Pseudotumor cerebri: clinical and neuroradiological findings

Pseudotumor cerebri (PTC) is a diagnosis per exclusionem applied to a condition of increased intracranial pressure in the absence of an intracranial infection, a space-occupying lesion, or hydrocephalus. Diagnostic criteria should include the evaluation of possibly disturbed cerebral venous outflow, which may result in similar clinical findings. Disturbed venous drainage should be separated from the syndrome of PTC because it represents a condition of well-defined origin and therapeutic regimen. Course and prognosis of PTC are not related to the increased intracranial pressure, the degree of papilledema, or to the duration of the disease. Functional cerebral disorders and EEG abnormalities are rare, indicating that brain tissue is not primarily affected. Correspondingly, computerized tomography (CT) scans with respect to the cerebrum are normal in about 90% of the cases; but enlarged optic nerve sheaths (46.7%) and empty sella (45.7%) are frequent findings on CT-scans. They most likely represent a direct consequence of long-term increased pressure within CSF spaces. This observation favors the assumption of disturbed CSF-pressure regulation either by increased production of CSF or its decreased rate of absorption. Brain edema (slit ventricles) as assessed by CT is a rare finding (11.4% of our cases). It may be a hint towards a different pathogenetic entity.