Arnold-Chiari 1 malformation type 1 with syringohydromyelia presenting as acute tetraparesis: A case report

Context: A 19-year-old woman who presented to a community hospital after awakening with tetraparesis, generalized paresthesia, and severe neck pain, and was transferred to an acute care hospital. Findings: Magnetic resonance imaging of the head and spine was performed and revealed a cystic lesion extending from the C1 level to the C6 level as well as an Arnold-Chiari type 1 malformation. Emergent surgical posterior fossa decompression with duraplasty and C1 laminectomy was undertaken. Most symptoms improved immediately postoperatively. On post-operative day 15, the patient was transferred to our acute rehabilitation hospital for an additional 16 days. With continued aggressive therapy, she demonstrated complete resolution of tetraparesis as well as significant improvement in muscle strength and function in addition to resolution of paresthesia and neck pain. Functional independence measure scores were 69/126 on admission to 110/126 on discharge from the rehabilitation hospital. Her tetraparesis eventually resolved; manual muscle testing scores on follow-up 2 months later were 5/5 in all four extremities. Clinical relevance: This is the first reported case of Chiari I malformation with syringohydromyelia presenting as acute tetraparesis, generalized paresthesia, and neck pain. Surgical decompression leading to resolution of symptoms made other etiologies extremely unlikely and there was no history of trauma. The different theories on the pathogenesis of syringomyelia are discussed.