Encephalitis

Infection of brain parenchyma

Signs and symptoms include confusion, fever, coma, seizures, motor abnormalities, change of behaviour, drowsiness. Symptoms may overlap with meningitis and the 2 may coexist.

Learning bite- The clinical progress of encephalitis may be insidious in its presentation, sometimes manifesting as nothing more than altered behaviour. A high index of suspicion is needed, especially in the younger child and infant.

Causative organisms- HSV, adenovirus, arbovirus, enterovirus and Mycoplasma pneumoniae.

Investigations- CSF findings may be non specific, PCR for HSV and enterovirus should be performed. CT, MRI and EEG may also help with the diagnosis.

Treatment- Aciclovir, Cefotaxime and Azithromycin.

Prognosis- dependent on age (worse in <1s). Untreated Herpes simplex encephalitis has a mortality of 50-75%, with 40% of survivors have major or minor motor or mental sequelae.