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What is stiff-person syndrome? -

Stiff-person syndrome (SPS) is a autoimmune and neurological disorder that causes rigidity in the torso and limbs.

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Muscle spasms -

Besides stiffening across the body, symptoms of this rare condition also include episodes of severe muscle spasms.

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Chronic pain -

People with the syndrome can expect chronic pain, impaired mobility, and lumbar hyperlordosis (excessive spine curvature in the lower back).

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Triggers -

Symptoms can occur at random but are often triggered by environmental stimuli (like loud noises), touch, or emotional stress.

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Severe reaction -

Muscle spasms can be so severe they can dislocate joints and even break bones, in some cases causing the person to fall down. The muscles gradually relax after the stimulus is gone.

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Difficulty walking -

Over time, these symptoms can lead to difficulty in walking and eventually greater immobility.

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Emotional toll -

As the disease progresses, so does the emotional toll exerted on the patient. Symptoms of depression and anxiety are commonplace.

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Heightened anxiety levels -

Levels of nervousness and apprehension are heightened by the fact that sufferers of SPS have lower levels of the neurotransmitter gamma-aminobutyric acid (GABA), which regulates anxiety.

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One in a million -

SPS occurs in about one in a million people and is most commonly found in middle-aged people.

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Communication problems -

Stiff-person syndrome inhibits the normal pathways of communication between the brain and the muscles.

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SPS cause remains unknown -

The cause of SPS remains clouded in mystery. Research suggests that its onset may be caused by an autoimmune reaction.

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Autoimmune reaction? -

The immune system appears to attack a protein called glutamic acid decarboxylase (GAD), which helps make the aforementioned substance called GABA.

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Motor neuron irregularity -

GABA helps regulate motor neurons by decreasing their activity. But lower than normal levels of GABA can cause those neurons to fire continuously even when they’re not supposed to. This impairment probably causes the stiffness and spasms that characterize SPS.

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Related disorders -

SPS patients commonly have another autoimmune disorder, typically type 1 diabetes, vitiligo, or pernicious anemia.

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The link with cancer -

Those stricken with SPS also tend to be cancer patients, specifically those suffering from breast cancer, lung cancer, kidney cancer, thyroid cancer, colon cancer, and lymphomas. The reason for this link is unknown.

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SPS background -

Stiff-person syndrome was first described in 1956 by neurologists Moersch and Woltman (the disease is sometimes referred to as Moersch-Woltman syndrome). However, it was only in 1989 that criteria for an SPS diagnosis were adopted.

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Early signs and symptoms -

Generally, SPS begins slowly over several months or a few years. Affected individuals may initially experience aching discomfort, stiffness, or pain, especially in the lower back or legs.

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Worsening condition -

As the condition worsens, the shoulders, neck, and hips may also be affected.

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Slow, stiff gait -

Progression of SPS is characterized by stiffness of the leg muscles and a slow, rigid manner of walking.

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Slouched posture -

As stiffness increases, affected individuals may develop a hunched or slouched posture due to outward curving of the upper spine, a condition known as kyphosis. SPS can also cause hyperlordosis, where there is an excessive spine curvature in the lower back.

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Onset of muscle spasm -

Inevitably, sufferers of SPS will develop muscle spasms. The legs are often involved. But spasms can also involve the muscles of the chest and respiratory system, potentially requiring emergency medical treatment with ventilatory support.

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Wheelchair use -

The severity of advanced SPS can impact an individual's ability to perform daily activities and routines. Some patients may end up requiring the use of a wheelchair.

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Diagnosis -

Diagnosis of SPS can be tricky. Symptoms can mimic those of Parkinson’s disease, multiple sclerosis, fibromyalgia, or anxiety, and it often takes time to identify the exact cause.

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Treatment and prognosis -

There is no cure for stiff-person syndrome. A diagnosis of SPS is made based upon identification of characteristic symptoms, a detailed patient history, and a thorough clinical evaluation.

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Tackling the disorder -

Treatment for the condition typically involves relieving symptoms with medications such as sedatives, muscle relaxants, and steroids.

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Immunotherapy -

In some cases, immunotherapy may be prescribed, procedures such as intravenous immunoglobulin and plasmapheresis.

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Physical therapy -

When treating SPS, emphasis is also placed on regular activity. Physical, occupational, and aqua therapy are vital for patients with SPS.

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A difficult condition to treat -

By its nature, SPS is difficult to treat, more so than other autoimmune disorders like rheumatoid arthritis or Crohn's disease.

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Prognosis -

Symptoms of SPS and their severity levels vary. It's difficult therefore to predict whether a patient's condition will get worse over time.

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Outcome -

Early recognition and neurological treatment of SPS can limit its progression. But even with rapid intervention, quality of life generally declines as stiffness precludes many activities. Ultimately, about 65% of SPS patients are unable to function independently. About 10% of those will require intensive care at some point. 

Sources: (National Organization for Rare Disorders) (NBC News) (The Stiff Person Syndrome Research Foundation)

See also: Stars who suffer from rare diseases

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