Fat Embolism, Fat Embolism Syndrome and the Autopsy

Abstract

Fat embolism is common following trauma and is a common autopsy finding in these cases. It may also be seen in non-traumatic cases and is seen in children as well as adults. In comparison fat embolism syndrome (FES) only occurs in a small number of trauma and non-trauma cases. Clinical diagnosis is based on characteristic clinical and laboratory findings. Fat embolism exerts its effect by mechanical blockage of vessels and/or by biochemical means including breakdown of fat to free fatty acids causing an inflammatory response. Fat embolism can be identified at autopsy on microscopy of the lungs using fat stains conducted on frozen tissue, including on formalin fixed but not processed tissue. With FES fat emboli can be seen in other organs including the brain, kidney and myocardium. Fat can also be identified with post-fixation staining, typically with osmium tetroxide. Scoring systems have been developed to try and determine the severity of fat embolism in lung tissue. Fat embolism is also common following resuscitation. When no resuscitation has taken place, the presence of fat on lung histology has been used as proof of vitality. Diagnosis of fat embolism syndrome at autopsy requires analysis of the history, clinical and laboratory findings along with autopsy investigations to determine its relevance, but is an important diagnosis to make which is not always identified clinically. This paper reviews the history, clinical and laboratory findings and diagnosis of fat embolism and fat embolism syndrome at autopsy.

Post‐traumatic cerebral fat embolism syndrome with a favourable outcome: a case report

“…However, other possible causes include severe burns, infection, kidney transplant, liposuction, cardiopulmonary bypass, and transfusions. Some rare causes, such as gastrectomy or hepatocellular carcinoma, have also been reported [ 6 – 9 ]. The incidence of post-traumatic FES has been reported to be as low as 0.9–2.2 % in retrospective studies and as high as 35 % in prospective studies [ 10 – 12 ].…”

Transient cortical blindness due to cerebral fat embolism

“…It is also reported after spinal surgery, liposuction, severe pancreatitis, sickle cell disease, burns, cardiopulmonary bypass surgery, bone marrow harvesting, sternotomy, osteomyelitis, parenteral lipid infusion, tumor lysis syndrome, and fatty liver disease. [5] Systemic FES has a wide range of symptoms and signs. The diagnosis of FES is mainly clinical and is based on specific criteria.…”

Fatal Pulmonary Fat Embolism Occurring in Lumbar Spinal Fusion Surgery: Case Report and Review of Literature

“…FES may be induced by the presence of fat emboli or free lipid acids in the lung or circulatory system. Since the first case of fat embolism syndrome was described by Zenker [9] in 1862, cases of fat embolism have been reported and brought to clinical attention. However, the reported incidence of FES varies widely (1% to 29%) due to a number of factors, but is generally related to the severity of the trauma and the number of long tubular bone fractures.…”

“…Due to onset of FES, the mortality rate is as high as 10%~25%, especially the case fatality rate of fulminant patients can be higher than 50%. FES is not only the difficulty in clinical medical diagnosis and treatment, but also a difficulty in forensic medicine [1] . A large number of clinical studies and practices have demonstrated that FES is frequently discovered in bone trauma, especially in closed long bone fractures of lower limbs and in femur.…”