In the practice of forensic pathology, fat embolism is one of the common causes of death, which can be divided into two categories: traumatic and non-traumatic. Non-traumatic fat embolism refers to the blockage of small blood vessels by fat droplets in the circulatory blood flow caused by non-traumatic factors such as underlying diseases, stress, poisoning and lipid metabolism disorders. At present, it is believed that the production of non-traumatic fat embolism is related to the disturbance of lipid metabolism, C-reactive protein-related cascade reaction, the agglutination of chylomicron and very low-density lipoprotein. The forensic identification of the cause of death of non-traumatic fat embolism is mainly based on the case, systematic autopsy, HE staining and fat staining, but it is often missed or misdiagnosed by forensic examiners because of its unknown risk factors, hidden onset, the difficulty of HE staining observation and irregular implementation of fat staining. In view of the lack of attention to non-traumatic fat embolism in forensic identification, this paper reviews the concepts, pathophysiological mechanism, research progress, existing problems and countermeasures of non-traumatic fat embolism, providing reference for forensic scholars.
Autopsy ; Embolism, Fat/pathology* ; Forensic Medicine ; Forensic Pathology ; Humans ; Pulmonary Embolism/pathology*

This study was done to demonstrate the computed tomography (CT) and pathologic findings of the sequential changes for experimental pulmonary fat embolism (PFE), and to correlate the CT and pathologic findings of rabbit lung. PFE was induced by an intravenous injection of 0.2 mL linoleic acid in 24 rabbits. The rabbits were divided into 4 groups of 6 rabbits each. CT scans were obtained sequentially at 2 hr (n= 24), day 1 (n=18), day 3 (n=12) and day 7 (n=6) after fat embolization. The pathologic findings were analyzed and CT-pathologic correlation was done. CT scans showed bilateral ground-glass opacity (GGO), consolidation and nodule in all cases. The findings of PFE at 2 hr after fat embolization were areas of decreased attenuation, GGO, consolidation and nodule. These findings were aggravated on the follow- up CT after 1 day and 3 days. The follow-up CT revealed linear density in the subpleural lungs after 7 days. On CT-pathology correlation, wedge-shaped ischemic necrosis in the subpleural lungs correlated with nodule at 2 hr. GGO and consolidation at day 1 on CT correlated with congestion and edema, and these findings at day 3 were correlated with inflammation and hemorrhagic edema. The linear density in the subpleural lungs correlated with interstitial fibrosis and pleural contraction at day 7. In conclusion, PFE was caused by using linoleic acid which is kind of free fatty acid and this study served as one model of the occurrence of nontraumatic PFE. CT accurately depicted the natural evolution of PFE in the serial followup, and this correlated well with the pathologic findings.
Animals ; Embolism, Fat/*pathology/*radiography ; Pulmonary Embolism/*pathology/*radiography ; Rabbits ; *Tomography, X-Ray Computed

PURPOSE: Fat embolism syndrome is caused by traumatic and nontraumatic conditions, and most commonly associated with fractures of long bones of the lower extremity. Clinical manifestation of the fat embolism syndrome occurs in a minority of patients with fat emboli. The incidence of fat emboilsm has been reported 5-10%. The pulmonary symptoms of fat embolism are clinically important but hard to diagnose, so treatment was often delayed. The purpose of this study is to search for the development of fat embolism after long bone fracture of rabbit, and to demonstrate pulmonary fat embolism by high resolution computerized tomograhy (HRCT) and pathologic findings. MATERIALS AND METHODS: Twelve rabbits (Newzealand, 2.5-3 Kg) were divided into 2, 24, 72 hours and control groups after closed tibiofibular fracture. The presence of involvement was classified by high resolution computerized tomography with ground glass opacity, consolidation and focal hyperlucency. The extent was measured by 10% grading scale. Gross inspection, histologic examination and histochemistry (Oil red 0) were performed in removed lungs. RESULTS: Ground glass opacity was found in 100% of test subjects, consolidation was found in 89%, bronchovascular bundle thickening was found in 78% and focal hyperlucency was found in 33%. Fat embolism was developed in all groups with the 24-hour group showing maximal changes. Microscopically the vessel was occluded with fat globule which was stained with Oil red 0 stain. CONCLUSIONS: The abnormal density lesion on HRCT was correlated with pathologic finding and was induced by fat emboli after long bone fracture of the rabbit
Embolism, Fat* ; Fractures, Bone* ; Glass ; Humans ; Incidence ; Lower Extremity ; Lung ; Pathology ; Rabbits

A 23-year-old Indian man presented with shortness of breath and new-onset confusion along with a rash on his chest on Postoperative Day 2, following internal fixation of his femur fracture. Although computed tomography pulmonary angiography was negative for filling defects in the pulmonary vasculature, it showed mosaic attenuation changes with some interlobular septal thickening. Magnetic resonance imaging of the brain showed patchy signal abnormalities, predominantly in the grey-white matter junction region with extensive susceptibility artefacts, consistent with petechial haemorrhages. The laboratory work-up showed thrombocytopenia and anaemia. A diagnosis of fat embolism syndrome was established, based on the clinical presentation combined with laboratory and imaging findings. The clinical and imaging features of fat embolism syndrome are discussed.
Brain ; pathology ; Dyspnea ; Embolism, Fat ; diagnostic imaging ; Femoral Fractures ; diagnostic imaging ; Humans ; Hypoxia ; India ; Magnetic Resonance Imaging ; Male ; Pulmonary Embolism ; Thrombocytopenia ; Tomography, X-Ray Computed ; Young Adult

Pulmonary fat embolism (PFE) and pulmonary thromboembolism (PTE) are common post-operative complications of orthopedic surgical procedures, but are reported less often following maxillofacial plastic surgical procedures, especially with respect to PFE. Thrombi, or together with fat emboli in pulmonary vessels can induce hemorrhagic infarction and cause death. Herein this report introduced a death due to pulmonary hemorrhagic infarction following maxillofacial plastic surgery. The female patient underwent several osteotomies of the mandible, zygomas and autologous bone grafting within a single operation. The operative time was longer than normal and no preventive strategies for pulmonary embolism were implemented. The patient died 20 days after hospital discharge. The autopsy confirmed pulmonary hemorrhagic infarction. The fat emboli and thrombi were also noted in the pulmonary vessels, which were thought to have resulted from the maxillofacial osteotomy. Suggestions were offered to forensic pathologists that risk factors of PFE and PTE, such as the type and length of surgery, the surgical sites, and the preventive strategies, should be considered when handling deaths after maxillofacial operations.
Adult ; Autopsy ; Cause of Death ; Embolism, Fat/complications* ; Fatal Outcome ; Female ; Forensic Pathology ; Humans ; Infarction/etiology* ; Maxillary Osteotomy ; Postoperative Complications ; Pulmonary Embolism/complications* ; Surgery, Plastic/adverse effects* ; Thromboembolism/complications*

OBJECTIVE: To analyze the general and forensic pathological characteristics of death due to fat embolism syndrome (FES) and to provide reference data for forensic identification. METHODS: Twenty autopsy cases due to FES were selected from the forensic center of a medical college from 1999 to 2012. The general and forensic pathological characteristics such as the ways and types of injuries, clinical manifestation and the pathological changes were summarized. RESULTS: Fat embolism mainly occurred after long bone fracture or a large area of soft tissue injury with the majority of cases being fat embolism of lung and occasional cases being combined embolisms of lung and brain as well. The onset of symptoms appeared shortly after the injury or surgery. Lipid droplets could be observed within small pulmonary vessels and verified by special staining. CONCLUSION There are particular characteristics in death due to FES in concern with types of injuries, onset of symptoms and pathological findings. In order to find out the direct evidence of FES, special staining (oil red O staining) can be used in the forensic identification.
Autopsy ; Cause of Death ; Death ; Embolism, Fat/mortality* ; Forensic Pathology ; Fractures, Bone/complications* ; Humans ; Male ; Middle Aged ; Pulmonary Embolism/etiology* ; Soft Tissue Injuries/complications*

Adult ; Aged ; Aged, 80 and over ; Embolism, Fat ; diagnosis ; drug therapy ; pathology ; Female ; Humans ; Male ; Middle Aged ; Treatment Outcome

OBJECTIVE: To explore ultra-structural changes of fat embolism syndrome (FES) in the lung. METHODS: Fat embolism animal model was developed by fat intravascular injection to the experimental rabbits. The rabbits were sacrificed after thrombosis immediately (0 h), 3 h, 8 h and 1 d, 2 d, 7 d, 14 d after thrombosis, respectively. Rabbits were injected with the same dose of saline in the control group. All experimental procedures were same in experimental and control groups. The animal model of fat embolism was validated using HE and Sudan III staining. Ultra-structural changes of lung were observed by using transmission electron microscopy. RESULTS: Ultra-structural changes in capillaries and small blood vessels were found in experimental group. Type II alveolar cells, related cells and organelles showed time-dependent changes. Lipid drops and inflammatory cells were not found in control group. Lamellar body did not show emptying phenomenon and the amount of lamellar body was normal. CONCLUSION The study could provide the theoretical principle for fat embolism casesin forensic pathology.
Animals ; Capillaries/ultrastructure* ; Disease Models, Animal ; Embolism, Fat/pathology* ; Epithelial Cells/pathology* ; Forensic Pathology ; Lung/ultrastructure* ; Microscopy, Electron, Transmission ; Pulmonary Embolism/pathology* ; Rabbits ; Staining and Labeling ; Time Factors ; Wounds and Injuries/complications*

Fat embolism syndrome (FES) is a common and life-threatening clinical syndrome, which is a difficult problem frequently encountered in medical science, especially in forensic medicine and orthopaedics. FES would be easily mistaken or missed by forensic examiner due to the lack of the specific symptoms and signs. This article reviews the etiology, pathogenesis, pathology, the mechanism of death, as well as the advances of the forensic medicine diagnosis of FES with current literatures update.
Animals ; Disease Models, Animal ; Embolism, Fat/pathology* ; Forensic Pathology ; Fractures, Bone/complications* ; Humans ; Prognosis ; Rats ; Retrospective Studies ; Syndrome ; Wounds and Injuries/complications*