Dystonia (from Greek, meaning altered muscle tone) refers to a syndrome of involuntary sustained or spasmodic muscle contractions involving co-contraction of the agonist and the antagonist. The movements are usually slow and sustained, and they often occur in a repetitive and patterned manner; however, they can be unpredictable and fluctuate.

The frequent abnormal posturing and twisting can be painful, and the functional impact of dystonia can vary from barely noticeable to severely disabling. Consequently, dystonia can have a profound effect on the personal, vocational, and emotional life of a patient and can impact his/her ability to live independently.

Anatomic Classification

On the basis of its clinical distribution, dystonia is classified as follows:

  • Focal dystonia – Involves a single body part
  • Segmental dystonia – Affects 2 or more contiguous regions of the body; examples of segmental dystonia of the head and neck include cranio-cervical dystonia, blepharospasm, oromandibular dystonia, and laryngeal dystonia
  • Generalized dystonia – Generalized form of the disease, involves the trunk and limbs

Cervical (neck) dystonia can be classified as anterocollis, laterocollis, torticollis and retrocollis.

Pharmacologic Therapy

Medications can be somewhat effective in controlling dystonic movements, but the lack of knowledge about the exact pathophysiology of dystonia has made the development of specific pharmacologic therapies difficult. Systemic medications benefit about one third of patients and consist of a wide variety of options, including the following:

Cholinergics, benzodiazepams, anti-parkinsonism drugs, anti-convulsants, baclofen, etc.

Botulinum Toxin Injections

Botulinum toxin injections are used to reduce the excess muscle activity caused by dystonia. The injection enables the botulinum toxin to be targeted directly into the muscles affected by dystonia.

The use of Botulinum toxin injection in dystonic muscles is an important therapeutic option. Botulinum toxins (Botox, Xeomin, Myobloc and Dysport) injections have become powerful tools in improving the symptomatic treatment of focal dystonias. These injections temporarily reduce the ability of the muscles to contract and may be the treatment of choice for blepharospasm, cervical dystonia, and hemifacial spasm.

Patients treated with botulinum toxin injections usually notice the effects 3 days to 2 weeks following treatments. After approximately 3 months, the effects of the botulinum toxin will diminish. The success of a botulinum toxin injection depends on the severity of the dystonia and muscles affected.

The Injection Process

Botulinum toxin injections are administered by our highly trained neurologists Dr Kashouty and Dr Yono. The areas to be injected will be marked with a pen and then thoroughly cleaned with alcohol. A cold anesthetic spray may be used to numb the skin, and the botulinum toxin mixed with normal saline, will be injected. A thin needle will be used. The toxin will be injected through the skin into the targeted muscle. You will often need several injections in different locations. The number of injections will vary depending on your condition, and most people tolerate the procedure well with little discomfort.

Ultrasound-guided or EMG-guided techniques may be used to improve accuracy of the procedure. Each provides a clear advantage to guide botulinum toxin injections and to ensure that the needle is placed precisely in the desired location, avoiding the risk to damage the surrounding structures.

Post Procedure Care

There is no specific test preparation. The procedure is very short in duration, on average it takes about 15 to 20 minutes. Normal activities may be resumed after the procedure, however patient will be instructed to take it easy for the rest of the day, and to place an ice pack for a few minutes several times a day if pain persists at the injected site. A return office visit appointment will be made in few weeks for follow up. The patient is also encouraged to call at any time if any problems occur.

After the injection, you will start to see the benefit of the treatment within 4–7 days and sometimes longer. The positive effects of botulinum toxin injections can last up to 3 to 4 months.



URL: https://emedicine.medscape.com/article/312648-overview#a1