Rarer causes of dementia

Expert reviewer, Professor Graham Stokes, psychologist and dementia specialist
Next review due December 2019

Aside from the four main types of dementia, there are also other types, and conditions that can cause dementia symptoms. The information here is about other conditions that can lead to dementia or which can be mistaken for dementia. These conditions include:

• Parkinson’s disease
• normal pressure hydrocephalus
• multiple sclerosis
• progressive supranuclear palsy
• Huntington’s disease
• Creutzfeldt–Jakob disease
• Wilson's disease

Parkinson's disease

Around two to three out of every 10 people with Parkinson’s disease will develop some symptoms of dementia or slowing down mentally. This is more common when Parkinson’s is more advanced than in the early stages. Parkinson’s dementia is similar to a type of dementia called dementia with Lewy bodies. Both conditions have protein deposits called Lewy bodies found in brain cells. These may be harmful to the brain cells and cause dementia, but doctors don’t know this for sure.

A typical symptom of dementia with Lewy bodies  is seeing things that aren’t there (hallucinations). This also happens in Parkinson’s dementia, although it is less common than in dementia with Lewy bodies . Other symptoms of dementia in Parkinson’s can include:

• slowed thinking
• personality changes, such as loss of usual interests (apathy) and irritability
• memory loss
• loss of fluency in speech

As well as dementia, many people with Parkinson's dementia develop depression.

If someone with Parkinson’s has symptoms of dementia, there are medicines that can help. There are three available:

• donepezil (Aricept)
• galantamine (Reminyl)
• rivastigmine (Exelon)

There is more information about these medicines in our section on Alzheimer’s disease, as that is the condition they are most commonly prescribed for.

Normal pressure hydrocephalus (NPH)

Hydrocephalus is a condition where fluid builds up in the brain, causing increased pressure. Normal pressure hydrocephalus (NPH) has some of the same symptoms (eg difficulty walking), but the pressure in the brain isn’t actually significantly increased. In NPH, another sign is that some of the fluid-filled chambers in the brain (the ventricles) may appear enlarged on a scan.

Doctors aren’t quite sure what causes NPH. It may be to do with the reduced flow of blood leaving the brain, caused by blocked circulation (vascular disease). It may also be caused by problems with the circulation of fluid in the brain (cerebrospinal fluid).Symptoms of dementia caused by NPH include:

• a general mental slowing down
• poor attention span
• loss of or reduced short-term memory

Memory problems may show up later than problems with thinking and managing.

As well as dementia, people with NPH develop difficulty walking. If the doctor tries medicines for Parkinson’s disease but they don’t help, this can help them to diagnose NPH.

People with NPH may also develop loss of bladder control (urinary incontinence) later on in the disease. If there is a build-up of fluid in the brain, NPH can be treated by putting in a tube to drain the excess fluid. This is called a shunt and drains the extra fluid into the abdomen. If someone can’t have surgery, the doctor may be able to drain off some fluid by doing a lumbar puncture (also called a spinal tap). This can work well, but the effects won’t last and it may have to be repeated.

Multiple sclerosis

Multiple sclerosis (MS) is a condition where the insulation around nerve fibres is lost. This means the electrical signals that travel along the nerves are slowed down. There are different types of MS that develop at different rates. Memory problems and other dementia symptoms are most common if MS develops more rapidly.

As many as half of people with MS will have some loss of mental function. This doesn’t mean that they have dementia or need dementia treatment. In many people the effects will be slight. They may have:

• memory problems
• difficulty learning new information
• difficulty planning
• poor concentration

Up to one in 10 people with MS will develop dementia. People with MS also have a tendency to depression. This should be treated with anti-depressants as it can make these other dementia-like symptoms worse.

Treatment will generally be aimed at managing symptoms. As well as anti-depressants, doctors may suggest short-term medicines to help control anxiety if this is a problem.

Find out more about MS and its treatment.

Progressive supranuclear palsy (PSP)

Progressive supranuclear palsy (PSP) is an uncommon long-term condition that gradually gets worse over a number of years. It affects the nervous system and can eventually cause dementia. It usually starts in middle age, with difficulty moving the eyes to look up or down. Dementia usually happens in the later stages of the disease. Symptoms can include:

• memory problems
• slowed thinking
• personality changes, such as becoming more emotional

There are also physical symptoms. Muscles become rigid and movements are slowed.

Unfortunately, there is no cure for PSP and treatment aims to control symptoms. The doctor may suggest medicines to help with stiffness, or medicines called tricyclic anti-depressants.

Huntington's disease (HD)

Huntington's disease (HD) used to be called Huntington’s chorea. It is an inherited (genetic) condition that usually shows up in middle age. It affects the nervous system, causing characteristic jerky movements.

People with HD may have personality or behaviour changes as a first sign that they have the condition. This develops into the typical jerky movements. Over a number of years, people become less mobile and begin to develop dementia. Symptoms include:

• slowed thinking and poor concentration
• anxiety
• loss of interest in life (apathy)
• irritability and agitation
• developing obsessions or compulsive behaviour

People with HD are also likely to have depression, which may be more likely in the later stages of the disease.

Unfortunately, there is no cure for HD and treatment aims to control symptoms. The doctor may suggest medicines for depression or anxiety. If agitation or compulsive behaviour is a particular problem, they may prescribe medicines called anti-psychotics.

Creutzfeldt–Jakob disease (CJD)

Creutzfeldt–Jakob disease (CJD) is the most common type of ‘prion disease’. This is a disease where a brain protein is folded wrongly, which means it doesn’t work properly.

Although CJD is the commonest prion disease, it is still very rare. Over 20 years, fewer than 1,500 people died of CJD in the UK. There are different types of CJD and only just over one in 10 of these cases was the ‘new variant’ type of CJD that is linked to BSE (bovine spongiform encephalopathy) in cattle (sometimes called ‘mad cow disease’).

CJD is a progressive condition and deterioration can be very quick. One of the main features of CJD is memory loss and confusion. Other symptoms include:

• early signs of difficulty with organising, planning and multi-tasking
• loss of speech
• poor coordination and loss of control of body movements
• jerking muscle movements
• agitation and depression

Unfortunately, there is no cure for CJD. Treatment is aimed at managing the symptoms and keeping people as comfortable as possible. Doctors may prescribe anti-depressants and medicines for anxiety and agitation. People with CJD may also have medicines for difficulty sleeping and to try to control muscle spasms.

Wilson’s disease

Wilson’s disease is a condition where the body doesn’t deal properly with copper from your diet. This copper is deposited in the liver and other organs, where it causes damage. Wilson’s disease is a genetic condition that can be hard to detect properly.

Dementia-like symptoms associated with Wilson’s disease include changes in concentration and memory, behaviour and mood, and problems with co-ordination. As well as these, someone may experience:

• liver problems such as hepatitis and cirrhosis
• difficulty speaking
• tremor
• problems with balance
• excessive salivation (drooling)

Wilson’s disease tends to occur earlier in life, between the ages of five and 35. However, in theory, it can develop at any age.

Wilson’s disease is treatable. This is done by removing toxic levels of copper from the body, and stopping it from reappearing, usually with medicines. However, some symptoms that have developed before treatment starts may remain permanently. If Wilson’s disease isn’t treated, it is often fatal.