Cerebral infarction and an ascending aortic thrombus in a patient with systemic capillary leak syndrome: a case report

Background Systemic capillary leak syndrome (SCLS) is a rare disorder characterised by recurrent episodes of hypovolemic shock, haemoconcentration, and hypoalbuminaemia, caused by transient increases in vascular permeability. Although venous thromboembolic complications have been reported in patients with SCLS, arterial thrombosis involving the ascending aorta is rare. Herein, we report a case of cerebral infarction caused by an ascending aortic thrombus associated with SCLS and discuss the possible pathophysiological mechanisms. Case presentation A 62-year-old man presented with generalised oedema, oliguria, severe hypotension, marked haemoconcentration (haematocrit, 70%), acute kidney injury, and hypoalbuminaemia. Based on the recurrent episodes of hypotension, haemoconcentration, hypoalbuminaemia, and the presence of serum IgG-kappa monoclonal protein, the patient was diagnosed with SCLS. During the acute leak phase, the patient developed compartment syndrome requiring a decompressive fasciotomy. Two days after admission, he suddenly developed aphasia and right hemiplegia while eating breakfast. Magnetic resonance imaging (MRI) of the brain revealed an acute cerebral infarction due to occlusion of the left internal carotid artery. Endovascular thrombectomy achieved successful reperfusion (Thrombolysis in Cerebral Infarction grade 2b). Contrast-enhanced computed tomography angiography revealed a mural thrombus in the ascending aorta without evidence of an aneurysm, dissection, or significant atherosclerosis. Anticoagulation therapy with heparin, followed by warfarin, resulted in complete resolution of the thrombus. Histopathological examination revealed a fibrin-rich thrombus with neutrophil and lymphocyte infiltration, compatible with an early stage thrombus. Conclusions This case suggests that severe haemoconcentration, abnormal blood flow, and endothelial dysfunction during the acute phase of SCLS may synergistically promote de novo ascending aortic thrombus formation, resulting in cerebral embolism. Comprehensive vascular imaging should be considered to identify potential arterial embolic sources in patients with SCLS who develop acute neurological deficits. Further accumulation of similar cases is required to clarify the mechanisms and optimal management of arterial thrombotic complications in SCLS.