Respiratory Exam

Question 1

what is bilateral asterixis? and give examples of causes?

Answer 1

Bilateral Asterixis
bilateral flapping tremor at the wrist, metacarpophalangeal, and hip joints.2, 3 It may also be seen in tongue, foot, and any skeletal muscle. Except for the facial muscles, the tremors occur in an asynchronous (i.e. not symmetric) fashion on either side of the body.

Metabolic encephalopathies, especially hepatic and renal, are the most common causes of bilateral asterixis. Those caused specifically by hepatic failure are known as “liver (or hepatic) flap”.

Other causes of asterixis include

cardiac and respiratory disease,
electrolyte abnormalities and
drug intoxication.

Electrolyte abnormalities known to cause asterixis include hypoglycaemia, hypokalaemia and hypomagnesaemia. Drug intoxications include barbiturate intoxication, alcoholism, phenytoin intoxication (“phenytoin flap”) and primidone intoxication. Wilson’s disease and focal brain lesions in the rostral midbrain tegmentum may also cause asterixis.