Psychiatry
Geriatric Psychiatry
Geriatric psychiatry for MBBS and NEET-PG: delirium versus dementia, Alzheimer, vascular and Lewy body dementia, reversible mimics and cautious drug use, mapped to NMC codes PS16.
MedNext Academy | 3 min read
Geriatric Psychiatry
Geriatric psychiatry for MBBS and NEET-PG: delirium versus dementia, Alzheimer, vascular and Lewy body dementia, reversible mimics and cautious drug use, mapped to NMC codes PS16.
This chapter covers the mental health of older adults. It centres on the crucial distinction between delirium and dementia, the common types of dementia and their features, the reversible mimics that must be excluded, and the cautious use of medication, along with depression and psychosis in later life.
High-yield: Geriatric Psychiatry
- Delirium is an acute, fluctuating disturbance of attention and awareness caused by an underlying medical condition, and it is common and often reversible in older people.
- Dementia is a chronic, progressive decline in memory and other cognitive domains that impairs daily function, usually irreversible.
- The key distinction is that delirium is acute with clouded consciousness and fluctuating attention, whereas dementia is chronic with clear consciousness.
- Alzheimer disease is the commonest cause of dementia, with an insidious onset and prominent early memory loss.
- Vascular dementia has a stepwise decline linked to cerebrovascular disease and vascular risk factors.
- Lewy body dementia features fluctuating cognition, visual hallucinations and parkinsonism, and these patients are very sensitive to antipsychotics.
- Frontotemporal dementia presents earlier with personality and behavioural change or language difficulty rather than early memory loss.
- Reversible mimics of dementia include hypothyroidism, vitamin B12 deficiency, depression as pseudodementia, and normal pressure hydrocephalus.
- Cholinesterase inhibitors such as donepezil are used in Alzheimer disease, and memantine is added in moderate to severe disease.
- Antipsychotics are used cautiously in dementia because they increase the risk of stroke and death and are especially dangerous in Lewy body dementia.
- Depression in the elderly is common, often under-recognised, and may present as pseudodementia that improves with treatment.
- Late-onset psychosis and increased suicide risk are important issues in older adults.
- The first step in delirium is to find and treat the underlying cause, such as infection, drugs, dehydration or electrolyte disturbance.
- Polypharmacy and altered drug handling make older patients especially prone to adverse drug effects.
Delirium versus dementia
- **Delirium:** Acute, fluctuating, clouded consciousness. Find and treat the medical cause.
- **Dementia:** Chronic, progressive, clear consciousness. Alzheimer is the commonest cause.
- **Lewy body dementia:** Fluctuating cognition, visual hallucinations, parkinsonism. Antipsychotic sensitivity.
- **Reversible mimics:** Hypothyroidism, vitamin B12 deficiency, depression, normal pressure hydrocephalus.
NMC competencies in this chapter
- **PS16.1:** Magnitude and aetiology of geriatric psychiatric disorders
- **PS16.2:** Clinical features of delirium and dementia
- **PS16.3:** Indications and interpretation of investigations
- **PS16.4:** Treatment including behavioural methods
- **PS16.5:** Family education and specialist referral
Frequently Asked Questions
How do you distinguish delirium from dementia?
Delirium is acute and fluctuating with clouded consciousness and impaired attention, and it is often reversible, while dementia is chronic and progressive with clear consciousness and gradual cognitive decline.
What is the commonest cause of dementia?
Alzheimer disease is the commonest cause, with insidious onset and prominent early memory loss. Vascular, Lewy body and frontotemporal dementias are other important types.
Why are antipsychotics used with caution in dementia?
In dementia they increase the risk of stroke and death, and in Lewy body dementia they can cause severe sensitivity reactions, so they are used only when clearly necessary and at low dose.
What reversible conditions mimic dementia?
Hypothyroidism, vitamin B12 deficiency, depression presenting as pseudodementia and normal pressure hydrocephalus can mimic dementia and must be excluded because they are treatable.
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