Hyperhomocysteinemia has been associated with an increased risk of systemic atherosclerosis, cardiovascular disease, and stroke. It can result from an impaired homocysteine metabolism resulting from a dietary deficiency of folic acid, vitamin B6, and vitamin B12 or as a result of genetic predispositions due to impaired gene function involved in the methionine and homocysteine metabolism. Nitrous oxide use can also lead to hyperhomocysteinemia by irreversibly oxidizing the cobalt atom of vitamin B12, which results in an inhibition of the enzyme methionine synthase. Here, we report a rare case of a young patient who presented with acute ischemic stroke after years of recreational nitrous oxide use.

Community-acquired pneumonia (CAP) is a significant global health burden, particularly in severe cases. Corticosteroids have been proposed as adjunctive therapy to improve outcomes, though evidence remains mixed. To determine the effect of corticosteroid therapy on mortality and morbidities in patients with CAP. We conducted a systematic review and meta-analysis of 20 randomized controlled trials (RCTs) involving 5,866 adult patients with CAP. Studies comparing systemic corticosteroids to placebo or usual care were included. Risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs) were calculated using the Mantel-Haenszel and inverse variance methods under a random-effects model. Statistical heterogeneity was assessed using the I² statistic. Corticosteroids did not significantly reduce overall mortality (RR 0.84; 95% CI: 0.68-1.03; p = 0.10), but a significant reduction was observed in patients with severe CAP (n = 3,326; RR 0.73; 95% CI: 0.57-0.93; p = 0.01). No mortality benefit was seen in less severe CAP (n = 2,451; RR 1.14; 95% CI: 0.89-1.45; p = 0.31). Hospital length of stay was significantly reduced with corticosteroids (n = 4,175; MD -2.13 days; 95% CI: -3.07 to -1.19; p < 0.00001), with reductions observed in both less severe (-1.03 days) and severe CAP (-3.04 days). ICU stay was also shorter in the corticosteroid group (MD -1.70 days; p = 0.005). Corticosteroids did not significantly increase the need for mechanical ventilation (RR 0.57; p = 0.10), or increase the risk of secondary infections (RR 0.99; p = 0.92), or gastrointestinal bleeding (RR 0.80; p = 0.29). Corticosteroids improve outcomes in severe CAP by reducing mortality and duration of hospitalization without increasing adverse events. Routine use in less severe CAP is not supported.