Splenic sequestration in the adult: cross sectional imaging appearance of an uncommon diagnosis

Acute splenic sequestration crisis, the sudden pooling of red blood cells in the spleen, is an emergent process typically seen in children with homozygous sickle cell disease. Splenic sequestration has rarely been reported in adults with heterozygous sickle cell conditions, including sickle cell beta(+)-thalassemia disease (HbS/β⁺-thalassemia). Here we present a case of a 32-year-old man with HbS/β⁺-thalassemia who suffered an acute splenic sequestration crisis. We review the CT and ultrasound appearance of splenic sequestration, which include splenic enlargement and an irregular rim of hypoenhancing or hypoechoic tissue at the periphery of the spleen, and discuss imaging differential considerations. To our knowledge, this is only the nineteenth case of acute splenic sequestration to be reported in an adult with HbS/β⁺-thalassemia in the English literature, and only the second case in which ultrasound findings are reported.

Versatile cell ablation tools and their applications to study loss of cell functions

Targeted cell ablation is a powerful approach for studying the role of specific cell populations in a variety of organotypic functions, including cell differentiation, and organ generation and regeneration. Emerging tools for permanently or conditionally ablating targeted cell populations and transiently inhibiting neuronal activities exhibit a diversity of application and utility. Each tool has distinct features, and none can be universally applied to study different cell types in various tissue compartments. Although these tools have been developed for over 30 years, they require additional improvement. Currently, there is no consensus on how to select the tools to answer the specific scientific questions of interest. Selecting the appropriate cell ablation technique to study the function of a targeted cell population is less straightforward than selecting the method to study a gene's functions. In this review, we discuss the features of the various tools for targeted cell ablation and provide recommendations for optimal application of specific approaches.

The critical roles of platelet activation and reduced NO bioavailability in fatal pulmonary arterial hypertension in a murine hemolysis model

Pulmonary arterial hypertension (PAH) is suspected to be a strong mortality determinant of hemolytic disorders. However, direct contribution of acute intravascular hemolysis to fatal PAH has not been investigated. The roles of nitric oxide (NO) insufficiency and platelet activation in hemolysis-associated fatal PAH have been suspected but not been experimentally studied. We recently generated a unique intravascular hemolysis mouse model in which the membrane toxin, intermedilysin (ILY), exclusively lyses the erythrocytes of transgenically expressing human CD59 mice (ThCD59(RBC)), thereby inducing ILY-dose-dependent massive hemolysis. Using this murine hemolysis model, we found that the acute increase in pulmonary arterial pressure leading to right ventricle failure caused sudden death. Reduced NO bioavailability and massive platelet activation/aggregation leading to the formation of massive thrombosis specifically in the pulmonary microvasculature played the critical roles in pathogenesis of acute hemolysis-associated fatal PAH. Therapeutic interventions enhancing NO bioactivity or inhibiting platelet activation prevented sudden death or prolonged survival time via the suppression of the acute increase in pulmonary arterial pressure and improvement of right ventricle function. These findings further highlight the importance of the inhibition of platelet activation and the enhancement of NO bioavailability for the treatment and prevention of hemolysis-associated (fatal) PAH.

Sickle cell disease: two fatalities due to bone marrow emboli in patients with acute chest syndrome

Acute chest syndrome (ACS) in patients with sickle cell disease (SCD) is a common complication contributing to death. ACS can present as sudden, unexpected death, and the medical history of SCD may not be immediately available for the medical examiner. Forensic implications for ACS are more likely to be encountered in patients with the HgbSC variant of SCD because the presence of a spleen may obscure recognition of SCD. Pathologists commonly observe small bone marrow emboli within the lung vasculature postmortem after trauma or vigorous cardiopulmonary resuscitation. Consequently, the finding of pulmonary marrow emboli in ACS may be dismissed as incidental and nonpathologic. Pulmonary marrow emboli cause ACS in patients with SCD, when there is parvoviral infection with marrow necrosis. Pulmonary marrow embolism in ACS has special significance in forensic pathology. Forensic pathologists investigate sudden, unexpected deaths during exertion, such as athletics, police pursuit, or military training. A causal relationship linking sickling hemoglobinopathy with physical exertion and sudden death has been reported. In the absence of a specific and timely medical history of SCD, and with a normal or enlarged spleen in patients with HgbSC, pathologists may wrongly dismiss bone marrow emboli as consequences of cardiopulmonary resuscitation, when those emboli might actually have been causative of fatal ACS.

Acute splenic sequestration crisis in an adult with sickle beta-thalassemia

Acute splenic sequestration crisis (ASSC) is a major cause of morbidity and mortality in children with sickle cell disease. Reports of ASSC in adults with sickle beta-thalassemia (S-beta(thal)) are rare and consist of isolated case reports comprising a total of seven patients, three of whom died during the crisis. We report a 22-year-old man with S-beta(thal) who developed ASSC 1 day after suffering multiple blunt trauma. Systemic inflammatory response to severe blunt trauma may have precipitated ASSC in our patient. ASSC in adults with S-beta(thal) is a potentially life-threatening complication with a high risk of recurrence. Splenectomy is recommended after the first attack of ASSC in adults with S-beta(thal).

Is there progress in the autopsy diagnosis of sudden unexpected death in adults?

Sudden death is now currently described as natural unexpected death occurring within 1h of new symptoms. Most studies on the subject focused on cardiac causes of death because most of the cases are related to cardiovascular disease, especially coronary artery disease. The incidence of sudden death varies largely as a function of coronary heart disease prevalence and is underestimated. Although cardiac causes are the leading cause of sudden death, the exact incidence of the other causes is not well established because in some countries, many sudden deaths are not autopsied. Many risk factors of sudden cardiac death are identified: age, gender, heredity factors such as malignant mutations, left ventricular hypertrophy and left ventricle function impairment. The role of the police surgeon in the investigation of sudden death is very important. This investigation requires the interrogation of witnesses and of the family members of the deceased. The interrogation of physicians of the rescue team who attempted resuscitation is also useful. Recent symptoms before death and past medical history must be searched. Other sudden deaths in the family must be noted. The distinction between sudden death at rest and during effort is very important because some lethal arrhythmia are triggered by catecholamines during stressful activity. The type of drugs taken by the deceased may indicate a particular disease linked with sudden death. Sudden death in the young always requires systematic forensic autopsy performed by at least one forensic pathologist. According to recent autopsy studies, coronary artery disease is still the major cause of death in people aged more than 35 years. Cardiomyopathies are more frequently encountered in people aged less than 35 years. The most frequent cardiomyopathy revealed by sudden death is now arrhythmogenic right ventricular cardiomyopathy also known simply as right ventricular cardiomyopathy (RVC). The postmortem diagnosis of cardiomyopathies is very important because the family of the deceased will need counseling and the first-degree relatives may undergo a possible screening to prevent other sudden deaths. In each case of sudden death, one important duty of the forensic pathologist is to inform the family of all autopsy results within 1 month after the autopsy. Most of the recent progress in autopsy diagnosis of sudden unexpected death in the adults comes from molecular biology, especially in case of sudden death without significant morphological anomalies. Searching mutations linked with functional cardiac pathology such as long-QT syndrome, Brugada syndrome or idiopathic ventricular fibrillation is now the best way in order to explain such sudden death. Moreover, new syndromes have been described by cardiologists, such as short-QT syndrome and revealed in some cases by a sudden death. Molecular biology is now needed when limits of morphological diagnosis have been reached.

Fatal Splenic Sequestration Crisis with Multiorgan Failure in an Adult Woman with Sickle Cell-Beta+ Thalassemia

Acute splenic sequestration crisis is a potentially fatal condition mostly seen in children with sickle cell anemia (HbSS) up to 6 years of age. Sickle cell-beta thalassemia has been associated with development of splenic sequestration crisis in rare reports. There have also been rare reports of the development of fatal acute splenic sequestration crisis together with severe multiorgan failure in adult patients with sickle cell-beta thalassemia. We describe a case of fatal splenic sequestration crisis together with multiorgan failure in a 34-year-old African-American woman with sickle cell-beta thalassemia syndrome.

Sickle cell trait and sudden death

All athletes who will be undergoing intense physical training need to be counseled about hydration, nutrition, and acclimatization. However, athletes with sickle cell trait are of greater concern and should be more carefully counseled. However, routine testing for sickle cell trait in athletes is not recommended. The results of a sickle cell screen are generally used for genetic counseling purposes only.