My neighbor's brother was recently diagnosed with stiff-person syndrome. Can you tell me what it is and how it's treated?-R.D., LA.
Denise Drummond Hayes, MSN, RN, CRNP, replies: Formerly called stiff-man syndrome and sometimes called Moersch-Woltman syndrome, stiff-person syndrome (SPS) is a rare acquired neurologic disorder.1 Three SPS subcategories or variants have been described, but classic SPS is the focus here.
Although the exact cause of SPS isn't known, an autoimmune process is thought to be involved, especially because SPS has been associated with other autoimmune disorders such as diabetes mellitus type 1. SPS isn't easily recognized and because many disorders (such as Parkinson disease and multiple sclerosis) can cause similar signs and symptoms, its true prevalence is unknown. SPS can affect people of any age, but women appear to be affected twice as often as men. For this reason, the name has been changed from stiff-man to stiff-person syndrome.2-5
Symptom onset, which has been described as insidious, usually starts between the third and seventh decades of life, although children and older adults have also been affected. Initially, patients may report intermittent muscle tightness and aching in the neck, abdominal, and paraspinal muscles. The clinical hallmark of slowly progressive, fluctuating muscle stiffness and rigidity is often asymmetrical and may lead to pronounced lumbar lordosis (hyperlordosis). Unexpected noises, tactile stimuli, or emotional stress precipitate superimposed episodic painful muscle spasms, but spasms may also occur spontaneously. The muscle stiffness, rigidity, and spasms typically begin in the axial (trunk) muscles and may progress to involve the proximal limb muscles.
People with SPS are often described as having a "wooden" appearance and a "Frankenstein's monster" gait. Fracture risk is high because of postural instability, which often causes the patient to fall "like a tin soldier." Coexisting psychiatric disorders include generalized anxiety disorders, phobias, and depression.2,3,5
Diagnosis is based on a comprehensive patient history and a thorough clinical evaluation. About 60% of patients with classic SPS have circulating anti-glutamic acid decarboxylase (GAD) antibodies. Anti-GAD antibodies attack GAD-producing neurons, resulting in GAD deficiency. GAD is responsible for synthesizing gamma aminobutyric acid (GABA), the major inhibitory neurotransmitter that plays a role in controlling muscle movement. Serology may be positive for anti-GAD antibodies, and electromyography may demonstrate continuous motor unit activity in stiff muscles that resolves with benzodiazepine administration.2,3,5
If untreated, SPS can result in significant disability or life-threatening complications such as respiratory distress.2,3,5 Because SPS can't be cured, the goal of therapy is to improve signs and symptoms. Pharmacotherapy, which centers on increasing GABAergic tone and employing immunotherapy, may include benzodiazepines, baclofen, antiepileptic drugs, and I.V. immunoglobulin.6 Physical and occupational therapy and sometimes psychiatric therapy also play an important role. Investigational therapies have included I.V. monoclonal antibodies, corticosteroids, plasmapheresis, and autologous stem cell transplantation.7
Nursing interventions include patient education about the disorder and prescribed medications, including possible adverse drug reactions such as sedation. Teach patients to take their medications as prescribed-abrupt withdrawal of therapy may be life-threatening. Advise them to wear a medical-alert tag or bracelet.
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