Abstract
Introduction
Stiff-person syndrome (SPS) is a rare neurological disorder that causes progressive muscle rigidity, gait disturbances and functional impairment; type 1 is autoimmune, with postitive anti-GAD antibodies (Ab) while type 2 is paraneoplastic, associated with anti-amphiphysin Ab.
Case presentation
A 41-year-old man with silent medical history presented with stiffness and functional impairment; after numerous rheumatological and neurological investigations he was diagnosed with SPS, with evidence of high titer anti-GAD Ab. After treatment with benzodiazepines was started, the patient began to experience episodes of confusion, which persisted even after reducing the dosage. During one of these episodes, he was admitted to the emergency department and a glucose level of 26 mg/dL was found. Differential diagnosis led to an insulin secreting neuroendocrine tumor of the pancreas, thus a paraneoplastic origin of SPS was hypothesized. However, anti- amphiphysin Ab were negative, anti-GAD were persistently elevated and symptoms only transiently improved after removal of the tumor.
Conclusion
This is the first case, to our knowledge, of association between type 1 SPS and insulinoma, with partial and transient improvement of neurological symptoms after resolution of the associated hypoglycemic syndrome.