Short-Term Continuous Intraparenchymal Intracranial Pressure Monitoring in Presumed Idiopathic Intracranial Hypertension

Abstract

The management of idiopathic intracranial hypertension (IIH) depends on a reliable assessment of intracranial pressure (ICP), particularly when visual function measures or ophthalmoscopic indicators are confusing and when invasive surgical procedures are being considered. Although ICP monitoring has been widely applied in many neurologic conditions as a more reliable measure of ongoing ICP than lumbar puncture (LP), it has not often been widely used in the management of IIH. We searched the records of the University of Michigan between 2001 and 2008 for patients with IIH who had undergone LP and continuous ICP monitoring with an intraparenchymal Codman ICP Monitoring System and in whom at least 1 year of follow-up information was available. Ten patients met entry criteria. There were no complications from the ICP monitoring. ICP monitoring influenced management in all 10 patients. In 8 patients, LP had shown elevated opening pressures; in 7 of them, ICP monitoring failed to confirm a consistently high ICP. In these patients, the decision to withdraw ICP-lowering agents or shunts, or not to revise indwelling shunts, produced no change in visual function or optic disc appearance over a follow-up period of at least 1 year. In 1 patient, ICP monitoring confirmed the high ICP suggested by LP, justifying placement of a ventriculoperitoneal shunt. In 1 patient, ICP monitoring was performed instead of LP because a petroclival mass posed a danger to the performance of LP; a shunt was subsequently placed due to elevated ICP. In providing more accurate information about ICP than about LP, short-term continuous ICP intraparenchymal monitoring may be a useful adjunct in the management of IIH when clinical data are confusing and invasive interventions are under consideration.