Conditions that can cause dementia

About 10% of dementia cases are caused by a wide range of conditions, including:

HIV-associated (or AIDS-related) dementia

You may develop dementia if you contract HIV(human immunodeficiency virus, which leads to AIDS). Some people with HIV infection develop various short-term neurological problems such as encephalitis (inflammation of the brain), meningitis or neuropathy (damage to the nerves).

These problems often get better on their own, or can be reversed, but up to 15% of people in the advanced stages of infection may develop dementia.

Creutzfeld-Jakob disease (CJD)

This is one of a rare group of fatal diseases caused by infectious agents called prions that attack brain tissue. The prion infection leads to the destruction of nerve cells, which are replaced by a network of fine fibres, and microscopic holes appear in the brain making it look like a sponge. This leads to the term spongiform encephalopathy – or spongy brain disease.

There are four types of CJD: sporadic, familial, iatrogenic and new variant.

• The cause of sporadic CJD remains unknown.
• Familial CJD is inherited.
• Iatrogenic CJD is caused by contamination with infected tissues through medical procedures, such as human growth hormone treatment.
• New variant CJD (vCJD) was only identified in 1996. It is caused by exposure to BSE (bovine spongiform encephalopathy), commonly known as mad-cow disease.

CJD usually affects people between the ages of 40 and 80, but new variant CJD appears to be more prevalent in younger people. It has affected more than 10 people under the age of 30 since 1996. The Department of Health has set up a nationwide survey to identify all new cases of the condition. However, despite widespread concern about vCJD, most scientists believe an epidemic is unlikely.

Pick's disease

Here, brain cell damage is concentrated in certain areas usually starting with the frontal lobe. Personality and behaviour are more affected than memory at first, but later the symptoms are similar to Alzheimer's disease.

Alcohol abuse

This can also lead to dementia. General alcohol dementia damages cells throughout the brain. But in other types of alcohol-related dementia, such as Wernicke's encephalopathy and Korsakoff's syndrome, the destruction is concentrated in certain areas of the brain, particularly in the frontal lobes.

Head injury

A head injury accompanied by loss of consciousness may make people more prone to dementia. This is a particular risk for boxers.