1/28. akinetic mutism after fourth ventricle choroid plexus papilloma: treatment with a dopamine agonist.BACKGROUND: akinetic mutism is a behavioral state wherein a patient seems to be awake but does not move or speak. Several patients are reported to have developed mutism after posterior fossa surgery. We present a patient who developed akinetic mutism after total excision of a choroid plexus papilloma of the fourth ventricle, and who was treated with bromocriptine. CASE DESCRIPTION: An 18-year-old woman was admitted with akinetic mutism, which had developed 6 days after posterior fossa surgery. She had had no neurologic deficit in the first 5 days after surgery and could communicate with her family. Despite antioedematous therapy and daily lumbar punctures to drain cerebrospinal fluid, there was no clinical improvement after she entered the akinetic mute state. Brain magnetic resonance revealed ventriculomegaly; brain single photon emission computed tomography revealed bilateral reduction of perfusion in the frontal region. Because daily lumbar drainage did not result in clinical improvement, shunt placement was not considered. bromocriptine therapy was begun at a dose of 2x2.5 mg; 24 hours later, the patient started to speak and move her upper extremities. Further improvement occurred over the following week when the dose was increased to 3x2.5 mg. bromocriptine was replaced with a placebo to determine whether the neurologic improvement was caused by the medicine. The patient's neurologic status deteriorated progressively; therefore, bromocriptine was restarted and she was discharged from the hospital. During the 6 months of follow-up, the patient has remained in good health. CONCLUSIONS: The etiology of akinetic mutism is not clear. Monoaminergic pathways, particularly dopaminergic cell groups, are most probably involved in this syndrome, because bromocriptine has a dramatic effect on these patients, as demonstrated in our case.- - - - - - - - - - ranking = 1keywords = agonist (Clic here for more details about this article) |
2/28. Hyperekplexia in a patient with a brainstem vascular anomaly.OBJECTIVES: To describe a patient with a clinical picture suggestive of idiopathic hyperekplexia (IH), who was later found to harbour a subtle brainstem vascular anomaly. PATIENT: A 35-year-old man, 4 years earlier, developed sudden jumping and falling in response to unexpected sensory stimuli. RESULTS: Neurological examination was normal. electromyography showed an excessively large and non-habituating motor startle response. There were no mutations of the alpha1 subunit of the inhibitory glycine receptor which cause hereditary hyperekplexia. Although all these findings were consistent with a diagnosis of IH, a blink reflex study showed an enhanced recovery curve suggestive of a brainstem lesion. A detailed MRI study revealed a subtle vascular anomaly involving the lower brainstem. CONCLUSION: This is the first report of sporadic hyperekplexia related to a brainstem vascular anomaly. Subtle damage to the brainstem should always be excluded in patients with sporadic hyperekplexia, regardless of the coexistence of additional clear-cut neurological symptoms.- - - - - - - - - - ranking = 0.0019366024017175keywords = receptor (Clic here for more details about this article) |
3/28. Adverse effect of dopamine agonist therapy in a patient with motor-intentional neglect.Studies in animals and humans report dopamine agonists can improve neglect. Because dopamine deficit reduces intention to act, it has been suspected the dopamine agonist bromocriptine would improve deficient hemispatial intention. Thus, the effect of bromocriptine on line bisection was examined in a patient with neglect and failure of the action-intention system. The 58-year-old patient had left-sided neglect from a right cerebral infarction involving both cortical and subcortical (striatal) structures. It was determined that neglect on a line bisection task was attributable to a motor-intentional bias by testing under congruous and incongruous video monitoring. Testing sessions were held before starting bromocriptine, on 20 mg/d, and after stopping bromocriptine. The patient's ipsilesional bias increased on bromocriptine, and improved when bromocriptine was stopped. bromocriptine may worsen neglect if putamenal receptors are damaged. dopamine agonists may activate the normal hemisphere, increasing an intentional bias. Clinicians using dopaminergic pharmacotherapy should assess patients for this possible adverse effect.- - - - - - - - - - ranking = 1.7519366024017keywords = agonist, receptor (Clic here for more details about this article) |
4/28. Neuronal activity in the basal ganglia in patients with generalized dystonia and hemiballismus.Microelectrode recording was performed in the basal ganglia of 3 patients with generalized dystonia and 1 patient with hemiballismus secondary to a brainstem hemorrhage. Neuronal activity was recorded from the internal and external segments of the globus pallidus and assessed for mean discharge rate and pattern of spontaneous activity. The responses of neurons in the internal segment of the globus pallidus to passive and active movements were also evaluated. Mean discharge rates of neurons in both segments of the pallidum in patients with dystonia and the patient with hemiballismus were considerably lower than those reported for patients with idiopathic Parkinson's disease. In addition, the pattern of spontaneous neuronal activity was highly irregular, occurring in intermittent grouped discharges separated by periods of pauses. Although receptive fields in the dystonia patients were widened and less specific than those reported in normal monkeys, neuronal responses to movement were uncommon in the hemiballismus patient. Before surgery, patients with dystonia experienced abnormal posturing and involuntary movements. Coactivation of agonist-antagonist muscle groups was observed both at rest and during the performance of simple movements. After pallidotomy there was a significant reduction in the involuntary movement associated with these disorders and a more normal pattern of electromyographic activity during rest and movement. Given the improvement in dystonic and hemiballistic movements in these patients after ablation of the sensorimotor portion of the internal segment of the globus pallidus, we suggest that pallidotomy can be an effective treatment for patients with dystonia and also for patients with medically intractable hemiballismus. Based on the finding of decreased neuronal discharge rates in pallidal neurons, we propose that physiologically dystonia most closely resembles a hyperkinetic movement disorder. A model for dystonia is proposed that incorporates the observed changes in the rate and pattern of neuronal activity in the pallidum with data from neuroimaging with positron emission tomography and 2-deoxyglucose studies.- - - - - - - - - - ranking = 0.5keywords = agonist (Clic here for more details about this article) |
5/28. Treatment of phenothiazine induced bulbar persistent dyskinesia with deanol acetamidobenzoate.The late manifestation of neuroleptic-induced dyskinesia (persistent dyskinesia) is an irreversible complication of long-term treatment that is poorly understood and difficult to treat. Recently, a theory of dopamine receptor hypersensitivity in the dopaminergic-cholinergic system has suggested an explanation of choreiform movements and, thus, an implication for the management of persistent dyskinesia. The case presented is that of bulbar persistent dyskinesia in a patient who had been prescribed a phenothiazine derivative for eleven years; his symptoms improved with the use of deanol, which probably converts to acetylcholine after crossing the blood brain barrier. This improvement suggests that deanol may shift the neuroleptic-induced dopaminergic-cholinergic system unbalance toward equilibrium by matching predominant dopaminergic effect or by enhancing deficient cholinergic action in the dopaminergic-cholinergic system. This isolated finding needs to be confirmed by more research in neuropharmacology.- - - - - - - - - - ranking = 0.0019366024017175keywords = receptor (Clic here for more details about this article) |
6/28. Shift from hypermetria to hypometria in multiple system atrophy: analysis of distal and proximal movements.Dysmetria is a classical sign which designates the overshoot, also called hypermetria, and the undershoot, or hypometria, when the patient attempts to reach rapidly an aimed target. Dysmetria is typically observed in patients presenting a cerebellar dysfunction. Dysmetria of distal movements is associated with an imbalance between the timing and/or the intensity of agonist and antagonist EMG activities. So far, 1. there is only one description in human of a shift from hypermetria to hypometria for fast goal-directed single-joint movements during an aberrant recovery following a cerebellar infarction, and 2. such a shift has not been described for proximal movements. We report a patient presenting a multiple system atrophy (MSA). Initially, he exhibited a marked cerebellar syndrome. Fast wrist flexions and fast upper limb reaches in the sagittal plane were hypermetric. The distal hypermetria was associated with a delayed onset latency of the antagonist EMG activity and reduced intensities of both the agonist and the antagonist EMG activities. The proximal hypermetria was associated with a defect in the phasic spatial tuning of the EMG activities. He developed progressively severe extra-pyramidal signs. Distal hypermetria turned into hypometria, as a result of a decrease in the intensity of the agonist muscle. Proximal hypermetria turned into hypometria, as a result of the loss of directional preference of the EMG activities in proximal muscles. MSA is the second human model of a shift from hypermetria to hypometria.- - - - - - - - - - ranking = 1.5keywords = agonist (Clic here for more details about this article) |
7/28. Dominant and recessive central core disease associated with RYR1 mutations and fetal akinesia.We studied seven patients (fetuses/infants) from six unrelated families affected by central core disease (CCD) and presenting with a fetal akinesia syndrome. Two fetuses died before birth (at 31 and 32 weeks) and five infants presented severe symptoms at birth (multiple arthrogryposis, congenital dislocation of the hips, severe hypotonia and hypotrophy, skeletal and feet deformities, kyphoscoliosis, etc.). Histochemical and ultrastructural studies of muscle biopsies confirmed the diagnosis of CCD showing unique large eccentric cores. Molecular genetic investigations led to the identification of mutations in the ryanodine receptor (RYR1) gene in three families, two with autosomal recessive (AR) and one with autosomal dominant (AD) inheritance. RYR1 gene mutations were located in the C-terminal domain in two families (AR and AD) and in the N-terminal domain of the third one (AR). This is the first report of mutations in the RYR1 gene involved in a severe form of CCD presenting as a fetal akinesia syndrome with AD and AR inheritances.- - - - - - - - - - ranking = 0.0019366024017175keywords = receptor (Clic here for more details about this article) |
8/28. Pharmacotherapy for akinesia following anterior communicating artery aneurysm hemorrhage.The dopamine system may be involved in three situations: the nigral projection to the basal ganglia, the mesocortical projection to the anterior cingulate gyrus, or the medial forebrain bundle projection to cortical and limbic sites. Because of the close association of dopamine systems with the known neurological syndromes of akinesia, we elected to treat a patient with akinesia due to rupture of anterior communicating artery (ACA) aneurysm with the dopamine agonist, bromocriptine. This case has important implications for the understanding of brain/behavior relationships as well as for the development of new therapies for patients who have sustained neurological injury.- - - - - - - - - - ranking = 0.25keywords = agonist (Clic here for more details about this article) |
9/28. Centronuclear myopathy--an inherited neuromuscular disorder. A report of 3 cases.Three patients with the adult form of centronuclear myopathy are presented. The slow progression of this disorder is confirmed. The investigations included muscle and sural nerve biopsies. The electron microscopic findings in the muscle of these patients are unique, as are the results of histological examination and histochemical tests. The sural nerve studies were within normal limits. insulin estimations in response to glucose loading were normal, which largely negates the possibility of an insulin-receptor defect in this disorder.- - - - - - - - - - ranking = 0.0019366024017175keywords = receptor (Clic here for more details about this article) |
10/28. A rare case with diurnal fluctuation of head instability, hypotonia and choreoathetotic movements improved by L-dopa treatment.This report concerns a 6-year-old girl who showed peculiar symptoms but responded favourably to L-dopa. She developed normally until around 1 year of age, at which time head instability, hypotonia, increased deep tendon reflexes and choreoathetotic movements developed. These symptoms appeared to worsen in the afternoon and were alleviated after sleep. An extremely small dose of L-dopa (2 mg/kg) showed dramatic effects and her symptoms disappeared. This condition may be associated with the supersensitivity of the dopamine receptors, caused by hypofunction of the dopamine neurones.- - - - - - - - - - ranking = 0.0019366024017175keywords = receptor (Clic here for more details about this article) |
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