Sickle Cell Trait-Associated Deaths: A Case Series with a Review of the Literature*,†

Fatal Case of Exercise Collapse Associated with Sickle Cell Trait with Novel Underlying LAMA2 Mutation

ABSTRACT

Sickle cell trait is typically thought to be an asymptomatic carrier state, but it is rarely associated with exertional rhabdomyolysis in cases termed Exercise Collapse Associated with Sickle Cell Trait (ECAST). In a subset of these cases, underlying disease contributes to the development and/or severity of the ensuing medical complications. We describe the first ever case of ECAST reported in a previously asymptomatic, multiply deployed, highly physically active service member with an underlying heterozygous LAMA2 mutation. Moreover, the mutation identified via whole exome sequencing is a novel, likely pathogenic variant that has yet to be described in the literature.

Sudden Death in Diabetic Ketoacidosis Complicated by Sickle Cell Trait

ABSTRACT

In a sudden death investigation of a service member with sickle cell trait (SCT), evidence of sickle cell crisis further complicated by coexisting, undiagnosed diabetic ketoacidosis called into question the synergistic effects of diabetic ketoacidosis on red blood cell sickling. Sickle cell trait affects more than 4 million people in the United States (US) with the highest prevalence in non-Hispanic Blacks (7%-9%; Mil Med 2017;182(3):e1819-e1824). The heterozygous state of sickled hemoglobin was previously considered a benign condition causing sickling during hypoxic, high-stress conditions such as exercise and high altitude ( Am Assoc Clin Chem 2017). However, research within the last decade shows evidence of sudden death among SCT patients ( J Forensic Sci 2011;56(5):1352-1360). It has been shown that the presence of sickled hemoglobin artificially lowers levels of hemoglobin A1c making it a less effective biomarker for red blood cell glycosylation over time in sickle cell patients ( JAMA 2017;317(5):507-515). The limited scope of medical understanding of the effects of SCT in combination with other comorbidities requires further investigation and better diagnostic criteria. The uniqueness of the US Military and its screening program for sickle cell disease (SCD) and SCT allows for more detection. Since May 2006, newborn screening for SCD/SCT has been a national requirement; however, anyone older than 14 years may not know their SCD/SCT status ( Semin Perinatol 2010;34(2):134-44). The previous absence of such national screening makes it more challenging to identify SCT and SCD patients even within high-risk populations. Furthermore, patients may not know or understand the results of their SCD/SCT status testing. International standards for the autopsy of decedents with SCD and SCT exist ( R Coll Pathol 2017). Within the US, testing of vitreous electrolytes is a common practice in suspected natural death cases, but a review of the US literature did not demonstrate any autopsy standards or recommendations for persons with SCT or high-risk persons for sickling pathologies. The identification of a new diagnosis of type 2 diabetes mellitus, as the cause of death, is not uncommon; however, this case indicates that type 2 diabetes mellitus was not the sole contributing factor. It further illustrates that the US may be underestimating the impact of SCD and SCT as a cause of death, a contributing factor to death, and its synergistic effects with other pathologic processes. We propose a stringent literature review in conjunction with a review of international autopsy standards to develop national autopsy standards and possible SCT/SCD screening recommendations for high-risk persons at the time of autopsy.

Modifying priming techniques in cardiopulmonary bypass circuit in known case of sickle-cell trait undergoing open heart surgery

Modifying cardiopulmonary bypass (CPB) circuit’s priming technique before the onset of CPB in cardiac patients known with sickle-cell disease or sickle cell trait has been observed to be of substantial significance in dealing with such challenges without having any life-threatening consequences. We modified our routine heparinized crystalloid priming of the CPB circuit with partial exchange transfusion by adding donor blood (packed red blood cells), fresh frozen plasma (FFP), and bicarbonate. This has helped us bring down the overall sickle cell hemoglobin in the blood thereby reducing its risk of sickling.

Challenging the dogma of the healthy heterozygote: Implications for newborn screening policies and practices

Heterozygous (carrier) status for an autosomal recessive condition is traditionally considered to lack significance for an individual's health, but this assumption has been challenged by a growing body of evidence. Carriers of several autosomal recessive disorders and some X-linked diseases are potentially at risk for the pathology manifest in homozygotes. This minireview provides an overview of the literature regarding health risks to carriers of two common autosomal recessive conditions on the Recommended Uniform Screening Panel: sickle cell disease [sickle cell trait (SCT)] and cystic fibrosis (CF). We also consider and comment on bioethical and policy implications for newborn blood screening (NBS). Health risks for heterozygotes, while relatively low for individuals, are often influenced by intrinsic (e.g., other genomic variants or co-morbidities) and extrinsic (environmental) factors, which present opportunities for personalized genomic medicine and risk counseling. They create a special challenge, however, for developing screening/follow-up policies and for genetic counseling, particularly after identification and reporting of heterozygote status through NBS. Although more research is needed, this minireview of the SCT and CF literature to date leads us to propose that blanket terms such as "healthy heterozygotes" or "unaffected carriers" should be superseded in communications about NBS results, in favor of a more nuanced paradigm of setting expectations for health outcomes with "genotype-to-risk." In the molecular era of NBS, it remains clear that public health needs to become better prepared for the full range of applied genetics.

Fatal sickling-associated microvascular occlusive crisis in a young with sickle cell trait

Sickle cell trait (SCT), a heterozygous state characterized by hemoglobin AS, occurs commonly in sub-Saharan Africa, South America, Central America, India, and the Mediterranean countries. SCT is compatible with a normal lifespan and is not commonly regarded as a cause of morbid illness or death compared to its homozygous counterpart. We describe a case of fatal sickling-associated microvascular crisis, identified on post mortem evaluation in a previously undiagnosed 21-year-old military recruit with sickle cell trait. The individual presented with repeated syncope episodes during his training and was autopsied in the pursuit of cardiac anomalies and heat syncope. During the terminal episode, he collapsed and died of severe metabolic complications as he struggled to complete an organized run during routine training activities. To our knowledge, this is the first report of fatal sickling-associated crisis in a military recruit with sickle cell trait from India. This case serves to remind all armed forces and sports physicians of the importance of screening a recruit who is unable to complete exertional physical training for the presence of sickle cell trait.

Cardiovascular Screening in the U.S. Military: Time to Reconsider the Electrocardiogram

INTRODUCTION

The US Department of Defense (DoD) has adopted a model concept of the warrior athlete. Identifying latent disease that could compromise the military operator is critical to the warrior athlete concept. Cardiovascular complaints are the important problem recognized in service members evacuated from combat zones, and the incidence of sudden cardiac death in U.S. military recruits is comparable to or greater than that among National Collegiate Athletic Association Athletes. Nevertheless, the mandatory electrocardiogram (ECG) was removed from official U.S. military accession screening policy in 2002. Inclusion of ECG screening in high risk athletics is increasingly recognized as appropriate by professional organizations such as the American Heart Association and American Medical Society for Sports Medicine, though neither recommends ECG for generalized screening in large, low-risk populations.

MATERIALS AND METHODS

The appropriate DoD instructions were reviewed in the context of recent literature regarding the sensitivity and specificity of ECG screening for prevention of sudden cardiac arrest or debilitating arrhythmias.

RESULTS

Challenges to implementation of ECG as a screening modality in U.S. military accessions include clinician interpretation validity and reliability. Modern interpretation criteria and new interpretation technology each serve to mitigate these recognized limitations. Outside experience with implementation of modern ECG suggest potential benefits are significant in the highest risk military groups.

CONCLUSION

Prospective study of ECG screening is needed to determine the impact on cardiovascular outcomes in U.S. military populations.

Effect of Diabetes Mellitus on Sickle Hemoglobin Quantitation in Sickle Cell Trait

OBJECTIVES

We evaluated the effect of diabetes on sickle hemoglobin (HbS) measurement on two common clinical hemoglobin separation platforms.

METHODS

We performed a method comparison between the Bio-Rad Variant II high-performance liquid chromatography (HPLC) and Sebia Capillarys 2 Flex Piercing capillary electrophoresis (CE) using clinical specimens from 38 patients without hemoglobin variants and 57 patients with sickle cell trait (AS) (HbA1c%, 4.1%-15.4%). We investigated the effect of intermethod Hb% differences on result interpretation by a panel of expert clinical observers.

RESULTS

In diabetic specimens, HPLC undermeasured HbS% up to 7.4% vs CE, due to S1c eluting closely with A0 in HPLC. This increased concern for underlying α-thalassemia in diabetic patients with AS based on HPLC results. HPLC P2% was linearly related to HbA1c% and can be a screen for diabetic AS samples.

CONCLUSIONS

Glycosylation can interfere with HbS% measurement by HPLC. Susceptible specimens should be identified and preferentially analyzed via CE.

Sickle Cell Trait, Rhabdomyolysis, and Mortality among U.S. Army Soldiers

BACKGROUND

Studies have suggested that sickle cell trait elevates the risks of exertional rhabdomyolysis and death. We conducted a study of sickle cell trait in relation to these outcomes, controlling for known risk factors for exertional rhabdomyolysis, in a large population of active persons who had undergone laboratory tests for hemoglobin AS (HbAS) and who were subject to exertional-injury precautions.

METHODS

We used Cox proportional-hazards models to test whether the risks of exertional rhabdomyolysis and death varied according to sickle cell trait status among 47,944 black soldiers who had undergone testing for HbAS and who were on active duty in the U.S. Army between January 2011 and December 2014. We used the Stanford Military Data Repository, which contains comprehensive medical and administrative data on all active-duty soldiers.

RESULTS

There was no significant difference in the risk of death among soldiers with sickle cell trait, as compared with those without the trait (hazard ratio, 0.99; 95% confidence interval [CI], 0.46 to 2.13; P=0.97), but the trait was associated with a significantly higher adjusted risk of exertional rhabdomyolysis (hazard ratio, 1.54; 95% CI, 1.12 to 2.12; P=0.008). This effect was similar in magnitude to that associated with tobacco use, as compared with no use (hazard ratio, 1.54; 95% CI, 1.23 to 1.94; P<0.001), and to that associated with having a body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) of 30.0 or more, as compared with a BMI of less than 25.0 (hazard ratio, 1.39; 95% CI, 1.04 to 1.86; P=0.03). The effect was less than that associated with recent use of a statin, as compared with no use (hazard ratio, 2.89; 95% CI, 1.51 to 5.55; P=0.001), or an antipsychotic agent (hazard ratio, 3.02; 95% CI, 1.34 to 6.82; P=0.008).

CONCLUSIONS

Sickle cell trait was not associated with a higher risk of death than absence of the trait, but it was associated with a significantly higher risk of exertional rhabdomyolysis. (Funded by the National Heart, Lung, and Blood Institute and the Uniformed Services University of the Health Sciences.).

The Challenges and Opportunities Associated with Sickle Cell Disease Prevention, Education, and Management

Sickle cell disease (SCD) is a hereditary blood disorder affecting the shape of the red blood cells that block blood vessels leading to organ damage and frequent erratic painful episodes. SCD is a global public health issue affecting millions of people throughout the world. This article explores (a) what SCD is; (b) the physical and psychosocial impacts of the disease;

Diagnostic evaluation of rhabdomyolysis

Rhabdomyolysis is characterized by severe acute muscle injury resulting in muscle pain, weakness, and/or swelling with release of myofiber contents into the bloodstream. Symptoms develop over hours to days after an inciting factor and may be associated with dark pigmentation of the urine. Serum creatine kinase and urine myoglobin levels are markedly elevated. Clinical examination, history, laboratory studies, muscle biopsy, and genetic testing are useful tools for diagnosis of rhabdomyolysis, and they can help differentiate acquired from inherited causes of rhabdomyolysis. Acquired causes include substance abuse, medication or toxic exposures, electrolyte abnormalities, endocrine disturbances, and autoimmune myopathies. Inherited predisposition to rhabdomyolysis can occur with disorders of glycogen metabolism, fatty acid β-oxidation, and mitochondrial oxidative phosphorylation. Less common inherited causes of rhabdomyolysis include structural myopathies, channelopathies, and sickle-cell disease. This review focuses on the differentiation of acquired and inherited causes of rhabdomyolysis and proposes a practical diagnostic algorithm. Muscle Nerve 51: 793-810, 2015.

Sickle cell disease and venous thromboembolism in pregnancy and the puerperium

Recent data strongly suggest an increased risk of venous thromboembolism in subjects with sickle cell disease and to a lesser extent, sickle cell trait. However, most studies have been retrospective, case-control or cross-sectional based on data obtained from administrative databases. More data from adequately powered prospective studies that include matched controls are needed to definitely establish the link between venous thromboembolism during pregnancy and sickle hemoglobin disorders. Similarly, there remains a need for properly designed randomized control trials to establish the safety of various hormonal contraceptive methods in women with sickle cell disorders.

Sickle cell trait as a contributory cause of death in natural disease

Sickle cell trait (SCT) affects 300 million people globally, and awareness is growing that SCT is not an entirely benign condition; however, most reported cases have been non-natural deaths. Autopsy records from the Baylor University Medical Center (BUMC) in Dallas, Texas, contained seven natural deaths from January 2007 to October 2013 in which micro-occlusive sickling was identified at autopsy and SCT confirmed by postmortem hemoglobin fractionation. Sickle crisis was never diagnosed clinically. These cases illustrate the importance of red cell morphology in autopsy material. When sickling is suspected, hemoglobin fractionation should be performed. If confirmed, SCT should be listed as an autopsy finding and the severity and distribution of sickling documented. Extensive micro-occlusive sickling should be considered contributory to death; however, its relative importance depends on all facts of the case. Accurate reporting should facilitate further research and the development of evidence-based preventative and supportive strategies for these patients.

Exposures to conducted electrical weapons (including TASER® devices): how many and for how long are acceptable?

TASER(®) conducted electrical weapons (CEWs) are an important law-enforcement tool. The purposes of this study are a) to review recent literature regarding potential pathophysiological responses to applications of CEWs, and other related issues and b) to evaluate whether enough data exist to determine the acceptability of longer-duration (or repeated) exposures. This is a narrative review, using a multidisciplinary approach of analyzing reports from physiological, legal-medical, and police-strategy literature sources. In general, short-duration exposures to CEWs result in limited effects. Longer-duration or repeated exposures may be utilized with caution, although there are currently not enough data to determine the acceptability of all types of exposures. Data examined in the literature have inherent limitations. Appropriateness of specific types of CEW usage may be determined by individual police agencies, applying risk/benefit analyses unique to each organization. While more research is recommended, initial concepts of potential future long-duration or repeated CEW applications are presented.

Investigation of Sudden Death in Athletes: The Fittest Bodies in the Morgue

Sporting events are generally viewed as regulated activities with fit and healthy participants; therefore, when deaths occur, they draw considerable public interest. Athletic participants can be considered a vulnerable population based on inherent risks within certain sports and the associated physiologic stresses, which may complicate underlying medical conditions. Sudden deaths in young athletes participating in high school and collegiate organized sports occur at an average of four to six deaths per year; however, sudden deaths related to exercise outside of an organized sport setting remain unaccounted for in the overall prevalence of these deaths. A typical forensic pathology practice will see not only these higher-profile deaths occurring during an organized sporting event, but also lower-profile occurrences of individuals dying during more recreational or unstructured exercise. Sport-related deaths can essentially be categorized as those that occur due to dangers inherent in the sport itself, such as forms of heat-related illnesses, blunt force trauma, and water-related deaths, and those that occur due to susceptibilities of a given predisposed participant, including sickle cell trait, hypertrophic cardiomyopathy, and other cardiovascular diseases. This article will address both types of vulnerabilities and provide guidance for appropriate and specific medicolegal death investigation and autopsy procedures in these deaths.

Pediatric Natural Deaths

Autopsies are important in the investigation of childhood deaths. Most natural deaths are unlikely to come to the attention of the forensic pathologist, particularly in cases where death occurs in hospital. During the neonatal period (up to 28 days of age), deaths most commonly occur as a result of prematurity and related conditions, chromosomal abnormalities, or congenital malformations. Beyond the neonatal period, trauma-related deaths and sudden infant death syndrome are more common. In terms of natural acquired diseases of childhood, certain conditions are prevalent based on age and may be encountered at autopsy. Common acquired diseases that cause death in infants and children up to 5 years of age include pneumonia and other respiratory diseases, other infectious diseases, and malignancies. In older children, mortality due to natural disease declines substantially with trauma being the major cause of death, and malignancies the major cause of acquired disease. Sudden and/or unexpected deaths in which a natural disease state was previously unknown are most likely to come under the jurisdiction of the medical examiner or coroner and may be related to an underlying natural disease. Depending on the underlying disease process, the approach can differ, and therefore familiarity with common causes of death during childhood is important in order to focus the autopsy so that special techniques can be used along with obtaining proper ancillary testing to arrive at an accurate diagnosis and cause of death.

Sudden cardiac death in athletes: where do we stand

We aimed to review the literature to explore the magnitude of sudden cardiac death (SCD) in young athletes. Although SCD in athletes is not a common event, it represents a tragedy of the apparently fit young population. SCD varies according to countries, age groups, and sex. In addition, it varies in the underlying causes and the screening tool. Therefore, we are in need for further research efforts. Guidelines, public and physician awareness, and education regarding the warning signs are integral part in the strategy to reduce SCD tragedy. However, all these requirements raise concern for cost-effectiveness in some countries for proper implementation.

Sudden death in a case of sickle cell anemia: post-mortem computed tomography and autopsy correlation from a radiologist's perspective

Sickle cell anemia (SCA) is a hemolytic disease characterized by the production of abnormal hemoglobin chains and distorted red blood cell morphology or sickling. "Sickle cell crisis" includes vaso-occlusive crisis, a plastic crisis, sequestration crisis, haemolytic crisis and often culminating in serious complications, organ damage and even sudden death. Post-mortem computed tomography (PMCT) findings of sickle cell disease have never been reported in literature. This case of sudden death from acute hemolytic crisis in SCA where post-mortem computed tomography (PMCT) and autopsy findings complemented each other, both revealing findings invisible to the other and both crucial to the case.

Effort required to contact primary care providers after newborn screening identifies sickle cell trait

People with heterozygous status for sickle cell disease (also called sickle cell trait) are essentially healthy, but evidence of rare health problems has increased interest in screening adolescents and young adults prior to enlisting in athletics or military service. Ironically, almost everyone with sickle cell trait is already identified during routine newborn screening for sickle cell disease, but this identification may never reach the parents. As part of a larger statewide study of communication after newborn screening, we decided to document the amount of labor required to connect sickle cell trait screening results with primary care providers (PCPs). Case review methods examined records and call logs from the first 150 cases in a 42-month project. Our study procedures identified PCPs for 136 of 150 infants (90.6%); a total of 266 phone calls were needed. We identified 9 categories of experiences, ranging from incorrect baby names to restrictions on accepting Medicaid patients. Cases demonstrate that it is possible to connect with most PCPs after newborn screening despite warnings about difficulties with this population. Success was due to persistence, relationships with clinics and hospitals, and Internet search capabilities. If sickle cell trait identification is necessary to protect health, then only modest increases in effort will be needed to reduce disparities in service.

ACSM and CHAMP summit on sickle cell trait: mitigating risks for warfighters and athletes

INTRODUCTION

An estimated 300 million people worldwide have sickle cell trait (SCT). Although largely benign, SCT has been associated with exertional rhabdomyolysis and exercise-related sudden death in warfighters/athletes (WA). The National Collegiate Athletic Association's policy to confirm a student athlete's SCT status during their preparticipation medical examination prompted reaction from some organizations regarding the rationale and ethical justification of the policy.

METHODS

On September 26 and 27, 2011, a summit, composed of military and civilian experts in sports medicine and SCT, was convened at the Uniformed Services University in Bethesda, MD. The expert panel was charged with two objectives: 1) to provide specific recommendations to further mitigate the apparent risk with strenuous exercise in WA with SCT and 2) to develop clinical guidelines to identify, treat, and return to duty/play WA suspected to have incurred nonfatal sickle cell collapse.

RESULTS

New terminology is introduced, areas of current controversy are explored, consensus recommendations for mitigating risk and managing the WA with SCT are reviewed, and important areas for future research are identified.

CONCLUSION

Further research is needed before conclusions can be drawn regarding the etiology of the increased death rate observed in WA with SCT, and the possibility exists that SCT is a surrogate for as yet another contributing factor for the unexplained deaths.

Therapeutic plasmapheresis and red blood cell exchange in a sickle cell trait patient with rhabdomyolysis

We report a case of a 16-year-old African-American male with sickle cell trait and a past medical history significant for asthma that was transferred to our hospital for management of respiratory failure. On the fourth day of hospitalization, the patient was found to have increased creatine kinase (CK) levels and urine myoglobin levels consistent with rhabdomyolysis. No clear etiology was identified. Aggressive standard hydration and urine alkalization were applied without response. On the sixth day of hospitalization, the patient underwent a 1-1.5 plasma volume therapeutic plasma exchange (TPE) resulting in a transient reduction of serum CK and myoglobin by 50%, which became elevated once again within 4 h. Since his clinical presentation resembles exertional rhabdomyolysis documented in patients with sickle cell trait, RBC exchange was performed. The patient tolerated the procedure without complications. In addition to his improved overall condition, the patient's post-exchange CK and serum myoglobin levels dropped dramatically without rebound. To our knowledge, this case represents the first reported case of TPE followed by RBC exchange in a SCT patient with rhabdomyolysis.

Nucleation of sickle hemoglobin mixed with hemoglobin A: experimental and theoretical studies of hybrid-forming mixtures

Sickle hemoglobin (HbS) is a point mutation of the two β subunits in normal Hb (HbA) that leads to nucleated polymerization and accompanying pathology. We measured the rates of homogeneous and heterogeneous nucleation of HbS in the presence of up to 50% HbA under conditions in which hybrid HbAS molecules will also form. The replacement of 50% of HbS by HbA slows polymerization by factors of ∼100 in the physiological range, which is substantially less than previously thought. To provide a theoretical description of these data, we extended the double nucleation model for HbS polymerization to conditions in which hybridized mixtures are present. Measurements of homogeneous nucleation and the theory agree only when at least one of the molecules in the nucleus is not a hybrid. We attribute this to the necessary presence in the nucleus of a molecule that utilizes both β-subunit mutation sites in intermolecular contacts, whereas the remaining molecules engage only one of the mutation sites. Heterogeneous nucleation appears to require an even greater number of nonhybrid molecules, presumably because of the need for the nucleus to attach to the polymer as well as to form internal bonds. These results also provide insights into the pathophysiology of sickle cell disease, including the occasional severe events that strike persons in whom both HbS and HbA are expressed, a condition known as sickle trait. The studies reported here are necessary for understanding physiologically relevant polymerization in the presence of ligands as well as therapeutically relevant copolymerizing inhibitors.

Screening U.S. college athletes for their sickle cell disease carrier status

There are many issues surrounding the screening of collegiate athletes for their sickle cell disease carrier status (or sickle cell trait), a genetic condition. This paper summarizes the establishment of expert advice given to the Secretary's Advisory Committee on Heritable Disorders in Newborns and Children (SACHDNC) on the issue. The SACHDNC has developed a report to advise the Secretary of the USDHHS about the 2010 rule of the National Collegiate Athletic Association (NCAA) requiring testing for sickle cell trait in all incoming Division I student athletes. The SACHDNC does not support the NCAA's rule to screen collegiate athletes for sickle cell trait.