The parathyroid glands are small, inconspicuous, and variable in number, colour and position. Their identification is vital for excision of hyper-functioning glands and for preservation of normally functioning ones in patients undergoing thyroidectomy. Intravenous infusion of methylene blue at a dose of 7.5 mg/kg is commonly used to aid visualization of the parathyroid glands intra-operatively. Methylene blue is generally considered benign, and there are only two cases published in the literature reporting toxicity following intravenous infusion--such toxicity is a diagnosis of exclusion. We report a case of methylene blue toxicity resulting in expressive aphasia, confusion and disinhibition following infusion for parathyroid adenoma localization. The patient made a complete recovery over 48 hours. Methaemoglobinaemia was excluded as a cause. We suggest that the mechanism of toxicity was a direct effect of methylene blue, although an adverse interaction with serotonin re-uptake inhibitors could not be excluded. In keeping with the UK National Poisons Information Service recommendations, we have altered our practice and now use methylene blue at a dose not exceeding 4 mg/kg. This has not affected our success rate for identification of parathyroid glands. We report this case to highlight the rare occurrence of methylene blue toxicity when used at a dose of 7.5 mg/kg.

Antiplatelet therapies are an essential tool to reduce the risk of developing clinically apparent atherothrombotic disease and are a mainstay in the therapy of patients who have established cardiovascular, cerebrovascular, and peripheral artery disease. Strategies to intensify antiplatelet regimens are limited by concomitant increases in clinically significant bleeding. The development of novel antiplatelet therapies targeting additional receptor and signaling pathways, with a focus on maintaining antiplatelet efficacy while preserving hemostasis, holds tremendous potential to improve outcomes among patients with atherothrombotic diseases.

Background Assuring the safety of medical devices is challenged by reliance on voluntary reporting of adverse events. We evaluated a strategy of prospective, active surveillance of a national clinical registry to monitor the safety of a vascular closure device suspected as potentially associated with increased adverse events. Methods We used an integrated clinical-data-surveillance system to conduct a prospective, propensity-matched analysis of the safety of the Mynx vascular closure device, as compared with alternative approved vascular closure devices, using the National Cardiovascular Data Repository CathPCI Registry. Outcomes were vascular complications including the composite of access-site bleeding, access-site hematoma, retroperitoneal bleeding, any vascular complication requiring intervention or blood transfusion. Results Between 1/1/2011 and 9/30/2013, 73,124 patients receiving Mynx devices used following femoral percutaneous coronary intervention (PCI) procedures were analyzed. When compared with alternative vascular closure devices, the Mynx device was associated with an increased risk of vascular complications (absolute risk [AR]: 1.21% vs. 0.76%; relative risk [RR]: 1.59; 95% CI: 1.42-1.78), access-site bleeding (AR: 0.38% vs. 0.28%; RR: 1.34; 95% CI: 1.10-1.62) and transfusion (AR: 1.82% vs. 1.48%; RR: 1.23; 95% CI: 1.13-1.34). The initial alerts occurred within the first 12 months of monitoring. Relative risks were greater for three prespecified high-risk subsets (diabetics, elderly patients and women). These safety signals were confirmed in an independent sample of 48,992 cases between 4/1/14 and 9/30/15. Conclusions A strategy of prospective, active surveillance of a clinical registry was capable of rapidly identifying potential safety signals following use of an implantable medical device.