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Research: The Process

Stiff Person Syndrome is associated with a number of other diseases. The most common of these areType 1 diabetes, thyroid disease, vitiligo and pernicious anaemia. The list is almost endless. All these diseases have in common an autoimmune (self-allergic) nature. There are some variants of SPS, which have been more recently recognised. The first of these, sometimes called Stiff Limb Syndrome, is similar but painful spasms and occasionally fixed deformities usually affect the legs, including the feet, rather than the torso, More rarely, hands can also be affected. Patients with this variant of SPS are far less likely to have diabetes mellitus or other autoimmune conditions, and tend not to have anti-GAD antibodies (see later). Rarely, there are more aggressive forms of SPS, which lead to progressive disability over a number of years. This variant is sometimes called the Jerking Stiff Person Syndrome or Progressive Encephalomyelitis with Rigidity (PERM).

Investigations: The most important investigation is antibody testing. SPS carries an antibody marker, which is an antibody to an enzyme found both in the pancreas and in nerve tissue. This antibody is called anti-GAD and it occurs in high concentrations in SPS, although about 80% are GAD positive, which means 20% are GAD negative. Much lower concentrations are sometimes found in diabetics without SPS. More rarely, some other antibodies may be associated with Stiff Person conditions. One of these is called anti­amphiphysin. Where this is found there is often also a co-existing tumor. However, this combination is very rare. Electrical recordings from the affected muscles (termed EMG) can be useful in making the diagnosis, but it must be done by someone looking for SPS. Here the characteristic finding is an inability of the affected muscles to relax. Scans of the spinal cord can be useful in excluding a structural cause such as a disc or cyst in the spinal cord. The latter may rarely masquerade as SPS. Finally, it is sometimes necessary to examine the fluid from around the spine (CSF) by lumbar puncture. This is to look for signs of active inflammation. A local anaesthetic is given and once the proceedure begins, one should only feel a little pressure. You will be asked to lay flat for recovery.

Treatment: Patients usually respond to combinations of Diazepam and Baclofen, often in reasonably high dosage. These medications can be sedating. Unusually, Baclofen can cause a slight inflammation of the liver. Dependence does not seem to be a problem with Diazepam usage in SPS, as if it is helpful then the sufferer will be taking them for their lifetime. These drugs are given orally, usually three times a day. Other oral treatments may occasionally be helpful, such as Vigabatrin, Sodium Valproate, Tizanidine and Gabapentin. These, too, may be sedating in high dosages. Where all drug treatments fail to give sufficient relief from spasms and pain, treatments directed against the underlying allergic condition may be useful. The choices here consist of steroids (either intravenous or orally), plasma exchange (a technique in which your blood is washed of antibodies) or intravenous pooled immunoglobulins. The latter is probably the preferred treatment of this kind. It usually requires a few days in hospital and the treatment has to be repeated as the neurologist suggests. The infusion of immunoglobulins can be associated with headache. As immunoglobulins are a blood product there is a theoretical and remote risk of catching a viral illness. Precautions are taken to keep this risk to an absolute minimum. With IVIg it is essential one is well hydrated before and during the infusion. This helps to prevent headaches. If suffering with a headache, the treatment should be slowed down.

Outlook: None of these treatments leads to a cure. However, they are able to control symptoms in the majority of patients. This is particularly true in classical SPS, which has a reasonably good outlook. It tends to be a little bit more difficult to control symptoms in Stiff Limb Syndrome, and some of these patients will require help with mobility. Progressive encephalomyelitis with rigidity is a difficult condition to treat and has a poor prognosis.

Stem Cell Therapy: Although in its infancy, this has helped with the treatment of SPS in most cases.

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