Alzheimer’s disease (AD)

 

Alzheimer’s disease – most common from of dementia

 

In dementia there is a progressive irreversible loss of intellectual function.

 

Prognosis – 10 years

 

Dementia is common affecting 10% of people aged over 65 years and 20% of those over 80.

 

 

Aetiology of Alzheimer’s disease

 

AD is primary

 

Genetic component, a history of head injury or Down’s also increases risk.

 

 

Clinical features

 

Insidious - progressive loss intellect and memory

 

Personality changes

 

Inability to learn new things

 

Memories for recent events are lost first

 

Language function declines

 

Disorientation

 

 

Pathophysiology

 

General loss of neurones

 

Microscopically there are extracellular deposits of abnormal amyloid

Amyloid deposition may also damage the walls of blood vessels in the brain.

 

Within the cytoplasm of abnormal neurones are pathological structures called neurofibrillary tangles.

 

Reduction in production of acetylcholine may partly account for memory disturbance.

 

 

Other causes of dementia

 

The second most common cause of dementia has a vascular aetiology and is usually called multi-infarct dementia.

 

Third most common is Lewy bodies dementia.

Lewy bodies are collections of abnormal protein found inside neurones.

 

Other forms of dementia are Creutzfeldt – Jakob, Huntington`s and Parkinson’s disease.