HE presence of pneumocephalus (“air in the head”) in a patient without a history of undergoing intra- cranial or intrathecal procedures is a significant ra- diographic finding that portends a violation of the dural barrier or the presence of infection. When unexplained pneumocephalus is visualized on computerized tomogra- phy (CT) scanning, a thorough search for its cause must be pursued. We describe a case of iatrogenic intravascular pneumocephalus that confounded the evaluation and treat- ment of a patient. To determine the incidence of this radio- graphic finding, we performed a prospective analysis of 100 CT scans. We review our case and the differential di- agnosis of pneumocephalus. Case Report History. This 54-year-old woman with a history of a cystic craniopharyngioma that had been resected 10 years earlier presented to a referring emergency depart- ment with a 1-month history of slowly progressive confu- sion. The patient had a significant medical history that in- cluded insulin-dependent diabetes mellitus, seizures, and major depression. The patient’s sister reported that the patient had had a seizure 7 weeks prior to presentation, but otherwise her condition had been well controlled with 800 mg carbamazepine administered daily. The patient had fallen on ice approximately 1 week before presenta- tion and had been evaluated at her local emergency de- partment and found to have several superficial extremity contusions and a scalp contusion. On the day of admis- sion, the patient’s neighbors found her wandering the halls of her apartment building in a confused state. She was transported by ambulance to her regional emergency de- partment. Examination. On examination the patient was afebrile with normal vital signs. She was awake and alert but ori- ented only to person. Her mood fluctuated between som- nolence and agitation. Her pupils were 4 mm bilaterally with a left afferent pupillary defect and blindness of the left eye. The third through 12th cranial nerves were intact. The patient had generalized weakness without a focal mo- tor deficit. Sensation was intact bilaterally. There was no dysmetria or nystagmus. Her reflexes were normal and symmetrical bilaterally. There was no meningismus and no carotid bruits. The cardiopulmonary and gastrointesti- nal examinations were normal. A peripheral intravenous catheter was placed, the pa- tient’s metabolic status was evaluated, and CT scanning of the head was performed. Laboratory findings, including glucose, sodium, and carbemazepine levels and peripher- al leukocyte count, were normal. The CT scans revealed pneumocephalus in the cavernous sinus and superior sag- ittal sinus. There was no evidence of subarachnoid hemor- rhage, subdural or epidural hematoma, or a skull fracture (Fig. 1). The patient was transferred to the emergency depart- J Neurosurg 91:878–880, 1999 878 Iatrogenic pneumocephalus secondary to intravenous catheterization Case report TODD P. THOMPSON, M.D., ELAD LEVY , M.D., EMANUEL KANAL, M.D., AND L. DADE LUNSFORD, M.D. Departments of Neurological Surgery and Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania  The presence of pneumocephalus in a patient without a history of undergoing intracranial or intrathecal procedures is a significant radiographic finding that portends a violation of the dural barrier or the presence of infection. The authors re- port a case of iatrogenic pneumocephalus that confounded the evaluation of a patient with unrelated neurological disor- ders, resulting in unnecessary transfer of the patient and utilization of medical resources. A review of 100 sequential com- puterized tomography scans obtained in patients for any indication in the emergency department revealed a 6% incidence of iatrogenic intravenous pneumocephalus. Computerized tomography scans revealing pneumocephalus had been obtained for altered mental status, focal motor deficit, seizure, and trauma. More careful intravenous catheterization and recognition of the condition on imaging may avoid similar problems. KEY WORDS • iatrogenic complication • pneumocephalus • neuroradiology T J. Neurosurg. / Volume 91 / November, 1999