Pneumocephalous After Knee Surgery

Abstract

INTRODUCTION: Pneumocephalus is a rare complication of spinal anesthesia. CASE PRESENTATION: An 82 year old veteran was admitted to the ICU screaming about Korean wartime events. 24 hours prior, he had an elective left total knee replacement for an unstable prosthesis, done under spinal anesthesia and a femoral block with sedation. His medical history included stroke, osteoarthritis, alcoholism and three surgeries in recent years without psychologic or neurologic events. No new medications were started. Physical examination revealed tachycardia, hypertension, tremors and no signs of infection. Head computed tomography (CT) showed multiple, foci of air intracranially without acute stroke or hemorrhage (figure). Echocardiogram was normal without obvious shunt. He was treated with high flow oxygen in trendelenburg position, lorazepam, haloperidol and quetiapine. Serial CT scans showed resolution of pneumocephalus by the fifth postoperative day and his symptoms gradually resolved. DISCUSSION: Pneumocephalus is defined as the presence of gas within any of the intracranial compartments (intraventricular, intraparenchymal, subarachnoid, subdural and epidural) of the cranial vault and is also known as intracerebral aerocele or pneumatocele. It is usually diagnosed after disruption of the skull in cases of head and facial trauma or tumors of the skull base(1). Most reported post-procedure cases are following neurosurgery or otolaryngological procedures. Duration of surgery, head position, use of spinal or epidural anesthesia(2), continuous CSF drainage via lumbar drain are some of the contributing factors to the development of Pneumocephalus. Clinical presentation includes headache, nausea, vomiting, seizures, dizziness and depressed neurological status. Diagnosis is established with the presence of epidural or subdural air on a CT scan and treatment is conservative with high flow supplemental oxygen or hyperbaric oxygen. Resolution can be assessed by frequent neurologic examinations and serial CT scans. CONCLUSIONS: While there were several potential contributing factors to his acute delirium, management was changed to include supplemental oxygen and supine to trendelenburg positioning in addition to benzodiazepines and antipsychotic medications. Pneumocephalous is a rare complication of spinal anesthesia and possibly knee surgery and should be considered in a surgical patient with altered mental status or other neurological symptoms.