What is the clinical course of Parkinson's disease (PD)?

From the Guidelines

Parkinson's disease is a progressive neurological disorder that typically advances through several stages over many years, with significant morbidity and mortality implications, and thus requires regular monitoring of nutritional and vitamin status, particularly focusing on changes in body weight and the need for supplementing vitamin D, folic acid, and vitamin B12, as recommended by the ESPEN guideline 1. The clinical course of Parkinson's disease (PD) is characterized by subtle symptoms that may go unnoticed in the early stages, including mild unilateral tremor, rigidity, or bradykinesia. As the disease advances over 4-8 years, symptoms become bilateral with increasing motor difficulties, including postural instability, freezing of gait, and more pronounced tremor 1. Some key points to consider in the clinical course of PD include:

• Weight changes, both loss and gain, are common in PD patients, with weight loss being a key feature of the disease and associated with disease progression 1
• Malnutrition is associated with disease severity, and regular monitoring of body weight and nutritional assessment is recommended, at least on a yearly basis and whenever clinical conditions change 1
• Vitamin D supplementation should be considered, as low vitamin D levels have been associated with the risk of developing PD and slowing disease progression, particularly in patients with high-risk genotype of the vitamin D receptor 1
• Homocysteine levels should be monitored, as elevation of homocysteine is associated with levodopa treatment, and administration of vitamins B12 and folate can reduce homocysteine levels and prevent neuropathy and other complications associated with hyper-homocysteinemia 1
• The progressive nature of Parkinson's reflects ongoing dopaminergic neuron loss in the substantia nigra, with treatment becoming more complex as the therapeutic window narrows over time, and thus requiring a comprehensive and multidisciplinary approach to management, including medication regimens, device-aided therapies, and specific management of non-motor symptoms 1.

From the FDA Drug Label

Parkinson’s disease is a progressive, neurodegenerative disorder of the extrapyramidal nervous system affecting the mobility and control of the skeletal muscular system. Its characteristic features include resting tremor, rigidity, and bradykinetic movements. Current evidence indicates that symptoms of Parkinson’s disease are related to depletion of dopamine in the corpus striatum.

The clinical course of Parkinson's disease (PD) is a progressive, neurodegenerative disorder. The characteristic features of PD include:

• Resting tremor
• Rigidity
• Bradykinetic movements The symptoms of PD are related to depletion of dopamine in the corpus striatum 2.

From the Research

Clinical Course of Parkinson's Disease

The clinical course of Parkinson's disease (PD) is characterized by a varied and progressive clinical picture, with a variable rate of progression 3. The disease is marked by the presence of motor and non-motor symptoms, which can vary in severity and impact on daily life.

Motor Symptoms

• Bradykinesia is a core symptom of PD, and is often accompanied by different types of tremors, including rest tremor, action tremor, re-emergent tremor, and orthostatic tremor 3.
• Motor fluctuations and dyskinesias are common complications in advanced PD, resulting in disabled activities of daily life 4, 5.
• Motor symptoms can be managed with dopaminergic pharmacotherapy, including levodopa and other dopaminergic drugs, such as dopamine agonists and monoamine oxidase B (MAO-B) inhibitors 4, 5.

Non-Motor Symptoms

• Non-motor symptoms, such as cognitive, psychiatric, and autonomic problems, can become bothersome and disabling in some patients 3.
• In late-stage PD, non-motor symptoms can dominate the clinical presentation and have a sub-optimal response to dopaminergic treatment 6.
• Non-pharmacological interventions, including physiotherapy, cognitive stimulation, speech, occupational therapy, and specialized PD nursing, can play a key role in managing non-motor symptoms 6.

Disease Progression

• PD is a slowly progressive neurodegenerative disorder, with a clinical diagnosis that can be imprecise in the absence of a biomarker 3.
• The disease can be divided into different stages, including early, advanced, and late-stage PD, each with distinct clinical characteristics and management challenges 4, 6.
• Personalized medicine approaches, including genetic characterization and prediction of disease risk and progression, may offer new opportunities for individualized management and treatment of PD 7.