Geriatric Psychiatry and Neuropsychiatry
This domain tests the distinction between delirium, dementia and depression in older people, recognition of dementia subtypes, and safe prescribing. The single most examined point is that acute confusion in an older person is delirium until proven otherwise.
Core distinctions
Delirium has acute onset, fluctuating course and impaired attention, with altered consciousness; use the CAM or 4AT. Common causes are infection, drugs (especially anticholinergics, opioids, steroids and benzodiazepines), pain, urinary retention, constipation, dehydration and electrolyte disturbance. Non-pharmacological measures come first; antipsychotics are for short-term use when there is severe distress or risk.
Dementia is chronic and progressive with relatively preserved consciousness. Alzheimer disease shows insidious memory loss with medial temporal atrophy; vascular dementia shows a stepwise course with focal signs; Lewy body dementia shows fluctuating cognition, recurrent visual hallucinations, parkinsonism and REM sleep behaviour disorder, with severe neuroleptic sensitivity; frontotemporal dementia presents with personality change or language disorder at a younger age.
Depression in later life may mimic dementia (pseudodementia) with prominent apathy and answered-with-complaint responses; it also worsens cognition and increases mortality.
Capacity and prescribing
Capacity is decision-specific: the person must understand, retain, weigh and communicate the decision. Depression in older adults is treated with lower starting doses of SSRIs such as sertraline, avoiding tricyclics and paroxetine because of anticholinergic and cardiac risk. ECT is effective and safe when medically optimised. Falls, hyponatraemia and bleeding risk with SSRIs need attention.
Worked example
A 79-year-old becomes acutely confused and agitated two days after admission, having started oxybutynin. Reasoning: acute onset, inattention and fluctuation indicate delirium, and the anticholinergic drug is the likely precipitant. Management is stopping the drug, treating infection or retention, orientation and sleep hygiene, with antipsychotics only if needed briefly.
Traps that cost marks
Diagnosing dementia while delirium is present. Giving antipsychotics in Lewy body dementia. Missing hypothyroidism, B12 deficiency, subdural haematoma or normal pressure hydrocephalus. Attributing weight loss and low mood to age alone. Overlooking high-lethality suicide attempts in older men.