Brain Edema Edema often accompanies neoplastic lesions and is more commonly associated with metastatic tumors On CT scan, brain edema appears as an area of decreased density associated with brain shift Brain edema is commonly associated with ICH and contusion Edema associated with cerebral infarction generally indicates a severe stroke and may lead to herniation The treatment of brain edema depends on the cause of the lesion Edema (vasogenic edema) caused by neoplasia or inflammation respond to treatment with steroids The role of steroids in treating edema caused by trauma, infarction, or anoxia is unproven Brain edema (cytotoxic edema) that occurs after surgery for trauma, infarction, or hemorrhage represents increased tissue water and may require hyperosmolar therapy as described above Pneumocephalus Pneumocephalus is simply the accumulation of air in the intracranial spaces It commonly occurs after craniotomy if the air is not completely evacuated before the bone flap is replaced It may also occur after a traumatic basilar skull fracture when air is introduced into the subarachnoid space by communication with the exterior environment, usually through the ethmoid, sphenoid, or frontal sinuses A CT scan may show the accumulation of air beneath a bone flap or in communication with one of the sinuses Most cases of pneumocephalus are treated with 100% oxygen by a nonrebreather mask Tension pneumocephalus marked by an enlarging pocket of air causing mass effect (midline shift, sulcal effacement, or both) demands more aggressive and invasive intervention Emergency surgery is necessary to resolve the mass effect Pneumocephalus can be an indication of CSF leakage Although pneumocephalus indicates a tear in the dura, a CSF leak indicates a relatively large dural tear allowing a stream of CSF to flow CSF may drain through the ethmoid or sphenoid sinus complex, causing rhinorrhea; through the mastoid air cells, causing otorrhea; or from the scalp suture line When rhinorrhea or otorrhea occur postoperatively, they should be treated conservatively with a lumbar drain If a seal is not accomplished after 10 to 14 days of conservative treatment, surgical intervention is necessary The use of antibiotics to treat either pneumocephalus or pneumocephalus with subsequent CSF leak is controversial Treatment with antibiotics should not be initiated unless signs and symptoms of CSF infection develop