Background: Cerebral venous air embolism is a severe clinical condition related to an unfavourable outcome in patients with neurological impairment. Cerebral venous air embolism may occur secondarily to arterial or venous interventions. A rare mechanism of cerebral venous air embolism is retrograde embolism, which is characterized by gas flow in a direction that is opposite to that of the normal blood flow.
Case Report: A 69-year-old female was admitted to our hospital with shortness of breath and abdominal pain. Abdominal computed tomography revealed intramural gas in the bowel and free gas in the mesenteric veins and portal vein. Cranial computed tomography, which was performed due to impaired consciousness, demonstrated cerebral air embolism with the appearance of a gyriform pattern. A bedside echocardiography and chest computed tomography revealed no evidence of right-to-left shunt.
Conclusion: Cerebral venous air embolism may occur after pneumatosis intestinalis by a retrograde flow of air from the mesenteric veins and portal vein. Low cardiac output and supine position are contributing factors for a retrograde flow of air bubbles into the venous circulation of the brain.