asterixis

Ever heard of Asterixis? Have you seen people suffering from some unusual physical situations like inability to move hands, or uncontrolled shaking of hands?
Yes, this strange situation is called Asterixis.

What is Asterixis?

Asterixis is a disorder of motor control. It is observed when a person is unable to actively maintain a position and suffers from irregular myoclonic lapses of posture that can affect various parts of the body of an individual independently. It is described by a concise loss of muscle tone in agonist muscles that is trailed by a compensatory yank of the antagonistic muscles.

We can say that it occurs as a short but recurrent loss of sustained muscle contractions in the postural muscles of the extremities and trunk.

Even though Asterixis isn’t normal, it is an indication of a genuine and potentially progressed fundamental problem that needs quick clinical consideration.

Asterixis Pathophysiology

After years of research, the exact pathophysiology of asterixis remains unknown. Although several theories do suggest a role for the ascending activating systems associated with arousal, which is disturbed in encephalopathy and lesions of the thalamus and midbrain.

Some of the important aspects that are considered are:

  1. The abnormal function of diencephalic motor centers. The diencephalic center regulates the agonist and antagonist tones.
  2. Negative sharp waves have been revealed in the Electrophysiological check-up in the contralateral central area which suggests abnormal motor field activity of the cortex.

But how exactly these lead to asterixis remains unclear.

What are the Causes of Asterixis?

Although a great deal about asterixis remains unclear, here are some of the common causes of asterixis:

  1. Malfunction in the part of the brain that regularly controls the movement of muscles and posture.

  2. Triggers for this malfunction include:
    • Hepatic Encephalopathy– When the liver is impaired for some reason and isn’t able to perform its usual function of filtering toxins from the body, it may then build up toxins in the blood which enter the brain and disrupt brain function
    • Metabolic Encephalopathy– This type of encephalopathy occurs when extreme or excessively little specific nutrients or minerals such as ammonia cross the blood-brain barrier and cause neurological misfirings and disrupts brain function.
    • Drug Encephalopathy– Certain medications, such as anticonvulsants (used to treat epilepsy) and barbiturates (used for sedation), can affect brain responses.
    • Cardiac Encephalopathy– It occurs when the heart doesn’t pump enough oxygen throughout the body and consequently the brain is affected.

Some Symptoms of Asterixis:

  • Mental confusion
  • Tremors
  • Disturbed and irregular sleep
  • Personality changes

Associated Risk Factors with Asterixis

As we have understood so far that anything that causes changes in the way that our brain functions can cause asterixis, which can include:

  1. Stroke- This is a condition that occurs when blood flow is restricted to certain parts of the brain. It can be caused by blood clots blocking an artery or the narrowing and thinning of the arteries due to high blood pressure or smoking.

  2. Wilson’s Disease- This happens when the liver doesn’t properly process the mineral copper and it gets built up and can damage the brain. It should be noted that this is a genetic disorder and only about 1 in 30,000 are estimated to suffer from this. This can be observed through personality changes and muscle stiffness.

  3. Kidney Failure- When the function of kidneys is disrupted i.e. it doesn’t properly remove toxic materials from the blood, it leads to alteration in the brain function and can cause asterixis. This can happen due to diabetes, high blood pressure, lupus, and certain genetic disorders.

  4. Liver Diseases- Just like the kidney, the liver is responsible for removing toxic materials from our blood. Certain diseases such as cirrhosis or hepatitis cause the liver to malfunction and can ultimately lead to asterixis.

Diagnosis of Asterixis

It is done through a physical exam and lab tests. The usual procedure includes holding out your arm, flexing your wrist, and spreading your fingers. Any individual with asterixis would involuntarily “flap” their wrist downwards and then back up again.

Blood tests include an examination of any build-up of chemicals or minerals such as copper.

Imaging tests, such as CT scans, can also be used to examine brain function and check up on parts that may be malfunctioning.

Asterixis Treatment

The treatment is done based on the cause of asterixis, such as:

  1. If caused by encephalopathies of the liver or kidney
    • Antibiotics, such as rifaximin, reduce gut bacterias that cause a build-up of ammonia in your blood
    • Laxatives are often used to speed up the normal removal of toxins from the body.
    • Lifestyle and dietary changes
    • Transplant in severe cases
  2. Metabolic encephalopathy
    • Dietary changes
    • Drugs that bind to the mineral and help in the removal of toxins
  3. Cardiac encephalopathy
    • Heart conditions should be first brought under control which might require you to lose weight, taking high blood pressure medications, or quit smoking.
    • You may be prescribed ACE inhibitors and beta-blockers
  4. Wilson’s Disease
    • Drugs such as zinc acetate

FAQ’s

Ques. What is the difference between tremors and asterixis?
Ans. Tremor is the involuntary muscle contraction of one or more body parts. Asterixis is a sudden shaking of the hand extending the wrist.

Ques. Can the liver shut down cause asterixis?
Ans. Yes, most definitely, Liver shutdown can cause asterixis

So this was all about Asterixis, we hope you all are now completely familiar with asterixis.

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