amyloid

Amyloidosis occurs when abnormal proteins called amyloids build up and form deposits. The deposits can collect in organs such as the kidney and heart. This can cause the organs to become stiff and unable to work the way they should.

There are three main types of amyloidosis:

• Primary - with no known cause
• Secondary - caused by another disease, including some types of cancer
• Familial - passed down through genes

Symptoms can vary, depending upon which organs are affected. Treatment depends on the type of amyloidosis you have. The goal is to help with symptoms and limit the production of proteins. If another disease is the cause, it needs to be treated.

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body. Your nerves take in information from your senses and send it to the brain to be processed. Your brain and nerves also communicate to help you move and to control your body's functions.

When the brain is healthy, it works quickly and automatically. But when you have a brain disease, it may affect how well you can function and do your daily activities. Some common brain diseases include:

• Brain tumors, which can press on nerves and affect brain function.
• Degenerative nerve diseases, which can affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Types include Alzheimer's disease and Parkinson's disease.
• Encephalitis (inflammation in the brain), which can lead to problems such as vision loss, weakness, and paralysis.
• Genetic brain disorders, which are caused by changes in genes (also called variants or mutations). These disorders can affect the development and function of the brain.
• Strokes, which can cause a loss of brain cells and can affect your ability to think clearly.
• Traumatic brain injuries (TBIs), which can affect brain function. They may range from mild to severe. The effects of a TBI may be temporary or permanent.

The symptoms of brain diseases vary widely, depending on the specific problem. In some cases, damage is permanent. In other cases, treatments such as surgery, medicines, or therapies such as physical, occupational, and speech therapies, may cure the disease or improve the symptoms.

Dementia is a loss of mental functions that is severe enough to affect your daily life and activities. These functions include:

• Memory
• Language skills
• Visual perception (your ability to make sense of what you see)
• Problem solving
• Trouble with everyday tasks
• The ability to focus and pay attention

It is normal to become a bit more forgetful as you age. But dementia is not a normal part of aging. It is a serious disorder which interferes with your daily life.

The most common types of dementia are known as neurodegenerative disorders. These are diseases in which the cells of the brain stop working or die. They include:

• Alzheimer's disease, which is the most common form of dementia among older people. People with Alzheimer's have plaques and tangles in their brain. These are abnormal buildups of different proteins. Beta-amyloid protein clumps up and forms plaques in between your brain cells. Tau protein builds up and forms tangles inside the nerve cells of your brain. There is also a loss of connection between nerve cells in the brain.
• Lewy body dementia, which causes movement symptoms along with dementia. Lewy bodies are abnormal deposits of a protein in the brain.
• Frontotemporal disorders, which cause changes to certain parts of the brain:
  • Changes in the frontal lobe lead to behavioral symptoms
  • Changes in the temporal lobe lead to language and emotional disorders
• Vascular dementia, which involves changes to the brain's blood supply. It is often caused by a stroke or atherosclerosis (hardening of the arteries) in the brain.
• Mixed dementia, which is a combination of two or more types of dementia. For example, some people have both Alzheimer's disease and vascular dementia.

Other conditions can cause dementia or dementia-like symptoms, including:

• Creutzfeldt-Jakob disease, a rare brain disorder
• Huntington's disease, an inherited, progressive brain disease
• Chronic traumatic encephalopathy (CTE), caused by repeated traumatic brain injury
• HIV-associated dementia (HAD)

Certain factors can raise your risk for developing dementia, including:

• Aging. This is the biggest risk factor for dementia.
• Smoking
• Uncontrolled diabetes
• High blood pressure
• Drinking too much alcohol
• Having close family members who have dementia

The symptoms of dementia can vary, depending on which parts of the brain are affected. Often, forgetfulness is the first symptom. Dementia also causes problems with the ability to think, problem solve, and reason. For example, people with dementia may:

• Get lost in a familiar neighborhood
• Use unusual words to refer to familiar objects
• Forget the name of a close family member or friend
• Forget old memories
• Need help doing tasks that they used to do by themselves

Some people with dementia cannot control their emotions and their personalities may change. They may become apathetic, meaning that they are no longer interested in normal daily activities or events. They may lose their inhibitions and stop caring about other peoples' feelings.

Certain types of dementia can also cause problems with balance and movement.

The stages of dementia range from mild to severe. In the mildest stage, it is just beginning to affect a person's functioning. In the most severe stage, the person is completely dependent on others for care.

Your health care provider may use many tools to make a diagnosis:

• A medical history, which includes asking about your symptoms
• A physical exam
• Tests of your thinking, memory, and language abilities
• Other tests, such as blood tests, genetic tests, and brain scans
• A mental health evaluation to see whether a mental disorder is contributing to your symptoms

There is no cure for most types of dementia, including Alzheimer's disease and Lewy body dementia. Treatments may help to maintain mental function longer, manage behavioral symptoms, and slow down the symptoms of disease. They may include:

• Medicines may temporarily improve memory and thinking or slow down their decline. They only work in some people. Other medicines can treat symptoms such as anxiety, depression, sleep problems, and muscle stiffness. Some of these medicines can cause strong side effects in people with dementia. It is important to talk to your health care provider about which medicines will be safe for you.
• Occupational therapy to help find ways to more easily do everyday activities
• Speech therapy to help with swallowing difficulties and trouble speaking loudly and clearly
• Mental health counseling to help people with dementia and their families learn how to manage difficult emotions and behaviors. It can also help them plan for the future.
• Music or art therapy to reduce anxiety and improve well-being

Researchers have not found a proven way to prevent dementia. Living a healthy lifestyle might influence some of your risk factors for dementia.

A stroke is a medical emergency. There are two types - ischemic and hemorrhagic. Hemorrhagic stroke is the less common type. It happens when a blood vessel breaks and bleeds into the brain. Within minutes, brain cells begin to die. Causes include a bleeding aneurysm, an arteriovenous malformation (AVM), or an artery wall that breaks open.

Symptoms of stroke are:

• Sudden numbness or weakness of the face, arm or leg (especially on one side of the body)
• Sudden confusion, trouble speaking or understanding speech
• Sudden trouble seeing in one or both eyes
• Sudden trouble walking, dizziness, loss of balance or coordination
• Sudden severe headache with no known cause

It is important to treat strokes as quickly as possible. With a hemorrhagic stroke, the first steps are to find the cause of bleeding in the brain and then control it. Surgery may be needed. Post-stroke rehabilitation can help people overcome disabilities caused by stroke damage.

National Institute of Neurological Disorders and Stroke