Asterixis
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ICD-10 | R27.8 | |
---|---|---|
ICD-9 | 781.3 | |
DiseasesDB | 33950 | |
MeSH | C10.597.350 |
Asterixis is a flapping tremor of the hand that is an early sign of hepatic encephalopathy (damage to brain cells due to toxins not cleared from the blood by the liver). The exact cause of this disorder is not known but it is thought to be related to by abnormal ammonia metabolism.
Asterixis is the medical word to describe flapping tremor (sometimes said to resemble a "bird flapping its wings"). It is best shown in the hand-flapping tremor when the arms are outstretched in extension and the wrist is dorsiflexed. Adams and Foley first described asterixis in 1949 in patients with severe liver failure and encephalopathy. Typically there are brief, arrhythmic interruptions of sustained voluntary muscle contraction causing brief lapses of posture. It is bilateral, and may be asymmetrical with a frequency of 3-5 Hz. Asterixis is seen most often in drowsy or stuporose patients with metabolic encephalopathies, especially in decompensated cirrhosis or acute hepatic failure. It is also seen in some patients with renal failure and azotaemia, and in carbon dioxide narcosis of respiratory failure. Asterixis can also be a feature of Wilson's disease.
The word derives from a- + Greek. stērixis a fixed position.
Adams RD, Foley JM. The neurological changes in the more common types of severe liver disease. Trans American Neurology Association 1949; 74: 217-219.