A Case of Anti-glutamic Acid Decarboxylase-65 Antibody Positive Stiff Person Syndrome Presenting Initially as Acute Peripheral Vestibulopathy, Leading to Delayed Diagnosis After Multiple Hospitalizations.

Stiff person syndrome (SPS), with a prevalence of one to two per million, is an extremely rare neurological condition that is characterized by axial muscle stiffness and rigidity along with intermittent painful muscle spasms. It is often associated with psychiatric co-morbidities such as anxiety and depression. The pathophysiology, although poorly understood, is widely believed to be autoimmune in nature due to the association of anti-glutamic acid decarboxylase-65 (anti-GAD 65) antibodies with this condition. There is also a paraneoplastic variant that is more commonly associated with anti-ampiphysin antibodies. It occurs most commonly in patients with breast cancer followed by colon cancer. Most of the practising neurologists encounter just one or two cases of SPS in their entire careers, hence this condition remains underdiagnosed, leading to significant disability and distress to the patient. In this case report we describe a postmenopausal female who presented initially with symptoms of vertigo and dizziness and was hospitalized multiple times before the diagnosis was reached. Through this article, we attempt to increase awareness about this condition among practising physicians so as to increase the likelihood of earlier diagnosis and treatment.