Sudden death in young adults: an autopsy-based series of a population undergoing active surveillance.

OBJECTIVES: The purpose of this study was to define the incidence and characterization of cardiovascular cause of sudden death in the young. BACKGROUND: The epidemiology of sudden cardiac death (SCD) in young adults is based on small studies and uncontrolled observations. Identifying causes of sudden death in this population is important for guiding approaches to prevention. METHODS: We performed a retrospective cohort study using demographic and autopsy data from the Department of Defense Cardiovascular Death Registry over a 10-year period comprising 15.2 million person-years of active surveillance. RESULTS: We reviewed all nontraumatic sudden deaths in persons 18 years of age and over. We identified 902 subjects in whom the adjudicated cause of death was of potential cardiac etiology, with a mean age of 38 ± 11 years. The mortality rate for SCD per 100,000 person-years for the study period was 6.7 for males and 1.4 for females (p < 0.0001). Sudden death was attributed to a cardiac condition in 715 (79.3%) and was unexplained in 187 (20.7%). The incidence of sudden unexplained death (SUD) was 1.2 per 100,000 person-years for persons <35 years of age, and 2.0 per 100,000 person-years for those ≥ 35 years of age (p < 0.001). The incidence of fatal atherosclerotic coronary artery disease was 0.7 per 100,000 person-years for those <35 years of age, and 13.7 per 100,000 person-years for those ≥ 35 years of age (p < 0.001). CONCLUSIONS: Prevention of sudden death in the young adult should focus on evaluation for causes known to be associated with SUD (e.g., primary arrhythmia) among persons <35 years of age, with an emphasis on atherosclerotic coronary disease in those ≥ 35 years of age.

Incidence of primary blast injury in US military overseas contingency operations: a retrospective study.

OBJECTIVES: The present retrospective study was performed to determine the incidence and outcome of primary blast injury and to identify possible changes over the course of the conflicts between 2003 and 2006. SUMMARY BACKGROUND DATA: Combat physicians treating patients injured in overseas contingency operations observed an increase in the severity of explosion injuries occurring during this period. METHODS: This retrospective study included service members injured in explosions between March 2003 and October 2006. The Joint Theater Trauma Registry provided demographic information, injury severity score, and International Classification of Diseases 9 codes used to diagnose primary blast injury. Autopsy reports of the last 497 combat-related deaths of 2006 were also reviewed. RESULTS: Of 9693 admissions, of which 6687 were injured in combat, 4765 (49%) were injured by explosions: 2588 in 2003-2004 and 1935 in 2005-2006. Dates of injury were unavailable for 242 casualties. Injury severity score (9 +/- 10 vs. 11 +/- 10, P < 0.0001) and incidence of primary blast injury (12% vs. 15%, P < 0.01) increased. The return-to-duty rate decreased (40% vs. 18%, P < 0.001), but mortality remained low (1.4% vs. 1.5%, P = NS). There was no significant difference in incidence of primary blast injury between personnel who were killed in action and those who died of wounds at a medical facility. CONCLUSIONS: Injury severity and incidence of primary blast injury increased during the 4-year period, whereas return-to-duty rates decreased. Despite increasingly devastating injuries, the mortality rate due to explosion injuries remained low and unchanged.

Early mortality experience in a large military cohort and a comparison of mortality data sources.

BACKGROUND: Complete and accurate ascertainment of mortality is critically important in any longitudinal study. Tracking of mortality is particularly essential among US military members because of unique occupational exposures (e.g., worldwide deployments as well as combat experiences). Our study objectives were to describe the early mortality experience of Panel 1 of the Millennium Cohort, consisting of participants in a 21-year prospective study of US military service members, and to assess data sources used to ascertain mortality. METHODS: A population-based random sample (n = 256,400) of all US military service members on service rosters as of October 1, 2000, was selected for study recruitment. Among this original sample, 214,388 had valid mailing addresses, were not in the pilot study, and comprised the group referred to in this study as the invited sample. Panel 1 participants were enrolled from 2001 to 2003, represented all armed service branches, and included active-duty, Reserve, and National Guard members. Crude death rates, as well as age- and sex-adjusted overall and age-adjusted, category-specific death rates were calculated and compared for participants (n = 77,047) and non-participants (n = 137,341) based on data from the Social Security Administration Death Master File, Department of Veterans Affairs (VA) files, and the Department of Defense Medical Mortality Registry, 2001-2006. Numbers of deaths identified by these three data sources, as well as the National Death Index, were compared for 2001-2004. RESULTS: There were 341 deaths among the participants for a crude death rate of 80.7 per 100,000 person-years (95% confidence interval [CI]: 72.2,89.3) compared to 820 deaths and a crude death rate of 113.2 per 100,000 person-years (95% CI: 105.4, 120.9) for non-participants. Age-adjusted, category-specific death rates highlighted consistently higher rates among study non-participants. Although there were advantages and disadvantages for each data source, the VA mortality files identified the largest number of deaths (97%). CONCLUSIONS: The difference in crude and adjusted death rates between Panel 1 participants and non-participants may reflect healthier segments of the military having the opportunity and choosing to participate. In our study population, mortality information was best captured using multiple data sources.

Deaths attributed to suicide among enlisted U.S. Armed Forces recruits, 1980-2004.

OBJECTIVE: The purpose of this study was to describe the epidemiology of suicides among U.S. Air Force, Army, Marine Corps, and Navy recruits from 1980 through 2004. METHODS: Recruit suicides were identified through the Department of Defense Recruit Mortality Registry. We calculated crude, category-specific, and age-adjusted mortality rates as deaths per 100,000 recruit-years. RESULTS: There were 46 onsite suicides by gunshot (39%), hanging (35%), fall/jump (22%), and drug overdose (4%). An additional 20 recruits committed suicide from 1980 through 2004 after leaving the military training site. Methods included gunshot (70%), hanging (20%), fall/jump (5%), and poisoning (5%). Therefore, the overall recruit suicide rate was 6.9 (95% confidence interval = 5.4-8.8) deaths per 100,000 recruit-years. Only three (5%) suicides occurred among females resulting in a 3.5 times higher risk for males compared to females (95% confidence interval = 1.1-11.2). CONCLUSIONS: Suicide rates among military recruits were lower than those of comparably aged U.S. civilians. However, the occurrence of any suicide during basic military training emphasizes the importance of routine evaluation of the effectiveness of each military service's suicide prevention program as it applies to this population.

Chest wall thickness in military personnel: implications for needle thoracentesis in tension pneumothorax.

Needle thoracentesis is an emergency procedure to relieve tension pneumothorax. Published recommendations suggest use of angiocatheters or needles in the 5-cm range for emergency treatment. Multidetector computed tomography scans from 100 virtual autopsy cases were used to determine chest wall thickness in deployed male military personnel. Measurement was made in the second right intercostal space at the midclavicular line. The mean horizontal thickness was 5.36 cm (SD = 1.19 cm) with angled (perpendicular) thickness slightly less with a mean of 4.86 cm (SD 1.10 cm). Thickness was generally greater than previously reported. An 8-cm angiocatheter would have reached the pleural space in 99% of subjects in this series. Recommended procedures for needle thoracentesis to relieve tension pneumothorax should be adapted to reflect use of an angiocatheter or needle of sufficient length.

Virtual autopsy: preliminary experience in high-velocity gunshot wound victims.

PURPOSE: To retrospectively assess virtual autopsy performed with multidetector computed tomography (CT) for the forensic evaluation of gunshot wound victims. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant study and did not require informed consent of the next of kin. Thirteen consecutive male gunshot wound victims (mean age, 27 years) were scanned with 16-section multidetector CT prior to routine autopsy. Retrospectively, the total-body nonenhanced scans were interpreted at a three-dimensional workstation by radiologists blinded to autopsy findings. Images were evaluated for lethal wound, number and location of wound tracks, injured structures, and metal fragment location. After image review, autopsy reports and photographs were compared with the images and interpretations to validate the multidetector CT determinations. RESULTS: Multidetector CT aided in correct identification of all lethal wounds, and metallic fragment location was always precise. In four cases, multidetector CT aided in accurate assessment of organ injuries and lethal wounds but led to underestimation of the number of wounds if comingling paths occurred. In two cases of a chest wound, multidetector CT aided in accurate assessment of the chest as having the lethal wound but failed to help identify specific sites of hemorrhage. In two cases of craniofacial injury, the path of the wound was not clear. Autopsy revealed a total of 78 wound tracks (mean, 6; range, 1-24). Ten (13%) wound tracks were not identified at multidetector CT (six upper extremity wounds and four thigh wounds). In two cases, findings missed at autopsy (fracture of the cervical spine, bullet fragments in the posterior area of the neck) were identified at multidetector CT. CONCLUSION: Multidetector CT can aid prediction of lethal wounds and location of metallic fragments.

Venous thromboembolism among United States soldiers deployed to Southwest Asia.

INTRODUCTION: Military operations may represent a high-risk environment for venous thromboembolism (VTE). We sought to identify and describe cases of venous thromboembolism among US military personnel serving in Southwest Asia, and estimate relative disease rates compared to non-deployed personnel. MATERIALS AND METHODS: Retrospective review of imaging archives, hospital discharge codes, case logs and autopsy records for the diagnosis of deep vein thrombosis or pulmonary embolism occurring from 1 March 2003 through 29 February 2004 among U.S. military personnel deployed to Southwest Asia. Rates of disease in deployed and non-deployed active-duty soldiers were estimated using personnel data and deployment experience obtained from automated rosters. RESULTS: Forty cases of venous thromboembolism were identified. The case-fatality rate was 16% (3/19) among those with pulmonary embolism. Antecedent trauma followed by prolonged air evacuation was present in 55% (22/40). Compared to trauma-associated cases, non-trauma cases were more commonly over 40 years old (44% vs. 5%; p<0.05), assigned to a transportation or quartermaster company (56% vs. 14%; p<0.05), or had a history of remote venous thromboembolism (31% vs. 0%; p<0.05). The overall incidence among deployed active-duty soldiers was 22.1/100,000 person-years. Compared to non-deployed active-duty soldiers, the age-adjusted incidence rate ratio was 1.06 (CI(0.95) 0.68-1.67). CONCLUSIONS: VTE rates among deployed soldiers are relatively low compared to the general population, and are comparable to non-deployed soldiers. Fatalities from PE are not uncommon, and vigilance among clinicians remains warranted. Trauma followed by prolonged air evacuation or ground transport during military operations may represent unique interactive risk factors for venous thromboembolism.

Fatal meningitis in a previously healthy young adult caused by Streptococcus pneumoniae serotype 38: an emerging serotype?

BACKGROUND: In December 2001, a fatal case of pneumococcal meningitis in a Marine Corps recruit was identified. As pneumococcal vaccine usage in recruit populations is being considered, an investigation was initiated into the causative serotype. CASE PRESENTATION: Traditional and molecular methods were utilized to determine the serotype of the infecting pneumococcus. The pneumococcal isolate was identified as serotype 38 (PS38), a serotype not covered by current vaccine formulations. The global significance of this serotype was explored in the medical literature, and found to be a rare but recognized cause of carriage and invasive disease. CONCLUSION: The potential of PS38 to cause severe disease is documented in this report. Current literature does not support the hypothesis that this serotype is increasing in incidence. However, as we monitor the changing epidemiology of pneumococcal illness in the US in this conjugate era, PS38 might find a more prominent and concerning niche as a replacement serotype.

Sudden death in young adults: a 25-year review of autopsies in military recruits.

BACKGROUND: Sudden death among military recruits is a rare but devastating occurrence. Because extensive medical data are available on this cross-sectional and diverse population, identification of the underlying causes of sudden death may promote health care policy to reduce the incidence of sudden death. OBJECTIVE: To determine the causes of nontraumatic sudden death among a cohort of military recruits. DESIGN: Retrospective cohort study using demographic and autopsy data from the Department of Defense Recruit Mortality Registry. SETTING: Basic military training. PATIENTS: All nontraumatic sudden deaths from a monitored 6.3 million men and women age 18 to 35 years. MEASUREMENTS: Descriptive analysis, crude mortality rates of causes of sudden death, and frequency of events as a function of cause of death. RESULTS: Of 126 nontraumatic sudden deaths (rate, 13.0/100,000 recruit-years), 108 (86%) were related to exercise. The most common cause of sudden death was an identifiable cardiac abnormality (64 of 126 recruits [51%]); however, a substantial number of deaths remained unexplained (44 of 126 recruits [35%]). The predominant structural cardiac abnormalities were coronary artery abnormalities (39 of 64 recruits [61%]), myocarditis (13 of 64 recruits [20%]), and hypertrophic cardiomyopathy (8 of 64 recruits [13%]). An anomalous coronary artery accounted for one third (21 of 64 recruits) of the cases in this cohort, and, in each, the left coronary artery arose from the right (anterior) sinus of Valsalva, coursing between the pulmonary artery and aorta. LIMITATIONS: This cohort underwent a preenlistment screening program that included history and physical examination; this may have altered outcomes. CONCLUSIONS: Cardiac abnormalities are the leading identifiable cause of sudden death among military recruits; however, more than one third of sudden deaths remain unexplained after detailed medical investigation.