Vascular dementia

Synonym: vascular cognitive impairment

See the related separate articles Dementia, Supporting the Family of People with Dementia and Alzheimer's Disease.

Vascular dementia (VaD) is not a single disease but a group of syndromes of cognitive impairment caused by different mechanisms causing ischaemia or haemorrhage secondary to cerebrovascular disease (multiple infarcts, single strategic infarct or small vessel disease.) Increasingly the term vascular cognitive impairment (VCI) is used to encompass the spectrum of deficit, in which VaD is the most severe form of the disease¹ .

Aetiology

The main subtypes of VaD are:

• Stroke-related VaD. This incorporates multi-infarct dementia, the result of a series of small strokes, which in themselves may not be recognised, and single-infarct dementia, which occurs after a larger stroke.

• Subcortical VaD (small-vessel disease or Binswanger's disease)² .

• Mixed dementia. Changes of both VaD and Alzheimer's disease are found together in the brain. The distinction between VaD and Alzheimer's dementia is becoming increasingly blurred because vascular risk factors play a role in both diseases and both types of dementia may co-exist in the same patient. Similar patterns of biochemical abnormalities are also seen on proton magnetic resonance spectroscopy³ . However, where they are seen mostly in white matter in VaD, in Alzheimer's dementia they predominate in cortical grey matter.

Most VaD is sporadic, but some cases display familial traits. Risk factors for VaD include¹ :

• History of stroke or transient ischaemic attack (TIA).

• Atrial fibrillation.

• Hypertension.

• Diabetes mellitus.

• Hyperlipidaemia.

• Smoking.

• Obesity.young-onset VaD has a genetic cause in some people.

• Coronary heart disease.

• Family history of stroke or cardiovascular disease

Young-onset VaD has a genetic cause in some people⁴ .

Epidemiology

VaD is the second most common form of dementia in the West after Alzheimer's disease. It is the most common form in some parts of Asia. Incidence increases with age.

VaD is thought to account for around 17% of dementia in the UK.

Prevalence of dementia following a first stroke varies depending on location and size of the infarct, definition of dementia, interval after stroke and age among other variables. Overall, stroke doubles the risk of developing dementia¹ .

Presentation

Characteristically, VaD is a progressive disease where deteriorations may be sudden or gradual but tend to progress in a stepwise manner. In contrast to acute confusional state (which is usually of recent onset and may have a reversible cause), in dementia the history should go back at least several months and usually several years.

NINDS-AIREN criteria for the clinical diagnosis of PROBABLE vascular dementia (VaD) - as recommended by the National Institute for Health and Care Excellence (NICE) ⁴

Presentation varies significantly, as does speed of progression. Presenting features which may suggest a vascular cause include:

• Focal neurological abnormalities: visual disturbances (eg, field defects), sensory or motor symptoms (eg, dysphasia, hemiparesis, visual field defects) or extrapyramidal signs (eg, dystonias and Parkinsonian features).

• Difficulty with attention and concentration.

• Seizures.

• Depression and/or anxiety accompanying the memory disturbance.

• Early presence of disturbance in gait, unsteadiness and frequent, unprovoked falls.

• The patient has bladder symptoms (eg, incontinence) without a demonstrable urological condition.

• Features of pseudobulbar palsy

• Emotional problems - eg, emotional lability, psychomotor retardation or depression.

For objective evidence, carry out a test of cognitive functioning (see under 'Diagnosis', below).

Also consider dementia with Lewy bodies (DLB) in elderly patients presenting with hallucinations, lucid periods, movement disorders, falls or syncope. Making this diagnosis will have important implications for treatment, as the use of neuroleptics in these patients is associated with an increased risk of adverse reactions, and may cause an increase in mortality⁴ .

Diagnosis

VaD should not be diagnosed solely on the basis of a person having significant cardiovascular disease. The diagnosis of dementia requires⁴ :

• Comprehensive history and physical examination. The key to diagnosis is a good history of progressive impairment of memory and other cognitive functioning (usually requiring the help of a spouse, relative or friend).

• A formal screen for cognitive impairment - see the separate Screening for Cognitive Impairment article. Specific notes should be made on the following:
  

  • Memory - both short- and long-term.

  • Individual cognitive domains:
    

    • Orientation - time, place, person.

    • Attention and concentration ability.

    • Language function (usually evident during questioning).

    • Visuospatial functions.

    • Executive function - problem solving, etc.

    • Motor control.

    • Praxis - whether they can get dressed, lay a table, etc.

• Medication review to ensure cognitive decline is not due to medication.

• Other reversible organic causes to have been excluded.

• If the dementia subtype is uncertain and VaD is suspected, MRI is preferred. If MRI is unavailable or contra-indicated, use CT⁴ .

• MRI scanning may show evidence of infarcts, cortical lacunae, and extensive white matter changes⁵ . Appearances will vary depending on the pathogenesis. It may help distinguish VaD from Alzheimer's disease.

NB: it is important to identify depression and treat it appropriately. Sometimes it is difficult to distinguish between depression and dementia and depression is quite common in dementia. If in doubt, treat.

General management

Like other dementias the treatment is symptomatic, addressing the individual's main problems and supporting the carers. Detecting and addressing cardiovascular risk factors is also very important to try to slow progression. See the separate Cardiovascular Risk Assessment article.

General principles of management of people with dementia are addressed in the separate Dementia article, and in National Institute for Health and Care Excellence (NICE) Quality Standards^{6 7} .

Non-pharmacological interventions should be tailored to the individual person's preferences and abilities as well as to local resources, and adapted depending on response. These include:

• Cognitive stimulation programmes.

• Multisensory stimulation.

• Music and art therapy.

• Dancing.

• Massage.

• Aromatherapy.

• Structured exercise programmes.

• Animal-assisted therapy.

Comorbid emotional or psychiatric disorders should be addressed by non-pharmacological means (as above) and pharmacological methods as appropriate.

Community and hospital care

Patients should be cared for in the community as much as possible. However, if they become severely disturbed and need to be contained for their own safety or the safety of others, inpatient care should be considered (this might include those liable to be detained under the Mental Health Act 1983). Inpatient admission would also be justified for patients with complex physical and psychiatric problems who could not be properly assessed in the community.

People with challenging behaviour^{4 6}

This patient group is given a specific mention. They should be offered early assessment which includes:

• Physical health.

• Depression and any psychosocial issues.

• Possible undetected pain or discomfort.

• Adverse effects of medication.

• Life history, including spiritual, cultural and religious identity.

• Physical environment.

• Behavioural and functional analysis by a skilled professional.

Factors which may exacerbate violent or aggressive behaviour, or increase the risk of harm to self or others, include:

• Overcrowding.

• Lack of privacy.

• Boredom or lack of activity.

• Poor communication.

• Conflict.

• Weak clinical leadership in care home settings.

Staff should identify, monitor and address factors such as these, and be trained in managing aggression or agitation.

Pharmacological management⁴

There is no specific pharmacological treatment approved for the treatment of VaD. Only consider anticholinesterase (AChE) inhibitors or memantine for people with VaD if they have suspected comorbid Alzheimer's disease, Parkinson's disease dementia or dementia with Lewy bodies.

Cerebrolysin continues to be used and promoted as a treatment for VaD, but the supporting evidence base is weak⁸ .

Medication for non-cognitive symptoms (eg, emotional symptoms) and challenging behaviour

This should only be used if there is severe distress or immediate risk of harm to the patient or others. NICE does not recommend the use of antipsychotics for mild-to-moderate non-cognitive symptoms in dementia with VaD or mixed dementia because of the increased risk of cerebrovascular adverse events and death. For severe symptoms (eg, psychosis and/or agitated behaviour causing significant distress), antipsychotics should only be prescribed once the risks and benefits have fully been considered and discussed with carers, risk factors have been assessed and a regular assessment has been made of changes in cognition. Treatment, when considered appropriate, should be time-limited. Comorbid conditions such as depression should be considered and treated.

Urgent treatment of challenging behaviour

If intramuscular agents are required for behavioural control, NICE recommends lorazepam, haloperidol or olanzapine.

If possible, a single agent should be used. If rapid tranquilisation is required, lorazepam and haloperidol should be used in combination. The patient should be monitored for dystonia and other extrapyramidal effects. Anticholinergic drugs may be used if side-effects become distressing, but monitor for deteriorating cognitive function.

Diazepam or chlorpromazine should be avoided.

Prevention¹

VaD is modifiable and preventable. Modifying vascular risk factors in mid-life may help to prevent stroke and VaD. The single most important modifiable risk factor in mid-life is hypertension, but the value of treating this is more debatable as age increases¹ . There is not yet any convincing evidence that the treatment of hypertension reduces the incidence of dementia, although it appears likely that this is the case in mid-life treatment. There is evidence that lowering high blood pressure after stroke decreases the risk of post-stroke dementia.

Complications

• Behavioural problems, including wandering, delusions, hallucinations and poor judgement.

• Depression.

• Falls and gait abnormality.

• Aspiration pneumonia.

• Decubitus ulcers.

• Caregiver burden and stress: this should be considered a complication of any dementia, including VaD. This can lead to increased psychiatric and medical morbidity in the caregiver.

Prognosis

The prognosis of VaD is thought to be worse than that of Alzheimer's disease, carrying an average life expectancy of three to five years⁹ .