Paroxysmal dyskinesias: causes, symptoms, diagnosis

Paroxysmal dyskinesia is a polyetiological disease manifested by attacks of dystonic (as well as choreic, myoclonic and ballistic) movements and pathological postures without loss of consciousness. There is still no unified classification of these attacks. The classification criteria used are: time of day when attacks occur (daytime - nighttime), provoking factors (kinesiogenic - non-kinesiogenic), duration of attack (short - long), heredity (familial - acquired or primary - secondary).

The main clinical forms of paroxysmal dyskinesia:

1. Paroxysmal kinesiogenic dyskinesia.
2. Paroxysmal nonkinesiogenic dyskinesia.
3. Paroxysmal exercise-induced dyskinesia.
4. Paroxysmal hypnogenic dyskinesia.
5. Benign paroxysmal torticollis in infants.
6. Paroxysmal dyskinesia in the picture of alternating hemiplegia in children.
7. Psychogenic hyperkinesis of paroxysmal nature.

Paroxysmal kinesiogenic dyskinesia

Primary (hereditary and sporadic) kinesiogenic dyskinesia begins in 80% of cases between the ages of 8 and 17 (variations are possible from 1 year to 30 years and older), is more common in men and manifests itself in short attacks (in most cases less than 1 minute) of violent movements. A high frequency of attacks is characteristic: almost all patients suffer from daily single attacks; many have them several times a day, and during an exacerbation - up to 100 per day and more often. One of the distinctive features of paroxysmal kinesiogenic dyskinesia is the provocation of attacks by movement. Usually this is a sudden, unprepared, automatically performed movement. Fright and flinching can also provoke an attack. The paroxysm develops on the side of the body on which the movement was performed (usually an arm or a leg). An attack, starting in the arm (or leg), can spread by hemitype or (less often) be limited to one region of the body or even part of it. In one and the same patient, left-sided, right-sided and bilateral attacks can alternate from attack to attack. In the motor pattern of an attack, tonic and dystonic, less often other, movements and postures dominate.

Immediately before an attack, most patients experience a sensory aura in the form of a feeling of constriction, tingling, numbness, stiffness, and tingling in the limb that will be involved in the paroxysm. In the case of bilateral attacks, the aura is usually bilateral. Some patients report the ability to exert some control over attacks: feeling the approach of an attack, some patients can prevent it by completely stopping all movements or holding the affected limb with the other hand. Sometimes an attack can be prevented by slowly performing the movement, turning it from automatic to highly controlled. Almost all patients report a refractory period, when for a short time after the attack (usually 5-20 minutes) no provoking stimuli are able to cause an attack. Consciousness during the attack and the absence of post-ictal confusion are typical. The neurological status during the attack and in the interictal period is normal.

Paroxysmal nonkinesiogenic dyskinesia

Primary (hereditary and sporadic) non-kinesiogenic dyskinesia begins almost exclusively in childhood (in two thirds of cases, the onset of the disease occurs before the age of 5), and males predominate among those affected. This form is characterized by less frequent attacks (once a week or 2-3 times a month). The attacks themselves are longer: from 5 minutes to 4-5 hours or more. In adulthood, there is a tendency for spontaneous improvement. Attacks develop either spontaneously or are provoked by alcohol, coffee, analgesics, stress, menstruation, and other factors. Sensory aura and partial control over attacks (usually through relaxation) are also characteristic here. The motor pattern of an attack is almost the same as with kinesiogenic dyskinesia.

Paroxysmal exercise-induced dyskinesia

Paroxysmal dyskinesia induced by physical exertion is singled out as a separate form, since dyskinesia attacks in this form are provoked only by prolonged physical exertion, the paroxysm most often involves the legs (dystonic spasm), and the attack itself lasts for 5-30 minutes. Such an attack is never provoked by a sudden movement. The frequency of attacks varies from 1 per day to 2 per month. Such duration and frequency of attacks served as the basis for calling this form "intermediate".

Paroxysmal hypnogenic dyskinesia

Paroxysmal hypnogenic dyskinesia is characterized by nocturnal attacks that are phenomenologically similar in many ways to daytime paroxysmal dyskinesia. Attacks most often occur in stages 3-4 of slow-wave sleep and are manifested by choreic, dystonic, myoclonic, and ballistic movements without impairment of consciousness. It has been noted that attacks are sometimes provoked by body movements during sleep. Short (15-45 sec) and long attacks (from 2 minutes to 2 hours) are also distinguished here. According to most researchers, short nocturnal attacks of "dyskinesia" are a type of epileptic seizures. Long attacks are classified as parasomnias. Attacks can occur every night and sometimes multiple times per night (more than 10). Bilateral generalized attacks are observed more often. Sporadic and familial forms of hypnogenic paroxysmal dyskinesia have been described. With frequent attacks, sleep deprivation due to attacks and compensatory daytime sleepiness are possible.

All the above-mentioned variants of paroxysmal dyskinesia are primary (hereditary or sporadic) forms. EEG and neurological status in the interictal period usually do not reveal any deviations from the norm. EEG during an attack is difficult to register due to artifacts associated with movements (dyskinesias). Secondary (symptomatic) forms of the above-mentioned dyskinesias are described in many diseases. These include: cerebral palsy, multiple sclerosis, hypoparathyroidism, pseudohypoparathyroidism, hypoglycemia, thyrotoxicosis, cerebral infarction (including systemic lupus erythematosus), transient ischemic attacks, hemorrhage in the medulla oblongata, arteriovenous malformation, traumatic brain injury, encephalitis (including HIV infection), iatrogenic (cerucal, methylphenidate) and toxic (cocaine, alcohol) forms. Here, more diverse changes in EEG and neurological status are possible. In all the above-mentioned forms of paroxysmal dyskinesia, the therapeutic effect of anticonvulsants is noted.

Benign paroxysmal torticollis in infants

Benign paroxysmal torticollis in infants is even rarer and, as the name suggests, only occurs in infants. The disease occurs in the first months of life and is characterized by recurring episodes of head twitching and torticollis lasting from 15 minutes to several hours. These episodes are sometimes accompanied by nausea, vomiting, and ataxia. Attacks recur monthly and spontaneously cease in the coming years. A genetic predisposition to migraine is characteristic. Many patients with benign paroxysmal torticollis later develop migraine. EEG and caloric testing during an attack of torticollis usually show a normal picture.

Paroxysmal dyskinesia in the picture of alternating hemiplegia in children

Alternating hemiplegia in children is a rare disease and is characterized by: onset of the disease before the age of 3 years (sometimes at the age of 3 months); repeated attacks of hemiplegia (alternating the affected side of the body) lasting from several minutes to several days; the presence of other paroxysmal phenomena (dystonia, chorea, nystagmus, autonomic disorders in the form of tachycardia, mydriasis and hyperhidrosis during hemiplegia or independently of it); episodes of bilateral hemiplegia; improvement during sleep and progressive deterioration of neurological and mental functions.

The first attacks may be hemiplegic, dystonic, or both. Short episodes of nystagmus lasting 1-3 minutes often accompany both dystonic (hemidystonia or opisthotonos) and hemiplegic attacks. Hemiplegia is usually flaccid, regardless of whether or not it is superimposed on sciatica. Attacks begin suddenly, which often leads to an erroneous diagnosis of epilepsy or stroke with hemiplegia. Generalized tonic-clonic seizures may sometimes appear in children with this disorder at an older age. During prolonged attacks, hemiplegia may "shift" from one side of the body to the other or involve both halves of the body. The arms are usually more severely affected than the legs. Walking may be impaired, but not very severely. Hemiplegia disappears during sleep and returns upon awakening, but usually not immediately. Headaches are sometimes noted at the onset of an attack. Flunarizine reduces the frequency of attacks in some children.

Mental retardation is characteristic. Neurological status is characterized by a stepwise deterioration, since recovery of functions after individual attacks may be incomplete. The most common symptoms are dystonia, spasticity, pseudobulbar palsy, and ataxia. MRI reveals progressive atrophy of the cerebellar vermis. Most cases (except one family) are sporadic.

Differential diagnosis includes paroxysmal dyskinesias, hemiplegic migraine, epilepsy, stroke, and dopamine-sensitive dystonia (dystonia sensitive to dopamine).

Psychogenic hyperkinesis of paroxysmal nature

Psychogenic hyperkinesias occur paroxysmally in approximately 50% of cases. Paroxysmal manifestations are generally extremely characteristic of psychogenic disorders. Tremor accounts for approximately 50% of all psychogenic hyperkinesias, dystonia - 18%, myoclonus - 14%, "parkinsonism" - 7%, other types of psychogenic dyskinesias account for about 11% of their total number. All psychogenic hyperkinesias are highly characteristic of: sudden onset with an obvious provoking event (emotional debut); multiple movement disorders (pseudoparesis, dysphonia, pseudostuttering, convergence spasm, pseudoseizures, dysbasia, mutism, etc.); variable and contradictory movement disorders, fluctuating during one examination or from examination to examination; movement manifestations do not correspond to known organic syndromology; hyperkinesis increases when examination is focused on the affected body part and decreases when the patient's attention is distracted; hyperekplexia or excessive startle reactions are common; hyperkinesis often responds to placebo or suggestion; there is a characteristic syndromic environment (various functional-neurological "stigmas") and typical mental disorders; hyperkinesis is eliminated by psychotherapy or ceases when the patient is unaware that he is being observed.

In general, any psychogenic hyperkinesis differs from organic hyperkinesis by four factors: motor pattern, dynamics of hyperkinesis, syndromic environment and course of the disease. For a well-founded diagnosis, it is important to positively diagnose psychogenic ("neurotic") disorder and exclude classical forms of organic hyperkinesis. Currently, diagnostic criteria for psychogenic tremor, psychogenic myoclonus, psychogenic parkinsonism, psychogenic dystonia, as well as diagnostic criteria for a combination of psychogenic and organic hyperkinesis have been developed; criteria for proven (documented), reliable, probable and possible psychogenic movement disorders have been formulated. However, their presentation is beyond the scope of this section of the book.

[ 1 ]