Cerebral fat embolism after bone fractures Jurjan Aman, Laurien van Koppenhagen, Alexander M Snoek, Johannes G van der Hoeven, Ary-Jan van der Lely
After a forklift accident, a 44-year-old man was admitted to our hospital in July, 2014, with fractures of the right ﬁbula and tibia, the left femur, and the pelvis. A proximal femoral nail antirotation was done to stabilise the left femur. 1 h after the operation, he developed acute respiratory failure, requiring reintubation and admission to the intensive-care unit. CT angiography of the thorax showed bilateral ground-glass opacities and distinct nodular opacities (ﬁgure), without pulmonary embolism or aspiration. Despite intensive mechanical ventilation, severe hypoxaemia persisted (partial pressure of blood oxygen 6·7 kPa; normal range 11–13 kPa). We started antibiotic therapy because he had fever and tachycardia. 4 days later, we stopped sedative medication to allow neurological assessment, which showed he had a Glasgow Coma Scale score of 3. He developed axillar and inguinal petechiae, so 10 days after surgery we did MRI of the brain, which showed bilateral conﬂuent white matter abnormalities with diﬀusion restriction (ﬁgure). This pattern of cytotoxic cerebral oedema, with lesions in the white matter rather than the grey matter, is indicative of the subacute stage of fat embolism (5–14 days after an embolic event). Electroencephalography showed diﬀuse encephalopathy. On the basis of acute respiratory failure, petechiae in non-dependent areas, and typical ﬁndings on MRI, we diagnosed cerebral fat embolism syndrome. Cardiographic imaging showed no evidence of a patent foramen ovale or rightto-left shunt. We continued supportive care, and 16 days A
after surgery the patient was extubated following respiratory and neurological recovery. At the end of August, 2014, our patient was transferred to a neurorehabilitation centre. The clinical triad of respiratory failure, unconsciousness, and petechiae observed in cerebral fat embolism syndrome is a direct consequence of mobilisation of bone marrow. The syndrome typically results from fractures of the pelvis and long bones, or fracture stabilisation with intramedullary devices. After trauma, medullary fat enters the circulation and can embolise to the lung. Altered pulmonary haemodynamics and the systemic inﬂammatory reaction to trauma are thought to contribute to acute respiratory failure. The pliable nature of the fat emboli allows subsequent passage through the pulmonary capillaries with systemic embolisation to the skin and brain, causing petechiae and cerebral ischaemia with neurological symptoms. Although cerebral fat embolism is a clinical diagnosis, MRI showing a starﬁeld pattern of scattered spot lesions with diﬀusion restriction in the acute phase (1–4 days) or conﬂuent cytotoxic cerebral oedema in periventricular and subcortical white matter in the subacute phase (5–14 days), supports the diagnosis.
Published Online June 26, 2015 http://dx.doi.org/10.1016/ S0140-6736(15)60064-2 Department of Intensive Care (J Aman PhD, L van Koppenhagen MD, A-J van der Lely MD), Department of Internal Medicine (J Aman), Department of Anaesthesiology (L van Koppenhagen, A-J van der Lely), and Department of Radiology (A M Snoek MD), Sint Antonius Ziekenhuis, Nieuwegein, Netherlands; and Department of Intensive Care, Radboudumc, Nijmegen, Netherlands (Prof J G van der Hoeven) Correspondence to: Dr Jurjan Aman, Department of Pulmonary Disease, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, Netherlands [email protected]
Contributors JA, LvK, and A-JvdL cared for the patient. AS analysed the radiological examinations. JGvdH had a key role in establishing the clinical diagnosis. JA, LvK, and AS wrote the report, which was revised by JGvdH and A-JvdL. Written consent to publish was obtained.
Figure: Radiographical assessment of a cerebral fat embolism (A) CT angiography; coronal multiplanar reconstruction of the thorax show thickened interlobular septa, bilateral ground-glass opacities, and distinct nodular opacities consistent with ﬁndings in pulmonary fat embolism. Axial ﬂair (B) and diﬀusion-weighted (C) MRI images show bilateral conﬂuent white matter abnormalities in the periventricular and subcortical regions, the posterior limb of the capsula interna, and splenium of the corpus callosum, with corresponding diﬀusion restriction on diﬀusion-weighted imaging.
www.thelancet.com Published online June 26, 2015 http://dx.doi.org/10.1016/S0140-6736(15)60064-2