From the Guidelines
The most consistent finding in a person with Parkinson's disease is resting tremor, characterized by a frequency of 4-6 Hz, and is most noticeable when the affected limb is at rest, diminishing with voluntary movement. Parkinson's disease is a neurodegenerative disorder resulting from dopamine depletion in the brain, leading to a variety of motor symptoms, including tremor, muscular rigidity, bradykinesia, and postural instability 1. The disease is characterized by progressive degeneration of dopaminergic neurons in the substantia nigra, leading to dopamine deficiency in the basal ganglia, which disrupts normal motor control pathways, producing the characteristic symptoms 1. Other consistent findings include bradykinesia (slowness of movement), rigidity (increased muscle tone), and postural instability. Early symptoms may be asymmetric, often beginning in one hand before progressing to affect other limbs. Additional findings may include a shuffling gait, reduced facial expression (hypomimia), micrographia (small handwriting), and a forward-stooped posture. Non-motor symptoms like depression, cognitive changes, and autonomic dysfunction may also be present but are less immediately recognizable than the classic motor manifestations. According to the most recent study 1, Parkinson's disease is the most common cause of Parkinsonism, with other common causes, including progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal degeneration (CBD), and vascular Parkinsonism.
Some key points to consider in the diagnosis and management of Parkinson's disease include:
- The clinical presentation of PD is characterized by resting tremor, bradykinesia, and rigidity and is related to progressive degeneration of the dopaminergic neurons in the substantia nigra projecting to the striatum 1.
- The estimated interval between initial loss of dopaminergic neurons and the appearance of symptoms is approximately 5 years (after approximately 40% to 50% of the dopaminergic neurons in the substantia nigra have been lost) 1.
- Patients with PD are at increased risk of malnutrition and weight loss, and nutritional status should be monitored routinely throughout the natural history of the disease 1.
- Dysphagia in PD usually occurs in the advanced phases of the disease, although sometimes it is present at onset, and functional alterations in oropharyngeal and esophageal motility can be present in about 60-80% of patients, but must be asymptomatic 1.
Overall, the diagnosis and management of Parkinson's disease require a comprehensive approach, taking into account the motor and non-motor symptoms, as well as the nutritional and gastrointestinal complications that may arise. The most consistent finding in a person with Parkinson's disease is resting tremor, and early recognition and treatment of this symptom can significantly improve the quality of life for patients with this condition.
From the FDA Drug Label
The Unified Parkinson's Disease Rating Scale (UPDRS) is a four-part multi-item rating scale intended to evaluate mentation (part I), Activities of Daily Living (ADL) (part II), motor performance (part III), and complications of therapy (part IV). Part II of the UPDRS contains 13 questions relating to ADL, which are scored from 0 (normal) to 4 (maximal severity) for a maximum (worst) score of 52 Part III of the UPDRS contains 27 questions (for 14 items) and is scored as described for part II. It is designed to assess the severity of the cardinal motor findings in patients with Parkinson's disease (e.g., tremor, rigidity, bradykinesia, postural instability, etc.), scored for different body regions, and has a maximum (worst) score of 108
The most consistent findings in a person with Parkinson’s disease are:
- Tremor
- Rigidity
- Bradykinesia
- Postural instability These are the cardinal motor findings in patients with Parkinson's disease, as assessed by the Unified Parkinson's Disease Rating Scale (UPDRS) part III 2.
From the Research
Motor Complications in Parkinson's Disease
- Motor complications, such as response fluctuations, dyskinesia, and psychiatric problems, are common in patients with Parkinson's disease 3, 4, 5
- These complications are related to the intermittent delivery of dopamine-replacing drugs to the brain 4
- Levodopa, a dopamine precursor, is an effective and well-tolerated dopamine replacement agent used to treat Parkinson's disease, but its chronic use is associated with the development of motor complications 3, 5
Treatment Options for Parkinson's Disease
- Dopamine agonists, such as cabergoline, pramipexole, ropinirole, and rotigotine, are effective for treating Parkinson's disease, both as monotherapy and in combination with levodopa 6
- Monoamine oxidase type-B (MAO-B) inhibitors, such as selegiline, rasagiline, and safinamide, are also effective for treating Parkinson's disease, with selegiline being the best option in combination with levodopa 6
- Levodopa/carbidopa/entacapone, a combination tablet, is available for use in Parkinson's disease patients with end-of-dose wearing off 5
Current Pharmacological Treatment for Parkinson's Disease
- Current dopaminergic pharmacotherapy for Parkinson's disease consists of levodopa and other dopaminergic drugs, such as dopamine agonists and MAO-B inhibitors 7
- Non-dopaminergic pharmacological approaches, including zonisamide and istradefylline, are also available for treating Parkinson's disease 7
- Device-aided therapies, such as deep brain stimulation and levodopa-carbidopa intestinal gel infusion therapy, can be performed at the advanced stage of Parkinson's disease 7