[A case of autoimmune polyglandular syndrome-related Parkinsonian syndrome that required differentiation from...

A 76-year-old woman experienced unsteadiness in walking in 1996. On the basis of clinical and imaging findings, the patient was diagnosed multiple system atrophy. During follow-up, her gait disturbance became aggravated leaving her unable to walk unaided. She was referred to our department in 2003. T2-weighted images on brain magnetic resonance imaging (MRI) revealed low signal intensity in both putamina and a linear high-signal-intensity area on their outsides. Single photon emission computed tomography (SPECT) disclosed a reduced blood flow in both corpora striata. These findings were consistent with the diagnosis of Parkinsonian-type multiple system atrophy. The patient had anti-glutamic acid decarboxylase (GAD) antibody-positive type 1 diabetes mellitus and a normal thyroid function, and was positive for antithyroid antibodies. She was not found to have anemia on blood tests, but was positive for intrinsic factor antibodies. Vitamin B12 was markedly reduced to below the detection limit. The findings suggested that the patient's condition was autoimmune polyglandular syndrome type 3. In 2004, treatment with intramuscular injection of vitamin B12 was initiated, after which the patient's gait disturbance was improved and she was able to walk unaided. In 2009, her unsteady gait returned and was again unable to walk unaided. Autoimmune encephalopathy was suspected, and thus high-dose intravenous immunoglobulin therapy was performed. Following treatment she was able to walk steadily. This case suggests the importance of detailed tests for autoantibodies, including endocrine autoantibodies, and the measurement of vitamin B12 and total homocysteine levels in view of the possibility of autoimmune polyglandular syndrome-related neurological disorders in diabetic patients with intractable neurological disorders that are difficult to diagnose.