Differential diagnosis of the types of muscular hypertonicity

Extrapyramidal rigidity has other features: it is observed in many muscle groups (agonists and antagonists), but it usually prevails in the flexor muscles ("flexor posture"). It is not typical for the pyramidal spasticity phenomena "jackknife". The study of passive movements can detect discontinuities or aliasing muscle resistance to passive tension ("gear" symptom).

Hypokinesia and rigidity can be observed in isolation, but they are often joined to hyperkinesis as a tremor of fingers and rarely of the lower limbs and chin area. This rhythmic tremor of fingers resembles such actions as counting coins or rolling the pills. This triad of symptoms (hypokinesia, rigidity, rhythmic tremor) is characteristic for chronic disease described by the English physician J. Parkinson in 1817 and known as "shaking palsy." The syndrome that is very close to shaking palsy was found in patients in the chronic stage of epidemic encephalitis with vascular lesions of the brain with some exogenous intoxications (manganese compounds, chlorpromazine, reserpine, etc.). It was named Parkinson's disease. The most pronounced hypertonicity and tremors arise in the case of substantia nigra lesions.

There are another autonomic disorders (face greasiness, skin peeling, hypersalivation, etc.) and violations of emotional tone as symptoms of parkinsonism. Latest is evident as a reduction in motor activity, inidiopathetic in action. Sometimes there can be noted the tendency of patients to pester (it was described by M.I. Astvatsaturov (1939)). The patients are obsessed to ask the same questions, reapply for frivolous reasons. Their thinking is delayed (bradypsychia).

A characteristic feature of Parkinson's disease is the disappearance of all its evidences during patient’s falling sleep (the severity of muscle tone decreases, tremor stops).

In the case of long-term treatment of parkinsonism 1-dopa some psychiatric and neuroendocrine symptoms develop in the form of adverse symptoms. It is associated with dysfunction of dopamine-containing systems such as Mesocortical (from the core of the operculum of the midbrain to the cortex of the frontal lobe), tuberoinfundibular (from neurons agcuatus tuberculum infundibulum of the hypothalamus to anterior lobe of the pituitary).

Extrapyramidal hyperkinesis. Hyperkineses is an excessive violence automatic movement preventing the execution of unconditioned motor acts. In the study of hyperkinesis it is necessary to pay attention to the side, rhythm, character, shape, symmetry, localization of motor manifestations. There are the following main types of hyperkinesis: trembling (tremor), myoclonus, choreal hyperkinesia, athetosis, torsion dystonia, hyperkinesia hemiballismu, etc. They arise in the case of lesions of different parts of the extrapyramidal system (mainly striatal system). Tremor is the most frequent type of hyperkinetic varied in amplitude, rate and localization. In the case of neuroses, exogenous and endogenous intoxications the tremor is commonly observed in fingers, it has small amplitude and changing rhythm. Tremor in the case of Parkinson disease has different rhythm (4-6 in 1s) and is located in fingers and hands, but it can spread to the lower limbs, head, chin and torso. Trembling is sharply expressed in quiescent state, it is reduced or it even disappears during active movements. It makes it different from the intention tremor with lesions of the cerebellar system. Large-swinging tremor occurs in lesions of the red nucleus ("rubral tremor"). Extrapyramidal tremor keeps constantly and disappears only during the sleep.

Myoclonia is fast, usually irregular, reduction of individual muscles or their groups. They are visible in time of examination of limbs, trunk and face. Small amplitude does not lead to a marked locomotor effect. Myoclonia can be generalized and local (e.g. tongue and soft palate – palatal nystagmus). Myoclonia remains at rest and in motion, increase with excitement. They can be found in lesions of red nucleus, substantia nigra, striate body, dentate nucleus and inferior olive. The same reduction of muscle (not of all) is denoted as myokymia.

Choreal hyperkinesia is characterized by erratic involuntary movements with severe locomotor effect. It occurs in different parts of the body both at rest and during movement of unconditioned acts. Movement always follow each other in the most unusual sequence resembling appropriate, although exaggerated, actions. The patient screw up his eyes, sticks out his tongue, licks his lips, makes faces, etc. Sometimes there are sudden impulsive changes of limbs, changes in posture. They are compared with the clowning, dancing (Greek choreia - Dance). The patient cannot keep stretched forward upper limbs at rest or he cannot stick his tongue out. These signs are used to detect weakly expressed forms of trochaic hyperkinesia.

Choreal hyperkinesis occurs in lesions of neostriatum system (rheumatism, hereditary Huntington's chorea, etc.). There is often a small decrease of muscle tone in the case of chorea hyperkinesis.

Athetosis (Greek athetos - unstable) is a hyperkinetic form which is characterized by slow tonic muscles contractions which look like a slow rhythm bizarre "worm-like" movements. They occur at rest and in the time of voluntary movements. They are amplified under the influence of emotions. These rather strong, periodically coming muscle spasms are usually localized in the distal parts of upper limbs. They are called mobile spasm (spasmusmobilis). Straightened fingers at metacarpophalangeal joints are bent or unbent alternately. Hand takes a bizarre shape at this time (fig. 49). Athetosis can be bilateral. Unlike chorea athetosis is characterized by slowness of movements and usually lower prevalence. Sometimes there is a difficulty in distinguishing these hyperkinesia, then we should speak about choreoathetosis. Athetosis develops in lesions larger striatal system cells with function discoordination of the globus pallidus, subthalamic and red nucleus.

Hyperkinesia called torsion dystonia should be distinguished from athetosis. These patients especially during active movements have incorrect tone distribution of trunk and limb muscles. It leads to pathological body postures. While walking the trunk and limbs make corkscrew violent movements - equivalents of their turning around long axis, which is reflected in the title of the disease. Torsion dystonia may be terminated at any compensatory techniques such as fixation of the cervical spine by hands, reinforced shoulder turn, etc.

Torsion- dystonic phenomena can be bound by any part of the muscle system such as neck muscles (spasmodic torticollis - torticolis spactica).

The pathogenetic basis of torsion dystonia is considered to be the spasm of antagonistic muscles, i.e. involuntary muscle tension counteracting the desired movement. Torsion-dystonic phenomena can occur in lesions of different parts of extrapyramidal system (basal ganglia, brain stem cells).

The convulsive twitching in fingers at the time of writing is referred to be writer's cramp (graphospasm). Musicians (violinists, pianists, guitarists), typists and the others have the similar professional spasms.

A special form of extrapyramidal hyperkinesis is "hemiballismus" (from the Greek. hemi - half, ballismos - jumping, dancing). This rare variant of hyperkinesis as the title indicates occurs on one side of the body. Upper limb suffers more. When both sides are involved we should speak about paraballizm. Hyperkinesis develops with fast sweeping movements on a large scale, resembling the ball throwing or pushing and at the same time there can be rotator trunk movements. This clinical picture is described in focal lesions of hypothalamic nucleus (subthalamic Lewis’ body).

Quick involuntary muscle contractions (usually a circular eye muscle or muscle causing twitching of the mouth corners) are called tic. Unlike the functional (neurotic) tics this kind of tics of extrapyramidal genesis are persistent and rigid.

Along with the local forms there is a generalized common tick involving facial muscles, breathing muscles, and also the muscles of limbs and trunk. A generalized impulsive tick - Gilles de la Tourette's disease has a special place here. There are impulsive jumping, squatting, grimacing, vocal phenomena in the form of shouting swearwords(coprolalia), grunting etc.

With the lesion of the extrapyramidal system there may arise local hyperkinesis and spasms of eyeballs muscles and facial muscles. The tonic spasm of sight is included here. Eyeballs involuntarily discharged upwards. Such stroke occurs suddenly and lasts for several minutes. Occasionally there may be involuntary tonic contraction of the circular muscles of both eyes (blepharospasm). In other casesthere is facial mimic muscle spasm innervated by facial nerve on one or both sides (front hemi- or paraspazm): convulsions accompanied by knitting one’s brow, eyebrows lifting, srewing up one’s eyes, pulling back the corner of the mouth outwards and upwards, tension of hypodermic neck muscle. With functional facial gemispazm is no paradoxical synkineses of upper facial muscles, i.e. the brow do not go up with screwing up one’s eye, the forehead is not wrinkled.

Sometimes permanent extrapyramidal hyperkinesis is interrupted by common convulsive attacks. It is so-called hyperkinesis epilepsy. Thus myoclonic hyperkinesis is constant in the case of epilepsia partialis continua and myoclonus epilepsy. There is a combination of trochaic hyperkinesis with convulsive attacks in trochaic epilepsy spondylitis.

The detection of hyperkinesias described above helps to diagnose lesion of the extrapyramidal system. However, the clinical-anatomical and experimental investigations show that at the same localization of the centre hyperkineses of different types may occur, so more precise definition of the lesion is complicated. The results of surgical treatment of extrapyramidal disorders also show it. Intact neuronal systems (usually ventrolateral nucleus of the thalamus) are usually destroyed during stereotactic operations. There is a gap between the ring bonds of separate extrapyramidal entities by which the impulses pass causing a variety of movement disorders (torsion dystonia, parkinsonism). As a result of such operations extrapyramidal violations are exposed to significant regression. However in 2 or 3 years after surgery extrapyramidal disorder has a tendency to recover.

Asterixis (from the Greek. sterigma - failure to maintain a fixed position) is one of tremor’s variants. With the upper limbs stretched forward patient produces hyperpronation of hands: in 20-30s there comes propulsive movements of the fingers in the metacarpophalangeal joints in the anterior-posterior direction with the rotary component and a slower phase flexion than extension. The disorder of posture sense and malfunction of afferent information at dysfunction of upper brainstem structures and thalamencephalon involved in the integration of motion and regulation of muscle tone lie in the origin of asterixis. It occurs mostly in the case of dysmetabolic lesions of the nervous system (renal failure, an overdose of anti-Parkison remedies, exogenous intoxication), rarely in the case of stenosis of the internal carotid artery or diapedetic haemorrhage of the brainstem or cerebellum.

Chapter 6

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