Acute Paraparesis Triggered by Cough as the First Sign of Thoracic Arachnoid Web
Angelica Emili Hernandez Mondragon1, Jason Schick1, Joseph Corey1
1Neurology, Trinity Health Grand Rapids
Objective:
To present a case of a dorsal thoracic arachnoid web presenting with acute paraparesis that developed after a night of severe coughing.
Background:
Arachnoid webs are intradural bands of thickened arachnoid tissue that may disrupt CSF flow. This can lead to syringomyelia formation, and in severe cases, spinal cord compression.
CSF flow is naturally subject to variations. Increased intrathoracic and intraabdominal pressure during cough is communicated to the CSF via the venous system. In the presence of an arachnoid web, CSF flows preferentially in one direction which can contribute to syrinx formation.
Results:
A 22-year-old female presented with acute onset bilateral lower extremity weakness and lower back pain radiating to bilateral knees. Her weakness began after a severe bout of coughing and gradually progressed over hours until she was unable to walk unassisted. Neurologic exam was significant for symmetric weakness of bilateral lower extremities (3/5 strength) with 3+ reflexes of bilateral patella and intact pinprick and vibratory sensation. MRI of the thoracic spine showed anterior displacement of the spinal cord at the T5/T6 level, with pathognomonic "scalpel sign." Thoracic 5-7 laminectomy revealed an arachnoid web at T5/T6 level obstructing CSF flow. Following dissection of the web from the surrounding dura and spinal cord, normal CSF flow returned. Pathology later confirmed that this was arachnoid tissue. On follow up evaluation, her weakness resolved and she was able to ambulate without difficulties by the time of discharge 4 days after surgery.
Conclusions:
Arachnoid webs are thickened bands of arachnoid tissue that typically present with weakness that gradually progresses over months. Despite their typically insidious course, asymptomatic thoracic arachnoid webs may become acutely symptomatic due to factors that alter CSF dynamics, such as coughing or Valsalva maneuvers. Early identification and surgical resection are paramount to achieving an excellent functional outcome.
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.