Efficacy and safety of therapeutic plasma exchange in stiff person syndrome

The stiff person syndrome (SPS) is an extremely rare neurological disorder with primarily immune-mediated etiology. The cardinal symptoms are progressive, fluctuating axial/proximal limb muscle stiffness and spasms. The diagnosis is based on the clinical picture, electromyography examination and detection of antibodies to glutamic acid decarboxylase (anti-GAD). Adverse effects of medications might preclude its use or increase in dosing, therefore symptomatic and/or immunomodulatory medical therapy might be ineffective in acute exacerbation of the disease. We present a case of a 49-year-old female with exacerbation of SPS, in whom some standard pharmacotherapy could not be introduced (clonazepam, baclofen used in the past) and doses of existing standard medications could not be increased (diazepam, gabapentin, and levetiracetam) due to adverse effects. Moreover, a newly introduced medication (methylprednisolone) also led to a serious adverse effect (severe hyperglycemia). The patient underwent therapeutic plasma exchange (TPE) with good effect and no complications. We review the literature regarding the efficacy and safety profile of TPE in exacerbation of SPS unresponsive to medical therapy. The procedure seems to have a good safety profile as an adjunct therapy for exacerbation of SPS not responding to standard medical therapy in this patient population.