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Medical News Today: What is the autonomic nervous system?

The autonomic nervous system is a complex network of cells that controls the body's internal state. It regulates and supports many different internal processes, often outside of a person's conscious awareness.

This article will explain the autonomic nervous system, or ANS, how it works, and the disorders that can affect its functioning.

Anatomy

a man exercising and checking his heart rate which is regulated by the Autonomic nervous systemShare on Pinterest
The ANS helps to regulate many of the body's internal functions, such as heart rate.

The nervous system is a collection of cells that send and receive electrical and chemical signals throughout the body.

The nervous system consists of two main parts:

  • The central nervous system: This consists of the brain and spinal cord.
  • The peripheral nervous system: This contains all the neurons outside of the central nervous system.

The ANS is part of the peripheral nervous system. It is a collection of neurons that influence the activity of many different organs, including the stomach, heart, and lungs.

Within the ANS, there are two subsystems that have mostly opposing effects:

  • The sympathetic nervous system (SNS): Neurons within the SNS generally prepare the body to react to something in its environment. For example, the SNS may increase heart rate to prepare a person to escape from danger.
  • The parasympathetic nervous system (PNS): Parasympathetic neurons mostly regulate bodily functions when a person is at rest.

Function

The nervous system regulates the internal environment of the body. It is essential for maintaining homeostasis.

Homeostasis refers to the relatively stable and balanced conditions inside the body that are necessary to support life. Some of those that homeostasis regulates include:

The ANS receives information from the environment and other parts of the body and regulates the activity of the organs, accordingly.

The ANS is also involved in the following bodily functions:

  • producing bodily fluids, such as sweat
  • urination
  • sexual responses

One critical function of the ANS is to prepare the body for action through the "fight or flight" response.

If the body perceives a threat in the environment, the sympathetic neurons of the ANS react by:

  • increasing heart rate
  • widening the airways to make breathing easier
  • releasing stored energy
  • increasing strength in the muscles
  • slowing digestion and other bodily processes that are less important for taking action

These changes prepare the body to respond appropriately to a threat in the environment.

Factors that affect how it works

The fight or flight response of the ANS evolved to protect the body from dangers around it. However, many stressful aspects of daily life can also trigger this response.

Examples include:

  • work-related stress
  • financial concerns
  • relationship problems

Chronic stress can cause the ANS to trigger the fight or flight response over long periods. This continuation will eventually harm the body.

Some drugs can also affect the way the ANS functions. Examples include:

Autonomic disorders and their causes

Autonomic disorders affect the functioning of the ANS. They can sometimes occur as a result of the following:

  • aging
  • damage to neurons within the ANS
  • damage to specific parts of the brain

Certain medical conditions can also affect the ANS. Some common causes of autonomic disorders include:

Less common causes of autonomic disorders include:

  • multiple system atrophy (MSA)
  • spinal cord disorders
  • Lambert-Eaton syndrome
  • botulism
  • viral infections
  • damage to nerves in the neck

Autonomic disorder symptoms

Autonomic disorders can cause a wide range of symptoms, including:

  • dizziness and lightheadedness due to orthostatic hypotension (OH), which is a significant drop in blood pressure when standing up after sitting
  • reduced or absent sweating, leading to intolerance of heat
  • dry eyes and mouth
  • digestive issues
  • nausea
  • vomiting
  • constipation
  • difficulty urinating
  • erectile dysfunction
  • pupils being less reactive to light

When to see a doctor

Autonomic disorders can be serious. People who experience symptoms of an autonomic disorder should see a doctor for a full diagnosis.

Talking to a doctor is particularly important for people with diabetes or other conditions that can increase the likelihood of autonomic disorders.

Testing

To diagnose the cause of ANS symptoms, a doctor will first assess a person's medical history for risk factors.

A doctor may also request one or more of the following:

  • Tests to detect orthostatic hypotension: A doctor may measure OH using a tilt-table test. In this test, a person lies on a bed that tilts their body at different angles while a machine records their heart rate and blood pressure.
  • Electrocardiogram: This test measures electrical activity within the heart.
  • Sweat test: This test assesses whether the sweat glands are functioning correctly. A doctor uses electrodes to stimulate the sweat glands and measures the volume of sweat they produce in response to the stimulus.
  • Pupillary light reflex test: This test measures how sensitive the pupils are to changes in light.

Summary

The ANS regulates the internal organs to maintain homeostasis or to prepare the body for action. The sympathetic branch of the ANS is responsible for stimulating the fight or flight response. The parasympathetic branch has the opposite effect and helps regulate the body at rest.

Autonomic disorders have many different causes. They can occur as a natural consequence of aging or as a result of damage to parts of the brain or ANS. They may also occur as a result of an underlying disorder, such as diabetes or Parkinson's disease.

A person should see a doctor if they experience symptoms of a possible autonomic disorder. A doctor will work to diagnose the cause of the symptoms and prescribe appropriate treatments.

Original Article

Medical News Today: What to know about brain atrophy

Brain atrophy refers to a loss of brain cells or a loss in the number of connections between brain cells. People who experience brain atrophy typically develop poorer cognitive functioning as a result of this type of brain damage.

There are two main types of brain atrophy: focal atrophy, which occurs in specific brain regions, and generalized atrophy, which occurs across the brain.

Brain atrophy can occur as a result of the natural aging process. Other causes include injury, infections, and certain underlying medical conditions.

This article describes the symptoms and causes of brain atrophy. It also outlines the treatment options available in each case, as well as the outlook.

Symptoms

an old man looking confused because he is experiencing Brain atrophyShare on Pinterest
The natural aging process is a possible cause of brain atrophy.

Brain atrophy can affect one or multiple regions of the brain.

The symptoms will vary depending on the location of the atrophy and its severity.

According to the National Institute of Neurological Conditions and Stroke, brain atrophy can cause the following symptoms and conditions:

Seizures

A seizure is a sudden, abnormal spike of electrical activity in the brain. There are two main types of seizure. One is the partial seizure, which affects just one part of the brain. The other is the generalized seizure, which affects both sides of the brain.

The symptoms of a seizure depend on which part of the brain it affects. Some people may not experience any noticeable symptoms, whereas others may experience one or more of the following:

  • behavioral changes
  • jerking eye movements
  • a bitter or metallic taste in the mouth
  • drooling or frothing at the mouth
  • teeth clenching
  • grunting and snorting
  • muscle spasms
  • convulsions
  • loss of consciousness

Aphasia

The term aphasia refers to a group of symptoms that affect a person's ability to communicate. Some types of aphasia can affect a person's ability to produce or understand speech. Others can affect a person's ability to read or write.

According to the National Aphasia Association, there are eight different types of aphasia. The type of aphasia a person experiences depends on the part or parts of the brain that sustain damage.

Some cases of aphasia are relatively mild, whereas others may severely impair a person's ability to communicate.

Dementia

Dementia is the term for a group of symptoms associated with a continuing decline in brain function. These symptoms may include:

  • memory loss
  • slowed thinking
  • language problems
  • problems with movement and coordination
  • poor judgment
  • mood disturbances
  • loss of empathy
  • hallucinations
  • difficulty carrying out daily activities

There are several different types of dementia. Alzheimer's disease is the most common.

A person's risk of dementia increases with age, with most cases affecting people aged 65 years and older. However, experts do not consider it to be a natural part of the aging process.

Causes

Brain atrophy can occur as a result of injury, either from a traumatic brain injury (TBI) or a stroke. It may also occur as a result of one of the following:

In some cases, brain atrophy may occur as a result of a chronic disorder or condition, such as:

  • cerebral palsy
  • multiple sclerosis (MS)
  • Huntington's disease
  • frontotemporal dementia
  • Alzheimer's disease
  • Pick's disease
  • mitochondrial encephalomyopathies, which are a group of disorders that affect the nervous system
  • leukodystrophies, which are a group of rare genetic conditions affecting the nervous system

Diagnosis

When diagnosing brain atrophy, a doctor may begin by taking a full medical history and asking about a person's symptoms. This may include asking questions about when the symptoms began and if there was an event that triggered them.

The doctor may also carry out language or memory tests, or other specific tests of brain function.

If they suspect that a person has brain atrophy, they will need to locate the brain damage and assess its severity. This will require an MRI or CT scan.

Treatment

The treatment options for brain atrophy will vary depending on its location, severity, and cause. The following sections list some treatment options by cause.

Injuries

Brain atrophy can occur as a long-term consequence of an injury. In these cases, treatment tends to focus on helping the surrounding brain issue heal over time.

Brain injuries typically require a rehabilitation period that may involve one or more of the following:

Infections

Medications will be necessary to treat infections that result in brain inflammation or atrophy.

Doctors prescribe antibiotics to treat bacterial infections and antiviral medications to treat viral infections. These medications will help fight the infection and alleviate the symptoms.

Disorders and conditions

Several disorders and conditions can lead to brain atrophy. Many of these conditions currently have no cure, so treatment generally focuses on managing the symptoms.

Treatment may involve a combination of medications and therapies such as occupational or speech therapy. These therapies may be necessary to help a person regain brain function or learn strategies to help them cope.

Some conditions, such as MS, cause symptoms to occur in cycles. A person's doctor or healthcare team will adapt their treatment plan accordingly if this is the case.

Is it possible to reverse brain atrophy?

Until recently, many scientists considered the brain to be a relatively unchanging organ. However, research is increasingly showing how the brain adapts its structure and functioning throughout life.

It is currently unclear whether or not it is possible to reverse brain atrophy. However, the brain may alter how it works to compensate for damage. In some cases, this may be enough to restore functioning over time.

Exercise for brain atrophy

A 2011 review suggests that regular exercise could slow or even reverse brain atrophy related to aging or dementia.

However, one 2018 study found that high intensity exercise and strength training did not slow cognitive impairment in people with mild-to-moderate dementia. Additional research is therefore necessary to determine what effect, if any, exercise has on preventing or reversing brain atrophy due to dementia.

Drugs to reverse brain atrophy

Scientists are currently working to develop drugs that can reverse brain atrophy. For example, one 2019 study investigated whether or not the dementia drug donepezil could reverse alcohol-induced brain atrophy in rats.

The researchers found that the rats they treated with donepezil experienced a reduction in brain inflammation and showed an increased number of new brain cells. However, it was not clear if donepezil would have similar effects on brain atrophy resulting from causes other than alcohol-induced damage.

It is also not clear whether or not the same effects would occur in humans. Clinical trials involving human participants are necessary.

Outlook

The outlook for brain atrophy varies depending on the location and extent of the damage, as well as its underlying cause. For people with mild cases, there may be few long-term consequences.

When brain atrophy occurs due to a disease or condition, however, symptoms may worsen over time. Long-term treatments and therapies can help slow this process and help a person manage any resulting cognitive impairments.

For injuries such as TBI and stroke, receiving immediate and effective care can significantly improve the outlook.

Summary

Brain atrophy refers to a loss of neurons within the brain or a loss in the number of connections between the neurons. This loss may be the result of an injury, infection, or underlying health condition.

Mild cases of brain atrophy may have little effect on daily functioning. However, brain atrophy can sometimes lead to symptoms such as seizures, aphasia, and dementia. Severe damage can be life threatening.

A person should see a doctor if they experience any symptoms of brain atrophy. The doctor will work to diagnose the cause of the atrophy and recommend appropriate treatments.

Original Article

Medical News Today: What to know about vasovagal syncope

The term vasovagal syncope describes fainting that occurs in response to a sudden drop in heart rate or blood pressure. The resulting lack of blood and oxygen to the brain is what causes a person to pass out.

Doctors sometimes refer to vasovagal syncope (VVS) as neurocardiogenic syncope or reflex syncope. This condition typically occurs when the body overreacts to a stimulus that induces a state of fear or emotional distress.

Other causes may include severe pain, exhaustion, or sudden changes in body posture. Some people have a predisposition to these episodes due to a health condition that affects blood pressure or the heart.

Although a person may sometimes sustain injuries as a result of passing out, VVS is generally harmless. However, a medical diagnosis is necessary to rule out more serious medical conditions.

In this article, we outline some common symptoms and causes of vasovagal syncope. We also cover the treatment options available and provide tips on how to prevent fainting episodes.

Symptoms

a man looking faint as he is experiencing Vasovagal syncopeShare on Pinterest
Lightheadedness, dizziness, and weakness can be signs that a person will faint.

Some people who experience VVS do not notice any warning signs before fainting. Others may have symptoms such as:

People who experience these symptoms before fainting should lie down somewhere safe. Lying down will help the body maintain adequate blood flow to the brain, which may prevent fainting. It will also minimize the risk of a fall or injury in the event of fainting.

A person who has fainted may feel tired, lightheaded, or nauseated when they come round.

Causes

VVS occurs when the nerves that regulate heart rate and blood vessel constriction temporarily lose some of their normal regulation.

Malfunctions generally occur when a stimulus, such as fear, or an abrupt change in body posture causes the blood vessels to widen suddenly. This widening leads to a sudden drop in blood pressure and a resulting lack of blood and oxygen to the brain. This lack of oxygen is what causes fainting.

People may experience VVS for different reasons. Some common triggers include:

  • fear
  • the sight of blood or gore
  • getting blood drawn
  • standing for a long time
  • sudden changes in posture
  • straining, such as during bowel movementssevere pain
  • intense exercise
  • exposure to heat

What to do after fainting

A person who has experienced VVS may feel tired, weak, and nauseated when they come round. It is important that they rest before getting up and continuing with their day.

In some cases, people may need to seek emergency medical attention after a fainting episode. Generally, medical care is only necessary for people who experience the following scenarios and symptoms:

  • fainting while pregnant
  • falling from a significant height
  • sustaining a head injury or other severe injury
  • loss of consciousness
  • chest pain or difficulty breathing
  • confusion, slurred speech, or issues with vision or hearing
  • involuntary movements of the body

When to see a doctor

People who have previously experienced VVS should talk to their doctor if they experience any new triggers or symptoms.

People should also see a doctor if they experience fainting for the first time. However, it is not always possible to diagnose VVS from a single episode of fainting.

Some types of syncope can occur as a result of an underlying medical condition that requires treatment. Examples of such conditions include:

Diagnosis

Typically, doctors will begin a diagnosis of VVS with a review of the person's medical history and any other symptoms. They will also conduct a physical examination. As part of this examination, the doctor will take blood pressure readings while the person is standing, sitting, and lying down.

A doctor may also attempt to rule out alternative causes of fainting using one or more tests. Examples of such tests include:

  • Electrocardiogram (EKG), which measures electrical activity in the heart.
  • Echocardiogram, which assesses heart motion and blood flow through the heart.
  • Exercise stress test to evaluate heart function in response to exercise.
  • Tilt-table test, in which the doctor will secure a person to a padded table that tilts at different angles. Various monitors detect and record heart activity, blood pressure, and oxygen levels while the table positions the person at different angles.

Treatment

VVS does not typically require treatment. However, a person may sometimes be slow to regain consciousness after an episode of fainting. A bystander can intervene by laying the person on their back and raising their legs in the air. Doing this may help restore blood flow to the brain, thereby helping the person regain consciousness.

According to a 2016 review, there are limited treatment options for people with VVS. Doctors advise people with this condition to avoid known fainting triggers and take precautions to prevent injury when signs of imminent fainting begin.

Medications are not usually necessary for VVS. However, in some circumstances, the following medications may be effective in reducing the frequency of VVS episodes:

  • Alpha-1 adrenergic agonists: These drugs help raise blood pressure.
  • Fludrocortisone: A type of corticosteroid that can help maintain blood pressure by increasing sodium and fluid levels in the body.
  • Selective serotonin reuptake inhibitors (SSRIs): Antidepressant medications that may help moderate the nervous system response.

However, further studies are necessary to determine the effectiveness of these and other medical treatments for VVS.

Prevention tips

VVS is not always completely preventable. However, a person may be able to reduce the number of fainting episodes that they experience.

A person's doctor may provide the following recommendations for preventing VVS and the associated complications:

  • identifying and avoiding situations that trigger fainting episodes
  • engaging in moderate exercise
  • drinking plenty of fluids to maintain blood volume
  • consuming a diet that is higher in salt
  • wearing compression stockings
  • discontinuing medications that lower blood pressure
  • immediately sitting or lying down when feeling faint

As with prescription medications, these preventive lifestyle approaches may work for some people and not others. Various factors, such as the person's blood pressure and heart function, may determine the effectiveness of these approaches.

Summary

Vasovagal syncope refers to fainting that occurs in response to a sudden drop in heart rate or blood pressure.

Vasovagal syncope is usually not dangerous. However, people should seek medical attention if they faint when pregnant, experience additional symptoms, or fall and injure themselves when fainting. People should also see a doctor if they are unsure of the cause of fainting.

There are no standard treatments for vasovagal syncope. Instead, treatment generally involves making certain dietary and lifestyle changes, as well as avoiding potential triggers of fainting.

Original Article