Asterixis describes a motor disturbance characterised by intermittent lapses of an assumed posture. It is commonly associated with liver failure where it produces the flapping tremor of hepatic encephalopathy characterised by jerky, irregular flexion-extension movements at the wrist and metacarpophalangeal joints, often accompanied by lateral movements of the fingers.
The motor disturbance may rarely involve the arms, neck, tongue, jaw and eyelids. It is usually bilateral, absent at rest, and asynchronous on each side.
The mechanism is attributed to interference with the inflow of joint position sense to the reticular formation in the brainstem.
Last reviewed 01/2018