Pediatric Arnold-Chiari I Malformation With Syrinx Presenting With Unilateral Hand Weakness: A Case Report

Abstract

Diagnostic suspicion of Chiari I malformations (CM-I) can be challenging in the pediatric population due to highly variable neurologic symptoms and cognitive immaturity impairing symptom identification. Especially in an atypical presentation without obvious central neurological abnormalities, the diagnosis can often be missed. We present a case of a left-hand-dominant 14-year-old boy presenting to an orthopedic hand clinic with right-hand weakness, tingling, and impaired grip strength. The medical history was notable for mild scoliosis and acute lymphoblastic leukemia in remission treated with chemotherapy. The patient denied headaches, neck pain, or balance dysfunction on initial presentation. Neurodiagnostic studies were consistent with C7 and C8 radiculopathies, and magnetic resonance imaging of the brain and entire spine revealed herniation of the cerebellar tonsils with expansive syrinx extending into the lower thoracic spine. After successful posterior fossa decompression, upper extremity strength and hand clawing improved, which was corroborated with postoperative imaging. The patient met his physical therapy goals 6 months after surgery. A thorough history and neurologic examination are essential for earlier detection of pediatric CM-I and a favorable prognosis, particularly in patients with an unclear neurologic cause.

Keywords: Chiari I malformation; hand surgery; orthopedic surgery; pediatric; unilateral hand weakness.

Figure 1.

Preoperative magnetic resonance imaging of the cervical spine. Note. (a) Sagittal T2 illustrating 2.2 cm cerebellar tonsillar descent and multilocations within an apparent cervical syrinx. (b) T1 hypointense signal demonstrating the expansile central intramedullary syrinx beginning at the level of C2, measuring at least 0.9 × 1.4 cm.

Figure 2.

Preoperative magnetic resonance imaging of the brain and entire spine. Note. (a) Sagittal T2 of the upper spine demonstrating crowding at the cervicomedullary junction with C2 multiloculations and an expansile hydrosyringomyelia. (b) Sagittal T2 demonstrating the associated longitudinal extensive pronounced hydrosyringomyelia extending from the craniocervical junction to the T9 to T10 level, with internal septations at the C2 level. (c) Axillary T2 of the brain demonstrating associated venous congestion within the right cerebellar tonsil and mild deformity of the medulla.

Figure 3.

Postoperative magnetic resonance imaging of the brain and entire spine. Note. (a) Sagittal T2 demonstrating interval improvement of the crowding and cerebrospinal fluid columns through the craniocervical junction and improvement of the pointed morphology of cerebellar tonsils. (b) Sagittal T2 showing interval improvement of hydrosyringomyelia extending to the level of T9 to T10, measuring now up to 0.65 cm in diameter. At the C2 level, the multiloculated syrinx is significantly improved with residual cystic component in the right posterolateral region.