Injection of botulinum toxin (Botox) into muscles affected by dystonia can provide relief for several months at a time.  Botox helps relieve involuntary contractions causing pain, twisting, abnormal posture or changes in person’s voice or speech, by causing temporary weakness in those muscles. The injections weaken muscle activity sufficiently to reduce a spasm but not enough to cause paralysis. Because each affected muscle must be injected, this is most practical when an individual has dystonia significantly affecting a specific body area, such as the hand or jaw.

It is important that a trained doctor give the shots. The physician should be familiar with the clinical features of dystonia and the involuntary movements of the person being treated. Some physicians use an electromyograph (EMG) to locate overactive muscles and to measure and record muscle activity.

Injections with the overactive muscle are done with a small needle, with one to three injections per muscle. Discomfort at the site of injections is usually temporary, and a local anesthetic may be used to minimize any pain from the shot.

In general, side effects are temporary and clear up on their own. Depending on the part of the body treated, some side effects include muscle weakness, difficulty swallowing, flu-like symptoms and soreness at the injection site. Adjusting the dosage or site of injection for future treatments may help avoid these side effects.

The effects on the muscle usually start within days of the injection, peaking in approximately four weeks and lasting two to four months.

Some individuals might benefit from the injections indefinitely. Based on more than a decade of clinical experience, patients who respond well to botulinum toxin may continue treatment over the course of many years without side effects. In some cases, a patient who has previously been successfully treated begins to experience a loss in benefit, possibly because the nature and pattern of muscle contractions may change over time. It’s also possible that a person may develop antibodies that “neutralize” the injected toxin.

Most forms of NBIA involve eye disease. The most common problems are retinal degeneration and optic atrophy.

Retinal Degeneration

The most classic symptom of retinal degeneration is difficulty seeing at night or in poor illumination. With loss of rod function there is a narrowing of the field of vision, and as the degeneration progresses, patients feel as though they are looking into a tunnel. This is why it is sometimes called "tunnel vision."

The retina is a thin membrane that lines the back of the eyeball; it acts like the film in a camera, receiving and processing everything a person sees. The retina is a delicate layer of cells. The cells that initially respond to light are the rods and cones.

Rod cells pick up movement out of the corner of the eye and also operate in poor light or at night. There are about 120 million rods in each eye and they are more numerous towards the outer edge of the retina. The cone cells are used in color vision and in close precision work, such as reading. They are more concentrated in the center of the retina.

Other symptoms include difficulty adapting to changes in lighting and differentiating between certain objects. For example, children in the classroom may have problems seeing writing on the blackboard, and an overhead projector may be difficult to read. Other patients may have problems negotiating concrete or carpeted stairs that lack edge markings. Loss of peripheral vision may contribute to falling and gait problems.

Finally, central vision or one’s fine, detail reading vision may be affected. This is usually late in the course of the disease. Some individuals may go blind.

The essential diagnostic test is an electroretinogram or ERG. The ERG is a measure of the retina’s electrical activity in response to light stimulation. The procedure requires a contact lens with electrodes attached. The electrodes monitor the retinal response to a series of light flashes under light and dark conditions.

Evaluation by electroretinogram often detects retinal changes that are asymptomatic. Individuals with a normal eye examination at the time of diagnosis generally do not develop retinopathy.

In the early stages of PKAN the retinal degeneration follows a typical clinical course, with nyctalopia (night blindness) followed by progressive loss of peripheral visual fields and sometimes eventual blindness.

About two out of three individuals with PKAN develop retinal degeneration; it is more common in classic PKAN.

Retinal degeneration was also found in 93 percent of Japanese individuals with aceruloplasminemia.

Optic Atrophy

Optic atrophy affects the optic nerve, which sends messages between the retina and the brain. The optic nerve is like a cable with thousands of tiny electrical wires, each carrying some visual information to the brain. When the nerve is damaged or breaks down, vision can become blurry, side vision or color vision may be abnormal, the pupil may not work properly, or there may be decreased lightness in one eye compared to the other. Eventually, optic atrophy can cause blindness.

Optic atrophy is only found in 3% of PKAN patients and has not been observed in atypical PKAN. For infantile neuroaxonal dystrophy (INAD), a form of PLAN, optic atrophy is common later on and can cause poor vision and eventual blindness. MPAN and FAHN individuals also may have optic atrophy.

Definitions

Dystonia: Involuntary movements and prolonged muscle contractions that result in twisting body motions, tremors and abnormal posture. These movements may involve the entire body or only an isolated area.

Dystonic Storm: Continuous, unremitting, severe dystonic movements, either worsening on a background of dystonia or beginning anew. It can last at least hours to days, producing severe physical and psychological distress.

Treatments

• Intrathecal or oral baclofen
• Oral trihexyphenidyl
• Intramuscular botulinum toxin (Botox)
• Deep Brain Stimulation surgery – replaces pallidotomy and thalamotomy surgeries done in the past

Pain Management

Pain management for NBIA disorders can be very difficult. As the disease progresses, many affected individuals may experience episodes of extreme dystonia lasting for days or weeks. It is especially important during these episodes to evaluate for treatable causes of pain, which may include occult GI bleeding, urinary tract infection and occult bone fractures. The combination of osteopenia in a non-ambulatory person with marked stress on the long bones from dystonia places many individuals with NBIA at high risk for fractures without apparent trauma.

While strong pain medications can have side effects and complications, these problems can be minimized when actively managed by physicians and are often necessary to help combat pain for NBIA individuals.

One of the most consistent forms of relief from dystonia is baclofen. Not every patient on baclofen eventually becomes resistant to it, making it a long-haul treatment for some NBIA patients. This medication is first taken orally, but a baclofen pump may be an option for some individuals. An evaluation can be done to determine the likelihood a patient would respond positively to a pump.

Deep brain stimulation (DBS) is another option used to treat dystonia in NBIA individuals. It involves the placement of electrodes in the brain, which are attached to wires leading to a battery-operated neurostimulator implanted in the chest. The neurostimulator sends pulses to targeted areas in the brain and takes “off line” the part of the brain that is sending too many signals and causing the muscles to move in painful ways.

Injection of botulinum toxin (Botox) into muscles affected by dystonia can also provide relief for several months at a time.  Botox helps relieve involuntary contractions causing pain, twisting, abnormal posture or changes in person’s voice or speech, by causing temporary weakness in those muscles. Because each affected muscle must be injected, this is most practical when an individual has dystonia significantly affecting a specific body area, such as the hand or jaw. Resistance to Botox is a real phenomenon.  As a result, that treatment could lose its effectiveness over time because the body makes antibodies to combat the toxin.

Many individuals with NBIA have ongoing constipation due to decreased activity, diet and/or medication side-effects. Constipation can cause dystonia. Over-the-counter fiber supplements and stool softeners can often improve the situation.

Other triggers for dystonia can be emotional stress, illness and puberty.

Standard approaches to pain management are generally recommended where there is no identifiable treatment for the underlying cause of pain.