Fat Embolism Syndrome in a Child with Sickle Cell Disease

Do you know the diagnostic importance of susceptibility-weighted imaging on MRI for patients with cerebral fat embolism?

Key Clinical Message

If you suspect cerebral fat embolism (CFE) of the diagnosis for the patients who present with impaired consciousness and hypoxia following a fracture, susceptibility-weighted imaging should be included of head MRI imaging.

Abstract

We report a case of cerebral fat embolism (CFE) that could be identified only by susceptibility-weighted imaging (SWI). Collection and analysis of previous case reports of CFE revealed utilization of SWI in less than one third of suspected cases, despite its known diagnostic ability for CFE.

Fat embolism after intraosseous catheters in pediatric forensic autopsies

In our center, we performed the autopsy of a child who died from drowning and presented, at autopsy, a major pulmonary fat embolism (PFE). A cardiopulmonary resuscitation (CPR) was performed, including infusion by intraosseous catheter (IIC). No other traumatic lesions and diseases classically related to a risk of PFE were detected. According to some animal studies, we considered the IIC as the only possible cause for PFE. However, we could not find literature to confirm this hypothesis in humans, especially in a pediatric population. To verify the occurrence of PFE after IIC in a pediatric population, we retrospectively selected 20 cases of pediatric deaths autopsied in our center, in which a CPR was performed, without bone fractures or other possible causes of PFE: 13 cases with IIC (group A) and 7 cases without IIC (group B). Several exclusion criteria were considered. The histology slides of the pulmonary tissue were stained by Oil Red O. PFE was classified according to the Falzi scoring system. In group A, 8 cases showed PFE: 4 cases with a score 1 of Falzi and 4 cases with a score 2 of Falzi. In group B, no case showed PFE. The difference between the two groups was statistically significant. The results of our study seem to confirm that IIC can lead to PFE in a pediatric population and show that the PFE after IIC can be important (up to score 2 of Falzi). To the best of our knowledge, our study is the first specifically focused on the occurrence of PFE after IIC in a pediatric population by using autoptic data.

Single-case metanalysis of fat embolism syndrome

BACKGROUND

Only one large series has been reported on fat embolism syndrome (FES), a condition caused by fat globules release into the circulation, primarily as consequence of bone fracture. Thus, more data on clinical features, therapies, and prognosis are needed.

METHODS AND RESULTS

The study screened 1090 manuscripts in PubMed and Web of Science on cases of FES published from June 2010 to June 2020. The authors identified 124 studies and included in the pooled-analysis 135 patients (>14 years), plus one additional unpublished case managed in Tongji hospital. All had confirmed diagnosis of FES with complete clinical data. The median age at presentation was 39 years, and 82 (61.8%) were men. FES was predominantly associated with bone fractures (78, 57.4%), particularly femur fracture (59, 43.4%). The most common clinical finding at the onset was respiratory abnormalities in 34.6% of all clinical presentations. Therapies included respiratory supportive care in 127 (93.4%) patients, application of corticosteroids in 22 (16.2%) and anticoagulant in 5 (3.7%) cases. Overall mortality was 30.2% (N = 41), and logistic regression analysis showed that corticosteroid therapy was significantly associated with reduced mortality with an OR of 0.143 (95%CI 0.029-0.711), while age ≥ 65 years and non-orthopedic conditions were significantly associated with increased mortality with an OR of 4.816 (95%CI 1.638-14.160) and 4.785 (95%CI 1.019-22.474).

CONCLUSIONS

FES has been associated with a larger mortality rate than previously observed, although publication bias can have led to overestimation of mortality. Finally, a potential protective effect of corticosteroid therapy has been suggested by the current analysis.

Diverse manifestations of a sickle cell crisis

We describe the case of a 21-year-old man with a background of sickle cell disease (SCD) who was on acute presentation in a sickle cell crisis required immediate intensive care admission with red blood cell exchange and ventilatory support. He had right frontal lobe infarcts and extensive bilateral deep white matter lesions most likely secondary to fat embolism. Inpatient investigations demonstrated a patent foramen ovale, explaining the route of spread of the fat embolus. He then had a transcatheter closure of the atrial defect. The patient needed prolonged inpatient rehabilitation. He was discharged from hospital in a wheelchair secondary to severe lower limb neurology and bilateral knee heterotopic ossification. He lives with the possibility of early onset dementia and cognitive decline, requiring constant care. The case highlights the multiple manifestations of SCD and their diverse and debilitating consequences.

Fat Embolism Syndrome in Sickle Cell Disease

Fat embolism syndrome is a devastating complication of sickle cell disease resulting from extensive bone marrow necrosis and associated with high mortality rates, while survivors often suffer severe neurological sequelae. Despite that, the syndrome remains under-recognised and under-diagnosed. Paradoxically, it affects exclusively patients with mild forms of sickle cell disease, predominantly HbSC and HbSβ⁺. A significant number of cases occur in the context of human parvovirus B19 infection. We provide here a brief summary of the existing literature and describe our experience treating 8 patients in our institution. One patient had HbSS, 6 HbSC and 1 HbSβ⁺. All patients developed type I respiratory failure and neurological involvement either at presentation or within the first 72 h. The most striking laboratory abnormality was a 100-fold increase of the serum ferritin from baseline. Seven patients received emergency red cell exchange and 1 simple transfusion. Two patients (25%) died, 2 patients (25%) suffered severe neurological impairment and 1 (12%) mild neurological impairment on discharge, while 3 (38%) patients made a complete recovery. With long-term follow-up, 1 patient with severe neurological impairment and one patient with mild neurological impairment made dramatic improvements, making the long-term complete recovery or near complete recovery rate 63%. Immediate red cell exchange transfusion can be lifesaving and should be instituted as soon as the syndrome is suspected. However, as the outcomes remain unsatisfactory despite the increasing use of red cell exchange, we suggest additional therapeutic measures such as therapeutic plasma exchange and pre-emptive transfusion for high risk patients.