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Show Journal of Neuro- Ophthalmology 21( 2): 118- 120, 2001. © 2001 Lippincott Williams & Wilkins, Inc., Philadelphia When Does Low Mean High? Isolated Cerebral Ventricular Increased Intracranial Pressure in a Patient With a Chiari I Malformation Raymond R. Lancione, Jr., MD, and Gregory S. Kosmorsky, DO Objective: To present an unusual case of pseudotumor cerebri with increased intracranial pressure isolated to the cerebral ventricles resulting from a Chiari I malformation. Materials and Methods: The patient received a complete ophthalmologic examination on initial presentation and subsequent visits, including visual acuity, pupillary examination, intraocular pressures, dilated fundus examination with assessment of degree of papilledema, and visual field testing. Intracranial pressure was measured by lumbar puncture and subsequently by intracranial pressure bolt monitoring. Magnetic resonance imaging ( MRI) was used to diagnose the Chiari I malformation. Results: The patient initially presented with bitemporal headaches, elevated opening pressure on lumbar puncture, and mild papilledema with a normal MRI. After lumboperitoneal shunt Manuscript received September 28, 2000; accepted March 30, 2001. From the Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio. Address correspondence and reprint requests to Raymond R. Lancione, Jr., MD, Department of Ophthalmology, 985540 Nebraska Medical Center, Omaha, NE 68198- 5540; e- mail: rlancione@ unmc. edu. placement and several revisions, the patient presented with decreased vision OD secondary to Terson syndrome and worsening papilledema. Subsequent evaluation revealed normal lumbar opening pressures and a Chiari I malformation. She underwent ventriculoperitoneal shunt placement with resolution of her symptoms. Conclusions: Tonsillar herniation is a well- documented complication of lumboperitoneal shunt revision. Obstruction of cerebrospinal flow through the foramina of Magendie and Lus-chka can result in increased intracranial pressure isolated to the cerebral ventricles. In a patient with signs and symptoms of increased intracranial pressure but normal lumbar opening pressure, a Chiari I malformation should be suspected, particularly with a history of multiple lumboperitoneal shunt revisions. Key Words: Pseudotumor cerebri- Increased intracranial pressure- Chiari malformation- Tonsillar herniation- Terson syndrome. A 42- year- old woman presented initially in July 1994 with severe bitemporal headaches and was diagnosed with pseudotumor cerebri based on a normal magnetic FIG. 1. Optic disc and fundus photos A: OD and B: OS, showing 4+ papilledema and subretinal hemorrhage consistent with Terson syndrome. Note subretinal hemorrhage involving the fovea OD. 118 WHEN DOES LOW MEAN HIGH? 119 followed by loss of central vision OD. She was evaluated the next day. Vision was counting fingers at 15 feet OD and 20/ 20 OS. Near vision was 20/ 400 OD and Jl OS. Pupillary reactions were 2+ OU without a relative afferent pupillary defect. Extraocular muscle motility was full OU. Slit lamp examination of the anterior segment was within normal limits OU. Applanation tensions were 18 mm Hg OD and 17 mm Hg OS. Dilated fundus examination revealed 4+ papilledema and subretinal hemorrhage OU with involvement of the fovea OD, findings consistent with Terson syndrome and accounting for her loss of acuity and the lack of a relative afferent pupillary defect ( Fig. 1) ( 1,2). On March 12, 1999, the patient underwent a fluoroscopic lumbar puncture, which yielded clear fluid and an opening pressure of 150 cm H20. MRI of the brain showed a large Chiari I malformation with herniation of the cerebellar tonsils through the foramen magnum ( Fig. 2). On March 29, 1999, the patient noticed a sudden decrease in visual acuity OS. Her vision was 20/ 400 OD and 20/ 200 OS. Dilated fundus examination revealed subretinal hemorrhage involving the fovea OS. The fundus OD also worsened, with the development of more extensive retinal edema ( Fig. 3). Despite two normal lumbar opening pressures, an elevation of intracranial pressure was strongly suspected given her high- grade papilledema. Intraoperative intracranial pressure bolt monitoring was used to record a pressure of 340 cm H20 in the lateral ventricles, confirming increased intracranial pressure and noncommunication of the cerebral ventricular system with the lumbar thecal space, presumably at the level of the foramina of Magendie and Luschka. Subsequently, the patient underwent ventriculoperitoneal shunt placement with rapid resolution of her papilledema ( Fig. 4). The extensive subretinal hemorrhage OU also regressed with treatment. FIG. 3. Fundus photos A: OD and B: OS, showing worsening Terson syndrome with bilateral foveal involvement of subretinal hemorrhage. J Neuro- Ophthalmol, Vol. 21, No. 2, 2001 FIG. 2. Magnetic resonance image of the brain showing tonsillar herniation through the foramen magnum. resonance imaging ( MRI) scan and an opening pressure on lumbar puncture of 320 cm H20, with a normal cerebrospinal fluid constituency. The patient had mild papilledema and no visual field loss at that time. Her headaches persisted, and in February 1995, the patient had her first lumboperitoneal shunt. From this time until November 30, 1998, she had seven shunt revisions. On February 10, 1999, the shunt was confirmed to be nonfunctional and was removed. Opening pressure by lumbar puncture was 140 cm H20 at that time, despite a nonfunctioning shunt. On March 1, 1999, the patient began having seizures. One week later, she had a seizure 120 R. R. LANCIONE AND G. S. KOSMORSKY FIG. 4. Optic disc photographs A: OD and B: OS, showing resolution of papilledema after ventriculoperitoneal shunt placement. DISCUSSION The Chiari I malformation is a well- documented complication of lumboperitoneal shunting, and in this case, the patient had several revisions of her shunt, which led to an acquired Chiari I malformation ( 3,4). Obstruction of the outflow of cerebrospinal fluid at the foramen magnum caused by tonsillar herniation led to an elevated intracranial pressure isolated to the cerebral ventricles. Although this event is rare, isolation of increased intracranial pressure to the ventricles must be considered when the signs and symptoms of increased intracranial pressure persist in the face of normal lumbar puncture opening pressures. This finding is more likely if the patient has undergone multiple lumboperitoneal shunts, a common cause of an acquired Chiari I malformation. REFERENCES 1. Medele RJ, Stummer W, Mueller AJ, et al. Terson's syndrome in subarachnoid hemorrhage and severe brain injury accompanied by acutely raised intracranial pressure. J Neurosurg 1998; 88: 851^ 4. 2. Schultz PN, Sobol WM, Weingeist TA. Long- term visual outcome in Terson syndrome. Ophthalmology 1991; 98: 1814- 9. 3. Chumas PD, Armstrong DC, Drake JM, et al. Tonsillar herniation: the rule rather than the exception after lumboperitoneal shunting in the pediatric population. J Neurosurg 1993; 78: 568- 73. 4. Sullivan LP, Stears JC, Ringel SP. Resolution of syringomyelia and Chiari I malformation by ventriculoatrial shunting in a patient with pseudotumor cerebri and a lumboperitoneal shunt. Neurosurgery 1988; 22: 744- 7. / Neuro- Ophthalmol, Vol. 21, No. 2, 2001 |
