Neurologic complications of metronidazole.

Metronidazole (Flagyl®) is an antimicrobial agent commonly used in clinical practice. Although it is generally well tolerated with minimal side effects, there are a host of still under-recognized neurologic complications of metronidazole treatment. The following review is aimed at summarizing current literature pertaining to metronidazole-induced neurotoxicity including clinical syndromes, neuroradiological findings, prognosis and proposed pathophysiology. Recognition of the neurotoxic effects of metronidazole is critical as prompt discontinuation is generally associated with full clinical recovery and radiological resolution. Complications neurologiques du métronidazole. Le métronidazole (Flagyl®) est un agent antimicrobien utilisé couramment en pratique clinique. Bien qu'il soit généralement bien toléré et que ses effets secondaires soient minimes, il existe une myriade de complications neurologiques du traitement par le métronidazole qui ne sont pas toujours reconnues. Le but de cette revue constitue un sommaire de la littérature actuelle concernant la neurotoxicité induite par le métronidazole dont les syndromes cliniques, les constatations neuroradiologiques, le pronostic et l'hypothèse physiopathologique expliquant cette neurotoxicité. Il est important d'identifier ces effets neurotoxiques du métronidazole étant donné que l'arret immédiat du traitement est généralement associé à une guérison clinique complète et à la disparition des signes radiologiques.

Demographics and Clinical Characteristics of Autosomal Dominant Spinocerebellar Ataxia in Canada.

Background: Autosomal dominant (AD) spinocerebellar ataxias (SCAs) encompass a large group of rare disorders, which occurs in individuals of different ethnic backgrounds. To date, demographics, and clinical descriptions of AD SCA in Canada are lacking. Methods: A retrospective chart review of patients with a genetically confirmed diagnosis of AD SCAs was performed at five tertiary centers across Canada in the provinces of Quebec, Alberta, and Ontario. Demographic, genetic, and clinical information were collected and analyzed. Results: A total of 203 patients with AD SCA were identified. Weighted estimated prevalence of AD SCA in three large Canadian provinces was calculated (2.25 cases per 100.000) which is in keeping with the figures documented worldwide. We found that the distribution of the most common SCA differed when comparing provinces. The most prevalent SCA diagnosis in Ontario was SCA3 (49%), while the most prevalent SCA diagnosis in Alberta and Quebec was SCA2 in 26% and 47%, respectively. SCA6 was the third most prevalent SCA subtype in Quebec (14%), which was not seen as commonly in other provinces. SCA1 was uncommonly seen in both Alberta and Quebec, despite being common in Ontario. Conclusions: In this largest Canadian study, we describe the prevalence, distribution, and clinical characteristics of AD SCA. We found that the distribution of the most common SCA differed in the three provinces studied. This finding reflects the heterogenous nature of the Canadian population.

Cerebellar Brain Inhibition Is Associated With the Severity of Cervical Dystonia.

PURPOSE: Cerebellar connectivity is thought to be abnormal in cervical dystonia (CD) and other dystonia subtypes, based on evidence from imaging studies and animal work. The authors investigated whether transcranial magnetic stimulation-induced cerebellar brain inhibition (CBI), a measure of cerebellar efficiency at inhibiting motor outflow, is abnormal in patients with CD and/or is associated with clinical features of CD. Because of methodological heterogeneity in CBI reporting, the authors deployed additional controls to reduce potential sources of variability in this study. METHODS: Cerebellar brain inhibition was applied in 20 CD patients and 14 healthy control subjects. Cerebellar brain inhibition consisted of a cerebellar conditioning stimulus delivered at four different interstimulus intervals (ISIs) before a test stimulus delivered to hand muscle representation in the motor cortex. The average ratio of conditioned to unconditioned motor evoked potential was computed for each ISI. Cervical dystonia clinical severity was measured using the Toronto Western Spasmodic Torticollis Rating Scale. Control experiments involved neuronavigated transcranial magnetic stimulation, neck postural control in patients, and careful screening for noncerebellar pathway inhibition via cervicomedullary evoked potentials. RESULTS: There was no difference between CBI measured in healthy control subjects and CD patients at any of the four ISIs; however, CBI efficiency was significantly correlated with worsening CD clinical severity at the 5 ms ISI. CONCLUSIONS: Cerebellar brain inhibition is a variable measure in both healthy control subjects and CD patients; much of this variability may be attributed to experimental methodology. Yet, CD severity is significantly associated with reduced CBI at the 5 ms ISI, suggestive of cerebello-thalamo-cortical tract dysfunction in this disorder.

Stress and Coping: A Literature Review of Everyday Stressors and Strategies to Cope in Pediatric Patients With Cancer.

Although cancer survival rates are improving, pediatric patients with cancer still face numerous stressors. Using an integrative approach, a literature review was conducted to identify stressors and synthesize effective coping strategies among pediatric patients with cancer. The CINAHL® Complete, ProQuest, and PubMed® databases were searched for relevant studies using key terms. Eight studies were included in the final analysis. Three factors contributing to everyday stressors of pediatric patients with cancer and four major coping categories were identified.

Patterns of brain activity during a set-shifting task linked to mild behavioral impairment in Parkinson's disease.

Mild behavioral impairment (MBI) is a neurobehavioral syndrome characterized by later life emergence of sustained neuropsychiatric symptoms, as an at-risk state for incident cognitive decline and dementia. Prior studies have reported that neuropsychiatric symptoms are associated with cognitive abilities in Parkinson's disease (PD) patients, and we have recently found a strong correlation between MBI and cognitive performance. However, the underlying neural activity patterns of cognitive performance linked to MBI in PD are unknown. Fifty-nine non-demented PD patients and 26 healthy controls were scanned using fMRI during performance of a modified version of the Wisconsin card sorting task. MBI was evaluated using the MBI-checklist, and PD patients were divided into two groups, PD-MBI and PD-noMBI. Compared to the PD-noMBI group and healthy controls, the PD-MBI group revealed less activation in the prefrontal and posterior parietal cortices, and reduced deactivation in the medial temporal region. These results suggest that in PD, MBI reflects deficits in the frontoparietal control network and the hippocampal memory system.

Mild behavioral impairment is linked to worse cognition and brain atrophy in Parkinson disease.

OBJECTIVE: To evaluate the associations of mild behavioral impairment (MBI) with cognitive deficits and patterns of gray matter changes in Parkinson disease (PD). METHODS: Sixty patients with PD without dementia and 29 healthy controls underwent a cognitive neuropsychological evaluation and structural MRI scan. MBI was evaluated with the MBI Checklist (MBI-C), a rating scale designed to elicit emergent neuropsychiatric symptoms in accordance with MBI criteria. We divided the patients with PD into 2 groups: 1 group with high MBI-C scores (PD-MBI) and the other with low MBI-C scores (PD-noMBI). RESULTS: Among 60 patients with PD, 20 were categorized as having PD-MBI (33.33%). In healthy controls, no participants met the MBI cut-point threshold. The PD-MBI group had significantly lower Montreal Cognitive Assessment and z scores in all 5 domains and the global score compared to healthy controls and those with PD-noMBI. In addition, all cognitive domains except language and global cognition negatively correlated with the MBI-C total score in all patients with PD. For cortical structures, the PD-MBI group revealed middle temporal cortex thinning and decreased volume compared with the PD-noMBI group, and decreased volume in this area negatively correlated with the MBI-C total score. CONCLUSIONS: The impaired cognitive function over all domains and atrophy in the temporal area in the PD-MBI group are in line with posterior cortical circuit deficits in PD, which have been associated with a faster rate of progression to dementia. These initial results suggest that MBI might be an early and important marker for incident cognitive decline and dementia in patients with PD.

Neuropathy as a potential complication of levodopa use in Parkinson's disease.

The presence and potential etiologies of peripheral neuropathy (PN) in patients with Parkinson's Disease (PD) is unknown. We examined for presence of PN in patients with PD. From a PD patient population of 500 patients screened for features of symptomatic PN, patients were further selected for clinical, electrophysiological, and laboratory studies related to PN. This PD patient population with idiopathic PN (PD-IPN) was compared to a group of PD patients without PN (PD-only), and a large group of patients without PD with idiopathic PN (IPN) for abnormalities in Cbl, fasting homocysteine (Hcy), and fasting methylmalonic acid (MMA) levels. PD-IPN and IPN patients identified with abnormalities in Cbl, Hcy, or MMA levels were treated with intramuscular Cbl for 1 to 2 years. Of 49 PD patients with symptomatic PN, 34 patients (69%) had PD-IPN, and 32/34 (94%) had abnormal Hcy or MMA levels as compared to 26/258 (10%) of IPN patients. Cumulative lifetime L-dopa dosage and fasting MMA levels were associated with PN severity. Cbl therapy led to improvements in Hcy and MMA levels in all groups, and PN in PD-IPN patients stabilized during therapy. PN in PD patients may be associated with iatrogenic Cbl metabolic abnormalities. Alternatively PN may be a peripheral nervous system manifestation of PD.

Prevalence of problem and pathological gambling in Parkinson's disease.

Pathological gambling (PG) has been identified in patients with Parkinson's disease (PD) treated with dopamine agonists suggesting that dysregulation of brain dopaminergic activity may contribute to the development of gambling problems. The current study was undertaken to further establish the prevalence of problem and PG in patients with PD, identify any clinical correlates, and determine if psychiatric or substance use co-morbidity contributes to the increased prevalence of problem and PG. A cross-sectional survey of 140 serially recruited moderate to severe PD patients was undertaken utilizing the Canadian Problem Gambling Index, Alcohol Use Disorders Identification Test, Drug Abuse Screening Test, Beck Depression Inventory, Beck Anxiety Inventory, and Mini-Mental State Exam augmented by chart review, completed over an 8 month period. The 12 month prevalence of problem and PG in PD was 9.3% compared to 1.6% in the general population within a comparably aged sample. The increased prevalence of problem and PG in the PD group was related to dopamine agonist use and younger age, but not co-morbidity. Most subjects with problem and PG reported their gambling increased after being diagnosed with PD and starting treatment. The results suggest that brain dopaminergic activity is involved in the underlying neurobiology of problem and PG.

Caffeine as symptomatic treatment for Parkinson disease (Café-PD): A randomized trial.

OBJECTIVE: To assess effects of caffeine on Parkinson disease (PD). METHODS: In this multicenter parallel-group controlled trial, patients with PD with 1-8 years disease duration, Hoehn & Yahr stages I-III, on stable symptomatic therapy were randomized to caffeine 200 mg BID vs matching placebo capsules for 6-18 months. The primary research question was whether objective motor scores would differ at 6 months (Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale [MDS-UPDRS]-III, Class I evidence). Secondary outcomes included safety and tolerability, motor symptoms (MDS-UPDRS-II), motor fluctuations, sleep, nonmotor symptoms (MDS-UPDRS-I), cognition (Montreal Cognitive Assessment), and quality of life. RESULTS: Sixty patients received caffeine and 61 placebo. Caffeine was well-tolerated with similar prevalence of side effects as placebo. There was no improvement in motor parkinsonism (the primary outcome) with caffeine treatment compared to placebo (difference between groups -0.48 [95% confidence interval -3.21 to 2.25] points on MDS-UPDRS-III). Similarly, on secondary outcomes, there was no change in motor signs or motor symptoms (MDS-UPDRS-II) at any time point, and no difference on quality of life. There was a slight improvement in somnolence over the first 6 months, which attenuated over time. There was a slight increase in dyskinesia with caffeine (MDS-UPDRS-4.1+4.2 = 0.25 points higher), and caffeine was associated with worse cognitive testing scores (average Montreal Cognitive Assessment = 0.66 [0.01, 1.32] worse than placebo). CONCLUSION: Caffeine did not provide clinically important improvement of motor manifestations of PD (Class I evidence). Epidemiologic links between caffeine and lower PD risk do not appear to be explained by symptomatic effects. CLINICALTRIALSGOV IDENTIFIER: NCT01738178. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for patients with PD, caffeine does not significantly improve motor manifestations.

Levodopa-induced changes in synaptic dopamine levels increase with progression of Parkinson's disease: implications for dyskinesias.

Peak-dose dyskinesias are abnormal movements that usually occur 1 h after oral administration of levodopa, and often complicate chronic treatment of Parkinson's disease. We investigated by PET with [11C]raclopride whether Parkinson's disease progression modifies the striatal changes in synaptic dopamine levels induced by levodopa administration, and whether this modification, if present, could have an impact on the emergence of dyskinesias. We found that, 1 h after oral administration of standard-release 250/25 mg of levodopa/carbidopa, levodopa-induced increases in synaptic dopamine levels (as estimated by striatal changes in [11C]raclopride binding potential) correlated positively with duration of Parkinson's disease symptoms (for the caudate nucleus, r = 0.79, P < 0.001; for the putamen, r = 0.88, P < 0.0001). Patients with peak-dose dyskinesias had larger 1-h increases in synaptic dopamine levels than stable responders, but there were no between-group differences in [11C]raclopride binding 4 h post-levodopa. The corresponding (time x group) interaction term in the repeated measures analysis of covariance was significant, even after adjusting for between-group differences in duration of Parkinson's disease symptoms (for the caudate nucleus, P = 0.030; for the putamen, P = 0.021). Our results indicate that, at the synaptic level, an identical dose of levodopa induces increasingly larger 1-h changes in dopamine levels as Parkinson's disease progresses. Large levodopa-induced increases in synaptic dopamine concentration can lead to dramatic changes in receptor occupancy, which may be responsible for the emergence of peak-dose dyskinesias in Parkinson's disease.

Adult onset spinocerebellar ataxia in a Canadian movement disorders clinic.

BACKGROUND: The spinocerebellar ataxias (SCAs) are a genetically and clinically heterogeneous group of neurodegenerative disorders. Relative frequencies vary within different ethnic groups and geographical locations. OBJECTIVES: 1) To determine the frequencies of hereditary and sporadic adult onset SCAs in the Movement Disorders population; 2) to assess if the fragile X mental retardation gene 1 (FMR1) premutation is found in this population. METHODS: A retrospective chart review of individuals with a diagnosis of adult onset SCA was carried out. Testing for SCA types 1, 2, 3, 6, 7, and 8, Dentatorubral-pallidoluysian atrophy (DRPLA), Friedreich ataxia and the FMR1 expansion was performed. RESULTS: A total of 69 patients in 60 families were identified. Twenty-one (35%) of the families displayed autosomal dominant and two (3.3%) showed autosomal recessive (AR) pattern of inheritance. A positive but undefined family history was noted in nine (15%). The disorder appeared sporadic in 26 patients (43.3%). In the AD families, the most common mutation was SCA3 (23.8%) followed by SCA2 (14.3%) and SCA6 (14.3%). The SCA1 and SCA8 were each identified in 4.8%. FA was found in a pseudodominant pedigree, and one autosomal recessive pedigree. One sporadic patient had a positive test (SCA3).Dentatorubral-pallidoluysian atrophy and FMR1 testing was negative. CONCLUSION: A positive family history was present in 53.3% of our adult onset SCA patients. A specific genetic diagnosis could be given in 61.9% of dominant pedigrees with SCA3 being the most common mutation, followed by SCA2 and SCA6. The yield in sporadic cases was low. The fragile X premutation was not found to be responsible for SCA.

Degradation of stored movement representations in the Parkinsonian brain and the impact of levodopa.

Parkinson's disease (PD) results from the depletion of dopamine and other neurotransmitters within the basal ganglia, and is typically characterized by motor impairment (e.g., bradykinesia) and difficulty initiating voluntary movements. Difficulty initiating a movement may result from a deficit in accessing or executing a stored representation of the movement, or having to create a new representation each time a movement is required. To date, it is unclear which may be responsible for movement initiation impairments observed in PD. In this study, we used functional magnetic resonance imaging and a task in which participants passively viewed familiar and unfamiliar graspable objects, with no confounding motor task component. Our results show that the brains of PD patients implicitly analyze familiar graspable objects as if the brain has little or no motor experience with the objects. This was observed as a lack of differential activity within brain regions associated with stored movement representations for familiar objects relative to unfamiliar objects, as well as significantly greater activity for familiar objects when off levodopa relative to on medication. Symptom severity modulated this activity difference within the basal ganglia. Levodopa appears to normalize brain activity, but its effect may be one of attenuation of brain hyperactivity within the basal ganglia network, which is responsible for controlling motor behavior and the integration of visuomotor information. Overall, this study demonstrates that difficulty initiating voluntary movements experienced by PD patients may be the result of degradation in stored representations responsible for the movement.

Positron emission tomography after fetal transplantation in Huntington's disease.

Huntington's disease (HD) is a progressive disorder with no known cure. We report two-year postoperative positron emission tomography (PET) data from 7 HD patients who underwent intrastriatal fetal transplantation. Patients showed widespread reductions in glucose uptake with no significant change over 2 years. Dopamine receptor binding was significantly reduced in HD striatum. D1 binding did not change significantly following transplantation, but there was a significant loss of D2 binding. These findings may reflect loss of graft viability and/or disease progression. There was no significant relationship between changes in PET and clinical function. In summary, there was no benefit from transplantation.

VMAT2 binding is elevated in dopa-responsive dystonia: visualizing empty vesicles by PET.

Dopa-responsive dystonia (DRD) is a lifelong disorder in which dopamine deficiency is not associated with neuronal loss and therefore it is an ideal human model for investigating the compensatory changes that occur in response to this biochemical abnormality. Using positron emission tomography (PET), we examined the (+/-)-alpha-[(11)C]dihydrotetrabenazine ([(11)C]DTBZ) binding potential of untreated DRD patients and normal controls. Two other PET markers of presynaptic nigrostriatal function, d-threo-[(11)C]methylphenidate ([(11)C]MP) and 6-[(18)F]fluoro-L-dopa ([(18)F]-dopa), and [(11)C]raclopride were also used in the study. We found increased [(11)C]DTBZ binding potential in the striatum of DRD patients. By contrast, no significant changes were detected in either [(11)C]MP binding potential or [(18)F]-dopa uptake rate constant. In addition, we found evidence for increased dopamine turnover in one DRD patient by examining changes in [(11)C]raclopride binding potential in relation to levodopa treatment. We propose that the increase in [(11)C]DTBZ binding likely reflects the dramatic decrease in the intravesicular concentration of dopamine that occurs in DRD; upregulation of vesicular monoamine transporter type 2 (VMAT2) expression may also contribute. Our findings suggest that the striatal expression of VMAT2 (as estimated by [(11)C]DTBZ binding) is not coregulated with dopamine synthesis. This is in keeping with a role for VMAT2 in other cellular processes (i.e., sequestration and release from the cell of potential toxic products), in addition to its importance for the quantal release of monoamines.