Parkinson's disease
is a slowly progressive degenerative disease of the central nervous system, the main manifestations of which are motor disorders such as hypokinesia, muscle rigidity, resting tremor, and postural disorders. In addition, with Parkinson's disease, autonomic, affective and other disorders develop. There are true parkinsonism (Parkinson's disease) and parkinsonism syndrome, which can accompany many neurological diseases (TBI, brain tumors, strokes, encephalitis, etc.). If Parkinson's disease is suspected, the patient must undergo electroencephalography, rheoencephalography, and MRI of the brain.
Classification of Parkinson's disease
Classification of Parkinson's disease is based on age of onset:
- juvenile (juvenile parkinsonism)
- with an early start
- with a late debut
There are also various classifications of parkinsonism syndrome:
- trembling
- trembling-rigid
- rigid-trembling
- akinetic-rigid
- mixed
However, the data on the classification of Parkinson's disease and parkinsonism syndrome are not considered flawless. Therefore, today there is no generally accepted approach to this issue.
Consequences and life prognosis
According to the above tables, the need for outside care can be noted already at stage 4 of the disease. However, at stages 2.5 and beyond, a person’s ability to work is practically lost.
The life prognosis for patients with Parkinson's disease is usually favorable. With proper care and adequate therapy, the average life expectancy practically does not decrease. Timely initiation of adequate therapy, non-drug methods of rehabilitation and the provision of psychological support allow patients to maintain social activity for a long time and maintain the quality of life at the proper level.
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Etiology and pathogenesis of Parkinson's disease
Modern medicine has made some progress in understanding the molecular and biochemical mechanisms of Parkinson's disease. Despite this, the true etiology of sporadic forms of this disease remains unknown. Genetic predisposition and environmental factors are of great importance. The combination and interaction of these two factors initiates the process of degeneration in pigment-containing and subsequently other neurons of the brain stem. Such a process, once established, becomes irreversible and begins to spread expansively throughout the brain. More than other protein substances of the nervous system, alpha-synuclein is subject to the greatest destruction. At the cellular level, the mechanism of this process looks like a lack of respiratory functions of mitochondria, as well as oxidative stress - the main cause of neuronal apoptosis. However, other factors are also involved in the pathogenesis of Parkinson's disease, the functions of which remain unclear to this day.
Clinical picture of Parkinson's disease
There is a tetrad of motor symptoms of Parkinson's disease: tremor, rigidity, hypokinesia, and disturbances in postural regulation. Tremor is the most obvious and easily detected symptom. The most typical type of tremor for parkinsonism is resting tremor, but other types of tremor are also possible, for example: postural tremor or intention tremor. Muscle rigidity may be subtle in the initial stages, more often in the trembling form of Parkinson's disease, but obvious in severe Parkinson's syndrome. Early identification of minimal asymmetry of tone in the limbs is of great importance, since asymmetry of symptoms is a characteristic feature of all stages of Parkinson’s disease.
Hypokinesia is an obligate symptom of parkinsonism of any etiology. In the initial stages of Parkinson's disease, identifying hypokinesia can be difficult, so they resort to demonstrative techniques (for example, quickly clenching and unclenching a fist). Early manifestations of hypokinesia can be observed in elementary actions aimed at self-care (shaving, brushing teeth, fastening small buttons, etc.). Hypokinesia is bradykinesia (slowness of movements), oligokinesia (decreased number of movements), as well as a decrease in the amplitude of movements and a decrease in their speed. Due to hypokinesia in Parkinson's disease, individual “body language” is disrupted, including gestures, facial expressions, speech and motor plasticity.
Postural disturbances in Parkinson's disease appear quite early (for example, asymmetry of the arms extended forward). However, most often they attract the attention of doctors already in their maladaptive stage (stage III). An explanation for this may be the fact that postural disturbances, compared to other symptoms of Parkinson's disease, are less specific to it.
In addition to the above-mentioned main manifestations of parkinsonism, Parkinson's disease is accompanied by other symptoms, which in some cases may come to the fore of the clinical picture. Moreover, the degree of patient maladjustment in such cases is no less. Let's list just a few of them: drooling, dysarthria and/or dysphagia, constipation, dementia, depression, sleep disorders, dysuric disorders, restless leg syndrome and others.
There are five stages of Parkinson's disease, each of which reflects the severity of the disease. The most widespread classification was proposed in 1967 by Hoehn and Yahr:
- Stage 0
- no motor manifestations - Stage I
- unilateral manifestations of the disease - Stage II
- bilateral symptoms without postural disturbances - Stage III
- moderate postural instability, but the patient does not need outside assistance - Stage IV
- significant loss of motor activity, but the patient is able to stand and move without support - Stage V
- in the absence of outside help, the patient is confined to a chair or bed
Hypokinesia
Hypokinesia is the third and most severe symptom of Parkinson's disease. The decrease in motor activity becomes so pronounced that it can paralyze the patient’s body for several hours. Most patients report sensations reminiscent of clumsiness and severe fatigue, awkwardness in previously familiar movements. Simply changing clothes or eating becomes long and difficult. The patient can only move in small steps, there is facial expression, rare blinking of the eyelids, and delayed expression of emotions on the face.
In the later stages of the disease, people lose the ability to perform basic actions: fastening buttons, writing. A characteristic feature of the letter is the beginning of the line in large letters and the end in small letters. Many patients find it difficult to get out of bed or a chair, get out of the car, and do anything that requires torso mobility or difficult postures. In special cases, Parkinson's disease leads to a complete loss of the ability to move, when a person freezes in one position when wanting to move.
Diagnosis of Parkinson's disease
Clinical diagnosis of Parkinson's disease occurs in three stages.
1st stage
- recognition of parkinsonism syndrome and its syndromic differentiation from neurological and psychopathological syndromes, one way or another similar to true parkinsonism. True parkinsonism is hypokinesia in combination with one of the following symptoms: resting tremor (4-6 Hz), muscle rigidity, postural instability not associated with primary vestibular, visual and cerebellar disorders.
2nd stage
- exclusion of other diseases that may manifest as parkinsonism syndrome. There are several criteria for excluding Parkinson's disease:
- oculogyric crises
- antipsychotic therapy before the onset of the disease
- a history of repeated strokes with stepwise progression of parkinsonian symptoms, definite encephalitis or repeated TBI
- long-term remission
- exclusively unilateral manifestations for more than 3 years
- cerebellar symptoms
- supranuclear gaze palsy
- early onset of dementia
- previously clear manifestation of autonomic failure
- Babinski's sign
- brain tumor or open hydrocephalus
- ineffectiveness of large doses of levodopa
- MPTP intoxication
3rd stage
- identification of symptoms confirming Parkinson's disease. To do this, at least three of the following criteria must be present:
- unilateral manifestations at the onset of the disease
- presence of rest tremor
- asymmetry of symptoms (with a greater degree of severity on the side of the body on which the disease began)
- 70-100% response to levodopa therapy
- progressive course of the disease
- effectiveness of levodopa for 5 years or more
- disease duration 10 years or more
To examine patients with suspected Parkinson's disease, rheoencephalography, EEG, and neuroimaging methods are used: brain CT and MRI.
Diagnostics
Diagnosing Parkinson's disease is challenging. Indeed, despite common misconceptions, not a single neuroimaging study, except positron emission tomography, can reliably establish a diagnosis. Neither MRI of the brain, nor even ultrasound examination of the substantia nigra allows us to speak about the presence of the disease with a high degree of probability.
The only research method that allows us to talk about the presence of the disease is positron emission tomography (PET). When performing PET, there is a decrease in the accumulation of a special radioactive drug - fluodopa in the striatum and substantia nigra. Moreover, detection of the disease is possible even at the preclinical stage. However, the prevalence of the study is very limited, the study is extremely expensive at the present stage and in Russia it can only be carried out in large research src=»https://neurosys.ru/wp-content/uploads/posts/2014-02/1392397744_parkinsona-diagnostika. jpg" class="aligncenter" width="350″ height="324″[/img] As a rule, the diagnosis is made based on the clinical picture. In this case, the presence of characteristic symptoms, the typicality of the clinical picture and complaints, as well as the sequence of progression of symptoms must be taken into account. Also, a neurological examination reveals the presence of bradykinesia, the “cogwheel” phenomenon and other specific symptoms of the disease.
A good response to therapy with levodopa-containing drugs also plays an important role in diagnosis. Symptoms usually disappear completely or almost completely at the first appointment.
Differential diagnosis
Parkinson's disease must be differentiated from all diseases that are accompanied by parkinsonism syndrome: secondary parkinsonism, pseudoparkinsonism, “parkinsonism plus”. About 80% of parkinson's syndrome cases are due to Parkinson's disease.
One should remember certain clinical features of parkinsonism that should raise doubts about the diagnosis of Parkinson's disease, for example: ineffectiveness of levodopa, absence of tremor, symmetry of motor disorders, early manifestations of signs of peripheral autonomic failure.
Treatment of Parkinson's disease
Treatment options for Parkinson's disease differ significantly in the early and late stages of the disease, so they should be considered separately.
Treatment of Parkinson's disease in the early stages.
An early diagnosis of Parkinson's disease does not always mean immediate initiation of any drug therapy. To determine the timing of the start of drug treatment, it is necessary to take into account the severity of the disease, the duration of the disease, the rate of its progression, any concomitant diseases, as well as “personal factors” (professional, social and family status of the patient, mental state, personality characteristics, etc.). The goal of such therapy is restoration (sufficient regression) of impaired functions using the lowest possible doses.
Drug therapy in the early stages of Parkinson's disease involves the use of drugs that increase the synthesis of dopamine in the brain, stimulate its release and block its reuptake, inhibit the breakdown of dopamine, stimulate dopamine receptors and prevent the death of neurons. Such drugs include amantadine, selective MAO-B inhibitors (selegiline, etc.), dopamine receptor agonists (piribedil, pramipexole, etc.). The above drugs can be used both as monotherapy (more often) and in various combinations.
The above drugs are significantly inferior in effectiveness to levodopa drugs, but they are quite suitable for the treatment of Parkinson's disease in the early stages. Theoretically, in the early stages of Parkinson's disease, dopamine receptor agonists can delay the initiation of levodopa, and in later stages, reduce its dose. However, a large number of side effects (gastric ulcer, orthostatic hypotension, mental disorders, erythromelalgia, retroperitoneal fibrosis, etc.) and the ability to reduce the sensitivity of postsynaptic dopamine receptors do not speak in their favor.
There are no clear criteria determining the optimal time to start treatment with levodopa. However, one should take into account the patient’s age (if possible after 60-70 years), avoid early prescription of levodopa, and when selecting a dose, focus on the patient’s “responsiveness” to the drug, improvements in his professional and social activities.
Treatment of Parkinson's disease in advanced stages.
Regardless of the nature of the course of Parkinson's disease, a gradual transformation of the clinical picture of the disease necessarily occurs. Over time, existing disorders progress and new ones appear, most of which are difficult to treat, thereby exerting a strong stressor effect on the patient. In addition, the usual effect of levodopa changes - the effectiveness of the drug decreases, drug-induced dyskinesias increase (as a result of hypersensitivity of dopamine receptors).
A decrease in the effectiveness of therapy is manifested by a decrease in the duration of the therapeutic effect of each levodopa vine. An “on-off” phenomenon is formed, the only way to combat which is to gradually increase the dose of levodopa, and this in turn starts a vicious circle that gives rise to new problems, which become increasingly difficult to combat. Real help in this case can be provided in two ways: by prescribing an additional dose of levodopa in order to reduce the intervals between doses; adding a COMT inhibitor to the treatment regimen and transferring the patient to therapy with a combination drug of levodopa and entacapone.
Side effects of levodopa therapy. One of the manifestations of a decrease in the threshold of sensitivity to certain side effects is the tendency to the appearance of oral (or other) hyperkinesis against the background of symptoms of hyperkinesia. Thus, the clinical picture of Parkinson's disease paradoxically combines symptoms of dopamine excess (oral hyperkinesis) and its deficiency (hypokinesia). Reducing the dose of levodopa in such a situation provides only a temporary elimination of hyperkinesis; after a while it appears again. Orthostatic hypotension in Parkinson's disease is usually manifested by a relatively sharp decrease in blood pressure shortly after taking levodopa. Both levodopa and dopamine receptor agonists have this side effect, so after determining the cause of the side effect, it is necessary to reduce the dose of the appropriate drug.
Mental disorders in Parkinson's disease can manifest themselves in the form of depression, anxiety, apathy, visual hallucinations, and agitation. In addition, the appearance of memorable, vivid dreams is typical. Over time, all of the above disorders progress and sooner or later appear in the waking state. Treatment of such mental disorders must be carried out together with a psychiatrist. Sometimes it is enough to relieve the patient of anxiety and fear, since it is they that provoke more severe mental disorders. Most drug-induced dyskinesias occur at the peak of the drug's effect. The most reliable way to eliminate them is to reduce the single dose of levodopa while maintaining the daily dose of the drug. Therefore, split doses of levodopa are the best way to prevent this type of dyskinesia.
In end-stage Parkinson's disease, the main difficulties are associated with cachexia, loss of the ability to stand, walk and self-care. At this time, it is necessary to carry out a whole range of rehabilitation measures aimed at providing optimal conditions for the patient’s daily activities. It should be remembered that in the later stages, Parkinson's disease becomes a heavy burden not only for the patient himself, but also for his family, whose members may require not only therapeutic, but sometimes specialized help.
Surgical treatment of Parkinson's disease involves stereotactic destruction of the ventrolateral nucleus of the thalamus and subthalamic nucleus, as well as deep brain stimulation. In cases of severe akinetic-rigid syndrome, pallidotomy is recommended, as well as deep electrical stimulation of the globus pallidus and subthalamic nucleus.
