Fat Embolism Syndrome

Pulmonary CT imaging findings in fat embolism syndrome: case series and literature review

BACKGROUND

Fat embolism syndrome (FES) is a rare life-threatening complication, which commonly affects the lung. Currently, the most widely accepted criteria for the diagnosis of FES are the Gurd and Wilson Criteria established nearly 40 years ago, but without pulmonary images involved. Our study aims to analyse the pulmonary computed tomography (CT) findings seen in FES.

CASE PRESENTATION

This report enrolled four cases of FES with lung involvement. The mainly symptoms and signs included dyspnea, disturbance of consciousness, anemia, thrombocytopenia and, most notably, ground-glass opacities, septal thickening, ill-defined centrilobular nodules, and patchy consolidation were demonstrated on bilateral lungs. Combining the clinical manifestations and laboratory tests, the diagnosis of FES was confirmed. With the treatment of steroids, anti-coagulation and supportive treatment, the four patients' symptoms were relieved, abnormalities in chest CT were absorbed significantly and the patients were finally discharged.

CONCLUSIONS

There are several common manifestations of FES in pulmonary CT images, and the lung parenchymal features give more information for the diagnosis of FES than the pulmonary vessel findings. Given the absence of a gold standard diagnostic test for FES, further investigation to explore new diagnostic criteria of FES involving pulmonary radiological features is needed in the future.

Pathologic mechanism of hidden blood loss after total knee arthroplasty: oxidative stress induced by free fatty acids

BACKGROUND

Hidden blood loss (HBL) often occurs after joint replacement; however, the mechanism of HBL is not clear. We conducted a prospective study to analyze the correlation between high-level free fatty acids (FFA) and erythrocyte injury, and explore the pathologic mechanism of hidden blood loss (HBL) after total knee arthroplasty (TKA).

METHODS

Perioperative blood indexes were tested in 120 patients who underwent unilateral total knee replacement for end-stage knee osteoarthritis. The changes in FFA, reactive oxygen species (ROS), hemoglobin (Hb), and red blood cells (RBC) in the blood samples were detected. The activity of glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD) and hydrogen peroxide (H₂O₂) levels were measured. Morphologic changes of blood cells were analyzed under a microscope.

RESULTS

HBL occurred in all patients after TKA. The Hb and RBC decreased significantly 24 h after surgery (P <0.05), while FFA and ROS concentration were substantially elevated, and heteromorphic red blood cells appeared under the microscope. The hemoglobin content decreased to its lowest level at 48 h after the operation (P<0.01). With the increase of FFA and ROS levels, HBL appeared more obvious (P<0.01). GSH-PX activity, T-SOD activity, and H₂O₂ levels significantly decreased compared to preoperative tested samples (P<0.01). Microscopically, atypical erythrocytes increased significantly with cellular rupture and lysis identified.

CONCLUSIONS

High levels of FFA in blood can induce oxidative stress and damage red blood cells, leading to the occurrence of HBL after surgery.

TRIAL REGISTRATION

Chinese Clinical Trials Registry (the trial number: ChiCTR17010681, URL: http://www.chictr.org.cn).

A Rare Case of Cerebral Fat Embolism With No Respiratory or Dermatologic Involvement

Fat embolism syndrome is potentially lethal. It is frequently a complication of long bone fractures and/or orthopedic surgery. Cerebral fat embolism is an unusual condition characterized by purely cerebral involvement. Neurological signs can be variable and brain MRI has a pivotal role in the diagnosis. We report the case of a 69-year-old male who presented motor impairment and a disorder of consciousness in the early postoperative course of total hip arthroplasty for a left femoral neck fracture, which occurred 24 hours before surgery. He had no dermatologic or respiratory signs. No respiratory or dermatologic signs were found. Blood samples showed moderate thrombopenia and hemolytic anemia. Multiple lesions were found on brain MRI. Diagnosis of cerebral fat embolism was established after ruling out differentials.

Superior Ophthalmic Vein Embolism Following Forehead Augmentation with Autologous Fat Injection

Background

Facial rejuvenation and reconstruction with autologous fat injection are a common and effective procedure used worldwide. Most surgeons and patients are satisfied with the favorable outcomes. However, catastrophic complications from arterial and venous occlusion resulting in visual loss and stroke may occur.

Case presentation

We herein report a case of isolated venous occlusion from fat embolism. The patient developed acute painful proptosis and blurred vision of her right eye while undergoing an esthetic autologous fat injection into her forehead. Based on her clinical manifestations and radiologic findings, the patient was diagnosed with superior ophthalmic vein occlusion. Symptomatic and supportive treatments were given. Spontaneous clinical improvement occurred without secondary complications. Therefore, the initially planned endovascular therapy with transfemoral transvenous embolectomy of the right superior ophthalmic vein was canceled.

Conclusions

Facial augmentation with autologous fat injection can cause superior ophthalmic vein embolism. Surgeons should therefore perform this procedure very cautiously. Prompt ophthalmological evaluation and proper management are important for improving clinical outcomes.

Level of Evidence V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Physical and Chemical Compatibility of Etomidate and Propofol Injectable Emulsions

INTRODUCTION

The mixture of etomidate and propofol is widely used in clinical practice to improve efficacy of general anesthesia and to minimize side effects. As a thermodynamically unstable system, emulsion is prone to destabilization through mechanisms including coalescence, flocculation, and creaming. Such unwanted phenomenon can induce fat embolism after intravenous administration. This study was aimed to investigate the physical and chemical stability of the mixture of etomidate and propofol in the dosage form of emulsion.

METHODS

This compatibility study focused on the critical quality attributes (CQAs) of drug-containing emulsions, such as appearance, pH, particle size and distribution, zeta potential, the observation under centrifugation, and drug content and impurity.

RESULTS

As the results, there were no significant changes in the CQAs of the mixed emulsions up to 24 h after mixing at refrigeration temperature (4°C), room temperature (25°C), and body temperature (37°C).

CONCLUSIONS

These results demonstrate that etomidate emulsion is physically and chemically compatible with propofol emulsions up to 24 h at 4°C, 25°C, and 37°C, suggesting that etomidate and propofol can be administrated in mixture without adversely affecting product characteristics, at least in vitro.

[Cerebral fat embolism syndrome after polytrauma : Complication after fracture treatment of several long bones of the lower extremities]

In consequence of a car accident a 20-year-old woman with bilateral fractures of the femur and an unilateral lower leg fracture was treated with external fixation. Afterwards she was soporific with signs of impaired consciousness and required intubation and intensive medical care surveillance. A cerebral fat embolism syndrome could be detected as the reason, which was characterized by acute respiratory insufficiency, neurological symptoms and petechiae. Subsequently, definitive treatment was performed by intramedullary nailing. After neurological and orthopedic rehabilitation no performance inhibiting limitations remained.

Nontraumatic Multiple-Organ Fat Embolism: An Autopsy Case and Review of Literature

The patient was an 88-year-old woman with a 10-year history of hypertension. She was suspected to have been hit by a car. At the time of the event, she was conscious and able to stand on her own and had no obvious injuries. She was sent home, but she lapsed into unconsciousness and was nonresponsive after 2 hours. She was sent to the hospital, and her heartbeat and breathing stopped. After half an hour of rescue attempts, her heartbeat did not recover, and she was declared dead. During the autopsy, a small subcutaneous hemorrhage was observed below the right knee joint. No obvious internal organ injuries or bone fractures were observed. The deceased also had mild atherosclerosis in the coronary arteries and an old cerebral infarction in the right cerebellum. The tissue histopathological tests showed distinct fat embolism in multiple organs, including the brain, lungs, kidneys, liver, and pancreas. A postmortem blood biochemistry test of the heart blood showed that the levels of low-density lipoprotein, cholesterol, triglycerides, and free fatty acids in the blood were increased, and the level of C-reactive protein was elevated. According to the autopsy results, the direct cause of death was multiorgan fat embolism. This case suggests that aging, hypertension, and hyperlipidemia may be risk factors for nontraumatic fat embolism under stressful conditions.

COVID-19 mimics on chest CT: a pictorial review and radiologic guide

Chest imaging is often used as a complementary tool in the evaluation of coronavirus disease 2019 (COVID-19) patients, helping physicians to augment their clinical suspicion. Despite not being diagnostic for COVID-19, chest CT may help clinicians to isolate high suspicion patients with suggestive imaging findings. However, COVID-19 findings on CT are also common to other pulmonary infections and non-infectious diseases, and radiologists and point-of-care physicians should be aware of possible mimickers. This state-of-the-art review goal is to summarize and illustrate possible etiologies that may have a similar pattern on chest CT as COVID-19. The review encompasses both infectious etiologies, such as non-COVID viral pneumonia, Mycoplasma pneumoniae, Pneumocystis jiroveci, and pulmonary granulomatous infectious, and non-infectious disorders, such as pulmonary embolism, fat embolism, cryptogenic organizing pneumonia, non-specific interstitial pneumonia, desquamative interstitial pneumonia, and acute and chronic eosinophilic pneumonia.

Fat embolism syndrome in blunt trauma patients with extremity fractures

OBJECTIVE

This study sought to provide a national, descriptive analysis to determine fat embolism syndrome (FES) risk factors, hypothesizing that femur fractures and multiple fractures are associated with an increased risk.

METHODS

The Trauma Quality Improvement Program was queried (2010-2016) for patients with extremity fractures. A multivariable logistic regression analysis model was used.

RESULTS

From 324,165 patients, 116 patients (0.04%) were diagnosed with FES. An age ≤30, closed femur fracture, and multiple long bone fractures were associated with an increased risk of FES.

CONCLUSION

Future research to validate these findings and develop a clinical risk stratification tool appears warranted.

Clinical significance of increased peripheral venous blood adipocyte-specific protein FABP4 after joint replacement

A new method of diagnosing fat embolism (FE) at the molecular level was proposed, and the diagnostic value of adipocyte-specific protein fatty acid-binding protein 4 (Homo sapiens [human]) gene ID = 2167 (FABP4) for FE was preliminarily explored. Eight joint replacement patients, 5 internal medicine patients, and 6 healthy persons were recruited. Serum of internal medicine patients, healthy people, and patients before and 24 hours after joint replacement were taken as study samples. Subcutaneous adipose, intra-articular adipose and intramedullary yellow bone marrow of patients undergoing joint replacement were taken as study samples. The level of FABP4 in the above samples was detected by enzyme-linked immunoassay. Normal distribution was tested. Paired sample T test was used for self-control. Univariate analysis of variance was used for multigroup comparison.There was no significant difference in serum FABP4 level between healthy persons, medical patients, and preoperative patients. The FABP4 level in yellow bone marrow and subcutaneous adipose was significantly higher than that in serum of healthy people, medical patients, and preoperative patients. FABP4 level in the serum after joint replacement was significantly higher than that before joint replacement. FABP4 may be a specific indicator of FE diagnosis, but further studies are needed to confirm its clinical value.