Asterixis: a study of 103 patients.

In 1949, asterixis was first described in patients with hepatic encephalopathy. It was quickly recognized that this phenomenon also occurs in other generalized encephalopathies and sometimes results from structural brain lesions. This paper is a study of asterixis in the general neurology clinic and on the inpatient neurology consultation service. The neurologists recorded the findings on inpatients and clinic patients for 12 consecutive months. Of the 1,109 inpatients with adequate examination, asterixis was documented in 97. Eighteen of the 97 cases were unilateral (18.6%) and 79 cases were bilateral (81.4%). Of the 614 outpatient visits with well documented examination, 6 (1%) individuals had asterixis. Since a small number of patients were examined more than once, the study yielded 103 individuals with adequate data for analysis. Asterixis resulted from varied causes: medications, renal disorder, hepatic dysfunction, pulmonary insufficiency, stroke and other brain lesions (including malignancy, subdural hematoma, and epidural abscess). Asterixis occurred in various patterns: in some cases it was easier to elicit in the upper extremities, in some it was easier to elicit in the lower limbs, and some it was solely or predominantly unilateral. The findings are discussed in light of the literature on asterixis with regard to its varied causes, patterns and presentations. Lastly, asterixis is examined from a historical perspective and the terminology is elucidated.