Causes of Acute delirium

Infection Particularly UTI, pneumonia; rarely, encephalitis/meningitis

Drugs Opioids, sedatives, levodopa, anticonvulsants, recreational drugs

Metabolic Hypoglycaemia, hyponatraemia, uraemia, liver failure, hypercalcaemia, other electrolyte imbalance (rarer)

Alcohol or drug withdrawal

Hypoxia, e.g. pneumonia, exacerbation of COPD, cardiac failure

Cardiovascular MI, stroke, TIA

Intracranial lesion Space-occupying lesion,  increased ICP, head injury (especially subdural haematoma)

Thyroid disease

Carcinomatosis

Epilepsy Temporal lobe epilepsy, postictal state.

Nutritional deficiency B12, thiamine, or nicotinic acid deficiency