into or from the meningeal space (commonly early in the disease presentation). IV empiric therapy should be commenced immediately if encephalitis is suspected. Even with treatment, the mortality rate is up to 30%.
- Signs and symptoms
- Fever
- Headache
- Nausea
- Vomiting
- Meningism (nuchal rigidity, positive Kernig, positive Brudzinski)
- Focal neurologicla deficits (may present as a ”stroke” in a young patient)
- Confusion
- Behavioral disturbances
- Altered Mental Status
- Seizures
- Investigations
- Head CT: best first diagnostic step;
- Temporal lobe enhancement can be seen in CT (Herpes encephalitis)
- Hypodense lesions in the temporal lobe
- Cerebral edema
- LP with CSF analysis and HSV PCR: to differentiate encephalitis from meningitis, will show a viral picture (high protein, high lymphocytes, normal glucose)
- Head CT: best first diagnostic step;
- Treatment
- IV empiric therapy
- Acyclovir + dexamethasone
- Ganciclovir or foscarnet for suspected CMV encephalitis (HIV/AIDS, immunocompromised patient)
- Seizure prophylaxis (in patients with raised ICP)
- Scheduled Benzodiazepines (Lorazepam and diazepam)
- Diuretics (Furosemide and Mannitol) to lower ICP
- Prophylaxis for treatment of close contacts
- Ciprofloxacin OR Rifampin
- IV empiric therapy
- Complications of encephalitis
- Residual neurological deficits
- Epilepsy
