Flapping Tremor/ Asterixis

Flapping Tremor: Usually there are brief, arrhythmic interruptions of sustained voluntary muscle contraction causing brief lapses of posture, with a frequency of 3–5 Hz. It is bilateral, but may be asymmetric. Unilateral asterixis may occur with structural brain disease. It can be a sign of hepatic encephalopathy, damage to brain cells presumably due to the inability of the liver to metabolize ammonia to urea. The cause is thought to be predominantly related to abnormal ammonia metabolism. Asterixis is seen most often in drowsy or stuporous patients with metabolic encephalopathies, especially in decompensated cirrhosis or acute liver failure. It is also seen in some patients with kidney failure and azotemia, and in carbon dioxidetoxicity. It can also be a feature of Wilson’s disease. Asterixis is also seen in respiratory failure. Some drugs are known to cause asterixis, particularly phenytoin (when it is known as phenytoin flap). Other drugs implicated include