Retrograde cerebral air embolism.

Pneumocephalus is a clinical condition caused by dysbarism, trauma, and iatrogenic causes. The most common iatrogenic causes of pneumocephalus are major interventions as a neurosurgery and cardiovascular operations, endoscopy, and minor interventions as a peripheral and central venous access. Especially during insertion of central venous line and intravenous drug and fluid infusion, the venous air embolism may occur in emergency department. In these patients, retrograde pneumocephalus occurs as a result of the air entering the right atrium to the brain. Clinical effects of the air delivery rates are known to be more specific than the total amount of air. In general, intravenous administration of 300 to 500 mL air in the speed of 100 mL/min is considered to be lethal. Large amounts of air embolism can cause hypotension and acute circulatory collapse with intracardiac obstruction. The most common symptoms of venous air embolism are anxiety, dyspnea, chest pain, cyanosis, tachycardia, tachypnea, headache, confusion, agitation, syncope, slurred speech, blurred vision, seizures, and ataxia. The mortality of pneumocephalus caused by central venous catheters in patients presented with symptoms of focal neurologic was 8%, whereas the mortality of pneumocephalus in patients presented with encephalopathy was 36%. In our report, a case of pneumocephalus secondary to disconnection of catheter cap in chronic renal failure patient who has hemodialysis via catheter has been presented.