encephalopathy

Creutzfeldt-Jakob disease (CJD) is a rare, degenerative brain disorder. Symptoms usually start around age 60. Memory problems, behavior changes, vision problems, and poor muscle coordination progress quickly to dementia, coma, and death. Most patients die within a year.

The three main categories of CJD are :

• Sporadic CJD, which occurs for no known reason
• Hereditary CJD, which runs in families
• Acquired CJD, which occurs from contact with infected tissue, usually during a medical procedure

Cattle can get a disease related to CJD called bovine spongiform encephalopathy (BSE) or "mad cow disease." There is concern that people can get a variant of CJD from eating beef from an infected animal, but there is no direct proof to support this.

NIH: National Institute of Neurological Disorders and Stroke

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.

Epilepsy is a brain disorder that causes people to have recurring seizures. The seizures happen when clusters of nerve cells, or neurons, in the brain send out the wrong signals. People may have strange sensations and emotions or behave strangely. They may have violent muscle spasms or lose consciousness.

Epilepsy has many possible causes, including illness, brain injury, and abnormal brain development. In many cases, the cause is unknown.

Doctors use brain scans and other tests to diagnose epilepsy. It is important to start treatment right away. There is no cure for epilepsy, but medicines can control seizures for most people. When medicines are not working well, surgery or implanted devices such as vagus nerve stimulators may help. Special diets can help some children with epilepsy.

NIH: National Institute of Neurological Disorders and Stroke

A genetic brain disorder is caused by a variation or a mutation in a gene. A variation is a different form of a gene. A mutation is a change in a gene. Genetic brain disorders affect the development and function of the brain.

Some genetic brain disorders are due to random gene mutations or mutations caused by environmental exposure, such as cigarette smoke. Other disorders are inherited, which means that a mutated gene or group of genes is passed down through a family. They can also be due to a combination of both genetic changes and other outside factors.

Some examples of genetic brain disorders include:

• Leukodystrophies
• Phenylketonuria
• Tay-Sachs disease
• Wilson disease

Many people with genetic brain disorders fail to produce enough of certain proteins that influence brain development and function. These brain disorders can cause serious problems that affect the nervous system. Some have treatments to control symptoms. Some are life-threatening.

Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many of these diseases are genetic. Sometimes the cause is a medical condition such as alcoholism, a tumor, or a stroke. Other causes may include toxins, chemicals, and viruses. Sometimes the cause is unknown.

Degenerative nerve diseases include:

• Alzheimer's disease
• Amyotrophic lateral sclerosis
• Friedreich ataxia
• Huntington's disease
• Lewy body disease
• Parkinson's disease
• Spinal muscular atrophy

Degenerative nerve diseases can be serious or life-threatening. It depends on the type. Most of them have no cure. Treatments may help improve symptoms, relieve pain, and increase mobility.

Metabolism is the process your body uses to make energy from the food you eat. Food is made up of proteins, carbohydrates, and fats. Chemicals in your digestive system (enzymes) break the food parts down into sugars and acids, your body's fuel. Your body can use this fuel right away, or it can store the energy in your body tissues. If you have a metabolic disorder, something goes wrong with this process.

Mitochondrial diseases are a group of metabolic disorders. Mitochondria are small structures that produce energy in almost all of your cells. They make it by combining oxygen with the fuel molecules (sugars and fats) that come from your food. When the mitochondria are defective, the cells do not have enough energy. The unused oxygen and fuel molecules build up in the cells and cause damage.

The symptoms of mitochondrial disease can vary. It depends on how many mitochondria are defective, and where they are in the body. Sometimes only one organ, tissue, or cell type is affected. But often the problem affects many of them. Muscle and nerve cells have especially high energy needs, so muscular and neurological problems are common. The diseases range from mild to severe. Some types can be fatal.

Genetic mutations cause these diseases. They usually happen before age 20, and some are more common in infants. There are no cures for these diseases, but treatments may help with symptoms and slow down the disease. They may include physical therapy, vitamins and supplements, special diets, and medicines.

A concussion is a type of brain injury. It involves a short loss of normal brain function. It happens when a hit to the head or body causes your head and brain to move rapidly back and forth. This sudden movement can cause the brain to bounce around or twist in the skull, creating chemical changes in your brain. Sometimes it can also stretch and damage your brain cells.

Sometimes people call a concussion a "mild" brain injury. It is important to understand that while concussions may not be life-threatening, they can still be serious.

Concussions are a common type of sports injury. Other causes of concussions include blows to the head, bumping your head when you fall, being violently shaken, and car accidents.

Symptoms of a concussion may not start right away; they may start days or weeks after the injury. Symptoms may include a headache or neck pain. You may also have nausea, ringing in your ears, dizziness, or tiredness. You may feel dazed or not your normal self for several days or weeks after the injury. Consult your health care professional if any of your symptoms get worse, or if you have more serious symptoms such as:

• Convulsions or seizures
• Drowsiness or inability to wake up
• A headache that gets worse and does not go away
• Weakness, numbness, or decreased coordination
• Repeated vomiting or nausea
• Confusion
• Slurred speech
• Loss of consciousness

To diagnose a concussion, your health care provider will do a physical exam and will ask about your injury. You will most likely have a neurological exam, which checks your vision, balance, coordination, and reflexes. Your health care provider may also evaluate your memory and thinking. In some cases, you may also have a scan of the brain, such as a CT scan or an MRI. A scan can check for bleeding or inflammation in the brain, as well as a skull fracture (break in the skull).

Most people recover fully after a concussion, but it can take some time. Rest is very important after a concussion because it helps the brain to heal. In the very beginning, you may need to limit physical activities or activities that involve a lot of concentration, such as studying, working on the computer, or playing video games. Doing these may cause concussion symptoms (such as headache or tiredness) to come back or get worse. Then when your health care provider says that it is ok, you can start to return to your normal activities slowly.

Centers for Disease Control and Prevention

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.

Developmental disabilities are severe, long-term problems. They may be physical, such as blindness. They may affect mental ability, such as learning disabilities. Or the problem can be both physical and mental, such as Down syndrome. The problems are usually life-long, and can affect everyday living.

There are many causes of developmental disabilities, including:

• Genetic or chromosome abnormalities. These cause conditions such as Down syndrome and Rett syndrome.
• Prenatal exposure to substances. For example, drinking alcohol when pregnant can cause fetal alcohol spectrum disorders.
• Certain infections in pregnancy
• Preterm birth

Often there is no cure, but treatment can help the symptoms. Treatments include physical, speech, and occupational therapy. Special education classes and psychological counseling can also help.

NIH: National Institute of Child Health and Human Development

When you eat, your body breaks food down to a form it can use to build and nourish cells and provide energy. This process is called digestion.

Your digestive system is a series of hollow organs joined in a long, twisting tube. It runs from your mouth to your anus and includes your esophagus, stomach, and small and large intestines. Your liver, gallbladder and pancreas are also involved. They produce juices to help digestion.

There are many types of digestive disorders. The symptoms vary widely depending on the problem. In general, you should see your doctor if you have:

• Blood in your stool
• Changes in bowel habits
• Severe abdominal pain
• Unintentional weight loss
• Heartburn not relieved by antacids

NIH: National Institute of Diabetes and Digestive and Kidney Diseases