Stiff person syndrome and prior temporal lobectomy: Is it a case of misplaced autoimmunity?

Background: Stiff person syndrome (SPS) is a rare autoimmune disorder, characterized by progressive rigidity and muscle spasms affecting the axial and limb muscles. Anti-glutamic acid decarboxylase (anti-GAD65) antibodies are linked to pathogenesis of both epilepsy and SPS. We aim to highlight epilepsy surgery as a potential trigger for development of SPS. Case presentation: A 35-year-old female with medically refractory temporal lobe epilepsy underwent right amygdala-hippocampectomy in 2009. The patient was seizure-free until 2019 when she developed spells of severe muscle spasms, palpitations, dyspnea, and restlessness. Examination revealed increased spasticity in bilateral lower extremities, a wide based gait, and hyperreflexia with crossed adductor sign and bilateral Babinski sign. Serum and cerebrospinal fluid (CSF) labs were obtained, and two typical spells occurred during continuous video electroencephalogram (cvEEG) monitoring. Typical spells did not correlate with seizure activity on cvEEG. CSF analysis showed normal opening pressure, Gram stain, culture, cell count, protein, and glucose. Serum and CSF GAD65 antibody levels were 5153 nMol/L and 53 nMol/L, respectively, along with 14 oligoclonal bands in CSF. Diagnosis of SPS was made. Treatment with diazepam caused improvement in spells and myalgia. Conclusion: The diagnosis of SPS can be delayed in a patient with history of epilepsy. Although SPS and epilepsy are often linked by anti-GAD antibodies as common etiology, it is possible that epilepsy surgery might be a trigger for development of SPS in a small subset. Development of autoimmunity to neuronal GAD65 protein, exposed during surgery, is suspected in pathogenesis.