Severe pulmonary and cerebral fat embolism with sudden cardiac and respiratory arrest after cesarean section: a case report

Abstract Background Fat embolism syndrome (FES) is commonly associated with orthopedic trauma, but the diagnosis is challenging with an uncommon nontraumatic cause. It is difficult to discriminate from thrombo-embolism in post-partum women with a hypercoagulable condition. Case presentation A 26-year-old woman experienced cardiac and respiratory arrest 34 h after cesarean section. She showed limb convulsions with teeth gritted. Cardiopulmonary resuscitation and adrenaline were administered, followed by endotracheal intubation with balloon-assisted ventilation. Her autonomic heart rate recovered after 19 min. Arteries blood gas analysis showed severe respiratory and metabolic acidosis. Blood examination showed increased level of d-dimer and increased troponin-I. Computed tomography (CT) of the chest showed multiple high-density patches and pleural effusion in bilateral lungs. CT angiography (CTA) showed expanded pulmonary artery trunk, indicating increased pulmonary artery pressure, but it did not detect thrombo-emboli in the pulmonary artery trunk. Brain CT showed dot-like low-density shadow in bilateral cerebral cortex. Extracorporeal membrane oxygenation (ECMO) was initiated, and low-molecular-weight heparin was given. Color Doppler ultrasound did not detect any thrombus in lower limbs. She developed seizures on her left limbs, and valproate and phenobarbital were initiated. ECMO was terminated four days later. Repeated chest CTA still did not detect any thrombi in the pulmonary arteries. Repeated brain CT demonstrated multiple focal hypo-density lesions in two hemispheres. No embolus was found in the cerebral and cervical vascular. Brain magnetic resonance imaging showed multiple subacute wedge-shaped infarctions. Diffusion-weighted imaging showed restricted diffusion in the bilateral basal ganglia and frontal cortex. Signs of occlusion were not found in the cerebral arteries. After reviewing the patients’ materials, an embolic event in the lung and brain was considered. We found multiple filling defects in bilateral pulmonary artery branches and measured its CT value (-48 to -45 Hounsfield Units (HU)), suggesting pulmonary fat embolism. Consistently, dot-like low-density shadows (-26 to -42 HU) in the brain highly suggested cerebral fat emboli. Transesophageal echocardiography confirmed a patent foramen ovale of 1.0 mm, which precipitated cerebral fat embolism. After systematic treatment, she was almost recovered to functional independence at 3 months. Conclusion FES can occur after cesarean section and with atypical clinical manifestations. CT density measurement of the emboli is critical to differentiate fat embolism from thrombo-embolism.