Endocrine Abstracts

Introduction: T1DM is an autoimmune condition. At diagnosis, 80% of patients have positive glutamic-acid decarboxylase antibodies (GADA). We report a case of T1DM diagnosed 1 year after the onset of autoimmune limbic encephalitis (LE).

Case: A 13-year-old female was diagnosed with voltage-gated-potassium channel (VGKC) positive LE after presenting with complex partial seizures and auditory hallucinations. A year later and prior to the diagnosis of diabetes her neurological condition deteriorated with worsening of axial stiffness, escalation of seizure frequency, short memory deterioration, hallucinations and emotional lability. At the time of a PET scan to exclude neoplasia, the patient was found to have hyperglycaemia. Her HBA1C was 7.1% and high levels of GADA were detected (>2000 U/ml). There was evidence of acanthosis nigricans and a strong family history of type 2 diabetes. She was initiated on subcutaneous insulin with multiple daily injections. She received intravenous corticosteroids, plasmapharesis, mycophenolate mofetil and intravenous immunoglobulin as part of her neurology management which complicated the management of her diabetes. Her total daily insulin dose varied between 0.5 and 2.0 units/kg per day depending on her fluctuating neurological status.

Conclusion: Neurological conditions with GADA have been described in adults and diabetes may pre-exist or manifest after the onset of the neurological symptoms. LE is associated with antibodies such as VGKC-antibodies and GADA and has been most commonly described as a paraneoplastic phenomenon. To date, 16 children with LE have been reported (six paraneoplastic); five were GADA positive; one was diagnosed with T1DM 2 years prior to the onset of LE. Our patient developed T1DM 1 year after the onset of LE and her glycaemic control was complicated by her fluctuating insulin sensitivity, her underlying neurological condition and its management.