Dementia is a progressive illness impairing the mental function of many men and women across the UK. Different modalities of cognitive function can be affected, including memory, language, orientation, behaviour, attention, visual-spatial functions, executive functions and motor control.

There are currently thought to be four main types of dementia:

1. Alzheimer’s disease (AD) – the commonest form of dementia – CC by Progressive cognitive impairment & memory loss between the ages of 40 and 90 years
   • Initially, people may seem slightly more forgetful than otherwise expected for their age and lose the ability to perform tasks they previously enjoyed such as cooking and playing cards.
   • They may become repetitive, telling the same story time and time again, neglectful of their personal hygiene or have difficulties making decisions.
2. Vascular dementia (VD) – CC by
   • Cognitive decline and memory loss plus Cerebrovascular disease defined as either:‎ Presence of focal neurological signs or Evidence of cerebrovascular disease on brain imaging, CT or MRI
   • Typically, patients with VD develop symptoms within three months of an acute neurological event i.e., stroke. Deterioration is stepwise and abrupt. Mood swings are common.
3. Dementia with Lewy bodies (DLB) – CC by Progressive cognitive decline with 2 of the following:
   • Fluctuating cognition with pronounced variations in attention and alertness
   • Recurrent, visual hallucinations that are typically well formed and detailed
   • Spontaneous motor features of parkinsonism (such as shuffling gait, rigidity, bradykinesia, and loss of spontaneous movement) and autonomic dysfunction (such as postural hypotension, difficulty in swallowing, and incontinence or constipation) may be present
4. Frontotemporal dementia (FTD) – Personality change and behavioural disturbance (such as apathy or social/sexual disinhibition) and spoken communication.

Clinical features and diagnosis of dementia: –

The ED may be the first port of call for patients with changes in behaviour associated with dementia. The ED is frequently attended by dementia sufferers who have had either:

• An acute deterioration in their condition
• A fall, or collapse either at home, or elsewhere, such as a residential/nursing home

Using a systematic approach to history taking, examination and investigation of these patients will hopefully minimise errors and help identify reversible co-morbidities.

Classical differentiating features of delirium, dementia and depression: –

Feature	Delirium	Dementia	Depression
Onset	Hours to days	Months to years	Weeks to months
Pattern	Fluctuant throughout the day	Progressive over time Often worse at night	Episodic Often worse in the morning
Areas of impairment	Global	At least two areas affected	Specific impairments within several areas of function
Alertness	Often impaired	Often normal	Often normal
Affect	Often agitated but can be hypoactive	Dependent on subtype or severity	Flattened
Course	Reversible	Irreversible over time	Reversible

Differential diagnosis:

• Vitamin deficiency – Thiamine deficiency can lead to Wernicke encephalopathy and Korsakoff psychosis. Symptoms include confusion, memory loss, problems with learning new information and gait disturbances. Vitamin B12 deficiency can lead to ataxia, psychiatric abnormalities, memory loss, and gait disturbance.
• Hypothyroidism – Symptoms of hypothyroidism can include low mood, and impaired concentration and memory.
• Adverse drug effects – Many drugs, including benzodiazepines, analgesics (such as opioids, naproxen, and ibuprofen), anticholinergics, antidepressants (such as tricyclics), antipsychotics (such as haloperidol), anticonvulsants (especially older preparations, such as phenytoin and phenobarbital), and corticosteroids can affect cognition.
• Normal pressure hydrocephalus – can present with triad of symptoms of early cognitive impairment, urinary incontinence, and gait disorder. 
  • Pressure on the frontal lobes gives the dementia and pressure on the medial side of the motor cortex, and the pyramidal tract fibres, cause incontinence and pyramidal leg weakness.
  • Diagnosis is by lumbar puncture (to demonstrate a normal CSF opening pressure) followed by head computed tomography (CT)/magnetic resonance imaging (MRI) (showing enlarged ventricles).
  • Treatment is with ventriculoperitoneal shunting.

Management: –

The management of patients with dementia should be a patient-centred, multi-disciplinary approach, utilising pharmaceuticals and supportive strategies to minimise distress and maximise the activities of patient and carer. Treatments can aim to improve the cognitive impairment and the behavioural changes associated with dementia.

• Memantine is a drug prescribed in the past for moderate to severe dementia. It is now advised to be started only as part of well-designed trials.
• Dementia patients may also be on antidepressants and antipsychotics to try to help control the behavioural aspects of their disease.
• For moderate AD, current NICE guidance advises the use of: Acetylcholinesterase inhibitors, Donepezil, Galantamine or Rivastigmine
• In an urgent situation, where the behaviour of a patient with dementia may cause danger to themselves or others, NICE advises the following strategy:
  • Lorazepam or haloperidol are the drugs of choice.
  • IM injection is the preferred route of delivery
  • The lowest effective dose should be used
  • A single agent should be used except where rapid tranquilisation is required.