Acute hemichorea in a young type 1 diabetic.

Purpose/Aim: Acute movement disorder is an uncommon presenting symptom in patients with diabetes mellitus. We report a 20-year-old lady with poorly controlled type 1 diabetes, who presented with acute hemichorea and was found to have two rare diabetes-related central nervous complications of diabetic striatopathy and severe moyamoya disease (MMD).Materials and methods: She was treated with aggressive glycemic control; clonazepam and tetrabenazine as well as aspirin stroke prophylaxis for her MMD with resolution of her chorea 3 months later. She subsequently underwent cerebral revascularization surgery for her MMD.Results: This case highlights the possible differentials of acute chorea in diabetic patients and explores the pathophysiological mechanisms that may underlie both conditions in patients with type 1 diabetes.Conclusion: We recommend performing both magnetic resonance imaging (MRI) and magnetic resonance angiogram (MRA) brain for comprehensive evaluation of diabetic patients with new onset chorea. Prompt and accurate diagnosis is crucial as it guides prognostication and treatment strategies.

A diagnostic curiosity of isolated androstenedione elevation due to autoantibodies against horseradish peroxidase label of the immunoassay.

Two sisters with hirsutism presented with mild hirsutism and isolated, grossly elevated (>34.9nmol/L) serum concentrations of androstenedione measured by competitive, homogeneous immunoassay. The clinically discordant laboratory results prompted us to look for assay interference. In this immunoassay, horseradish peroxidase (HRP)-conjugated androstenedione competes with endogenous androstenedione for binding with the solid-phase polyclonal rabbit IgG antibodies. After a wash step, the amount of signal generated by the bound HRP conjugate is inversely proportional to the androstenedione concentration. Alternative analysis by tandem mass spectrometry (a good first line option for troubleshooting) and repeating the competitive immunoassay after polyethylene glycol treatment returned androstenedione concentrations within reference limits. These findings suggested that the original result was spuriously elevated due to assay interference. Additionally, the patient samples were pre-incubated with heterophile blocking reagents, normal rabbit IgG antibodies and HRP-conjugated normal goat IgG antibodies, followed by repeat measurement using the immunoassay. Only samples pre-incubated with HRP-conjugate returned significantly lower androstenedione (9.5 and 12.5nmol/L, respectively), implying neutralisation of the interfering antibodies. Androstenedione remained grossly elevated in the other experiments. This deductive exercise showed that the interference is due to autoantibodies against the HRP label used in the immunoassay. Another immunoassay using HRP label (5α-dihydrotestosterone) also produced gross elevation that was normal by tandem mass spectrometry analysis. Assay interferences, though not uncommon, are frequently overlooked. Laboratory results discordant with clinical features should prompt consideration of assay interference to avoid unnecessary investigations and treatment. This is the first report of autoantibodies against the HRP label used in immunoassay.