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Asterixis ?
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Table of Contents
Asterixis?
Asterixis is a symptom where your muscles briefly relax while you’re using them. Depending on which muscles you’re using, it can cause movements that look like flapping or tremor-like movements.
Asterixis is a form of negative myoclonus (pronounced “my-OCK-lon-us”). The term “negative” here doesn’t mean “bad.” Positive myoclonus is a sudden, brief muscle twitch or spasm, so positive here means “more activity.” Negative myoclonus is when a flexed muscle suddenly relaxes, so negative means “less activity.”
This symptom can happen because of issues that are directly affecting your brain. It can also be a secondary condition, meaning something else is affecting your brain and causing asterixis.
What does asterixis look like?
Asterixis affects muscle movements. Most of the time, it affects both sides of your body. But it may not affect both sides of your body as strongly. One side may be affected more strongly or the muscle movements may not be synchronized. It’s common for asterixis to be associated with sleepiness, mental confusion, or disorientation.
The most common way healthcare providers will look for this is by having you hold your wrists and hands in certain ways. There are other methods to see asterixis that involve your legs and feet. But hand-related methods are the most commonly used.
The hand-related methods that providers can look for asterixis include:
- Palms-out method. A healthcare provider will have you extend your arms forward. You’ll spread your fingers and hold your hands like you’re pushing against an invisible wall with the flat surfaces of your palms. That flexes muscles in your wrist. Asterixis will cause your hands to “flap” when those muscles briefly stop flexing.
- Grip method. A healthcare provider using this method will have you grip their hands with yours. They’ll ask you to squeeze tightly and hold your grip. Asterixis will cause split-second losses of grip strength that the provider can feel.
Asterixis commonly doesn’t show right away during either of these methods. Your provider may have you hold the position for 30 seconds or more to be sure they don’t miss it.
POSSIBLE CAUSES
What are the most common causes of asterixis?
Asterixis can happen for several reasons, but the most common ones involve certain types of organ failure. Medications and other conditions may also cause it.
Organ-related conditions
Your liver and kidneys filter toxic substances out of your blood. When your liver and kidneys aren’t working properly, toxic substances can build up in your blood. Your brain is sensitive to many of those substances, so that buildup can disrupt brain function and damage brain cells.
Organ-related conditions that can interfere with liver and kidney function and lead to asterixis include:
- Cirrhosis.
- Liver cancer.
- Liver disease.
- Liver failure.
- Kidney disease.
- Kidney failure.
Brain injuries
Injuries to your brain can cause brain lesions. These lesions are areas that don’t work properly because of damage or other kinds of disruptions that affect their cells. When these lesions affect certain areas responsible for muscle control, it can cause asterixis. When this happens, asterixis is usually one-sided.
Other conditions
Many other conditions can also cause or contribute to asterixis. Almost all of them have to do with changes in your blood chemistry. Examples include:
- Electrolyte imbalances, especially low blood sugar (hypoglycemia), low potassium (hypokalemia) and low magnesium (hypomagnesemia).
- Heart failure.
- Respiratory failure (especially when it causes carbon dioxide buildup in your blood).
- Wilson disease (a genetic condition that causes copper to build up, affecting your brain.
Medications-related asterixis
Certain medications that affect your nervous system can also cause asterixis as a temporary side effect. People with reduced kidney or liver function may also be more prone to asterixis from medications.
These medications include:
- Antiseizure medications, especially phenytoin (asterixis is often called “phenytoin flap” when that drug is the cause). Other antiseizure medications like gabapentin, valproate, and carbamazepine can also cause it.
- Barbiturates.
- Benzodiazepines.
- Certain antibiotics (especially cephalosporins such as cefepime and ceftazidime).
- Lithium (mood stabilizer).
- Metoclopramide (antinausea).
CARE AND TREATMENT
How is asterixis treated?
Asterixis isn’t treatable directly. Instead, healthcare providers will try to find the cause and treat it. Treating the cause generally improves this symptom. Because there are many different causes, the treatment options vary widely. Your healthcare provider (or a provider caring for a loved one with this symptom) can tell you more about possible treatments and which they recommend.
What can I do at home to treat asterixis?
Asterixis isn’t a symptom that you can self-diagnose or self-treat. Because it happens with conditions that are very serious (or even deadly), you should talk to a healthcare provider if you think you have this symptom.
What are the possible complications or risks of not treating asterixis?
The biggest risk from not diagnosing and treating asterixis is from unmanaged or severe medical conditions that might be causing it. In addition to being life-threatening, some untreated medical conditions causing asterixis can also cause brain damage
