Myocardial Injury and Bacterial Pneumonia Contribute to the Pathogenesis of Fatal Influenza B Virus...
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Transcript of Myocardial Injury and Bacterial Pneumonia Contribute to the Pathogenesis of Fatal Influenza B Virus...
The Journal of Emergency Medicine 209
months (HR 0.63, 95% CI 0.50–0.79), and there was no differ-ence in epilepsy diagnosis later in life (HR 1.01, 95% CI 0.66–1.56). The authors concluded that although there is a small in-creased risk of febrile seizures after the first and second vaccina-tions, there was no increased risk of epilepsy overall later in life.
[Austin Johnson, MD
Denver Health Medical Center, Denver, CO]
Comments:Although this study does demonstrate a small in-creased risk of febrile seizures within the first day after vaccina-tion, it seems that there is no long-term risk for seizure disorder.
, MYOCARDIAL INJURY AND BACTERIAL PNEU-MONIA CONTRIBUTE TO THE PATHOGENESIS OFFATAL INFLUENZA B VIRUS INFECTION. Paddock CD,Liu L, Denison AM, et al. J Infect Dis 2012;205:895–905.
In this study of cadavers with fatal influenza B infections,Paddock et al. described the demographics of the disease, aswell as associations with myocardial injury and bacterial pneu-monia. Tissue samples were analyzed from 45 case patients withfatal influenza B infection, as confirmed at the Centers for Dis-ease Control via polymerase chain reaction. Demographic datashowed that the median age of death was 11 years, and 76% ofthe case patients were < 18 years old. Average time from symp-tom onset to death was 3 days. This is faster than any historicinfluenza A pandemic or seasonal infection. Tissue sample anal-ysis revealed evidence of concomitant bacterial pneumonia in38% of patients; 76% of these were infected with Staphylococ-cus aureus. Age > 18 years was the only variable that correlatedsignificantly with the presence of histologically confirmed bac-terial pneumonia (p < 0.001). Finally, the authors evaluated casepatients for the presence of myocardial injury. Immunohisto-chemical assays detected C4d and C9 as evidence of myocardialinjury in 69% of the 29 case patients from whom cardiac tissuewas available. Ninety percent of individuals with evidence ofmyocardial injury were aged < 18 years. Importantly, no viralantigens were detected in the myocardium of any patient.
[Mike Miller, MD
Denver Health Medical Center, Denver, CO]
Comments: From 2004–2008, influenza B accounted for 34%of influenza-associateddeaths in children in theUnitedStates.Thisstudy emphasizes that fatal influenza B can progress rapidly, isoften accompanied by evidence of myocardial injury in children,and is infrequently associated with bacterial pneumonia in thatsame age group. The clinical significance of this disease is oftenovershadowed by its more well-known counterpart, influenza A.
, INTRAVENOUS THROMBOLYSIS IN YOUNGSTROKE PATIENTS: RESULTS FROM THE SITS-ISTR.Toni D, Ahmed N, Anzini A, et al. Neurology 2012; 78:880–7.
Stroke in younger patients (18–50 years) can have importantlong-term outcomes. Aggressive treatment of this condition isimportant given the longer expected survival of this populationwhen compared to those over 50 years of age. Conflicting dataexist about the relative benefit of acute treatment with intrave-nous alteplase in younger patients, though all prior studieshave been limited by small sample size. This study sought toevaluate the safety and efficacy of this medication in youngerpatients when compared to older patients. A post hoc analysisof data from the Safe Implementation of Thrombolysis in Stroke– International Stroke Thrombolysis Register (SITS-ISTR) wasperformed on data of patients aged 18–80 years that received in-travenous alteplase within 4.5 h of stroke onset between 2002and 2010. Primary outcomes were symptomatic intracerebralhemorrhage (SICH), mortality, and functional independence at3 months. The SITS-ISTR contained data on 3246 patientsaged 18–50 years and 24,425 patients aged 51–80 years. Multi-variable logistic regression models were performed for eachoutcome variable. Regressions were also performed for subdivi-sion of patients in deciles (under 30 years, 31–40 years, 41–50years, and over 50 years). There was a significant difference inthe baseline characteristics of the two groups, with increasingrates of comorbidities such as hypertension, diabetes mellitus,hyperlipidemia, and atrial fibrillation, among others. The au-thors found that SICH occurred in 0.6% of younger patientsand 1.9% of older patients (adjusted odds ratio [OR] 0.53, p =0.02). Three-month mortality was 4.9% and 14.4% in youngvs. old patients (adjusted OR 0.49, p < 0.001). Functional inde-pendence was 72.1% vs. 54.5% for young vs. old patients (ad-justed OR 1.61, p < 0.0001). Evaluation of the age decilesshowed progressive rates of SICH, mortality, and lower func-tional independence with increasing age, with steepest changeof rates after age 50 years. The authors concluded that treatmentwith intravenous alteplase is safe in young patients, with greaterbenefit than in older cohorts.
[Peter Emiley, MD
Denver Health Medical Center, Denver, CO]
Comments: Although limited by its retrospective design, thisstudy suggests greater benefit from the treatment of acute strokein younger patients. This seems somewhat intuitive and is likelyexplained by less comorbidity and improved plasticity in the in-jured brain at a younger age.