Fat embolism syndrome: State-of-the-art review focused on pulmonary imaging findings

Fat embolism: the hidden murder for trauma patients!

INTRODUCTION

fat embolism syndrome (FES) is an acute respiratory disorder that occurs when an inflammatory response causes the embolization of fat and marrow particles into the bloodstream. The exact incidence of FES is not well defined due to the difficulty of diagnosis. FES is mostly associated with isolated long bone trauma, and it is usually misdiagnosed in other trauma cases. The scope of this study was to identify and search the current literature for cases of FES in nonorthopedic trauma patients with the aim of defining the etiology, incidence, and main clinical manifestations.

METHODS

we perform a literature search via the PubMed journal to find, summarize, and incorporate reports of fat embolisms in patients presenting with non-orthopedic trauma.

RESULTS

the final literature search yielded 23 papers of patients presenting with fat embolism/FES due to non-orthopedic trauma. The presentation and etiology of these fat embolisms is varied and complex, differing from patient to patient. In this review, we highlight the importance of maintaining a clinical suspicion of FES within the trauma and critical care community.

CONCLUSION

to help trauma surgeons and clinicians identify FES cases in trauma patients who do not present with long bone fracture, we also present the main clinical signs of FES as well as the possible treatment and prevention options.

CT pulmonary arteriogram diagnosis of macroscopic fat embolism to the lung

Pulmonary fat embolism (PFE) is a recognised complication of long bone fractures. The majority of cases represent microscopic embolism and are not detectable at CT pulmonary arteriography (CTPA). CT can be used to detect macroscopic fat based on Hounsfield attenuation. This case describes a case of macroscopic fat embolism to the pulmonary arteries which was confidently diagnosed at CTPA. Distinction from thromboembolism is important as treatment is supportive and may avoid risks of anticoagulation.

Femoral Nailing in a Porcine Model Causes Bone Marrow Emboli in the Lungs and Systemic Emboli in the Heart and Brain

Background

Shaft fractures of the femur are commonly treated with intramedullary nailing, which can release bone marrow emboli into the bloodstream. Emboli can travel to the lungs, impairing gas exchange and causing inflammation. Occasionally, emboli traverse from the pulmonary to the systemic circulation, hindering perfusion and resulting in injuries such as heart and brain infarctions, known as fat embolism syndrome. We studied the extent of systemic bone marrow embolization in a pig model.

Methods

Twelve anesthetized pigs underwent bilateral intramedullary nailing of the femur, while 3 animals served as sham controls. Monitoring included transesophageal echocardiography (TEE), pulse oximetry, electrocardiography, arterial blood pressure measurement, and blood gas and troponin-I analysis. After surgery, animals were monitored for 240 minutes before euthanasia. Post mortem, the heart, lungs, and brain were biopsied.

Results

Bone marrow emboli were found in the heart and lungs of all 12 of the pigs that underwent intramedullary nailing and in the brains of 11 of them. No emboli were found in the sham group. The pigs subjected to intramedullary nailing exhibited significant hypoxia (PaO2/FiO2 ratio, 410 mm Hg [95% confidence interval (CI), 310 to 510) compared with the sham group (594 mm Hg [95% CI, 528 to 660]). The nailing group exhibited ST-segment alterations consistent with myocardial ischemia and a significant increase in the troponin-I level compared with the sham group (1,580 ng/L [95% CI, 0 to 3,456] versus 241 ng/L [95% CI, 0 to 625] at the 240-minute time point; p = 0.005). TEE detected emboli in the right ventricular outflow tract, but not systemically, in the nailing group.

Conclusions

Bilateral intramedullary nailing caused bone marrow emboli in the lungs and systemic emboli in the heart and brain in this pig model. The observed clinical manifestations were consistent with coronary and pulmonary emboli. TEE detected pulmonary but not systemic embolization.

Clinical Relevance

Femoral intramedullary nailing in humans is likely to result in embolization as described in our pig model. Focused monitoring is necessary for detection of fat embolism syndrome. Absence of visual emboli in the left ventricle on TEE does not exclude the occurrence of systemic bone marrow emboli.

A 68-Year-Old Patient With Dyspnea and Hypoxemia After Total Hip Arthroplasty

CASE PRESENTATION

A 68-year-old patient with obesity (BMI, 4 7 kg/m2) was transferred to the ED of our hospital because of dyspnea and pronounced hypoxemia. The patient underwent total right hip arthroplasty in an outside hospital because of osteoarthritis; there was no history of trauma. After 48 h, she experienced dyspnea with severe hypoxemia. The next day she was transferred to our hospital. Her history was notable for arterial hypertension and depression, but not heart failure. Her medications included candesartan (16 mg once daily) and sertraline (100 mg once daily). Perioperatively, she received enoxaparin 4.000 International Units subcutaneously once daily. There was no family history of respiratory diseases. The patient currently smokes (50 pack-years) with no recent increase in her habit and denied vaping, alcohol consumption, illicit drug use, and any home or occupational exposures. Prior to surgery, the family of the patient reported that she maintained modest mobility despite her osteoarthritis and was able to fulfill her daily activities. Interestingly, she reported a similar event of severe dyspnea and hypoxemia after total knee arthroplasty 3 years earlier; however, no further details were available.

Fat Embolism: A Rare Complication of Bone Biopsy

We report a woman who was admitted to the hospital with a sudden onset of extensive maculopapular erythematous rash involving the trunk and extremities, six weeks after initiating antihypertensive medication. She had atypical lymphocytosis with Gumprecht shadows, elevated liver enzymes, and acute kidney injury. The diagnosis of drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome secondary to antihypertensive drugs was suspected and the antihypertensive drugs were suspended. A hypothesis of lymphoproliferative disease was also considered, and consequently, a myelogram and bone biopsy of the iliac crest were performed. After the procedure, the patient developed acute hypoxemia. After the exclusion of pulmonary thromboembolism by CT angiography, we assumed a presumptive diagnosis of iatrogenic fat embolism syndrome (FES) associated with bone biopsy. The patient deteriorated with worsening hypoxemia and ultimately died. This case represented a diagnostic challenge and highlighted iatrogenesis's undesirable and potentially fatal effects. Careful consideration of the risk-benefit ratio of all medical procedures is paramount in daily medical practice and knowledge of the possible risks is necessary for their early recognition and therapeutic approach.

Fat Pulmonary Embolism With Crazy-Paving Pattern Opacities and Pneumothorax: A Rare Complication of Liposuction

Fat embolism syndrome (FES) is a rare multiorgan disease caused by microvascular obstruction by fat globules and free fatty acid-mediated endothelial injury leading to pro-inflammatory cytokine release. We present a rare case of a 54-year-old woman who underwent elective aesthetic liposuction and developed FES and pneumothorax within 12 hours of the procedure.

Rare case of pulmonary fat embolism and acute respiratory distress syndrome after liposuction and fat grafting: a case report

Background

Pulmonary fat embolism usually occurs after fracture, yet rarely observed after liposuction and fat grafting.

Case presentation

We describe a 19-year-old female patient who presented with acute respiratory failure and diffuse pulmonary opacities on chest radiographic image shortly after liposuction and fat grafting. Bronchoalveolar lavage was performed and lipid content in alveolar cells contribute to the diagnosis of the fat embolism syndrome. The patient was successfully treated with noninvasive mechanical ventilation and a short course of glucocorticoids.

Conclusions

Early recognition and appropriate treatment are very important to improve the outcome of pulmonary fat embolism. Considering that liposuction and fat grafting are increasingly common cosmetic surgeries, our aim is to raise awareness for this rare adverse event.

Pulmonary Fat Embolism Following Liposuction and Fat Grafting: A Review of Published Cases

BACKGROUND

One of the most severe complications of liposuction and fat grafting is pulmonary fat embolism (PFE). However, most healthcare workers are not familiar with PFE. We performed a systematic review to describe the details of PFE.

METHODS

PubMed, EMBASE, and Google Scholar were searched up to October 2022. Further analysis focused on clinical, diagnostic, and outcome parameters.

RESULTS

A total of 40 patients from 19 countries were included. Chest computed tomography (CT) yielded 100% accuracy in the diagnosis of PFE. More than 90% of the deceased died within 5 days after surgery, and in 69% of patients, onset of symptoms occurred within 24 h after surgery. The proportions of patients who required mechanical ventilation, had a cardiac arrest event, or died among all patients and among those whose onset of symptoms occurred within 24 h after surgery were 76%, 38%, and 34% versus 86%, 56%, and 54%, respectively.

CONCLUSIONS

The earlier the onset of symptoms was, the more severe the clinical course was. Once a patient presents with PFE-related symptoms, surgery should be halted, supportive care initiated, and chest CT used to diagnose PFE. According to our review results, if a patient with PFE survives the initial episode without permanent sequelae, a complete recovery can be anticipated.

Fat Embolism Syndrome After Knee Arthroscopy in a Pediatric Patient

Fat embolism syndrome describes a constellation of symptoms that follow an insult and that results in a triad of respiratory distress, neurologic symptoms, and petechia. The antecedent insult usually entails trauma or orthopedic procedure, most frequently involving long bone (especially the femur) and pelvic fractures. The underlying mechanism of injury remains unknown but entails biphasic vascular injury with vascular obstruction from fat emboli followed by an inflammatory response. We present an unusual case of a pediatric patient with acute onset of altered mental status, respiratory distress, hypoxemia, and subsequent retinal vascular occlusions after knee arthroscopy and lysis of adhesions. Diagnostic findings most supportive of the fat embolism syndrome included anemia, thrombocytopenia, pulmonary parenchymal, and cerebral pathologic findings on imaging studies. This case highlights the importance of fat embolism syndrome as a diagnostic consideration after an orthopedic procedure, even absent major trauma or long bone fracture.

Multisystemic involvement of post-traumatic fat embolism at a Pediatric Trauma Center: a clinical series and literature review

Post-traumatic fat embolism syndrome (FES) is a severe complication consequent to bone fractures. The authors describe its clinical features and management in a population of teenagers by detailing demographics, organ involvement, laboratory, and imaging findings, as well as outcome. Moreover, a systematic review of pediatric published case reports of post-traumatic FES is provided. First, a series of eight episodes of post-traumatic FES that occurred in seven patients (median age 16.0 years, IQR 16.0-17.5) admitted to a pediatric intensive care unit (PICU) in an 8-year period was analyzed through a retrospective chart review. Secondly, a systematic research was performed on PUBMED database. Trauma patients ≤ 18 years without comorbidities in a 20-year period (2002-2022) were included in the review. Neurological impairment was present in five out of seven patients, and a patent foramen ovale was found in four cases. Hemodynamic instability requiring vasoactive drugs was recorded in four patients. A severe form of acute respiratory distress syndrome (ARDS) occurred in five cases, with the evidence of hemorrhagic alveolitis in three of them. In the literature review, eighteen cases were examined. Most cases refer to adolescents (median age 17.0 years). More than half of patients experienced two or more long bone fractures (median: 2 fractures). Both respiratory and neurological impairment were common (77.8% and 83.3%, respectively). 88.9% of patients underwent invasive mechanical ventilation and 33.3% of them required vasoactive drugs support. Neurological sequelae were reported in 22.2% of patients.

CONCLUSION

Post-traumatic FES is an uncommon multi-faceted condition even in pediatric trauma patients, requiring a high level of suspicion. Prognosis of patients who receive prompt support in an intensive care setting is generally favorable.

WHAT IS KNOWN

•Post-traumatic fat embolism syndrome is a severe condition complicating long bone or pelvic fractures. •Little is known about clinical features and management in pediatric age.

WHAT IS NEW

•Post-traumatic fat embolism syndrome can cause multiple organ failure, often requiring an intensive care management. •Prompt supportive care contributes to a favorable prognosis.

Fat in the brain: Facts and features

The presence of fat within a lesion in the brain is not only easy to identify on both CT/MRI but also can help narrow the differential. The purpose of this paper is to illustrate the spectrum of common and rare fat-containing lesions in the brain that are encountered in clinical practice. This paper intends to discuss 15 such lesions which are confirmed by MRI findings and histopathological correlation. We divided the spectrum of fat-containing lesions into lesions with adipose cells, lesions with cholesterol-rich content and tumours with lipomatous differentiation/transformation. Knowledge of these common and rare fat-containing lesions is essential for making the right diagnosis or narrowing the differential diagnosis.

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.

Use of Point-of-Care Ultrasound and Focus-Assessed Transthoracic Echocardiography to Diagnose Acute Right Heart Failure Due to Fat Emboli in a Parturient

Fat embolism syndrome (FES), causing right heart dysfunction, is a rare disease that is often difficult to diagnose with imaging modalities such as computed tomography (CT). FES is the clinical presentation that follows the entry of fat globules into the systemic circulation, which typically results in respiratory failure, scattered petechiae, cardiovascular collapse, and neurological sequelae. It is mostly observed in the cases of orthopedic trauma but may occur in any circumstance where fat can enter the circulatory system. In this case report, the authors describe an atypical presentation of FES in a 24-week parturient. The use of bedside point-of-care ultrasonography (POCUS) and the focus-assessed transthoracic echocardiography (FATE) protocol aided in the prompt diagnosis of right heart failure and helped to confirm the diagnosis of FES with more advanced imaging technology.

Fat Embolism Syndrome and in-Hospital Mortality Rates According to Patient Age: A Large Nationwide Retrospective Study

Introduction

Fat embolism syndrome (FES) is a rare life-threatening condition that can develop after traumatic orthopedic injuries. Controversy remains concerning the epidemiology in the elderly population. Therefore, this study aims to report FES related to in-hospital mortality stratified by age.

Methods

A retrospective trauma cohort study was conducted using data from the National Trauma Data Bank (NTDB) from 2007 to 2014. All FES cases were included in the study with the diagnosis of FES (ICD9 958.1). Death on arrival cases were excluded. Patients were stratified by age cohort: less than 40 (G1), 40–64 (G2), and greater than 65 (G3) years of age. The primary outcome evaluated was in-hospital mortality. Multivariable regression models were performed to adjust for potential confounders.

Results

Between 2007 and 2014, 451 people from a total of 5,836,499 trauma patients in the NTDB met the inclusion criteria. The incidence rate was 8 out of 100,000. The inpatient mortality rate was 11.8% for all subjects with the highest mortality rate of 17.6% in patients over 65. Multivariable analyses demonstrated that age greater than 65 years was an independent predictor of mortality (aOR 24.16, 95% CI 3.73, 156.59, p=0.001), despite higher incidence and injury severity of FES among patients less than 40. No significant association with length of hospital stay, length of intensive unit care, or length of ventilation use was found between the groups. Subgroup analysis of the elderly population also showed a higher mortality rate for FES in femoral neck fracture patients (18%) than other femoral fractures (14%).

Conclusion

In this retrospective cohort analysis, old age (≥ 65 years) was found to be an independent risk factor for in-hospital mortality among fat embolism syndrome patients. Elderly patients specifically with femoral neck fractures should be monitored for the development of FES.

Fat embolism syndrome in patients with bilateral femur fractures: a systematic review and case comparison

Objectives:

Fat embolism and fat embolism syndrome (FES) remain common complications following long bone fractures. Incidence is highest after bilateral femur fractures. We performed a systematic review of FES after bilateral femur fractures and present two cases.

Data sources:

Systematic literature search of the Cochrane, EMBASE, MEDLINE, Scopus, and, Web of Science Library databases was performed in August 2021. Terms used including plural and alternate spellings: “fat embolism,”“fat embolism syndrome,”“fat embolus,” and “bilateral femur fracture.” Articles in German and English were considered. No time frame was applied.

Study selection:

Original studies, case series and case reports on fat embolism after bilateral femur fracture were included. Insufficient documentation or patients with relevant previous heath conditions were excluded.

Data extraction:

Abstracts were organized using EndNote X9 by Carivate. Three authors independently screened the abstracts; cross check of the extracted data was performed by the senior author.

Data synthesis:

Scarcity of articles only allowed for a qualitative synthesis. Data was compared with our cases and situated within the scientific background.

Results:

Ten articles were included for qualitative synthesis (n = 144 patients). The symptoms were inhomogeneous with neurological deficits being most prominent. Degree of displacement was high, when reported. Although the modes and timing of surgery varied, this appeared unrelated with outcome.

Conclusions:

FES remains a relevant complication after bilateral femur fractures, despite damage control strategies and improved reaming techniques. Fracture displacement and reduction maneuvers might play a more substantial role in the formation than previously accredited.

Level of evidence:

4

Fat embolism syndrome in a patient with a right undisplaced femoral neck fracture

Fat embolism syndrome (FES) is a rare condition characterised by the classic triad of respiratory distress, neurologic symptoms and petechial rash. Here, we encountered a case of FES in a patient with an asymptomatic right undisplaced femoral neck fracture (Garden Stage II). FES was diagnosed based on the Gurd and Willson's diagnostic criteria and brain magnetic resonance imaging features. To the best of our knowledge, this is the first case of FES in a patient with an undisplaced femoral neck fracture. This study highlights the importance of considering the possibility of FES even in patients with undisplaced femoral neck fractures.

A case of diffuse alveolar hemorrhage secondary to fat embolism after long bone fracture

Fat embolism syndrome (FES) is a known complication of long bone fractures, frequently presenting with hypoxemia. Diffuse alveolar hemorrhage (DAH) is a rare complication of the condition. Imaging characteristics are frequently non-specific to FES, as are findings on bronchoalveolar lavage. No specific treatment exists, though steroids and albumin can be considered. We present the case of an 18 year old male who presented to the emergency room after a motorcycle collision. His CXR was initially clear, but he developed pulmonary infiltrates, a new oxygen requirement, and hemoptysis. Bronchoscopy confirmed DAH by serial lavage, and BAL was notable for abundant lipid-laden macrophages by Oil-red-O stain. He improved with methylprednisolone and albumin. This case highlights the need for a high index of suspicion both for FES, and for DAH as a complication that may develop days after trauma. We review treatment paradigm for this serious condition.

Subacute fat embolism syndrome in a young female trauma patient during COVID-19

We report the symptom evolution of a young female trauma patient leading to a diagnosis of fat embolism syndrome (FES). Twenty-four hours post-trauma she developed respiratory distress, followed by transient neurological compromise and later petechia. The subtle and fluctuating nature of her presentation made the diagnosis via existing clinical criteria challenging, as did the lack of specificity of thoracic computerized tomography due to the concurrent coronavirus (COVID-19) pandemic. Making the diagnosis was important as it changed the patient's management, likely preventing a diagnosis in extremis. This case emphasizes the importance of maintaining a high clinical suspicion of FES in any (poly)trauma patient. This is especially true during COVID-19, as correctly identifying non-COVID-19 causes of respiratory failure will prevent additional pandemic victims. In addition, this case supports the need for a diagnostic approach that balances clinical, biochemical and imaging features and takes a cumulative approach in order to identify subacute FES.

Radiological features of pulmonary fat embolism in trauma patients: a case series

PURPOSE

Fat embolism syndrome (FES) is a rare complication in trauma patients (usually with long bone fractures) in which migrating medullary fat precipitates multiorgan dysfunction, classically presenting with dyspnoea, petechiae and neurocognitive dysfunction. Although this triad of symptoms is rare, it nonetheless aids diagnosis of pulmonary fat embolism (PuFE). Typical imaging features of PuFE are not established, although increasing use of CT pulmonary angiography (CTPA) in this cohort may provide important diagnostic information. We therefore conducted a case series of FES patients with CTPA imaging at a Level 1 Trauma Centre in Melbourne, Australia.

METHODS

Medical records and various radiological investigations including CTPA of consecutive patients diagnosed clinically with FES between 2006 and 2018, including demographics, injury and their progress during their admission, were reviewed.

RESULTS

Fifteen FES patients with retrievable CTPAs were included (mean age 31.2 years, range 17-69; 12 males [80%]). 93.3% had long bone fractures. CTPA was performed 2.00 ± 1.41 days post-admission. Review of these images showed pulmonary opacity in 14 (93.3%; ground-glass opacities in 9 [64.3%], alveolar opacities in 6 [42.9%]), interlobular septal thickening in 10 (66.7%), and pleural effusions in 7 (46.7%). Filling defects were identified in three (20%) CTPAs, with density measuring - 20HU to + 63HU. Ten patients (66.7%) had neuroimaging performed, with two patients demonstrating imaging findings consistent with cerebral fat emboli.

CONCLUSION

CTPA features of PuFE are variable, with ground-glass parenchymal changes and septal thickening most commonly seen. Filling defects were uncommon.

Incidence of Fat Embolism Syndrome in Femur Fractures and Its Associated Risk Factors over Time-A Systematic Review

BACKGROUND

Fat embolism (FE) continues to be mentioned as a substantial complication following acute femur fractures. The aim of this systematic review was to test the hypotheses that the incidence of fat embolism syndrome (FES) has decreased since its description and that specific injury patterns predispose to its development.

MATERIALS AND METHODS

Data Sources: MEDLINE, Embase, PubMed, and Cochrane Central Register of Controlled Trials databases were searched for articles from 1 January 1960 to 31 December 2019.

STUDY SELECTION

Original articles that provide information on the rate of FES, associated femoral injury patterns, and therapeutic and diagnostic recommendations were included.

DATA EXTRACTION

Two authors independently extracted data using a predesigned form.

STATISTICS

Three different periods were separated based on the diagnostic and treatment changes: Group 1: 1 January 1960-12 December 1979, Group 2: 1 January 1980-1 December 1999, and Group 3: 1 January 2000-31 December 2019, chi-square test, χ² test for group comparisons of categorical variables, p-value < 0.05.

RESULTS

Fifteen articles were included (n = 3095 patients). The incidence of FES decreased over time (Group 1: 7.9%, Group 2: 4.8%, and Group 3: 1.7% (p < 0.001)). FES rate according to injury pattern: unilateral high-energy fractures (2.9%) had a significantly lower FES rate than pathological fractures (3.3%) and bilateral high-energy fractures (4.6%) (p < 0.001).

CONCLUSIONS

There has been a significant decrease in the incidence of FES over time. The injury pattern impacts the frequency of FES. The diagnostic and therapeutic approach to FES remains highly heterogenic to this day.

Cerebral fat embolism after traumatic bone fractures: a structured literature review and analysis of published case reports

Background

The incidence of cerebral fat embolism (CFE) ranges from 0.9–11%, with a mean mortality rate of around 10%. Although no univocal explanation has been identified for the resulting fat embolism syndrome (FES), two hypotheses are widely thought: the ‘mechanical theory’, and the ‘chemical theory’. The present article provides a systematic review of published case reports of FES following a bone fracture.

Methods

We searched MEDLINE, Web of Science and Scopus to find any article related to FES. Inclusion criteria were: trauma patients; age ≥ 18 years; and the clinical diagnosis of CFE or FES. Studies were excluded if the bone fracture site was not specified.

Results

One hundred and seventy studies were included (268 cases). The male gender was most prominent (81.6% vs. 18.4%). The average age was 33 years (±18). The mean age for males (29 ± 14) was significantly lower than for females (51 ± 26) (p < 0.001). The femur was the most common fracture site (71% of cases). PFO was found in 12% of all cases. Univariate and multivariate regression analyses showed the male gender to be a risk factor for FES: RR 1.87 and 1.41, respectively (95%CI 1.27–2.48, p < 0.001; 95%CI 0.48–2.34, p < 0.001).

Conclusions

FES is most frequent in young men in the third decades of life following multiple leg fractures. FES may be more frequent after a burst fracture. The presence of PFO may be responsible for the acute presentation of cerebral embolisms, whereas FES is mostly delayed by 48–72 h.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-021-00861-x.

Fat Embolism Syndrome - A Qualitative Review of its Incidence, Presentation, Pathogenesis and Management

Fat Embolism Syndrome (FES) is a poorly defined clinical phenomenon which has been attributed to fat emboli entering the circulation. It is common, and its clinical presentation may be either subtle or dramatic and life threatening. This is a review of the history, causes, pathophysiology, presentation, diagnosis and management of FES. FES mostly occurs secondary to orthopaedic trauma; it is less frequently associated with other traumatic and atraumatic conditions. There is no single test for diagnosing FES. Diagnosis of FES is often missed due to its subclinical presentation and/or confounding injuries in more severely injured patients. FES is most frequently diagnosed using the Gurd and Wilson criteria, like its rivals it is not clinically validated. Although FES is a multi-system condition, its effects in the lung, brain, cardiovascular system and skin cause most morbidity. FES is mostly a self-limiting condition and treatment is supportive in nature. Many treatments have been trialled, most notably corticosteroids and heparin, however no validated treatment has been established.

Postoperative complications of concomitant fat embolism syndrome, pulmonary embolism and tympanic membrane perforation after tibiofibular fracture: A case report

BACKGROUND

Fat embolism syndrome (FES) is a rare disease characterized by pulmonary distress, neurologic symptoms, and petechial rash and seriously threatens human life and health. It is still neglected clinically because of the lack of verifiable diagnostic criteria and atypical clinical symptoms. No studies on FES with pulmonary embolism (PE) and tympanic membrane perforation have been reported to date. Here, we report a rare case of concomitant FES, PE and tympanic membrane perforation after surgery in a patient with a tibiofibular fracture.

CASE SUMMARY

A 39-year-old man presented with right lower extremity pain due to a car accident while driving a motorbike on the road. X-ray and computed tomography scans revealed a fracture of the right mid-shaft tibia and proximal fibula categorized as a type A2 fracture according to the AO classification. A successful minimally invasive operation was performed 3 d after the injury. Postoperatively, the patient developed sudden symptoms of respiratory distress and hearing loss. Early diagnosis was made, and supportive treatments were used at the early stage of FES. Seven days after surgery, he presented a clear recovery from respiratory symptoms. The outcome of fracture healing was excellent, and his hearing of the left ear was mildly impaired at the last follow-up of 4 mo.

CONCLUSION

Concomitant FES, PE and tympanic membrane perforation are very rare but represent potentially fatal complications of trauma or orthopedic surgery and present with predominantly pulmonary symptoms. Early diagnosis and treatment can reduce the mortality of FES, and prevention is better than a cure.

Clinical Characteristics of Transarterial Chemoembolization in Treatment of Primary Hepatocellular Carcinoma Complicated With Respiratory Distress Syndrome

Objective:

The present study aims to analyze the clinical characteristics and etiology of transarterial chemoembolization (TACE) in the treatment of hepatocellular carcinoma (HCC) complicated with acute respiratory distress syndrome (ARDS), in order to improve the early diagnosis rate and cure rate.

Methods:

A total of 816 patients with primary HCC received 2,200 TACE treatments from January 2014 to May 2018. Among these patients, 6 patients developed ARDS after TACE. The clinical data, lesion characteristics, laboratory tests, treatment process and prognosis of 6 patients were retrospectively analyzed.

Results:

The longest lesion diameter ranged within 5.0-10.2 cm (mean: 6.6 cm) in the 6 patients with primary HCC. Among these patients, 4 patients had lesions mainly located in the left lateral lobe of the liver, while 5 patients had no hepatic arteriovenous fistula detected before TACE. Nedaplatin, epirubicin and iodinated oil suspension chemoembolization were used in all 6 patients during TACE, and all of them experienced ARDS symptoms within 24-48 hours after TACE. However, no clear pathogenic bacteria were incubated in the sputum culture after the onset of the disease. Diffused exudative changes of both lungs were found in the chest X-ray, and the oxygenation index (PaO₂/FiO₂) was within 100-300 mmHg. The symptoms of 6 patients improved after 3-6 days of hormone therapy.

Conclusion:

In this study, we found that although the incidence of ARDS after TACE was low in the treatment for HCC, the symptoms after onset were serious, and the early hormone therapy may be beneficial to improve the prognosis and reduce mortality. Further research with larger samples is still needed to confirm the pathogenesis of ARDS after TACE in the treatment for HCC.

Use of chest CT-scan images to differentiate between SARS-CoV-2 infection and fat embolism: A clinical case

The authors present the case of a young man victim of a traffic accident during the SARS-CoV-2 confinement, having presented a fracture of the femoral shaft that was soon complicated by respiratory failure with oxygen desaturation. In this pandemic context, Covid-19 RT-PCR tests were carried out but returned negative. The CT images could suggest either a fatty embolism, a SARS-CoV-2 infection or both. The patient's condition improved significantly after going into intensive care and only symptomatic treatment. This case demonstrates the difficulty of differential interpretation of CT images between fatty embolism and SARS-CoV-2 infection.

Posttraumatic subarachnoid fat embolism: Case presentation and literature review

Fat embolism in the subarachnoid space has a unique pathophysiology and clinical picture when compared to fat embolism syndrome. Lipid deposits in the subarachnoid space-most commonly the sequela of dermoid rupture in the neuraxis-can cause an inflammatory reaction leading to irritation of nearby neurovascular structures. Herein, we report the only case in the United States, to our knowledge, of a patient diagnosed with subarachnoid fat emboli secondary to sacral fracture who initially presented with a normal head CT and subsequently developed visual changes.

Imaging findings of pulmonary edema: Part 2. Infrequent or unusual pulmonary edema with definitive imaging findings

Pulmonary edema is a common condition with numerous causes, some of which are infrequently encountered. This review article describes various uncommon conditions/disease that are associated with pulmonary edema and which show characteristic imaging findings on chest computed tomography or other imaging modality. Thus, this review reflects the variety of factors involved in this frequently encountered condition. We demonstrate the wide range of situations that lead to the development of pulmonary edema by showing the imaging findings of unique cases. These rare varieties of pulmonary edema have distinctive imaging and clinical features that aid in providing an accurate diagnosis.

A young adult with post-traumatic breathlessness, unconsciousness and rash

A 23-year-old Bangladeshi male was referred to our hospital for gradual worsening of breathlessness over 3 h, developed following a road-accident about 14 h previously. He had a close fracture of mid-shaft of his right tibia, which was immobilised with back slab at the previous healthcare facility. During presentation at the emergency department, he was conscious and oriented (Glasgow coma scale 15/15), tachycardic (heart rate 132 per min), blood pressure 100/70 mmHg, tachypnoeic (respiratory rate 34 per min) with oxygen saturation 89% on room air, and afebrile. Chest examination revealed restricted chest movement, hyper-resonant percussion notes and reduced breath sound on the left, and diffuse crackles on both sides.

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Macro Fat Embolism After Gluteal Augmentation With Fat: First Survival Case Report

Gluteal augmentation with fat has become one of the most common cosmetic procedures worldwide. Gluteal augmentation is designed to increase the volume and contour of the gluteal region. Intramuscular lipoinjection has been linked to multiple reports of severe complications, including death due to macro fat embolism (MAFE). The authors present the first reported case of survival and successful recovery after MAFE secondary to gluteal augmentation with fat. A 41-year-old woman, ASA II, was scheduled for augmentation mammaplasty, liposuction, and gluteal augmentation with fat. The patient was operated under general anesthesia with a total intravenous anesthesia technique. A total of 3.5 liters of fat was liposuctioned with no complications. The patient was then positioned in a lateral decubitus position for gluteal augmentation with fat. Right after the last injection, the anesthesiologist noticed a sudden change in capnography followed by hypotension, bradycardia, and hypoxemia. The first reaction in the operating room was to consider that the patient was experiencing a severe episode of fat embolism. She was then resuscitated and transferred to a tertiary facility for intensive care management. To our knowledge, this is the first case report of successful resuscitation in a patient experiencing severe MAFE after gluteal augmentation with fat. We believe that this patient survived the event due to early detection, aggressive management, and proper transfer to an intensive care unit. Level of Evidence: 5.

Postmortem CT and MRI findings of massive fat embolism

OBJECTIVE

To elucidate postmortem computed tomography (PMCT) and postmortem magnetic resonance (PMMR) imaging findings suggesting massive fat embolism.

MATERIALS AND METHODS

Consecutive forensic cases with PMCT and PMMR scans of subjects prior to autopsy were assessed. For PMCT, 16- or 64-row multidetector CT scans were used; for PMMR, a 1.5 T system was used. MRI sequences of the chest area included T2- and T1-weighted fast spin-echo imaging, T2*-weighted imaging, T1-weighted 3-dimensional gradient-echo imaging with or without a fat-suppression pulse, short tau inversion recovery, and in-phase/opposed-phase imaging. At autopsy, forensic pathologists checked for pulmonary fat embolism with fat staining; Falzi's grading system was used for classification.

RESULTS

Of 31 subjects, four were excluded because fat staining for histopathological examination of the lung tissue could not be performed. In three of the remaining 27 subjects, histology revealed massive fat embolism (Falzi grade III) and the cause of death was considered to be associated with fat embolism. CT detected a "fat-fluid level" in the right heart or intraluminal fat in the pulmonary arterial branches in two subjects. MRI detected these findings more clearly in both subjects. In one subject, CT and MRI were both negative. There were no positive findings in the 24 subjects that were fat embolism-negative by histology.

DISCUSSION AND CONCLUSION

In some subjects, a massive fat embolism can be suggested by postmortem imaging with a "fat-fluid level" in the right heart or intraluminal fat in the pulmonary arterial branches. PMMR potentially suggests fat embolism more clearly than PMCT.

Clinical characteristics and management of patients with fat embolism syndrome in level I Apex Trauma Centre

PURPOSE

Fat embolism syndrome (FES) is systemic manifestation of fat emboli in the circulation seen mostly after long bone fractures. FES is considered a lethal complication of trauma. There are various case reports and series describing FES. Here we describe the clinical characteristics, management in ICU and outcome of these patients in level I trauma center in a span of 6 months.

METHODS

In this prospective study, analysis of all the patients with FES admitted in our polytrauma intensive care unit (ICU) of level I trauma center over a period of 6 months (from August 2017 to January 2018) was done. Demographic data, clinical features, management in ICU and outcome were analyzed.

RESULTS

We admitted 10 cases of FES. The mean age of patients was 31.2 years. The mean duration from time of injury to onset of symptoms was 56 h. All patients presented with hypoxemia and petechiae but central nervous system symptoms were present in 70% of patients. The mean duration of mechanical ventilation was 11.7 days and the mean length of ICU stay was 14.7 days. There was excellent recovery among patients with no neurological deficit.

CONCLUSION

FES is considered a lethal complication of trauma but timely management can result in favorable outcome. FES can occur even after fixation of the fracture. Hypoxia is the most common and earliest feature of FES followed by CNS manifestations. Any patient presenting with such symptoms should raise the suspicion of FES and mandate early ICU referral.

Fat Embolism and Fat Embolism Syndrome

Fat embolism (FE) occurs frequently after trauma and during orthopaedic procedures involving manipulation of intramedullary contents. Classically characterized as a triad of pulmonary distress, neurologic symptoms, and petechial rash, the clinical entity of FE syndrome is much less common. Both mechanical and biochemical pathophysiologic theories have been proposed with contributions of vascular obstruction and the inflammatory response to embolized fat and trauma. Recent studies have described the relationship of embolized marrow fat with deep venous thrombosis and postsurgical cognitive decline, but without clear treatment strategies. Because treatment is primarily supportive, our focus must be on prevention. In trauma, early fracture stabilization decreases the rate of FE syndrome; however, questions remain regarding the effect of reaming and management of bilateral femur fractures. In arthroplasty, computer navigation and alternative cementation techniques decrease fat embolization, although the clinical implications of these techniques are currently unclear, illustrating the need for ongoing education and research with an aim toward prevention.

Approaching pulmonary fat embolism on postmortem computed tomography

PURPOSE

Pulmonary fat embolism (PFE) is a relevant diagnosis playing a role as a sign of vitality or a cause of death. Its severity is assessed according to histological grading systems like that of Falzi. The aim of this study was to determine the utility of unenhanced postmortem computed tomography (PMCT) for PFE diagnosis based on the detection of fat layers.

METHODS

Consecutive cases with PMCT and autopsy were studied retrospectively. The case group consisted of cases with positive PFE, and the control group included cases with negative PFE. Three observers independently assessed PMCT data for fat layers in the pulmonary trunk and the right and left pulmonary artery. For cases with fat layers, autopsy protocols were assessed for the cause of death, relation to trauma, and undertaken resuscitation measures.

RESULTS

Eight hundred thirty cases were included: 366 PFE positive cases (144 of Falzi grade 1, 63 of 1.5, 99 of 2, 28 of 2.5, and 32 of 3) and 464 PFE negative cases. Interrater reliabilities varied between substantial and almost perfect, and discrepancies were solved according to majority. Eighteen cases showed fat layers on PMCT (2 controls-traumatic instantaneous deaths-, 16 PFE positive cases). PMCT showed low sensitivity but high specificity for PFE diagnosis. The layers were located at the same position in the pulmonary trunk directly adjacent to the pulmonary valve distal to the right ventricle.

CONCLUSION

Fat layer on PMCT is a rare finding but relates to PFE diagnosis, especially of severe histological grade. It is to be expected in a typical position within the pulmonary trunk.

Fat Embolism Syndrome

Fat embolisms are fat globules that enter the circulatory system, typically through trauma, that may or may not lead to the development of fat embolism syndrome (FES), a rare and ill-defined diagnosis that can cause multiorgan failure and death. The exact mechanism of FES remains unknown, although several theories support the involvement of inflammatory response activation that contributes to characteristic clinical findings. There is no gold standard for diagnosis of FES, and treatment at this time remains primarily supportive. Early recognition of FES symptoms is the most beneficial nursing intervention for combating this serious disorder.

Clinics in diagnostic imaging (184). Fat embolism syndrome (FES)

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.

Syndrome d’embolie graisseuse cérébrale post-traumatique

Le syndrome d’embolie graisseuse post-traumatique symptomatique est une complication rare et grave de fracture des os longs ou de polytraumatisme. L’expression typique de ce syndrome est respiratoire, neurologique et cutanée, associée à un certain nombre d’anomalies biologiques, consécutives à la dissémination de particules graisseuses dans la circulation, l’évolution est la plupart du temps favorable sans séquelle.

Fulminant Cerebral Fat Embolism: Case Description and Review of the Literature

The release of fat and bone marrow fragments is a common occurrence following traumatic and nontraumatic events. In most cases, they go symptomless or cause only minor disturbances, but occasionally they can determine a multiorgan dysfunction whose severity ranges from mild to fatal. The authors describe the case of a patient who became deeply comatose and ultimately died after a traffic accident in which he suffered the exposed right femoral and tibial fracture in the absence of other injuries. He underwent the external fixation of the fractured bones 2 hours after the admission under general anesthesia. Three hours later, he failed to awake at the suspension of the anesthetic agents and became anisocoric; a CT scan demonstrated a diffuse cerebral edema with the herniation of the cerebellar tonsils; these abnormalities were unresponsive to the treatment and the brain death was one day later. The causes, the mechanisms, the symptoms, the prevention, and the treatment of the syndrome are reviewed and discussed.

Diagnosis and management of Duchenne muscular dystrophy, part 2: respiratory, cardiac, bone health, and orthopaedic management

A coordinated, multidisciplinary approach to care is essential for optimum management of the primary manifestations and secondary complications of Duchenne muscular dystrophy (DMD). Contemporary care has been shaped by the availability of more sensitive diagnostic techniques and the earlier use of therapeutic interventions, which have the potential to improve patients' duration and quality of life. In part 2 of this update of the DMD care considerations, we present the latest recommendations for respiratory, cardiac, bone health and osteoporosis, and orthopaedic and surgical management for boys and men with DMD. Additionally, we provide guidance on cardiac management for female carriers of a disease-causing mutation. The new care considerations acknowledge the effects of long-term glucocorticoid use on the natural history of DMD, and the need for care guidance across the lifespan as patients live longer. The management of DMD looks set to change substantially as new genetic and molecular therapies become available.

Fat attacks!: a case of fat embolisation syndrome postliposuction

Liposuction is a procedure commonly performed in the UK usually with a low incidence of serious sequelae; however with larger patients and increased volumes of lipoaspirate, complications have been reported more frequently. One of the rare but very serious complications postliposuction is fat embolism syndrome (FES), a life-threatening condition difficult to diagnose and limited in treatment.The authors present the case of a 45-year-old woman who was admitted to the intensive care unit postelective liposuction for bilateral leg lipoedema. She presented with the triad of respiratory failure, cerebral dysfunction and petechial rash requiring a brief period of organ support. This case highlights that with the recent increase in liposuction procedures worldwide, FES is a differential to always consider. Although still a rare condition this article emphasises the importance of thinking outside the box and how to identify and manage such a life-threatening complication.

Integrating Fat Embolism Syndrome Scoring Indices in Sickle Cell Disease: A Practice Management Review

Fat embolism syndrome (FES) has been described in the literature as a rare complication of sickle cell disease (SCD). A review article published in 2005 reported 24 cases of FES associated with SCD. In many cases, a definitive diagnosis of FES in SCD is made on autopsy because of the lack of early recognition and the paucity of sensitive and specific testing for this syndrome. Patients with FES usually have a fulminant, rapidly deteriorating clinical course with mortality occurring within the first 24 hours. We postulate that FES is not well recognized in SCD and that FES scores are useful diagnostic tools in patients with SCD. We queried the electronic medical records with the diagnostic codes for SCD with acute chest syndrome (ACS), pulmonary embolism, or acute respiratory distress syndrome admitted to our hospital from 2008 to 2016 to identify patients suspected of having FES. In addition, we performed an extensive literature review to evaluate the management practice of pediatric patients with FES and SCD from 1966 to 2016. Six patients met our selection criteria from the hospital records, and 4 case reports from the literature search were also included. We applied the Gurd and Wilson criteria and the Schonfeld Fat Embolism Index to identify patients who met the criteria for FES. Nine patients fulfilled Gurd and Wilson criteria, and 9 patients who were evaluable met the Schonfeld criteria for FES. A rapidly deteriorating clinical course in a patient with SCD presenting with ACS or severe vaso-occlusive crisis should trigger a high index of suspicion for FES. Gurd and Wilson criteria or the Schonfeld Fat Embolism Index are useful diagnostic tools for FES in SCD.

Successful Management of Intraoperative Acute Bilateral Pulmonary Embolism in a High Grade Astrocytoma Patient

Patient: Female, 39

Final Diagnosis: Acute bilateral pulmonary embolism

Symptoms: Headache • amnesia • seizure • urinary incontinence

Medication: —

Clinical Procedure: —

Specialty: Anesthesiology