Mortality Rates and autopsy findings in fat embolism syndrome complicating sickle cell disease

Fat embolism syndrome is a rare but underdiagnosed complication of sickle cell disease associated with high morbidity and mortality. It affects predominantly patients with a previously mild course of their illness and those of non-SS genotypes while there is possibly an association with infection with human parvovirus B19 (HPV B19). Here, we present the mortality rates and autopsy findings of all reported cases to date. A systematic review has revealed 99 published cases in the world literature with a mortality rate of 46%. Mortality varied greatly according to the time of reported cases with no survivors in the 1940s, 1950s or 1960s and no deaths since 2020. 35% of cases had previously undiagnosed sickle cell disease and the latter was only identified at autopsy after developing fat embolism with a fatal outcome. 20% of cases reported after 1986 tested positive for HPV B19 with an associated mortality of 63% whereas in cases that have not documented HPV B19 infection the mortality was 32%. The organs most often staining positive for fat were the kidneys, lungs, brain and heart whereas ectopic haematopoietic tissue was found in 45% of the examined lung specimens.