Dystonia

Classification according to ICD-10
G24.-	Dystonia
ICD-10 online (WHO version 2019)

When dystonia ( ancient Greek δύς- dysplastic "bad," "wrong"; τόνος tonos "voltage") is, to a group of movement disorders, neurological origin in the motor centers in the brain is. It is counted among the extrapyramidal hyperkinesias . Dystonia usually manifests itself in cramps and bad posture, e.g. B. of the head ( torticollis ). Therapy is u. a. Botulinum toxin applied.

The dystonia described here has nothing to do with vegetative dystonia .

Types of dystonia

Dystonias include athetoses , tremors , ballism and chorea . A distinction can also be made between local (only one body region affected), segmental (more than one body region affected) and generalized (the whole body affected) dystonia according to the degree of spread. Furthermore, a distinction is made between primary dystonias without an identifiable cause (this includes all hereditary dystonias) and secondary dystonias with a specific cause (e.g. severe injury). Hemidystonia affects only one side of the body and the symptoms are not local.

Genetic causes

The THAP1 gene (synonym DYT6, Dystonia 6) has been described to play a role in hereditary movement disorders, including muscle contractions. THAP1 stands for Thanatos-associated [THAP] domain-containing apoptosis-associated protein 1 (THAP1) and is a DNA-binding protein that interacts with the protein PAWR / PAR-4, which plays a role in apoptosis .

Examples

Patient with symptoms of dystonia

Cervical dystonia or spasmodic torticollis , which manifests itself in a poor posture of the head.
The blepharospasm , and blepharospasm or Blink tic called, leading to uncontrollable blinking. In severe cases, those affected become functionally blind.
The oromandibular dystonia that affects the mouth area and the masticatory apparatus. Affected people find it difficult to eat.
The spasmodic dysphonia , which is also called vocal spasm. Affected people speak under breath or press and are barely understood.
Limb dystonia, which can appear as writer's cramp , musician's cramp or foot dystonia . In all cases it leads to cramping of the limbs, which makes it impossible for those affected to write, make music or walk.
The Segawa syndrome , which is characterized by positional anomalies of the legs and by a genetic defect on chromosome 14 is caused.
The Okulogyre Crisis , in which the eyeballs of those affected - usually - turn upwards.

Dystonias cannot be suppressed by those affected. But there is often the phenomenon of a gesture antagonist in which z. B. Tapping the chin or touching the skin alleviates the symptoms.

The cause of dystonia is a disturbance in the regulation of the unconscious motor function in the area of the basal ganglia in the brain . The globus pallidus internus in particular seems to play a role (see Parkinson's disease ). In most cases, no hereditary connections are found. When hemifacial spasm which is the facial nerve concentrated within the skull by an artery snare.

Diagnostically, short-lasting dystonias are often easy to confuse with tics . With the latter, those affected describe a kind of feeling of tension that forces them to perform a movement that can also be suppressed for a short time.

therapy

If the extent of the dystonia is limited, therapy is often given by local injections of botulinum toxin (usually serotype A). The effect starts slowly after three to seven days and reaches its peak after three weeks. The injections must be repeated at intervals of weeks to months, although the effect may decrease in some patients. In this case the dose can be increased up to a certain limit or switched to serotype 2. In the case of advanced resistance or extensive dystonia, the maximum dose that can be applied sets a limit; a possible side effect is e.g. B. Dry mouth.

Other drugs that are used therapeutically here are anticholinergics . The affected muscles can also be switched off surgically by cutting through the corresponding nerve fibers, which will later grow back again. The deep brain stimulation is a therapy approved for the treatment of dystonia, and is usually applied when the treatment with botulinum toxin is no longer sufficient or effective. Here, regions of the brain are electrically stimulated by an implant, which can improve the movement sequences.

literature

S1 guidelines for dystonia of the German Society for Neurology (DGN). In: AWMF online (as of 2012)
Andrea H. Nemeth: Dystonia Overview . PMID 20301334 .

Web links

Wiktionary: Dystonia - explanations of meanings, word origins, synonyms, translations

Individual evidence

↑ hemidystonia , German Dystonia Society
↑ T. Fuchs, S. Gavarini, R. Saunders-Pullman, D. Raymond, ME Ehrlich, SB Bressman, LJ Ozelius: Mutations in the THAP1 gene are responsible for DYT6 primary torsion dystonia . In: Nat Genet . tape 41 , no. 3 , February 2009, p. 286-288 , doi : 10.1038 / ng.304 , PMID 19182804 .
↑ Cem Sengel, Sophie Gavarini, Nutan Sharma, Laurie J Ozelius, D Cristopher Bragg: Dimerization of the DYT6 dystonia protein, THAP1, requires residues within the coiled-coil domain. In: J Neurochem. 2011 Jul 14, p. 21752024.

[1] ystonia , German Dystonia Society

[pmid19182804-2] T. Fuchs, S. Gavarini, R. Saunders-Pullman, D. Raymond, ME Ehrlich, SB Bressman, LJ Ozelius: Mutations in the THAP1 gene are responsible for DYT6 primary torsion dystonia . In: Nat Genet . tape 41 , no. 3 , February 2009, p. 286-288 , doi : 10.1038 / ng.304 , PMID 19182804 .

[3] Cem Sengel, Sophie Gavarini, Nutan Sharma, Laurie J Ozelius, D Cristopher Bragg: Dimerization of the DYT6 dystonia protein, THAP1, requires residues within the coiled-coil domain. In: J Neurochem. 2011 Jul 14, p. 21752024.