Multi-infarct dementia (MID) is a form of vascular dementia. Vascular dementia occurs due to one or more strokes. MID can develop following multiple strokes.

Dementia is the term for progressive diseases that cause a decline in cognitive ability. It can occur as part of various conditions, such as Alzheimer’s disease, or as a result of brain damage.

Multi-infarct dementia occurs due to brain damage as a result of multiple strokes. A person may not realize that they have had several strokes until they develop symptoms of MID.

This article will discuss MID in more detail, including its symptoms, causes, and possible complications.

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MID is the most common form of vascular dementia. Vascular dementia is the second most common cause of dementia after Alzheimer’s disease.

According to the National Institute of Neurological Disorders and Stroke (NINDS), MID is a common cause of memory loss in older adults. MID occurs when a disruption to the blood flow causes brain damage.

A person may not notice if they have a small stroke, in which case, doctors may refer to it as a “silent stroke.” A temporary block in the blood flow, known as a ministroke, can produce symptoms that only last for between a few minutes and 24 hours. As a result, a person may not seek treatment.

However, as more areas of the brain become damaged due to stroke, symptoms of MID can start to develop.

Early symptoms

According to the United Kingdom’s National Health Service (NHS), early symptoms of vascular dementia include:

  • slowness of thought
  • difficulty planning
  • trouble understanding
  • difficulty concentrating
  • changes in mood or behavior
  • problems with language and memory

Later symptoms

The symptoms of MID can worsen slowly or in sudden steps. Later symptoms may include:

  • confusion
  • trouble with short-term memory
  • wandering or getting lost in familiar places
  • problems maintaining balance while walking
  • losing bladder or bowel control
  • laughing or crying inappropriately
  • difficulty following instructions
  • trouble counting money and making monetary transactions

The symptoms of MID may improve for short periods but worsen after additional strokes.

MID can occur when a person has multiple strokes. A stroke happens when the blood supply to a small area of a person’s brain becomes interrupted. This may be due to a blocked or burst artery.

MID often develops due to a series of small strokes that each cause permanent damage. Small strokes occur when the brain experiences a temporary disruption in blood flow.

When a person has a stroke, blood and oxygen cannot reach a small section of the brain. This can lead to cells in the brain dying, resulting in brain damage.

MID usually occurs in people aged 60⁠–75 years. It generally affects males more frequently than females.

The most significant risk factor for MID is high blood pressure, or hypertension. It is rare for a person without high blood pressure to have MID.

The American Heart Association (AHA) notes that the following factors can cause high blood pressure:

  • smoking cigarettes and breathing in secondhand smoke
  • diabetes
  • having excess body weight
  • high cholesterol
  • a diet that is high in sodium and low in potassium
  • drinking too much alcohol
  • physical inactivity

Anyone who has a history of stroke or is showing signs of dementia should speak with a doctor. The doctor may ask them questions about:

  • their diet
  • any medications they take
  • sleep patterns
  • personal habits
  • past strokes and other medical issues
  • recent illnesses
  • any stress

The doctor may also perform a physical exam on the person to check for signs of stroke. They may check for weakness in the limbs, dizziness, or problems with speech.

The doctor may order tests to check that other medical problems are not causing the symptoms. These tests can include X-rays, blood pressure readings, and blood tests.

Brain scans can help a doctor determine whether a person has MID. The doctor may order other imaging tests, such as CT or MRI scans.

Imaging scans take photos of the person’s brain. A doctor can look at these images and check for signs of MID.

Currently, no treatments are available to reverse MID brain damage. Treatments instead focus on preventing future strokes, which involves treating the cause of the strokes. Possible causes include:

  • Diabetes: A person can manage diabetes with certain medications, such as insulin and metformin. Metformin is a drug that reduces the amount of glucose the liver makes. It also helps the body use insulin more efficiently.
  • High blood pressure: Various medications can treat high blood pressure. These can include diuretics, beta-blockers, and vasodilators. A person can speak with a doctor about what medication is right for them.
  • High cholesterol: Certain medications can help people reduce their cholesterol levels. Doctors recommend statins for most people with high cholesterol. Statins help prevent cholesterol from forming.
  • Cardiovascular disease: A person can take a variety of medications for the different forms of cardiovascular disease. A person can speak with a doctor about which medications they should take for their condition.

Certain lifestyle changes can also be beneficial for these conditions. Examples include:

A doctor may prescribe a person with aspirin or other drugs that help prevent blood clots.

Occasionally, a doctor may recommend a type of surgery called a carotid endarterectomy. This surgery removes blockages in a person’s carotid artery. The carotid artery is the main blood vessel to a person’s brain.

There is no cure for MID. According to the NINDS, the outlook for a person with MID is usually not very positive. A person’s symptoms can increase after each stroke.

Once a person develops MID, it will usually become worse over time. During this time, a person may experience periods of increased deterioration.

Having a stroke gives a person a 25% risk of having another one. Each additional stroke a person has can make their MID worse. This may lead to further loss of brain function.

The NINDS notes that causes of death for a person with MID can include:

This section answers some common questions about MID.

Is multi-infarct dementia hereditary?

Little information is available on the genetics of MID. However, certain risk factors of MID can be genetic.

For instance, high blood pressure tends to run in families. Additionally, many people with type 2 diabetes also have at least one family member with their condition.

What are the ICD-10 criteria for multi-infarct dementia?

The International Classification of Diseases, 10th Revision (ICD-10) is a system that healthcare professionals use to classify and store information on diseases and other health problems.

The ICD-10 criteria for MID is: “F01.1 Gradual in onset, following a number of transient ischemic episodes, which produce an accumulation of infarcts in the cerebral parenchyma. Predominantly cortical dementia.”

In other words, healthcare professionals classify MID as a gradual progression of dementia with several strokes in the cerebral cortex, which is the “thinking” area of the brain.

What are the final stages of dementia before death?

The National Institute on Aging notes that the final stages of dementia before death include:

  • being unable to move unassisted
  • being unable to speak or be understood
  • having difficulty eating

MID is a form of vascular dementia. It is the result of multiple strokes that cause brain damage.

The symptoms of MID can develop suddenly. A person may not realize that they have had multiple strokes until they develop MID symptoms.

High blood pressure is the main risk factor for MID. People can help control their blood pressure with a healthy lifestyle and medication.

There is no cure for MID. A doctor may instead treat the cause of a person’s strokes.

The outlook for people with MID is generally not positive. Although the symptoms can improve, they generally decline with each additional stroke.

If a person has any signs of MID or dementia, they should contact a doctor immediately.