Dementia

Published on 10/04/2015 by admin

Filed under Neurology

Last modified 10/04/2015

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Dementia

Introduction

Dementia can be defined in several ways but all include the following elements:

An acquired loss in multiple domains of higher mental function.

A progressive decline.

Occurring in clear consciousness.

The incidence is 50 per 100 000 population but is strongly age-related, being rare under the age of 60 years. The most common causes are neurodegenerative conditions, especially Alzheimer’s disease (AD), Lewy body disease (LBD) and diffuse cerebrovascular disease. An unusual cause should be suspected in patients under 55, where progression is rapid or if other features are present (Table 1). Most neurodegenerative conditions can only be diagnosed with certainty by neuropathological examination. Most of these conditions progress slowly over many years so the prevalence and social burden of the condition are very high.

Table 1 Dementias associated with prominent physical abnormalities

Clinical feature	Condition	Associated features
Apraxic gait disorder or Parkinsonism	Frontal lobe tumour Hydrocephalus Cerebral arteriosclerosis Parkinson’s disease/cortical Lewy body disease Wilson’s disease	Frontal lobe syndrome Headache, incontinence Prominent hallucinations Psychiatric disease/corneal Kayser–Fleischer rings

Myoclonus

Creutzfeldt–Jakob disease

Subacute sclerosing panencephalitis

Rapid progression

Chorea

Huntington’s disease

Systemic lupus erythematosus

Autosomal dominant

Systemic vasculitis, seizures and depression

Ataxia Wernicke–Korsakoff syndrome See above Supranuclear gaze palsy

Hydrocephalus

Whipple’s disease

Multiple sclerosis

Progressive supranuclear palsy

See above

Rare but treatable (p. 99)

See pages 84–87

See page 89

Neuropathy/spinal cord syndrome Vitamin B12 and folic acid deficiency Usually raised mean red blood cell volume Weakness and fasciculation Motor neurone disease (MND) dementia Evolves to MND with dementia (p. 108)

The role of the clinician is to identify less common treatable conditions, to advise regarding prognosis and to identify the rare familial diseases for which counselling may be important. The clinician forms part of a multidisciplinary team that coordinates care. Medical treatment may be helpful in the management of some associated problems, such as Parkinsonism, seen in some conditions, and complications such as behavioural abnormalities.