Neurocognitive Disorders, Delirium and Organic Psychiatry
Delirium
Acute onset, fluctuating course, inattention, altered consciousness, perceptual disturbance. Use the 4AT or CAM. Identify and treat the cause (infection, drugs, metabolic, hypoxia, pain, constipation, retention). Non-pharmacological measures first; antipsychotics only for severe distress or risk, at the lowest dose for the shortest time.
Dementia
Progressive cognitive decline affecting function. Distinguish Alzheimer's (memory-led), vascular (stepwise, focal signs), Lewy body (fluctuations, visual hallucinations, parkinsonism, neuroleptic sensitivity), frontotemporal (behaviour/language), and reversible mimics (hypothyroidism, B12 deficiency, depression, normal pressure hydrocephalus).
Organic psychiatry
Recognise psychiatric presentations of medical illness: psychosis in autoimmune encephalitis, depression in hypothyroidism, anxiety in hyperthyroidism, personality change in frontal lesions, and catatonia in medical illness.
Traps
Diagnosing dementia without excluding delirium; missing depression as pseudodementia; prescribing antipsychotics in Lewy body disease; forgetting capacity assessment in cognitive impairment.
Worked rule of thumb
Any acute confusion with inattention is delirium until proven otherwise, even in a patient with known dementia. Screen for causes and review medication before labelling as dementia progression.