RESUMO
Parkinson's disease (PD) has been linked to a vast array of vitamins among which vitamin B12 (Vit B12) is the most relevant and often investigated specially in the context of intrajejunal levodopa infusion therapy. Vit B12 deficiency, itself, has been reported to cause acute parkinsonism. Nevertheless, concrete mechanisms through which B12 deficiency interacts with PD in terms of pathophysiology, clinical manifestation and progression remains unclear. Recent studies have suggested that Vit B12 deficiency along with the induced hyperhomocysteinemia are correlated with specific PD phenotypes characterized with early postural instability and falls and more rapid motor progression, cognitive impairment, visual hallucinations and autonomic dysfunction. Specific clinical features such as polyneuropathy have also been linked to Vit B12 deficiency specifically in context of intrajejunal levodopa therapy. In this review, we explore the link between Vit B12 and PD in terms of physiopathology regarding dysfunctional neural pathways, neuropathological processes as well as reviewing the major clinical traits of Vit B12 deficiency in PD and Levodopa-mediated neuropathy. Finally, we provide an overview of the therapeutic effect of Vit B12 supplementation in PD and posit a practical guideline for Vit B12 testing and supplementation.
RESUMO
Fatigue is a common non-motor symptom in Parkinson's disease (PD), but even so, it may still be underdiagnosed or misdiagnosed in current practice due to its non-specific manifestations. The aims of this study were to investigate the prevalence of fatigue in PD patients compared to healthy controls and to identify the main characteristics and associations of fatigue with other non-motor symptoms and the impact of fatigue on sleep disturbances in Parkinson's disease. MATERIALS AND METHODS: case-control study in which 131 PD patients and 131 age- and sex-matched controls were enrolled. Main characteristics of fatigue, sleep, and other non-motor symptoms were assessed using specific validated questionnaires. RESULTS: According to the Chalder fatigue scale, fatigue is more prevalent in PD patients (38.16%) compared to healthy controls (26.71%). Fatigue was identified in 46.54% of the PD patients using the Parkinson's Fatigue Scale (PFS-16). PD patients with fatigue presented a worse motor status, more sleep disturbances (insomnia, daytime sleepiness), a broader spectrum of non-motor symptoms (pain, anxiety, urinary disturbances), worse cognitive performances, a lower level of happiness, and worse quality of life compared to PD patients without fatigue. CONCLUSION: Fatigue is a common symptom of PD and needs to be assessed, considering its consequences on quality of life. Sleep disturbances have a great influence over fatigue in PD patients.