Rarer causes and types of dementia

Dementia describes a set of symptoms, including problems with memory and thinking. There are four common types:

• Alzheimer's disease
• vascular dementia
• dementia with Lewy bodies
• frontotemporal dementia

Other conditions can cause rarer types of dementia.

Parkinson's disease

Around four out of every 10 people with Parkinson’s disease will develop dementia symptoms. This is more common when Parkinson’s is more advanced.

Parkinson’s dementia is similar to dementia with Lewy bodies. But in Parkinson’s, problems with physical movement usually start years before any problems with thinking and memory. In both conditions, protein deposits called Lewy bodies are found in brain cells. These may be harmful to the brain cells and cause dementia, but doctors don’t know 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, but is less common and the hallucinations are less severe.

Other symptoms of dementia in Parkinson’s include:

• slowed thinking, poor concentration and difficulty planning
• feeling sleepy during the day
• personality changes, such as loss of usual interests (apathy) and agitated
• memory loss
• difficulty making sense of surroundings, increasing risk of falls

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

There is no cure for Parkinson’s dementia, but medicines can help with symptoms. For mild-to-moderate dementia, you may be prescribed an acetylcholinesterase inhibitor such as rivastigmine (for example, Exelon). If this doesn’t help, you may be prescribed memantine hydrochloride for example, Ebixa).

Normal pressure hydrocephalus (NPH)

Normal pressure hydrocephalus (NPH) is a condition where fluid builds up in the brain. Although this causes dementia symptoms, the pressure in the brain isn’t significantly high.

Doctors aren’t sure what causes NPH. It may be:

• reduced flow of blood leaving the brain because of poor circulation due to vascular disease
• problems with the circulation of cerebrospinal fluid in the brain
• linked to a head injury or bleeding in the brain

Dementia symptoms in NPH include::

• general mental slowing down
• poor attention span
• poor short-term memory

Memory problems may show up later than problems with thinking and managing. People with NPH may also:

• have difficulty walking
• become slow and cautious
• be unsteady when standing and walking
• have difficulty changing direction
• lose bladder control (urinary incontinence) later on in the disease

You may have a lumbar puncture (spinal tap) to drain fluid from your brain. If this helps, your doctor may put in a tube (called a shunt) to drain excess fluid. This carries the fluid to another part of your body, usually your tummy. The fluid is then absorbed into your blood.

Treatment for preventing circulatory problems from getting worse can also help. This includes:

• stopping smoking
• taking medications for medicines for high blood pressure or cholesterol

Multiple sclerosis

In multiple sclerosis (MS) the insulation around nerve fibres is lost. So the electrical signals travelling along nerves slow down. Different types of MS develop at different rates. Memory problems and other dementia symptoms are most common in rapidly developing or advanced MS.

Between 4 and 7 out of every 10 people with MS will have difficulties with thinking and remembering at some stage of their illness. This can be slight in some people. Symptoms include:

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

Around 1 in 10 people with MS develop dementia. People with MS are also more likely to have depression. This should be treated with antidepressants because it can make dementia symptoms worse.

Treatment is generally aimed at managing the symptoms. Your doctor may suggest short-term medicines to help control anxiety.

Huntington’s disease

Huntington's disease (HD) is an inherited (genetic) condition that affects the nervous system. It usually starts when people are in their 30s and 40s.

The first signs of HD are personality or behaviour changes and jerky movements. Over several years, people become less mobile and develop severe dementia. Symptoms of dementia caused by Huntington’s disease include:

• slowed thinking and poor concentration
• anxiety
• depression
• loss of interest (apathy)
• irritability and agitation
• obsessions or compulsive behaviour (later in the illness)

There’s no cure for HD – the treatment aims to control the symptoms and includes:

• medicines for depression or anxiety
• anti-psychotic medicines for agitation or compulsive behaviour

Families can have genetic testing for Huntington’s disease. It can be difficult to decide whether to have this. It’s entirely your choice and you can take as long as you need. You have the tests at a genetic clinic where counsellors are available. You can talk to them about the testing and ask any questions you have before deciding.

Creutzfeldt–Jakob disease (CJD)

Creutzfeldt–Jakob disease (CJD) is a type of prion disease. In prion diseases, brain proteins (prions) become abnormal and don’t fold normally. This means the proteins don’t work properly.

CJD is very rare. Between 1985 and 2022 in the UK, 2,787 people were diagnosed with the most common type (sporadic CJD). Other types are even rarer, including variant CJD (vCJD). The vCJD form is linked to meat from BSE infected cattle (bovine spongiform encephalopathy, or ‘mad cow disease’).

CJD gets worse over time. This can happen very quickly, especially with sporadic CJD. The main features are memory loss and confusion. Other symptoms include:

• difficulty organising, planning and multi-tasking
• double vision or hallucinations
• poor coordination and loss of control of movement
• jerking muscles
• agitation and depression

There’s no cure for CJD. The treatment aims to manage the symptoms and keep people as comfortable as possible. Doctors may prescribe medicines to help with:

• depression (anti-depressants)
• anxiety and agitation
• difficulty sleeping
• muscle spasms

Wilson’s disease

Wilson’s disease is a genetic condition. If you have Wilson’s disease, your liver can’t process and remove copper from your body in the normal way. So copper builds up and damages the liver, brain and other organs. Most of the copper in the body comes from food such as liver, nuts, mushrooms, shellfish and chocolate.

Wilson’s disease is usually diagnosed between the ages of 10 and 40 but can develop at any age. It can be hard to spot because the symptoms can be similar to those of other diseases. For 5 to 10 in every 100 people with Wilson’s disease, the early signs are:

• greenish-brown rings around the iris (coloured part of the eye)
• blood in the urine
• periods stopping
• repeated miscarriages

People with early Wilson’s disease can also have liver problems such as hepatitis and cirrhosis.

They may also have problems with their nervous system – for example:

• slow or slurred speech
• tremor
• muscle spasms and twitches
• excessive saliva (drooling)

Wilson’s disease that isn’t diagnosed early may cause dementia symptoms, including:

• difficulty focusing on tasks
• memory loss
• behaviour and mood changes
• problems with coordination

If you have Wilson’s disease, you’ll usually need to eat a low-copper diet. The disease is also treated with medicines called chelating agents. These remove copper from your body. Doctors may also prescribe zinc. This stops your body from absorbing more copper. You take these medicines for life, to stop high levels of copper building up in your body.

If Wilson’s disease is treated early enough, you can live a normal life. Any liver or nerve damage will usually get better over time, though some symptoms may not go away completely. If Wilson’s disease isn’t treated, it can cause serious liver damage. This can be fatal.