It is a neurological disorder that causes a person to lose motor control of certain areas of the body.
Muscles, often in the wrists and fingers, although they can occur in other areas of the body, can become abruptly and intermittently lax.
This loss of muscle control is also accompanied by jerky, irregular and involuntary movements. For this reason, asterixis is sometimes called a “flutter tremor.”
Since certain liver diseases appear to be related to asterixis, it is also sometimes called a ‘liver flap’.
The flapping is said to resemble the wings of a bird in flight.
According to research, these “shaking” or “fluttering” movements of the wrist hand are more likely to occur when the arms are stretched and the wrists flexed.
Asterixis on both sides of the body is much more common than unilateral asterixis.
Symptoms of asterixis
Asterixis is a motor disorder, the symptoms of which include:
- Inability to maintain a neutral wrist position or a fixed position.
- Tremors in the hands with interrupted muscle contraction causing postural lapses with a frequency of 3 to 5 Hz.
- Arrhythmic jerks or movement of the hands, wrists, and fingers with outstretched hands.
- “Irregular flapping” of the hands.
- Involuntary movements
- Pain and discomfort in the hands.
- Weakness in the arms.
Causes of asterixis
The condition was first recognized nearly 80 years ago, but much remains to be learned.
The disorder is believed to be caused by a malfunction in the part of the brain that controls muscle movement and posture.
Why does this malfunction occur?
It is not entirely known. Researchers suspect that there may be certain triggers, including encephalopathies.
Encephalopathies are disorders that affect brain function.
- Mental confusion.
- Personality changes
- Disturbed sleep
Some types of encephalopathy that can result in asterixis are:
Hepatic refers to the liver. The main function of the liver is to filter toxins from the body. But when the liver is damaged for whatever reason, it may not remove toxins efficiently.
Consequently, they can accumulate in the blood and enter the brain, where they disrupt brain function.
A complication of liver and kidney disease is metabolic encephalopathy.
This occurs when too much or too little of certain vitamins or minerals, such as ammonia, cross the blood-brain barrier and cause neurological failure.
Certain medications, such as anticonvulsants (used to treat epilepsy) and barbiturates (used for sedation), can affect brain responses.
When the heart does not pump enough oxygen throughout the body, the brain is affected. Risk Factors for Asterixis Almost anything that affects brain function can lead to asterixis.
A stroke occurs when blood flow to part of the brain is restricted.
This can happen due to a blood clot blocking an artery or due to a narrowing of the arteries due to things like smoking or high blood pressure.
Liver diseases that put you at high risk for asterixis include cirrhosis or hepatitis. Both conditions can cause scarring of the liver. This makes it less efficient at filtering out toxins.
According to research, up to 45 percent of people with cirrhosis have hepatic (liver) encephalopathy, putting them at higher risk for asterixis.
Like the liver, the kidneys also remove toxic materials from the blood.
If too many of these toxins are allowed to accumulate, they can disrupt brain function and lead to asterixis.
The kidneys and their ability to do their job can be damaged by conditions such as:
- High blood pressure
- Certain genetic disorders.
In Wilson’s disease, the liver does not properly process the mineral copper. If left untreated and allowed to accumulate, copper can damage the brain.
This is a rare genetic disorder. Experts estimate that about 1 in 30,000 people have Wilson’s disease.
It is present at birth, but may not be apparent until adulthood.
Symptoms of toxic copper levels include:
- Muscular stiffness.
- Personality changes
Other risk factors
Both epilepsy and heart failure are also risk factors for asterixis.
Diagnosis of asterixis
A diagnosis of asterixis is often based on both a physical exam and laboratory tests.
Your doctor may ask you to extend your arms, flex your wrists, and spread your fingers. After a few seconds, a person with asterixis will involuntarily “shake” their wrists down and then lift them up.
Your doctor may also push against your wrists to prompt a response. Your doctor may also order blood tests to check for a buildup of chemicals or minerals in the blood.
Imaging tests, such as CT scans, can examine brain function and visualize areas that may be affected.
Treatment of asterixis
When the underlying condition causing asterixis is treated, the asterixis usually improves and even disappears completely.
Encephalopathies of the liver or kidney
Your doctor may recommend:
Lifestyle and Diet Changes : If you are abusing alcohol or have a condition that can damage your kidneys, such as diabetes, your doctor can talk to you about reducing your health risks.
Laxatives – Lactulose in particular can speed up the removal of toxins from the body.
Antibiotics : These drugs, such as rifaximin, reduce intestinal bacteria. Excess gut bacteria can cause a large amount of the ammonia waste product to build up in your blood and disrupt brain function.
Transplants : In severe cases of liver or kidney damage, you may need a transplant with a healthy organ.
Your doctor will likely recommend dietary changes, taking medications that will bind to the mineral to help eliminate it from the body, or both.
It will depend on which mineral is overabundant in the bloodstream.
Your doctor may change the dose of a drug or switch you to a completely different drug.
Getting any underlying heart condition under control is the first step.
That can mean one or a combination of the following factors:
- Lose weight.
- Give up smoking.
- Take medicine for high blood pressure.
Your doctor may also prescribe ACE inhibitors, which widen your arteries, and beta blockers, which slow your heart rate.
Your doctor may prescribe medications such as zinc acetate, which prevents your body from absorbing copper in the food you eat.
They may also prescribe chelating agents such as penicillamine. It can help excrete copper from tissues.
Asterixis is not common, but it is a symptom of a serious and possibly advanced underlying disorder that needs immediate medical attention.
In fact, one study reported that 56 percent of those with asterixis related to alcoholic liver disease died, compared with 26 percent of those without it.
If you’ve noticed any of the fluttering tremors characteristic of asterixis, or if you have any of the risk factors listed above, talk to your doctor.
In many cases, when the condition causing asterixis is successfully treated, the asterixis improves or even disappears.