Vitamin B12 deficiency in the setting of nitrous oxide abuse: diagnostic challenges and treatment options in patients presenting with subacute neurological complications.

OBJECTIVE: It is well recognized that nitrous oxide abuse can lead to vitamin B12 deficiency presenting with neurological complications. Nevertheless, establishing this diagnosis can be challenging, and treatment guidelines are lacking. METHODS: In this paper, we present a case series of eight patients and discuss the diagnostic challenges and treatment options for vitamin B12 deficiency due to nitrous oxide abuse presenting with neurologic complications. RESULTS: Biochemical findings are not always straightforward and complementary testing is often necessary. Magnetic Resonance Imaging (MRI) revealed a longitudinally myelopathy extending over a long segment typically involving the dorsal columns of the cervical cord. To increase the lesion conspicuity, dedicated MRI sequences are needed. In our practice, we recommend the use of T2-weighted images (WI) with fat suppression (FS). Treatment consists of cessation of nitrous oxide abuse and supplementation with intramuscular injections of cobalamin. Due to a lack of treatment guidelines, we also describe the treatment schedule used in our neurology clinic and give a brief overview of treatment options suggested in the literature. CONCLUSION: We described diagnostic steps en treatment plans in patients presenting with subacute neurological complications due to nitrous oxide abuse. ABBREVIATIONS: crea: creatinine; HCy: homocysteine; MCA: 2-methylcitric acid; MMA: methylmalonic acid; MRI: magnetic resonance imaging; SEP: somatosensory evoked potentials.

Adherence to quality indicators for ST-elevation myocardial infarction and its relation to mortality: a hospital network analysis from the Belgian STEMI database.

AIMS: To assess the adherence to established quality indicators (QIs) for ST-elevation myocardial infarction (STEMI) at the hospital-network level and its relation to outcome. METHODS AND RESULTS: The data of 7774 STEMI patients admitted to 32 STEMI networks during the period 2014-18 were extracted from the Belgian STEMI database. Five QIs [primary percutaneous coronary intervention use, diagnosis-to-balloon time (DiaTB) <90 min, door-to-balloon time (DoTB) <60 min, P2Y12 inhibitor and statin prescription at discharge, and a composite QI score ranging from 0 to 10] were correlated with in-hospital mortality adjusted for differences in baseline risk profile (TIMI risk score). The median composite QI score was 6.5 [interquartile range (IQR) 6-8]. The most important gaps in quality adherence were related to time delays: the recommended DiaTB and DoTB times across the different networks were achieved in 68% (IQR 53-71) and 67% (IQR 50-78), respectively. Quality adherence was better in networks taking care of more high-risk STEMI patients. The median in-hospital mortality among the STEMI networks was 6.4% (IQR 4.1-7.9%). There was a significant independent inverse correlation between the composite QI score and in-hospital mortality (partial correlation coefficient: -0.45, P = 0.013). Stepwise regression analysis revealed that among the individual QIs, prolonged DiaTB was the most important independent outcome predictor. CONCLUSION: Among established STEMI networks, the time delay between diagnosis and treatment was the most variable and the most relevant prognostic QI, underscoring the importance of assessing quality of care throughout the whole network.