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What does focal mean in medical terms

Overview

Dystonia is a movement disorder that causes the muscles to contract involuntarily. This can cause repetitive or twisting movements.

The condition can affect one part of your body (focal dystonia), two or more adjacent parts (segmental dystonia), or all parts of your body (general dystonia). The muscle spasms can range from mild to severe. They may be painful, and they can interfere with your performance of daily tasks.

There’s no cure for dystonia, but medications and therapy can improve symptoms. Surgery is sometimes used to disable or regulate nerves or certain brain regions in people with severe dystonia.

Symptoms

Dystonia affects different people in different ways. Muscle spasms might:

  • Begin in a single area, such as your leg, neck or arm. Focal dystonia that begins after age 21 usually starts in the neck, arm or face. It tends to remain focal or become segmental.
  • Occur during a specific action, such as writing by hand.
  • Worsen with stress, fatigue or anxiety.
  • Become more noticeable over time.

Areas of the body that can be affected include:

  • Neck (cervical dystonia). Contractions cause your head to twist and turn to one side, or pull forward or backward, sometimes causing pain.
  • Eyelids. Rapid blinking or spasms cause your eyes to close (blepharospasms) and make it difficult for you to see. Spasms usually aren’t painful but might increase when you’re in bright light, reading, watching TV, under stress or interacting with people. Your eyes might feel dry, gritty or sensitive to light.
  • Jaw or tongue (oromandibular dystonia). You might experience slurred speech, drooling, and difficulty chewing or swallowing. Oromandibular dystonia can be painful and often occurs in combination with cervical dystonia or blepharospasm.
  • Voice box and vocal cords (laryngeal dystonia). You might have a tight or whispering voice.
  • Hand and forearm. Some types of dystonia occur only while you do a repetitive activity, such as writing (writer’s dystonia) or playing a specific musical instrument (musician’s dystonia). Symptoms usually don’t happen when your arm is at rest.

When to see a doctor

Early signs of dystonia often are mild, occasional and linked to a specific activity. See your health care provider if you’re having involuntary muscle contractions.

Causes

The exact cause of dystonia isn’t known. But it might involve changes in communication between nerve cells in several regions of the brain. Some forms of dystonia are passed down in families.

Dystonia can also be a symptom of another disease or condition, including:

  • Parkinson’s disease
  • Huntington’s disease
  • Wilson’s disease
  • Traumatic brain injury
  • Birth injury
  • Stroke
  • Brain tumor or certain disorders that develop in some people with cancer (paraneoplastic syndromes)
  • Oxygen deprivation or carbon monoxide poisoning
  • Infections, such as tuberculosis or encephalitis
  • Reactions to certain medications or heavy metal poisoning

Complications

Depending on the type of dystonia, complications can include:

  • Physical disabilities that affect your performance of daily activities or specific tasks
  • Difficulty with vision that affects your eyelids
  • Difficulty with jaw movement, swallowing or speech
  • Pain and fatigue, due to constant contraction of your muscles
  • Depression, anxiety and social withdrawal

Overview

Typical and scarred glomeruli

Glomeruli in the kidneys showing a typical glomerulus and a scarred glomerulus

Typical and scarred glomeruli

Focal segmental glomerulosclerosis (FSGS) results from scar tissue that develops in the glomeruli. Glomeruli are tiny structures within the kidney that filter waste products from the blood to create urine. A healthy glomerulus is shown on the left. When scar tissue develops in a glomerulus, kidney function gets worse (shown right).

Focal segmental glomerulosclerosis (FSGS) is a disease in which scar tissue develops on the glomeruli, the small parts of the kidneys that filter waste from the blood. FSGS can be caused by a variety of conditions.

FSGS is a serious condition that can lead to kidney failure, which can only be treated with dialysis or kidney transplant. Treatment options for FSGS depend on the type you have.

Types of FSGS include:

  • Primary FSGS. Many people diagnosed with FSGS have no known cause for their condition. This is called primary (idiopathic) FSGS.
  • Secondary FSGS. Several factors, such as infection, drug toxicity, diseases including diabetes or sickle cell disease, obesity, and even other kidney diseases can cause secondary FSGS. Controlling or treating the underlying cause often slows ongoing kidney damage and might lead to improved kidney function over time.
  • Genetic FSGS. This is a rare form of FSGS caused by genetic changes. It is also called familial FSGS. It’s suspected when several members of a family show signs of FSGS. Familial FSGS can also occur when neither parent has the disease but each one carries a copy of an altered gene that can be passed on to the next generation.
  • Unknown FSGS. In some cases, the underlying cause of FSGS cannot be determined despite the evaluation of clinical symptoms and extensive testing.

Causes

Focal segmental glomerulosclerosis can be caused by a variety of conditions, such as diabetes, sickle cell disease, other kidney diseases and obesity. It can also be caused by an infection and drug toxicity. A rare form of FSGS is caused by inherited abnormal genes. Sometimes there’s no identifiable cause.

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this condition.

Seizures are not all alike. A seizure can be a single event due to an acute cause, such as medication. When a person has recurring seizures, this is known as epilepsy.

A seizure is a burst of uncontrolled electrical activity between brain cells (also called neurons or nerve cells) that causes temporary abnormalities in muscle tone or movements (stiffness, twitching or limpness), behaviors, sensations or states of awareness.

It is important for the doctor to get an accurate seizure diagnosis in order to implement the most appropriate kind of treatment. Focal and generalized onset seizures usually have different causes and accurately diagnosing seizure types often helps identify the cause for the seizures.

Whether or not the doctor can determine the cause for an individual’s seizures, treatment will likely mean medication. Seizures that are difficult to control may be improved with nerve stimulation or diet therapy. Patients whose seizures are due to a focal scar or other lesions in the brain may be good candidates for epilepsy surgery.

Focal, or Partial Seizures

Focal seizures are also called partial seizures since they begin in one area of the brain. They can be caused by any type of focal injury that leaves scar tangles. Medical history or MRI will identify a cause (such as trauma, stroke or meningitis) in about half of the people who have focal seizures. Developmental scars — ones that occur as part of fetal and early growth of the brain — are common causes of focal seizures in children.

Focal Seizures: What Happens

Focal seizures can start in one part of the brain and spread to other areas, causing symptoms that are mild or severe, depending on how much of the brain becomes involved.

At first, the person may notice minor symptoms, which is referred to as an aura. The person may have altered feelings or sense that something is about to happen (premonition). Some people experiencing an aura describe a rising sensation in the stomach similar to riding on a roller coaster.

As the seizure spreads across the brain, more symptoms appear. If the abnormal electrical activity involves a large area of the brain, the person may feel confused or dazed, or experience minor shaking, muscle stiffening, or fumbling or chewing motions. Focal seizures that cause altered awareness are called focal unaware seizures or complex partial seizures.

The electrical activity of the seizure can remain in one sensory or motor area of the brain, resulting in a focal aware seizure (also called simple partial seizure). The person is aware of what is happening, and may notice unusual sensations and movements.

Focal seizures can evolve into major events that spread to the entire brain and cause tonic-clonic seizures. These seizures are important to treat and prevent since they can cause respiratory problems and injuries.

Generalized-onset Seizures

Generalized-onset seizures are surges of abnormal nerve discharges throughout the cortex of the brain more or less at the same time. The most common cause is an imbalance in the “brakes” (inhibitory circuits) and “accelerator” (excitatory circuits) of electrical activity in the brain.

Generalized-onset Seizures: Genetic Considerations

Generalized seizures may have a genetic component, but only a small number of people with generalized seizures have family members with the same condition. There is a slight increase in risk for generalized seizures in the children or other family members of an affected person with generalized seizures, but the severity of the seizures can vary from person to person. Genetic testing may reveal a cause for generalized seizures.

Sleep deprivation or drinking large amounts of alcohol can increase the excitatory response and increase the risk of generalized-onset seizures, especially in people with a genetic tendency to have them.

Types of Generalized-Onset Seizures

Absence Seizures (“Petit Mal Seizures”)

Childhood absence epilepsy shows up as brief staring episodes in children, usually starting between ages four and six. Children usually outgrow these. Juvenile absence epilepsy starts slightly later and can persist into adulthood; people with these kinds of seizures may develop tonic-clonic seizures in addition to absence of seizures in adulthood.

Myoclonic seizures

Myoclonic seizures consist of sudden body or limb jerks that can involve the arms, head and neck. The spasms occur on both sides of the body in clusters, especially in the morning. When these seizures develop in adolescence along with tonic-clonic seizures, they are part of a syndrome called juvenile myoclonic epilepsy. People can also have myoclonic seizures as part of other epilepsy related-conditions.

Tonic and Atonic Seizures (“Drop Attacks”)

Some people, usually those with multiple brain injuries and intellectual disability, have tonic seizures consisting of sudden stiffness in the arms and body, which can cause falls and injuries. Many persons with tonic seizures have a syndrome called Lennox Gastaut syndrome. This condition may involve intellectual disability, multiple seizure types including tonic seizures. People with Lennox Gastaut syndrome can have a distinctive EEG pattern called slow spike and wave.

Persons with diffuse brain disorders also may have atonic seizures, characterized by a sudden loss of body tone that results in collapsing, often with injuries. A sequence of a brief tonic episode followed by an atonic seizure is called a tonic-atonic seizure. Tonic and atonic seizures are often managed with specific medications and sometimes with nerve stimulation and diet therapies.

Tonic, Clonic and Tonic-Clonic (Formerly called Grand Mal) Seizures

Tonic-clonic seizures can evolve from any of the focal or generalized seizure types. For example, a focal seizure can spread to both sides of the brain and cause tonic-clonic seizures. A cluster of myoclonic seizures can become continuous and evolve into a tonic-clonic seizure. Generalized onset tonic-clonic seizures can occur alone or as part of another syndrome such as juvenile myoclonic epilepsy (JME) or juvenile absence epilepsy during adulthood.