Metabolic/endocrine | Uraemic encephalopathy |
Hepatic encephalopathy | |
Hypo/hyperthyroid | |
Hypoglycaemia | |
Hyponatraemia (including central pontine myelinolysis) | |
Hypercalcaemia | |
Drug/toxic/nutritional | Chemotherapy (eg, methotrexate) |
Lithium toxicity | |
Alcohol | |
Chronic carbon monoxide poisoning | |
Wernicke–Korsakoff syndrome | |
Vitamin B12 deficiency | |
Infection | |
Systemic | Pneumonia, urinary tract |
CNS | HSV1/2, enterovirus, varicella zoster, Epstein–Barr, Lyme, HIV, TB, listeria |
In immunocompromised | Syphilis, HHV 6, cytomegalovirus, measles, JC virus (progressive multifocal leukoencephalopathy), fungal/parasitic |
Autoimmune antibody associated | Paraneoplastic |
Non-paraneoplastic—antivoltage gated potassium channel antibodies | |
Malignancy (non-paraneoplastic) | Malignant meningitis |
Primary CNS malignancy | |
Cerebral metastases | |
Inflammatory | Vasculitis |
Sarcoid | |
Systemic lupus erythematosus | |
Sjögren's syndrome | |
Hashimoto's encephalopathy | |
Multiple sclerosis/acute disseminated encephalomyelitis | |
Vascular | Intracranial venous thrombosis |
Behcet's disease | |
Neurodegenerative | Prion disease—sporadic, variant, genetic and iatrogenic CJD |
Rarely rapid presentations of other neurodegenerative diseases such as Alzheimer's disease, and dementia with Lewy bodies | |
Other | Mitochondrial cytopathy |
Psychiatric such as schizophrenia and severe depression | |
Irradiation |
CJD, Creutzfeldt–Jakob disease; HHV, human herpes virus; HSV, herpes simplex virus; TB, tuberculosis.