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<embedvideo service="youtube" Alignment="right">https://youtu.be/L92A-QbN0KwJUTOh9WYuAM</embedvideo>Seen primarily in metabolic encephalopathy, particularly hepatic and renal encephalopathy, asterixis is an inability to sustain normal muscle tone.(1-3) With the arms outstretched and wrists extended, “like stopping traffic,” the lapse in postural tone may cause the hands to suddenly flop downward, then quickly recover, causing a slow and irregular flapping motion that led to the term “liver flap.” (Video) When severe, the entire arm may drop. Other body parts may exhibit the phenomenon (e.g., inability to keep the foot dorsiflexed [foot flap]).
In unresponsive patients, asterixis at the hip joints can sometimes be brought out by passively flexing and abducting the hips and placing the feet together so that the thighs form a “V.” In this position, the periodic loss of adductor tone may cause the knees to flap up and down.(4)
[[Category: Motor Signs]]
