Fat Embolism Syndrome: Lung Computed Tomography Findings in 18 Patients

Fat embolism syndrome: A severe case diagnosed early using dual-energy CT and saved with VA-ECMO and inhaled nitric oxide

Diagnosing FES is difficult and time-consuming, and identify FES as an etiology of right ventricular volume overload for early diagnosis. Because FES is a reversible condition, even severe cases can bse treated if the patient survives the acute phase.

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.

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.

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.

Fat embolism syndrome with cerebral fat embolism through a patent foramen ovale: A case report

RATIONALE

Fat embolism syndrome with cerebral fat embolism, rarely observed at our neurology department, is often associated with long bone fractures. Its diagnosis is based on medical history and supportive imaging data and is usually not difficult. However, its pathogenesis remains poorly understood.

PATIENT CONCERNS

A 46-year-old woman was urgently presented to a nearby hospital because of a femur fracture caused by an accident. She rapidly developed somnolence and was suspected to have fat embolism syndrome.

DIAGNOSES

Due to patients history of trauma and supportive imaging data, she was diagnosed with fat embolism syndrome obviously. However, severe brain damage confused our understanding of the pathogenesis. The subsequent diagnosis of fat embolism syndrome with patent foramen ovale provided a reasonable explanation.

INTERVENTIONS

Initially, we did not consider the fact that the patient had developed fat embolism syndrome and thus designed a comprehensive treatment program for fat embolism syndrome. Then the routine cardiac and vascular ultrasound screening were followed up, but patent foramen ovale was diagnosed unexpectedly, which led to a more aggressive treatment of brain injury.

OUTCOMES

After relevant symptomatic treatment continued for nearly 3 months, an overall improvement was observed. Patients consciousness was restored but language disorders were left.

LESSONS

Clinicians should consider patent foramen ovale as the embolization pathway, particularly in young and middle-aged patients with cerebral embolism because it is often mistaken for a rare situation.

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.

Fat embolism syndrome: Experience from an Australian trauma centre

BACKGROUND

Fat Embolism Syndrome (FES) is a rare condition where circulating fat emboli can lead to life threatening multisystem dysfunction. Diagnosis of FES occurs mainly by exclusion. The aim of this study was to describe the injury, event details, and factors associated with the diagnosis of FES following trauma presenting to a Level 1 Trauma Centre in Melbourne, Australia.

METHODS

Medical records of all patients with a complication of FES between 2006 and 2018 were retrospectively reviewed. Demographics, injury factors, hospital event details, radiological procedures and length of stay were collected.

RESULTS

Thirty six patients, with median age of 26 years (IQR 19, 42) and median Injury Severity Score (ISS) of 18.5 (IQR 10, 27) were diagnosed with FES. Other associated factors included male gender (86%) and having one or more long bone fractures (97%). Of the major FES diagnostic criteria, 94% of patients experienced hypoxia, 36% had mental status changes, whereas only 11% had petechiae. Computed Tomography Pulmonary Angiogram (CTPA) was performed on 19 patients (53%) with all being negative for pulmonary embolus. Most demonstrated ground glass opacity (58%), and FES was reported as the likely cause of patient presentation in 53% of cases.

CONCLUSION

FES following trauma was rare, with its diagnosis based on clinical factors including long bone fracture and hypoxia, and the exclusion of other respiratory diagnoses. CTPA was frequently used since 2008 and further research is warranted to determine if this radiological procedure can assist with more definitive diagnosis of FES.

Pulmonary embolism occurring early after major trauma

Pulmonary embolism (PE) secondary to trauma is the third most common cause of death in trauma patients who have survived 24 hours following injury. We describe a case of PE diagnosed within 3 hours of a major trauma in a previously well adolescent female. The early occurrence of PE in this case is at odds with what is generally reported (3-5 days) after major trauma. General consensus is that patients who suffer major trauma move from an initial hypocoaguable state, with increased risk of bleeding, to normocoagulable or hypercoaguable state, with a subsequent increased risk of venothromboembolism. However, Sumislawski et al recently demonstrated that a marginally greater proportion of trauma patients were in fact hypercoaguable rather than hypocoaguable on arrival to hospital and that trauma-induced coagulopathy tended to resolve within 24 hours; such data cause us to re-evaluate when to commence thromboprophylaxis for major trauma patients.

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.

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.

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.

Non-infectious Parenchymal Lung Disease

Acute dyspnea is a common presenting complaint in the emergency room, emergency medicine and intensive care. It may have a cardiovascular or a non-cardiovascular origin, the latter including pulmonary parenchymal diseases. Depending on the cause, it may be associated with fever, cough, hemoptysis, and/or chest pain, with a duration of symptoms that can range from hours to days.

Prompt identification of the underlying cause of acute dyspnea is essential in guiding appropriate therapy and management, as patients may rapidly progress to acute respiratory failure. Evaluation with chest radiography is vital for initial assessment and may reveal diffuse parenchymal abnormalities, which may require further assessment with computed tomography (HRCT).

Acute non-infectious parenchymal lung diseases are often overlooked and may be under-diagnosed. Their diagnosis requires the evaluation, along with the HRCT pattern, of the clinical and laboratory features and of the bronchoalveolar lavage. Biopsy may be necessary in more complex cases.

Although the most frequent cause of diffuse non-infectious parenchymal lung involvement is acute hydrostatic pulmonary edema, there is a wide variety of diseases that may be encountered, including acute drug toxicity, hypersensitivity pneumonitis (HP), acute respiratory distress syndrome (ARDS) and diffuse alveolar hemorrhage (DAH). In trauma patients, fat embolism syndrome (FES) must be taken into account. Acute respiratory failure is an eventuality that can occur during the course of chronic lung diseases (UIP for example), which may have been unknown until then.