Cerebral air embolism complicating esophagogastroduodenoscopy (EGD).

progressive abdominal pain/distension, constipation, and vomiting. Abdominal computed tomography (CT) scan revealed ascites, omental deposits, and a thick− ened caecal wall (l" Fig. 1). Ascitic fluid cytology confirmed adenocarcinoma. He− matemesis ensued and esophagogastro− duodenoscopy (EGD) was performed to investigate this and the site of primary malignancy. This revealed distal erosive esophagitis (l" Fig. 2) from which biop− sies were taken. Toward the end of the procedure the patient became unrespon− sive, exhibiting tonic−clonic seizure activ− ity and a left hemiparesis. An emergency cerebral CT revealed pneumocephalus mostly affecting the right frontoparietal region (l" Fig. 3). Due to disseminated malignancy, transfer to the nearest opera− tional hyperbaric oxygen unit (> 200 miles) was felt to be unjustified. The patient died 6 days later. Postmortem examination within 24 hours showed no evidence of intracardiac air or shunt (l" Fig. 4). The underlying malignancy was appendiceal adenocarcinoma (l" Fig. 5, 6). We identified eight previously reported cases of air embolism complicating EGD. One case involved intracardiac air and the other seven intracerebral. Invariably patients developed coma, seizures, and a dense left−sided hemiparesis, in keeping with EGD being performed in the left lat− eral position. Air enters the vascular sys− tem via disrupted mucosa in the setting of a pressure gradient due to insufflation [1]. Cerebral CT is highly sensitive for air embolism but diagnostic only if per− formed immediately, as air is rapidly re− absorbed from brain arterioles [2]. Para− doxical embolism may arise, even when an intracardiac shunt cannot be demon− strated [3]. Air may pass from the venous to the arterial system via prepulmonary arteriovenous shunts or by directly cross− ing the pulmonary capillary bed [4]. Treatment involves prevention of further embolization, high−flow oxygen, and hy− perbaric oxygen therapy [5]. This case highlights a relatively unknown and very serious complication of an everyday hos− pital procedure. However, if signs are re− cognized early, prompt CT is diagnostic and hyperbaric oxygen therapy may im− prove the outcome.