Presentations

Abstract

Introduction:

Syringomyelia is the development of fluid-filled cavities within the spinal cord parenchyma and is typically caused by congenital or acquired alterations in cerebrospinal fluid flow. An arachnoid web is a pathologic thickening of arachnoid tissue bands within the spinal canal which inhibits laminar flow of cerebrospinal fluid. This can predispose patients to syringomyelia formation and occurs with increased frequency after spinal cord trauma and surgeries [2]. This case highlights a rare presentation of syringomyelia associated with arachnoid webs in a patient with neurologic deficits.

Case Information:

A 44-year-old male with no significant past medical history presented to the emergency department with a two-week history of left sided facial weakness and droop as well as left lower extremity numbness and tingling. He was a steel mill worker who often lifted heavy objects at work. He noted a history of left shoulder trauma due to a fall from a roof about 10 to 15 years ago with full recovery. Initial neurological exam revealed mild left facial droop with nasolabial fold flattening, left lower facial weakness, mildly decreased light, touch and pinprick sensation in the left V1-V3 facial distribution, and weakness with left eyelid closure. Bilateral patellar reflexes were mildly hyperactive without clonus and motor strength was normal in all extremities. Light touch sensation was diminished at the left thigh only and the spine had full strength and motion. Brain imaging was unremarkable. Spine imaging identified a syrinx extending from C2-T10 secondary to an arachnoid web at T5. Neurosurgery were consulted and recommended conservative management. On his subsequent outpatient follow up two weeks later, he endorsed new thoracic midline back pain radiating into the left hip. Examination at that time was notable for 3+ bilateral patellar reflexes without clonus as well as normal strength, tone and sensation to light touch in all extremities. Surgical arachnoid web removal was discussed, but the patient elected to pursue conservative management with repeat imaging in 6 months.

Discussion:

Based on our review of the current literature, the rarity of syringomyelia associated with arachnoid webs is demonstrated with only 29 other documented cases [3]. Average time of syrinx formation post spinal cord injury (SCI) is 5 years for patient's over 30 years and 17 years for those under 30 years at time of injury [1]. Patients over 30 years of age with SCI are at risk of more rapid syrinx formation and should be screened for syringomyelia with MRI, which may also help elucidate its underlying cause. Based on the neurosurgeon's review in this case, the leading differentials for our patient included post-traumatic versus primary spontaneous syringomyelia. Management depends on syrinx size, symptom severity and overall clinical status. Conservative management can be considered for stable patients with mild symptoms, whereas laminectomy with intradural arachnoid web excision is considered in those with refractory pain unresponsive to medical therapy or acutely worsening neurological symptoms [3].

Conclusion:

This case demonstrates a rare presentation of syringomyelia associated with a thoracic arachnoid web in a patient with neurologic deficits and a remote traumatic history.