Case Report: Downbeat Nystagmus Due to Epidural Puncture during Labor with Undiagnosed Arnold-Chiari Malformation.

Significance: Epidural anesthesia is a safe procedure used in pregnant patients during labor. However, caution should be exercised in those patients who have concurrent Arnold-Chiari malformation.

Purpose: This study aimed to report a rare and atypical presentation of downbeat nystagmus, in a pregnant patient with Arnold-Chiari malformation type 1 (ACM1), secondary to accidental dural puncture.

Case Report: A 31-year-old African American woman presented with a chief complaint of decreased vision and oscillopsia that occurred after giving birth, 6 months earlier. Her medical history before presentation was unremarkable. Her delivery was typical; however, the patient did receive epidural anesthesia, which resulted in a dural puncture. The patient noted her symptoms a few days after delivery. Upon examination, persistent downbeat nystagmus was noted in both eyes. Magnetic resonance imaging revealed a 2.5-cm inferior displacement of the cerebellar tonsils below the foramen magnum consistent with ACM1. The patient was referred to neurosurgery for posterior fossa decompression. However, surgery was deferred until appropriate weight reduction could be achieved. Follow-up examination 6 months later revealed no change in her clinical findings.

Conclusions: This case report highlights an atypical presentation of downbeat nystagmus secondary to an accidental dural puncture in a pregnant patient with undiagnosed ACM1. Clinicians should consider the importance of considering ocular complications that can occur in pregnant patients with ACM1. Questioning of women who have recently given birth about epidural anesthesia should be considered with an acute presentation of downbeat nystagmus.