Clinical, laboratory, radiological features, and outcome of acute fat embolism syndrome in sickle cell disease

Abstract

Non-traumatic fat embolism syndrome (FES) affecting brain, lung and hematopoietic system is a rare, but a serious complication of sickle cell disease (SCD), resulting from bone marrow necrosis. SCD-related FES is rare, with the spectrum of clinical, laboratory, radiological manifestations and patient outcome is not fully understood. After medical research & ethics committee approval, retrospectively, SCD-FES patients at our centre, were reviewed between January 2006 to December 2023. 27 patients (17 males, 10 females) with a median age of 24 years and length of hospital stay of 24 (16-38) days were enrolled. They had fever, chest/back pain, cough and crepitation in 100%, 96%, 56% and 100% respectively, with neurological manifestations in 96%. Abnormal chest X-rays and CT scans were observed in 96%, and 100% respectively. Patients had significant anemia, reticulocytopenia, and thrombocytopenia, with raised WBC (p < 0.05). There was a significant rise in LDH, ALP, Ferritin and C-reactive protein levels. All patients received antibiotics, and exchange transfusions, whereas 24%, 76% required non-invasive ventilation (NIV) and mechanical ventilation respectively, with 18.5% mortality. FES is a rapidly progressive respiratory and neurological syndrome, characterized by hypoxia, and cytopenia, with raised inflammatory markers, raised LDH and ALP, with distinctive multiple cerebral microbleeds.

Keywords: Bone marrow necrosis; Exchange transfusion; Fat embolism syndrome; Parvovirus B19; Sickle cell disease.

Fig. 1

Chest and neuroimaging findings in a patient with fat embolism syndrome. (A) A chest radiograph on presentation shows bilateral perihilar and lower lung predominant opacities. An endotracheal tube, central venous line, and nasogastric tube are seen in situ. (B) Axial CT chest in lung window done on the same day reveals bilaterally dependent subpleural lower lung predominant consolidative and ground-glass opacities. (C, D) Axial diffusion-weighted images from an MRI that was performed 24 h after presentation show bilateral scattered foci of diffusion restriction in the white matter and deep gray matter (ADC map is not shown). (E) A susceptibility-weighted image from an MRI done one week after the initial presentation demonstrates extensive microbleeds in the white matter, including the corpus callosum and deep gray matter.

Fig. 2

The Box-Whisker plot with interquartile ranges showing the statistically significant differences in the haematological and biochemical parameters. Panel A shows the haemoglobin levels at admission and nadir, Panel B shows the WBC levels at admission and maximal, Panel C shows the Platelet counts at admission and nadir, Panel D shows the Serum LDH levels at admission and Maximum whereas, Panel E shows the Serum CRP levels at admission and maximum. Statistical significance was demonstrated using the non-parametric Wilcoxon Signed Ranks test.

Fig. 3

Comparison of reported clinical and laboratory features (%) between the largest reported study and the present single institution study.