[A case of papilledema and Arnold-Chiari type I malformation].

CLINICAL CASE: A 12-year old girl was brought to the emergency ward because of headache and diplopia for 4 days. Bilateral papilledema was observed. Ancillary studies showed Arnold-Chiari Type I malformation without hydrocephalia. Cranial decompression treatment was performed but papilledema persisted and a progressive visual field deterioration was assessed. One month later, an optic nerve sheath fenestration was performed. DISCUSSION: Arnold-Chiari I malformation is characterized by downward displacement of cerebellar tonsils below the foramen magnum plane. It usually remains asymptomatic or appears in adulthood with brainstem compression-related symptoms. Surgical decompression of the posterior cranial fossa is mandatory in symptomatic cases. In our case, intracranial hypertension persisted because of postoperative subdural hygromas. Visual field deterioration was resolved by optic nerve sheath fenestration (Arch Soc Esp Oftalmol 2002; 77: 449-454).