Cerebral Fat Embolism: Clinical Presentation, Diagnostic Steps and Long-Term Follow-Up

Brain microbleeds resulting from presumed extensive fat emboli in a patient with bone marrow necrosis following a sickle cell disease vaso-occlusive crisis

Acute manifestations of sickle cell disease (SCD) are numerous and multisystemic. Cerebral fat embolism (CFE) is a rare but serious complication of SCD caused by bone marrow necrosis (BMN) during vaso-occlusive crises (VOC). We present the case of a 41-year-old man with SCD who developed severe VOC and multi-organ dysfunction. He subsequently experienced neurological deterioration with decreased consciousness and diffuse encephalopathy on serial electroencephalograms. Bone marrow aspiration confirmed BMN. Brain MRI revealed extensive diffuse leukoencephalopathy, vasogenic and cytotoxic edema in the white matter, patchy edema in the cranial vault bone marrow on fat-suppressed FLAIR sequence (a finding consistent with the confirmed BMN), and multiple cerebral microbleeds on susceptibility-weighted imaging consistent with CFE. The management of acute neurological complications of SCD varies depending on the specific complication. Brain MRI plays a crucial role in the accurate diagnosis of these complications to guide appropriate treatment.

Fat Embolization Syndrome Secondary to Steroid Treatment in a Case of Sickle Cell Vaso-Occlusive Crisis

Fat embolization syndrome (FES) is often seen as a complication of fractures and has been known to cause respiratory failure, rashes of the skin, thrombocytopenia, and neurological damage. Nontraumatic FES is uncommon and occurs due to bone marrow necrosis. Vaso-occlusive crisis in sickle cell patients secondary to steroid therapy is a rare entity and not widely acknowledged. We report a case of FES secondary to steroid therapy administered for a patient with intractable migraine. FES is an uncommon yet serious complication that occurs due to bone marrow necrosis and is usually associated with increased mortality or damaging neurologic sequelae for the surviving patient. Our patient was initially admitted for intractable migraine and worked up to rule out any acute emergency conditions. She was then given steroids for her migraine which did not subside with the initial treatment. Her condition worsened, and she developed respiratory failure along with altered mental status requiring care in the intensive care unit (ICU). Imaging studies showed microhemorrhages throughout the cerebral hemispheres, brainstem, and cerebellum. The imaging of her lungs confirmed severe acute chest syndrome. The patient also had hepatocellular and renal injuries indicative of multiorgan failure. The patient was treated with a red cell exchange transfusion (RBCx) leading to an almost complete recovery in a few days. The patient, however, had residual neurological sequelae with the presence of numb chin syndrome (NCS). This report thus highlights the need to recognize potential multiorgan failure secondary to steroid treatment and the importance of initiating treatment with red cell exchange transfusions to decrease the risk of such complications secondary to steroids.

Rare Encounter of Cerebral Fat Embolism Post Motor Vehicle Accident: A Case Report

Fat embolism syndrome (FES) is known to occur when fat macroglobules get embolized into the blood circulation, whereby they then get dispersed out to multiple organs including the brain. It's typically diagnosed when the patient sustains a neurological dysfunction, respiratory insufficiency, and petechial rash, the classical triad of FES. Cerebral fat embolism occurrence is rarely seen. In this case report, a 20-year-old male was admitted due to a closed left midshaft femur fracture from a motor vehicle accident, and sustained cerebral manifestation of fat embolism syndrome 32 hours post the incident. It was noted that the patient had the classical triad of FES and intubation was done for airway protection. MRI revealed features of cerebral fat embolism. Interlocking nail fixation of the left femur was done for this patient on day three after admission. On day 15 post trauma, the patient was successfully extubated. Adequate supportive management was given and the patient's prognosis improved. As a practitioner, it is important to recognize and diagnose cerebral fat embolism as early as possible so as to have a much better outcome and to avoid any unnecessary investigation.

Stars from the bones-An uncommon presentation of fat embolism syndrome

Trauma or surgery to the lower limbs can cause fat from the marrow within the leg bones to enter the bloodstream and form an embolus. However, if there is cerebral involvement without any pulmonary or dermatological manifestations at diagnosis, it could delay identifying cerebral fat embolism (CFE).

Fat emboli and critical illness-associated cerebral microbleeds (CICMs) in a patient with sickle cell disease: Do these 2 entities coexist?

We report the case of a 30-year-old female patient with sickle cell disease presenting with an acute chest syndrome and neurological deterioration. Cerebral magnetic resonance imaging revealed a handful of foci of diffusion restriction and numerous microbleeds with marked involvement of corpus callosum and subcortical white matter, with relative sparing of the cortex and deep white matter. Corpus callosum-predominant and juxtacortical microbleeds have been typically documented in cerebral fat embolism syndrome, but also in the so-called "critical-illness-associated cerebral microbleeds", a recently described entity associated with respiratory failure. We discussed whether these 2 entities may coexist.

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.

Intraparenchymal Neuromonitoring of Cerebral Fat Embolism Syndrome

Objectives:

We aimed to characterize the cerebrovascular physiology of cerebral fat embolism using invasive multimodal neuromonitoring.

Data Sources:

ICU, Vancouver General Hospital, Vancouver, BC, Canada.

Study Selection:

Case report.

Data Extraction:

Patient monitoring software (ICM+, Cambridge, United Kingdom), clinical records, and surgical records.

Data Synthesis:

None.

Conclusions:

Our integrated assessment of the cerebrovascular physiology of fat embolism syndrome provides a physiologic basis to investigate the importance of augmenting mean arterial pressure to optimize cerebral oxygen delivery for the mitigation of long-term neurologic ischemic sequelae of cerebral fat embolism.

Microbleeds show a characteristic distribution in cerebral fat embolism

This systematic review aims to test the hypothesis that microbleeds detected by MRI are common and show a characteristic pattern in cerebral fat embolism (CFE). Eighty-four papers involving 140 CFE patients were eligible for this review based on a systematic literature search up to 31 January 2020. An additional case was added from hospital records. Patient data were individually scrutinised to extract epidemiological, clinical and imaging variables. Characteristic CFE microbleed pattern resembling a "walnut kernel" was defined as punctuate hypointensities of monotonous size, diffusely located in the subcortical white matter, the internal capsule and the corpus callosum, with mostly spared corona radiata and non-subcortical centrum semiovale, detected by susceptibility- or T2* weighted imaging. The presence rate of this pattern and other, previously described MRI markers of CFE such as the starfield pattern and further diffusion abnormalities were recorded and statistically compared. The presence rate of microbleeds of any pattern, the "walnut kernel microbleed pattern", diffusion abnormality of any pattern, the starfield pattern, and cytotoxic edema in the corpus callosum was found to be 98.11%, 89.74%, 97.64%, 68.5%, and 77.27% respectively. The presence rate between the walnut kernel and the starfield pattern was significantly (p < 0.05) different. Microbleeds are common and mostly occur in a characteristic pattern resembling a "walnut kernel" in the CFE MRI literature. Microbleeds of this pattern in SWI or T2* MRI, along with the starfield pattern in diffusion imaging appear to be the most important imaging markers of CFE and may aid the diagnosis in clinically equivocal cases.

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

Background

Fat embolism syndrome (FES) is a change in physiology resulting from mechanical causes, trauma, or sepsis. Neurological manifestations of FES can vary from mild cognitive changes to coma and even cerebral oedema and brain death. Here, we present an unusual case of cerebral fat emboli that occurred in the absence of acute chest syndrome or right-to-left shunt.

Case presentation

A previously healthy 57-year-old right-handed male was admitted to our department because of unconsciousness after a car accident for 3 days. He suffered from multiple fractures of the bilateral lower extremities and pelvis. This patient had severe anaemia and thrombocytopenia. Head MRI showed multiple small lesions in the whole brain consistent with a “star field” pattern, including high signals on T2-weighted (T2w) and fluid-attenuated inversion recovery (FLAIR) images in the bilateral centrum semiovale; both frontal, parietal and occipital lobes; and brainstem, cerebellar hemisphere, and deep and subcortical white matter. Intravenous methylprednisolone, heparin, mannitol, antibiotics and nutritional support were used. Although this patient had severe symptoms at first, the outcome was favourable.

Conclusions

When patients have long bone and pelvic fractures, multiple bone fractures and deteriorated neurological status, cerebral fat embolism (CFE) should be considered. Additionally, CFE may occur without an intracardiac shunt. The early diagnosis and appropriate management of FES are important, and prior to and following surgery, patients should be monitored comprehensively in the intensive care unit. With appropriate treatment, CFE patients may achieve good results.

Unusual clinicopathological presentation of nontraumatic cerebral fat embolism: Two-case report

RATIONALE

Fat embolism syndrome (FES) is characterized by the classical triad of cerebral, respiratory, and cutaneous manifestations. In contrast, cerebral fat embolism (CFE), corresponding to incomplete pure type FES, is much rarer and usually follows trauma. CFE typically shows a "starfield" pattern on diffusion-weighted magnetic resonance imaging due to the involvement of multiple small arteries. We report 2 unusual cases of CFE that showed a nontraumatic etiology and the involvement of a single dominant cerebral artery.

PATIENT CONCERNS

Case 1 was a 33-year-old woman without a history of trauma who visited the emergency room due to hemiparesis and hemisensory deficits. She was a heavy smoker and had used oral contraceptives for several years. Most importantly, she had 2 experiences of autologous fat grafting 2 months previously. Magnetic resonance angiography (MRA) revealed acute occlusion of the right middle cerebral artery. Case 2 was an 80-year-old man suddenly presented with dizziness, ataxia, and left-sided sensorimotor dysfunction. He had a history of hypertension, untreated atrial fibrillation, and chronic alcoholism. MRA demonstrated the occlusion of the distal basilar artery.

DIAGNOSIS

Case 1: Microscopic findings demonstrated variable sized fat vacuoles intermixed with moderate amounts of thrombi. Case 2: Histologically, mature adipocytes were intermingled with fibrin, blood cells, and a fragment of entrapped soft tissue resembling the vessel wall.

INTERVENTION

Case 1 and 2 underwent aspirational thrombectomy guided by transfemoral cerebral angiography.

OUTCOME

Case 1 recovered well but Case 2 still suffers from gait ataxia.

LESSONS

CFE can rarely occur in various nontraumatic conditions, with or without evident etiology. Furthermore, it may not show characteristic clinicopathological manifestations. Therefore, careful follow up of those who have undergone procedures that are likely to trigger FES or who have hemodynamic or hypercoagulable risk factors is needed.

Neurologic Complications of Fat Embolism Syndrome

PURPOSE OF REVIEW

Fat embolism syndrome (FES) is a rare disorder with potentially devastating neurologic complications. This article reviews the history, pathophysiology, clinical features, diagnosis, and treatment of FES with a focus on its neurologic aspects.

RECENT FINDINGS

The neurologic complications of FES are more commonly recognized with current diagnostic testing and increase awareness of the disorder. FES may present initially with neurologic manifestations. Prompt diagnosis of FES and of its neurologic manifestations could be lifesaving. This includes respiratory support and management of neurological complications. The classic clinical triad of pulmonary insufficiency, neurologic disturbances, and petechial skin rash typically presents 24 to 72 h following an initial insult, most commonly a traumatic long bone fracture. Early onset (< 24 h) and delayed onset (> 72 h) have been described. Neurologic manifestations may include ischemic/hemorrhagic strokes, retinal ischemia, seizures, autonomic dysfunction, and diffuse brain injury. Diagnosis remains clinical. Management consists mainly of supportive care.

The fat embolism syndrome as a cause of paraplegia

The fat embolism syndrome is a well-known complication in trauma patients. We describe a rare case of traumatic fat embolism that leads to paraplegia. A 19-year-old male motorcycle accident victim was presented to our hospital. After stabilization and trauma survey, he was diagnosed with bilateral femur fractures, a spleen laceration and a tear in the inferior vena cava, for which damage control surgery was performed. Post-operatively, the patient became paraplegic and developed a fluctuating consciousness, respiratory distress and petechiae. Fat embolism syndrome was considered as the most plausible cause of the paraplegia. The fat embolism syndrome is seen in approximately 1% of trauma patients, mostly those with bilateral fractures of the femur. Prevention of the syndrome depends on early stabilization of fractures. However, even with optimal care, this syndrome can still occur and may have dramatic consequences, as we demonstrate in this case.