see also:

• encephalitis
• neurology
• progressive multifocal leukoencephalopathy (PML)
• multiple sclerosis (MS)

• a broad term which is variably used but essentially is used when there is acute or subacute global organic dysfunction of cerebral function which may or may not be reversible
• this usually results in inability to concentrate, personality changes, lethargy, loss of cognitive function, delirium and decreased conscious state.
• there may be associated myoclonus, asterixis, nystagmus, tremor, seizures, and restless picking at objects

• hypertensive
  • acute hypertensive encephalopathy, severe pre-eclampsia and eclampsia or some cytotoxics may cause:
    • posterior reversible encephalopathy syndrome (PRES)
• hepatic encephalopathy
• uraemic
• hypoxic or ischaemic
• Wernicke's
• chronic traumatic (repeated concussions)
• toxic - medications, substances
• metabolic derangements
• rare causes:
  • progressive multifocal leukoencephalopathy (PML) (mainly immunosuppressed patients including AIDS)
  • mitochondrial DNA dysfunction
  • glycine - genetic
  • Hashimoto's - autoimmune
  • Lyme disease
  • transmissible spongiform encephalopathy due to prions
  • encephalomyopathy due to chronic hypophosphatemia, as may occur in cystinosis or mitochonrial disease such as MELAS