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Parkinson's Disease

Author/s: 
Caroline M. Tanner, Jill L Ostrem

The global burden of Parkinson’s disease is projected to increase in future decades as the number and proportion of older adults increases. This review addresses research advances since 1998, when the disorder was last reviewed in the Journal, and includes recently introduced concepts relevant to clinical practice. For two centuries, Parkinson’s disease has been diagnosed clinically on the basis of the characteristic motor syndrome of bradykinesia accompanied by resting tremor, rigidity, and postural reflex impairment, all largely the result of dopaminergic dysfunction in the nigrostriatal system. Advances in our understanding of the disease suggest that a biologic definition may be possible, but many questions remain. In this review, we use the clinical definition of Parkinson’s disease.

Keywords 
Levodopa Parkinson Disease

Parkinson disease primer, part 2: management of motor and nonmotor symptoms

Author/s: 
Frank, C., Chiu, R., Lee, J.

Objective To provide family physicians with an approach to the management of
motor and nonmotor symptoms of Parkinson disease (PD).
Sources of information Published guidelines on the management of PD were
reviewed. Database searches were conducted to retrieve relevant research
articles published between 2011 and 2021. Evidence levels ranged from I to III.
Main message Family physicians can play an important role in identifying and
treating motor and nonmotor symptoms of PD. Family physicians should initiate
levodopa treatment for motor symptoms if they affect function and if specialist
wait times are long, and they should be aware of basic titration approaches
and possible side effects of dopaminergic therapies. Abrupt withdrawal of
dopaminergic agents should be avoided. Nonmotor symptoms are common and
underrecognized and are a major factor in disability, quality of life, and risk of
hospitalization and poor outcomes for patients. Family physicians can manage
common autonomic symptoms such as orthostatic hypotension and constipation.
Family physicians can treat common neuropsychiatric symptoms such as
depression and sleep disorders, and they can help recognize and treat psychosis
and PD dementia. Referrals to physiotherapy, occupational therapy, speech
language therapy, and exercise groups are recommended to help preserve function.
Conclusion Patients with PD present with complex combinations of motor
and nonmotor symptoms. Family physicians should have basic knowledge of
dopaminergic treatments and their side effects. Family physicians can play
important roles in management of motor symptoms and particularly nonmotor
symptoms and can have a positive impact on patients’ quality of life. An
interdisciplinary approach involving specialty clinics and allied health experts
is an important part of management.

Keywords 
Parkinson Disease Dopamine Agents Psychotic Disorders hospitalization dementia

Parkinson disease primer, part 1: diagnosis

Author/s: 
Frank, C., Chiu, R., Lee, J.

Objective To provide family physicians an updated approach to the diagnosis of Parkinson disease (PD).

Sources of information Published guidelines on the diagnosis and management of PD were reviewed. Database searches were conducted to retrieve relevant research articles published between 2011 and 2021. Evidence levels ranged from I to III.

Main message Diagnosis of PD is predominantly clinical. Family physicians should evaluate patients for specific features of parkinsonism, then determine whether symptoms are attributable to PD. Levodopa trials can be used to help confirm the diagnosis and alleviate motor symptoms of PD. “Red flag” features and absence of response to levodopa may point to other causes of parkinsonism and prompt more urgent referral.

Conclusion Access to neurologists and specialized clinics varies, and Canadian family physicians can be important players in facilitating early and accurate diagnosis of PD. Applying an organized approach to diagnosis and considering motor and nonmotor symptoms can greatly benefit patients with PD. Part 2 in this series will review management of PD.

Parkinson disease (PD) is the fastest growing neurodegenerative condition, with prevalence predicted to double from more than 6 million globally in 2015 to more than 12 million by 2040.1 Recognizing parkinsonism and having knowledge of the presentation, diagnosis, and management of motor and nonmotor symptoms of PD are increasingly important, particularly as access to neurologists and specialized clinics is limited in many parts of Canada.2 Family physicians are well placed to identify symptoms, participate in diagnosis, and collaborate with specialty clinics in management of patients through the course of the disease.

Keywords 
Levodopa Parkinson's Disease diagnosis Parkinson Humans

Dietary Approaches to Improve Efficacy and Control Side Effects of Levodopa Therapy in Parkinson's Disease: A Systematic Review

Author/s: 
Boelens Keun, J., Arnoldussen, I., Vriend, C., Van de Rest, O.

Although levodopa remains the most effective drug for symptomatic management of Parkinson's Disease (PD), treatment during advanced disease stages may raise unpredictable motor fluctuations and other complications. Counteracting these complications with other pharmacological therapies may prompt a vicious circle of side effects, and here, nutritional therapy may have great potential. Knowledge about the role of diet in PD is emerging and multiple studies have investigated nutritional support specifically with respect to levodopa therapy. With this systematic review, we aim to give a comprehensive overview of dietary approaches to optimize levodopa treatment in PD. A systematic search was performed using the databases of PubMed and Scopus between January 1985 and September 2020. Nutritional interventions with the rationale to optimize levodopa therapy in human PD patients were eligible for this study and their quality was assessed with the Cochrane risk-of-bias tool. In total, we included 22 papers that addressed the effects of dietary proteins (n = 10), vitamins (n = 7), fiber (n = 2), soybeans (n = 1), caffeine (n = 1), and ketogenic diets (n = 1) on levodopa therapy. Interventions with protein redistribution diets (PRDs), dietary fiber, vitamin C, and caffeine improved levodopa absorption, thereby enhancing clinical response and reducing motor fluctuations. Furthermore, supplementation of vitamin B-12, vitamin B-6, and folic acid successfully reduced high homocysteine concentrations that emerged from levodopa metabolism and promoted many metabolic and clinical complications, such as neuropathology and osteoporosis. In conclusion, dietary interventions have the potential to optimize levodopa efficacy and control side effects. Nutrition that improves levodopa absorption, including PRDs, fiber, vitamin C, and caffeine, is specifically recommended when fluctuating clinical responses appear. Supplements of vitamin B-12, vitamin B-6, and folic acid are advised along with levodopa initiation to attenuate hyperhomocysteinemia, and importantly, their potential to treat consequent metabolic and clinical complications warrants future research.

Keywords 
diet Levodopa Therapy Parkinson's Disease PD Side Effects
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