Parkinson’s Disease
Parkinson’s Disease is a common neurodegenerative disorder that generally affects people of middle and advanced age, although there are early onset forms that can occur in younger ages and are often due to genetic causes. The clinical manifestations are motor, with tremor, rigidity and bradykinesia, and non-motor, with common manifestations of sleep disorders, autonomic dysfunction, depression, anxiety and hyposmia. The disease is also associated with cognitive disturbances, which are usually mild, especially at the initial disease stages. The disease is managed to a large extent with the appropriate therapeutic regimen, especially with regards to the motor aspects. The regimen is based on the dopamine deficiency that characterizes the disease. Dopamine is the neurotransmitter that is produced by the substantia nigra pars compacta neurons that predominantly degenerate in this condition.
Parkinsonism
Parkinsonism is a term that characterizes the clinical picture of patients who manifest rigidity, meaning resistance to passive movements performed by the examiner, and bradykinesia, meaning slowness of movements, especially the repetitive ones, despite normal muscle strength. It is often associated with gait dysfunction, with the characteristic slow, shuffling steps, and hypomimia, meaning a reduction of the spontaneous face movements. There may be tremor, but this is not obligatory. Parkinsonism is a syndrome of which there may be a number of underlying causes. Commonly, it represents idiopathic Parkinson’s Disease, but the clinical picture of Parkinsonism may be due to cerebral vascular damage (vascular parkinsonism), certain drugs (drug-induced parkinsonism), Hydrocephalus, as well as a host of other Neurodegenerative conditions.
Atypical Parkinsonian Syndromes
These are neurodegenertave disorders where Parkinsonism is present together with other neurological manifestations that suggest a more extensive damage to the nervous system. These conditions do not respond well to dopamine supplementation therapy, and do not carry a good prognosis. Another nameu used for these syndromes is «Parkinson-plus». The specific forms of atypical Parkinsonism include a) Multiple System Atrophy, with additional involvement of the Autonomic, Pyramidal and Cerebellar Systems, b) Progressive Supranuclear Palsy (PSP), which is characterized by oculomotor deficits and gait instability, with early falls, and c) Corticobasl Syndrome (CBS), which is characterized by additional involvement of higher cortical function, in particular apraxia and aphasia.
Tremor
This is a pendular movement (‘trembling”) of a body part centered around a particular point. It can manifest at rest, or upon particular movements or positions, something that characterizes it as rest, postural or kinetic tremor. It more often manifests in the hands or head. It can be the first manifestation of Parkinson’s Disease, particularly if it is a unilateral rest tremor. More often though it represents a manifestation of more benign conditions, such as idiopathic tremor, dystonic tremor or tremor due to metabolic causes or drugs.
Dystonia
This represents an aberrant contraction of a group of muscles, leading to an abnormal twisting movement or position of body parts. More commonly, there is a particular muscle group that is affected, leading to focal forms of dystonia, which remain restricted to a certain region; examples include spasmodic torticollis, blepharospasm, writer’s cramp an dothers. These forms generally respond to local injections of botulinum toxin. Generalized dystonias are less common. They are often of a genetic cause, and can be managed with oral agents, or, in severe cases, with Deep Brain Stimulation (DBS).
Hyperkinetic Movement disorders (Hyperkinesias)
These are excessive involuntary movements that either manifest at rest, or intervene in the flow of normal voluntary movements. There are various forms depending on the particular phenomenology. These include tics, chorea, dystonia and myoclonus. In a number of hyperkinetic conditions, there may be a combination of hyperkinetic movements.
Myoclonus
This represents a lightning-like, brief, sudden limb movement, like a jerk. It can manifest in isolation or a series of movements in various body parts. Myoclonus can be physiologic, but it can also underlie serious conditions, such as metabolic disturbances or neurodegenerative conditions. The treatment for the reduction of the movements is based on dealing with the underlying cause, but also on symptomatic management with oral drug administration.
Chorea
This is a form of hyperkinetic movement disorder that is characterized by repetitive involuntary movements that flow from one body part to the next, without being able to predict which exactly is going to be the next movement. Causes are variable, and range from genetic/hereditary, as is the case of Huntington’s Disease, up to drug-induced and immune-mediated. Therapy is based on dealing with the underlying cause, but also on symptomatic management with oral drug administration.
Advanced Parkinson’s Disease
Advanced parkinson’s Disease represents the disease phase in which the patient’s quality of life is significantly affected due to the accumulating motor and non-motor manifestations and complications of the disease. Characteristically, the response of the patient to the drug treatment is erratic, and the patient manifests “off” episodes, with prominent Parkinsonism, alternating with episodes of drug-induced hyperkinetic movements, known as dyskinesias. For these motor complications, there are available interventional therapies, such as continuous infusions of suncutaneous apomorphine, or intestinal Levodopa-Carbidopa, as well as Deep Brain Stimulation (DBS).