Unilateral asterixis

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.

A combined pattern of movement disorders resulting from posterolateral thalamic lesions of a vascular nature: a syndrome with clinico-radiologic correlation

We report a series of seven patients in whom a combined pattern of complex movement disorders restricted to one upper extremity emerged as a result of posterolateral thalamic lesions of vascular origin. This disorder was mainly characterized by choreiform and dystonic movements associated with variable, rhythmic, alternating movements of low frequency (myorhythmia). All cases showed, on computed tomography scan and/or magnetic resonance imaging, focal lesions involving the posterolateral quadrant of the thalamus. Review of similar cases reported with identical clinico-radiologic features allows us to conclude that it is possible to establish an accurate anatomoclinical correlation based on the clinical phenomenology, even before imaging studies are performed, in these cases. The opposite is not entirely possible, however, because lesions in the same quadrant of the thalamus are often associated with different patterns of abnormal movements or present without abnormal movements.

Asterixis associated with anatomic cerebral lesions: a study of 45 cases

INTRODUCTION

Asterixis is an uncommon sign in structural central nervous system disorders. When asterixis is present, one cannot rule out the possibility of a focal lesion, but it is almost always due to a metabolic encephalopathy.

PATIENTS AND METHODS

In the last five years all patients with uni- or bilateral neurologic asterixis attended in our hospital have been studied. Cerebral computed tomogram or magnetic resonance imaging was performed in all patients with uni or bilateral asterixis.

RESULTS

We describe 45 patients with different forms of structural cerebral pathology who presented unilateral (37 patients) or bilateral (8 patients) asterixis not associated to either toxic or metabolic disorder. Central nervous system ischemic or hemorrhagic disorders were found to be the most frequent causes of asterixis (95.5%) and the thalamus the most frequent localization for unilateral asterixis to result (54%).

CONCLUSIONS

Bilateral asterixis is not always associated with toxic or metabolic disorders and it may be a sign of some structural neurologic alterations. A good correlation was found between the presence of unilateral asterixis and structural intracranial disease.

Movement disorders following lesions of the thalamus or subthalamic region

Reports of 62 cases with a movement disorder associated with a focal lesion in the thalamus and/or subthalamic region were analyzed. Thirty-three cases had a lesion confined to the thalamus. Sixteen cases had a thalamic lesion extending into the subthalamic region and/or midbrain. Thirteen cases had a lesion in the subthalamic region or a subthalamic lesion extending into the midbrain. Nineteen cases with dystonia, 18 with asterixis, 17 with ballism-chorea, three with paroxysmal dystonia, and five with clonic or myorhythmic movements have been described. No case with isolated tremor has been described. In 53 cases with unilateral thalamic or subthalamic lesions, all but one with bilateral blepharospasm (associated with right posterior thalamic, pontomesencephalic, and bilateral cerebellar lesions) had dyskinesias in the limbs contralateral to the lesion. The other nine cases had bilateral paramedian thalamic lesions; seven developed bilateral dyskinesias, and the remaining two had unilateral dyskinesias. Regarding the 19 patients with dystonia, the two with bilateral blepharospasm had thalamic and upper brainstem lesions, and one with hemidystonia and torticollis had a subthalamic lesion. The other 16 patients all had a unilateral thalamic lesion with contralateral dystonia (10 hemidystonia, five focal dystonia affecting a hand and/or and one segmental dystonia involving face, arm, and hand). The exact location of the thalamic lesion was mentioned in 10 cases; the posterior or posterolateral thalamus was involved in six and the paramedian thalamus in four. These areas are more posterior or medial to the ventrolateral and ventroanterior thalamic nuclei, which receive pallido-thalamic and nigro-thalamic afferents. Two cases developed dystonia immediately after thalamotomy, and one case developed it 4 days after head trauma. The others initially had a hemiplegia and developed dystonia 1-9 months after the acute insult. Fifteen of the 17 patients with chorea had a unilateral lesion in the subthalamic nucleus or subthalamic region (eight due to infarcts, one to hemorrhage, five to mass lesions, and one to multiple sclerosis). All had contralateral hemichorea or hemiballism. One other case had bilateral chorea of the hands and tongue due to paramedian thalamic infarction. Another case with generalized chorea and thalamic atrophy was complicated by stereotaxic surgery. Thirteen of the 18 cases with asterixis had lesions confined to the thalamus. Eight were associated with thalamotomy, and five others had a stroke (four infarction and one hemorrhage) affecting the contralateral thalamus.(ABSTRACT TRUNCATED AT 400 WORDS)

Asterixis induced by carbamazepine therapy

There are very few reports about asterixis as a side effect of treatment with psychopharmacologic agents. In this report we present four patients treated with a combination of different psychotropic drugs, in whom asterixis was triggered either by adding carbamazepine (CBZ) to a treatment regimen, or by increasing its dosage. Neither dosage nor serum levels of CBZ were in a higher range. We consider asterixis to be an easily overlooked sign of neurotoxicity, which may occur even at low or moderate dosage levels, if certain drugs as lithium or clozapine are used in combination with CBZ.