Literature Review: Parkinson's Disease (PD)

3. Review of Literature

3.1 Parkinson’s Disease7

Parkinson's disease (PD) is a neurodegenerative disease comprising of a spectrum of motor as well as non-motor manifestations. The classic motor manifestations of the disease include rigidity, rest tremors, bradykinesia and impairment of the gait. Along with these cardinal features of Parkinson’s disease, freezing of gait, postural instability, speech difficulty, autonomic disturbances, sensory alterations, mood disorders, sleep dysfunction, cognitive impairment, and dementia are associated manifestations. The median age at diagnosis is 55 years. The diagnosis in patients below 40 years of age is regarded as younger onset Parkinson’s disease. The diagnosis of the Parkinson’s disease is almost

The degeneration is associated with the reduction in the striatal dopamine. The basic cause of this has been identified as the deposition of the intracytoplasmic proteinaceous inclusions. These inclusions are known as Lewy bodies. α-synuclein is the main constituent of Lewy bodies in Parkinson’s disease. The exact cause of these changes is not identified but it is thought to be an age related phenomenon. In addition to the dopaminergic neurons, these inclusion bodies are deposited in the cholinergic neurons of nucleus basalis of Meynert and some nor-epinephric and autonomous neurons also1. The loss of dopaminergic neurons cancels the inhibitory control and modification of basal ganglia output to motor cortex and cerebellum. This results in the uncontrolled unintended motor manifestations in Parkinson’s

4.

Disadvantages Postural hypotension, nausea, confusion

Accentuation of levodopa induced involuntary movements and psychosis. Worsening of levodopa side effects like dyskinesia, postural hypotension

Diarrhea and yellow orange discoloration of urine

Advantages Selegiline if used in early PD prolongs the initiation of Levodopa by 9 months.

Disease modifying action in Parkinson’s disease.

Prolongs levodopa action

Useful in wearing off events and motor fluctuations Increases t1/2 of levodopa

Increases the availability of levodopa in CNS

Useful in advanced cases of Parkinson’s disease

Useful in on-off phenomenon

Mechanism Intracerebral degradation of dopamine is retarded by inhibition of MAO-B Inhibits metabolism of levodopa by COMT

Drug Name MAO-B (Monoamine oxidase B) inhibitors

Selegiline

Rasagiline COMT (Catecholamine o-methyl transferse) inhibitors

Entacapone, Tolcapone

Sr No 5. 6.

Disadvantages Dizziness, lethargy, anticholinergic effects, and sleep disturbance,

Nausea and vomiting Anticholinergic side effects

Sedation and mental confusion in elderly more pronounced

Advantages Modest anti Parkinsonian effect

Can be used as short course with levodopa for motor fluctuations Less side effects compared to