Hemispasmus

HEMISPASMUS, hemispasmus, is characterized by muscle contractions in some part of the body, but on one side only; these contractions are involuntary, appear in muscle groups innervated by the same peripheral nerve under the influence of analogous causes, always in the same region; the will has no influence on them. Contractions for the most part appear in the form of attacks, at various intervals, and of varying intensity. Most frequently, hemispasmus is observed in the facial musculature and in the muscles of the tongue. Hemispasmus facialis — H. in the facial muscles innervated by the facial nerve. The genesis of this spasm is very diverse: 1) the spasm may be of reflex origin — irritation of the conjunctiva, a carious process in the teeth, any disease of the sensory root of the trigeminal nerve, disease of internal organs can cause reflex convulsions in the area of the facial musculature; 2) the spasm may stem from irritation of the trunk of the facial nerve due to its compression at the base of the brain by some process; 3) the spasm may be a consequence of paralysis of the facial nerve, upon the appearance of movements in paralyzed muscles — regeneration irritation from the nucleus or from the nerve; 4) hemispasmus facialis enters as a symptom into the alternating Brissaud-Sicard syndrome in diseases of the pons — H. on the affected side and hemiplegia on the opposite side (see Alternating syndromes); 5) hemispasmus facialis, although very rarely, also occurs in diseases of the cortex in the lower sections of the anterior central gyrus; 6) finally, it may be of psychogenic origin as a consequence of a habitual grimace of some repeated movement in neuropathics. Clinically, the spasm proceeds as follows: it begins with light twitchings of a clonic character in several muscle bundles, then these twitchings spread and capture neighboring muscles, simultaneously the intensity of the twitchings increases, and from clonic they pass into tonic; the spasm first repeats in attacks during which the face is twisted to the affected side — the forehead is wrinkled more strongly, the eye is almost completely closed due to the spasm of the orbicularis oculi muscle, the tip of the nose deviates to the affected side, the corner of the mouth is pulled outward and upward, a dimple appears on the chin. Such an attack lasts from several seconds to a longer time, can repeat several times a day and even an hour; attacks can continue for many years, giving remissions. Under unfavorable conditions, the spasm can pass into a permanent contracture (see Facialis nervus). Treatment of hemispasmus depends on the etiological moment. Hemispasmus glosso-labialis is characterized by a spasm in one half of the tongue, combined with H. in the muscle that raises the upper lip, and sometimes in the orbicularis orbitae; it is observed in hysteria (Brissaud-Marie syndrome — see Brissaud reflex, syndromes).