The allergic myocardial infarction dilemma: is it the anaphylaxis or the epinephrine?

We highlight two distinct cases of myocardial infarction occurring concurrently with anaphylaxis at our centre in Singapore. The first case had cardiac symptoms and electrocardiogram changes concomitant with his anaphylaxis presentation, suggestive of Kounis syndrome, while the second case presented with anaphylaxis and only developed cardiac symptoms and electrocardiogram changes after treatment with intramuscular epinephrine, suggestive of epinephrine-induced myocardial infarction. Both these conditions are uncommon and under-recognised, and we review the current literature to compare the similarities and differences in their clinical manifestations, pathophysiology, and management. Kounis syndrome occurs secondary to mast cell degranulation ultimately resulting in coronary vasospasm, platelet activation and inflammatory response, whereas epinephrine causes platelet aggregation. Therefore, treatment priorities of Kounis syndrome are treatment of allergy, treatment of vasospasm, and treatment with anti-platelet therapy and revascularization if coronary plaques are present. For epinephrine-induced myocardial infarction, after epinephrine treatment is discontinued, considerations in management are re-vascularisation or pharmacotherapy. Further research will help with better understanding of both conditions and formulation of clinical management guidelines.

Trends in Stroke Incidence and 28-Day Case Fatality in a Nationwide Stroke Registry of a Multiethnic Asian Population.

BACKGROUND AND PURPOSE: This study investigated trends in stroke incidence and case fatality overall and according to sex, age, ethnicity, and stroke subtype in a multiethnic Asian population. METHODS: The Singapore Stroke Registry identifies all stroke cases in all public hospitals using medical claims, hospital discharge summaries, and death registry data. Age-standardized incidence rates and 28-day case-fatality rates were calculated for individuals aged ≥15 years between 2006 and 2012. To estimate the annual percentage change of the rates, a linear regression model was fitted to the log rates, and a Wald test was performed to test for trend. P values <0.05 were considered significant. RESULTS: A total of 40 623 cases were recorded. The total stroke incidence fell by ≈12.0%, and case fatality fell by 17.2% in the study. Declining trends in stroke incidence were stronger in women (female: -2.94; 95% confidence interval [CI], -3.43 to -2.44; male: -1.80; 95% CI, -2.58 to -1.02); in the older age groups (≥65 years: -3.62; 95% CI, -4.30 to -2.94; 50-64 years: -1.26; 95% CI, -1.97 to -0.55; <50 years: 3.33; 95% CI, 1.49 to 5.20), in Chinese (-2.64; 95% CI, -3.15 to -2.13), Indians (-3.78; 95% CI, -5.93 to -1.58), and others (-12.73; 95% CI, -18.93 to -6.06) compared with Malays (2.58; 95% CI, 1.17 to 4.02); and in ischemic stroke subtype (ischemic: -2.43; 95% CI, -3.13 to -1.73; hemorrhagic: -1.02; 95% CI, -2.04 to 0.01). Subgroup-specific findings for case fatality were similar. CONCLUSION: This is the first countrywide hospital-based registry study in a multiethnic Asian population, and it revealed marked overall reductions in stroke incidence and case fatality. However, it also identified important population groups with less favorable trends, especially younger adults and those of Malay ethnicity.