Drug-induced parkinsonism as a risk factor for Parkinson's disease: a historical cohort study in Olmsted County, Minnesota.

OBJECTIVE: To investigate whether subjects who experienced a reversible episode of drug-induced parkinsonism have an increased risk of subsequent Parkinson's disease. DESIGN: We undertook a historical cohort study based on the medical records-linkage system of the Rochester Epidemiology Project in Olmsted County, Minnesota. MATERIAL AND METHODS: All subjects in whom drug-induced parkinsonism developed between 1955 and 1990 and was indexed in the medical records-linkage system were identified. In the 24 eligible subjects, follow-up for the subsequent development of Parkinson's disease consisted of a total of 192.7 person-years. The observed number of cases of Parkinson's disease was compared with the expected number of cases in an age- and sex-matched cohort from the general population. RESULTS: In 2 of 24 subjects with drug-induced parkinsonism, Parkinson's disease later developed. A comparison with the expected number of cases in the general population (0.08) yielded a relative risk of 24.3 (95% confidence interval, 2.9 to 87.5; P = 0.006). CONCLUSION: Our findings suggest that drug-induced parkinsonism is associated with an increased risk of Parkinson's disease. Clarification of the mechanisms of this association may have preventive implications.

Psychogenic nonepileptic seizures.

Psychogenic nonepileptic seizures (NES) are commonly encountered in clinical practice, and they may pose difficult diagnostic problems. For appropriate evaluation and treatment of NES, a multidisciplinary team approach is needed; typically, a neurologist with expertise in epilepsy, a psychologist or psychiatrist, and a support staff should be involved. Psychogenic NES have no single initial clinical manifestation, and various etiologic factors may contribute to their development. Of importance, psychogenic NES are "real" seizures that may be as disabling as epileptic seizures. Most often, they occur on a subconscious level, and the patient may have no control over their occurrence. Precipitation or termination of a habitual seizure during video-electroencephalographic monitoring has often been used to distinguish NES from epileptic seizures, but the results can sometimes be misleading. Numerous additional diagnostic techniques can be used to assist in making the diagnosis. Treatment is based on the type of psychiatric disorder present. Favorable prognostic factors include being female and having an independent lifestyle, normal electroencephalographic findings, higher intelligence, and no prior psychotherapy.

Levetiracetam monotherapy for liver transplant patients with seizures.

Selecting an appropriate anticonvulsant for treatment of recipients of orthostatic liver transplants who have new-onset epileptic seizures can be challenging because first-line agents may contribute to worsening encephalopathy, alter the plasma concentration of immunosuppressive agents, and result in hepatotoxicity. We describe the case of a 55-year-old man who underwent orthotopic liver transplantation because of end-stage liver disease due to alcoholic cirrhosis and hepatitis C. He required two repeat transplantation procedures. After the last procedure, epileptic seizures developed, which were initially managed with phenytoin. However, the patient remained stuporous and mental status fluctuated. Breakthrough seizures later developed in the setting of rejection. Levetiracetam (500 mg orally, twice a day) was chosen for its favorable pharmacokinetic properties as an alternative to phenytoin. By the third day of levetiracetam therapy, the patient became more responsive. At most recent follow-up, 3 months after the start of levetiracetam therapy, the patient was still treated with levetiracetam monotherapy, and seizure control was judged to be excellent.

Periodic lateralized epileptiform discharges in multiple sclerosis.

We report an unusual cause of periodic lateralized epileptiform discharges (PLEDs) in a young man with a long history of multiple sclerosis. Two exacerbations of multiple sclerosis, 3 years apart, were complicated by complex partial status epilepticus. After each episode, serial electroencephalograms revealed PLEDs (right frontal PLEDs in the first episode and right frontotemporal and bifrontal PLEDs in the second one), which resolved within 2 weeks. With the first episode, magnetic resonance imaging revealed an enhancing white matter lesion in the right frontal area, which improved after 3 weeks. We concluded that in each instance an exacerbation of multiple sclerosis caused the seizures.

Quantitative effects of cerebral infarction on spatial learning in rats.

Outcome following stroke is difficult to measure because the behavioral response to infarction is variable. We hypothesized that cognitive function, such as spatial learning, may be a reproducible and sensitive outcome variable. We developed an animal model of multifocal cerebral ischemia in order to study the effects of infarction on learning. To cause ischemia, several hundred microspheres were injected into the internal carotid arteries of rats. After ischemia, behavior was measured using a global rating and a Morris water maze. Postmortem serial brain sections were stained and the size of the infarctions was measured. We found that intracerebral microspheres caused cortical infarction and an impairment of spatial learning. This impairment was not due to occlusion of the internal carotid artery and was not found in animals who received a sham injection of saline. The degree of learning impairment was not correlated with the volume density of the infarctions or with the volume density of the remaining cerebral hemisphere. The learning impairment clearly differentiated normal from lesioned animals, and the impairment was probably due to a delay in acquisition of spatial information rather than a defect in retention or retrieval. Measurement of learning deficit after cerebral ischemia is an efficient and sensitive method for evaluating new stroke treatments and possibly for exploring structure function relationships.