Shaking hands, stiff muscles, unsteady gait – the typical signs of Parkinson’s disease. Up to now only symptomatically treatable, intensive research is being conducted to find an individual therapeutic approach. One thing is clear: the more individually the pathophysiology of the disease can be addressed, the more promising the result. But even today, there is a wide range of treatment options that can at least be tailored to the symptoms.
Along with Alzheimer’s dementia and stroke, Parkinson’s disease is one of the most common diseases of the nervous system in older age. In Switzerland, more than 15,000 people are affected – and the number is rising. At the time of diagnosis, most affected individuals are over 60 years of age [1]. Cardinal symptoms include hypokinesia, rigor, tremor, and impaired postural stability [1,2]. Nevertheless, the disease manifests itself very differently from individual to individual. This is because there is underlying multi-system and multi-neurotransmitter dysfunction that characterizes the heterogeneity of the phenotype. Basically, however, Parkinson’s syndrome can be divided into three phases: the early phase, which usually does not yet involve any restrictions, the middle phase, in which the first symptoms manifest themselves, and the late phase. This is associated primarily with significant motor impairments such as fluctuations, freezing, hyperkinesias, and akinesia, in addition to nonmotor disturbances.
From symptom to cause
Medication interventions are available to alleviate symptoms in addition to exercise therapies. Primarily, dopamine, dopamine agonists or MAO inhibitors are used. However, the use of COMT inhibitors is also possible for motor fluctuations or dyskinesias. In the late phase of the disease, deep brain stimulation or apomorphine or duodopa pump may then have to be resorted to. The question now arises to what extent individualized treatment is already possible in this therapeutic spectrum. Prof. Dr. med. Karla Maria Eggert, Marburg (D), showed that in the case of a mild manifestation, initial therapy should be with an MAO inhibitor. This decreases striatal dopamine depletion but often has limited efficacy due to fixed dosing. Dopamine agonists are predominantly used in patients with lower disease age <70 years and/or without relevant comorbidities. They have a long half-life and are made available to the brain evenly and in a dose-dependent manner. Levodopa has a short half-life and is delivered to the brain in a pulsatile and dose-dependent manner rather than uniformly. Therefore, it is administered primarily to elderly patients and those with relevant comorbidities. Motor complications such as fluctuations, can be treated with COMT inhibitors or MAO inhibitors, and antiglutamatergic agents are used for dyskinesias.
In the future, however, personalized medicine should take much more account of genetic, epigenetic, and molecular pathological factors, she said. For this purpose, disease entities are no longer defined only syndromally, but molecularly and pathologically. This is because genetic variability influences the efficacy and side effect profile of drugs. On this basis, causal therapeutic approaches can be developed.
Congress: German Congress for Parkinson and Movement Disorders
Literature:
- www.parkinson.ch/parkinsonkrankheit/was-ist-parkinson (last accessed 21.05.2021)
- www.neurologen-und-psychiater-im-netz.org/neurologie/erkrankungen/parkinson-syndrom/was-ist-das-parkinson-syndrom (last accessed 21.05.2021)
InFo NEUROLOGY & PSYCHIATRY 2021; 19(3): 31 (published 6/3/21, ahead of print).
