Asterixis is the symptom of metabolic brain damage. For example, after liver or kidney damage, the brain can also be damaged. Asterixis patients suffer from gross tremor of the hands due to such damage.
What is asterixis?
Involuntary tremor is also called tremor by medical science. The tremors are a result of rhythmically repeated contractions of antagonistic muscle groups. Every person has a physiological tremor that is barely visible. Once there is clear visibility, tremor is a pathological phenomenon that can be associated with various diseases. Tremor characterizes asterixis. This disease is included under the coordination disorders and is characterized by coarse trembling movements of the hands. Most often, asterixis develops as a result of toxic or metabolic brain damage. In connection with liver damage, there is also talk of flutter tremor. Actually, asterixis in the narrower sense is not a tremor, since it is not based on the contraction of antagonistic muscles, but on a short-term loss of muscle tone. This loss of tone triggers a reflex correction that manifests as tremor. The first description of asterixis was in 1949, and Adams and Foley are considered the first describers. Asterixis of the legs interferes with standing and walking. Falls often occur as a result.
Causes
Asterixis is a symptomatic movement disorder that usually results from brain damage. The damage results in a temporary brief inhibition of the extensor muscles on the forearm muscles, which triggers flexion of the hands. As soon as the hand has moved down, a reflex compensates for this posture by an extension movement and thus aims to move the hand back to its initial position. This is often referred to as causative negative myoclonus, which is followed by a reflexive corrective movement. The most common cause of flutter tremor seems to be metabolic encephalopathies according to case reports so far. Metabolic brain damage is referred to as such. For example, asterixis may accompany hepatic encephalopathies. It is also a characteristic symptom in acute liver failure or in the context of Wilson’s disease. Much less commonly, the primary cause corresponds to renal failure or drug ingestion. Metabolic brain injury occurs due to substances produced or retained in the body during metabolic diseases. In this context, we can also talk about toxic substances. Patients of asterixis show symptoms as soon as they are supposed to stretch out their hands and hold them straight with stretched fingers. The trembling seems rough. A sudden flexion in the wrist is evident, which is rhythmic or arrhythmic and has a frequency of about four hearts. The flexion is followed by a reflex movement to correct it. When patients hold their arms at their sides, the movements appear to be wing beats. In most cases, the tremor is present on both sides of the body. In individual cases, however, a unilateral expression is also conceivable. In cases of bilateral tremor, there is often symmetry. Basically, asterixis itself is only the system of another disease. The symptoms accompanying the tremors depend on the primary cause. For example, in the context of renal insufficiency, accompanying symptoms include back pain, proteinuria, and discoloration of the urine. In all organ damage, brain damage may also be associated with concomitant symptoms that affect cognition, motor function, or other bodily processes, depending on the localization.
Diseases with this symptom
- Hepatic encephalopathy
- Liver failure
- Wilson’s disease
Diagnosis and course
The neurologist usually recognizes asterixis by visual diagnosis. For closer assessment and observation, he will ask the patient to position himself in the room with his outstretched hands side by side. If the gross tremor develops, brain damage is likely present. Imaging of the brain can confirm this damage. To diagnose the primary cause of the symptom, the physician can use the medical history.If, for example, kidney or liver disease is mentioned during the patient interview, the diagnosis of asterixis can be considered confirmed. If no metabolic diseases have been diagnosed to date, extensive general examinations of the metabolic organs take place. The prognosis of asterixis depends on the primary cause.
Complications
Asterixis, occurring predominantly as a result of metabolic or toxic brain injury or in renal failure, can lead to various complications when it occurs and as the underlying disease progresses. Thus, the symptom is primarily associated with severe malaise and impaired motor function for the patient. In addition, there may be severe pain in the arms and especially in the wrists, due to the constant tension and jerky flexion of the hands and fingers. In addition, asterixis leads to feelings of numbness in the affected limbs and can thus also severely restrict the affected person in everyday life. Early treatment by a physician is therefore advisable, although the treatment options vary greatly from cause to cause. In most cases, the asterixis itself does not lead to problems, but rather the underlying disease. This can range from a variety of muscle disorders such as tremor to kidney failure. In the latter case, the tremor that typically occurs with asterixis is just one of many symptoms. If asterixis occurs as a result of primary writing tremor, further complications often include inflammation in the affected limbs. Treatment with propranolol and primidone often promises improvement here. If the cause of asterixis is not treated, permanent nerve damage may result.
When should you see a doctor?
Asterixis syndrome is characterized by trembling of the hands. It is also known as “tremor” or “flapping tremor”. Typical of this type of hand tremor are coarse trembling movements of the hands. They are easily caused by the fact that affected persons do not manage to stretch their hands, including fingers, straight ahead without a clearly visible tremor. When the arms are stretched out to the side, the tremor resembles a flapping of wings. Asterixis usually occurs bilaterally, rarely unilaterally. Asterixis is an expression of metabolic impairment of the brain that has occurred due to liver or kidney damage. The damaged brain can no longer adequately control the muscles governing the forearm. For the family physician, asterixis primarily indicates liver damage. He must also consider possible kidney impairment as well as the genetic copper storage disease Wilson’s disease or a drug side effect as a cause of asterixis. In the case of asterixis, the general practitioner will refer his patient to specialists for further diagnosis, for example to an internist, gastroenterologist or nephrologist. In the therapy of the disease underlying asterixis, a conceivable alcohol abuse should also be discussed. If alcohol abuse is present, a rehab should be sought with the patient in addition to treatment of the underlying disease.
Treatment and therapy
Once asterixis is diagnosed, the treatment steps depend primarily on the primary disease in which the causative brain injury occurred. For example, in the case of renal insufficiency, transplantation may be a consideration in addition to dialysis. The symptom of asterixis cannot be treated causally in the strict sense. Brain damage has already occurred. As a rule, brain tissue cannot regenerate completely. Thus, the actual cause of asterixis cannot be remedied. However, the condition can be improved by supportive treatment methods so that it no longer affects the life of the affected person. With this goal in mind, patients participate in physiotherapy training sessions. After brain damage caused by strokes, physiotherapy was able to shift the function of damaged brain areas to intact brain areas in individual cases, for example. The patients were largely asymptomatic afterwards. Asterixis can therefore theoretically be brought to resolution despite irreversible damage to the brain. If the tremor does not improve with physiotherapy, patients at least learn coping strategies under ergo- or physiotherapeutic supervision.
Outlook and prognosis
Based on the underlying disease, the prognosis for asterixis varies widely. In principle, however, the disease cannot be expected to heal spontaneously. And even if the cause can be successfully corrected, symptoms may still persist. If the cause is brain damage, it cannot be cured according to current medical knowledge. Since the damaged brain tissue can no longer regenerate, the so-called flutter tremor cannot be reversed by medical treatment in this case. If acute liver failure or renal insufficiency is the causative factor, immediate treatment may improve the symptoms under certain circumstances. Both acute liver failure and renal failure are life-threatening. If dialysis is performed, for example, there may already be improvement. In cases of massive renal failure, a kidney transplant that is successful can help cure asterixis. Accompanying therapeutic measures also help the patient to cope better with the typical symptoms in everyday life. In addition to occupational and physical therapy for learning modified movement patterns, behavioral therapy also plays a role here, teaching how to integrate new strategies for coping with certain tasks into everyday life. As a rule, it is then also possible for those affected to return to a regular occupation.
Prevention
Asterixis can be prevented only to the extent that metabolic brain damage or diseases such as cirrhosis of the liver can be prevented. For example, conscientious handling of toxic substances can be widely described as a preventive measure.
What you can do yourself
Asterixis or flutter tremor is always caused by metabolic damage to certain areas of the brain or by a stroke. In the case of metabolic damage to brain cells, the main priority is to treat the affected metabolic organs, such as the liver or kidneys, to stop the progression of the disease if possible. Everyday and self-help is always aimed at mitigating the symptoms of asterixis. Since certain areas of the brain are already irreversibly damaged when the symptoms appear, other areas of the brain can be brought to take over the tasks and functions through targeted exercise training if successful. It is recommended to design an exercise program together with an experienced physiotherapist, which can also be carried out at home as self-help. The approach is similar to physiotherapeutic programs that are usually developed after a stroke to train other brain areas to take over certain functions. The use of active relaxation exercises such as autogenic training, yoga and meditation can also temporarily relieve symptoms. Both forms of therapy, physiotherapeutic training and active relaxation, can be performed as self-help. The ultimate goal is for those affected to be able to lead as normal and self-determined a life as possible under the condition that the underlying disease that triggered the symptoms of asterixis is also treatable and is also treated.
