Asterixis: Causes

Asterixis is considered a form of myoclonus.

HOW TO DETECT? Have the patient hold their arms outstretched with fingers and wrists extended. There will be intermittent loss of muscular tone causes sudden flexion at the wrists followed by a return to extension, so that the hands flap in a regular or, more often, an irregular rhythm.

See video here.

Major Causes for Asterixis include:

• Hepatic Encephalopathy
• Hypercapnia
• Uremic Encephalopathy

REFERENCES

1. Young RR, Shahani BT. Asterixis: one type of negative myoclonus. Adv Neurol. 1986;43:137-56.
2. Chapter 11: Movement Disorders. Clinical Neurology, 9e