Stiff Person syndrome: a case report

Abstract

Stiff person syndrome (SPS) is rather unique among neurologic diagnoses. At relaxation, motor- unit activation, continuous agonist and antagonist muscular contractions, as well as contractions triggered by tactile triggers, quiescent stretch, and involuntary movement of affected or unaffected musculature, startled sounds and emotional stimuli are the clinical signs of SPS. Sleep, general anesthesia, myoneural, and peripheral nerve blockage all help to reduce rigidity and spasms. The syndrome may be a sporadic autoimmune syndrome (associated with anti–glutamic acid decarboxylase (GAD) antibodies and often accompanied by other autoimmune diseases such as type 1 diabetes) or paraneoplastic (associated with anti–amphiphysin antibodies). People with SPS respond to high doses of diazepam and several anti-convulsants, gabapentin and tiagabine. Immunomodulatory drugs including steroids, plasmapheresis, and intravenous immunoglobulin appear to help significantly. The symptoms of our patient progressed slowly over time. Neuroimaging and electrophysiological studies ruled out other possible causes of comparable symptoms such as neuromyotonia. Raised anti-GAD autoantibodies titer in serum found by immunocytochemistry assays, our patient's history, clinical examination findings, and reaction to benzodiazepines all pointed to SPS.