Can a syrinx (syringomyelia) of the spinal cord in the thoracic spine cause headache?

Can Thoracic Syrinx Cause Headache?

A thoracic syrinx alone does not typically cause headache, but headache may occur if the syrinx is associated with Chiari malformation or if there is an underlying CSF flow disturbance affecting intracranial pressure dynamics.

Understanding the Relationship

The evidence regarding thoracic syringomyelia and headache is limited but informative:

Direct Mechanism (Rare)

• Syringomyelia-induced disruption of sympathetic fibers in the thoracic spinal cord is recognized as a rare mechanism of syncope, not headache 1
• The ACC/AHA/HRS guidelines specifically note that thoracic cord sympathetic disruption causes autonomic dysfunction leading to syncope, not cephalic symptoms 1

Indirect Mechanisms (More Common)

Chiari Malformation Association:

• Arnold Chiari malformations are the most common form of syringomyelia 1
• Isolated thoracic syrinx occurs in approximately 4.5% of all patients with Chiari malformation and represents 9.1% of all Chiari-associated syrinxes 2
• The headache in these cases originates from the Chiari malformation itself (posterior fossa crowding, tonsillar herniation) rather than the thoracic syrinx 2

CSF Flow Disturbances:

• Syringomyelia associated with spinal arachnoiditis can cause disturbances in CSF flow dynamics 3
• When arachnoiditis causes complete subarachnoid space block, this may theoretically affect intracranial CSF dynamics and potentially contribute to headache, though this is not the primary mechanism 3
• One case series documented that spontaneous intracranial hypotension with CSF leak at the cervicothoracic junction (T1-2) presented with severe postural headaches, demonstrating that thoracic-level CSF disturbances can cause headache through altered CSF dynamics 1

Clinical Approach

When evaluating a patient with thoracic syrinx and headache:

• First, assess for Chiari malformation - obtain brain MRI if not already performed, as this is the most common association and the likely source of headache 1, 2
• Evaluate headache characteristics - postural headaches suggest CSF leak or intracranial hypotension rather than the syrinx itself 1
• Look for cervicogenic features - neck pain accompanying headache suggests cervical spine pathology rather than isolated thoracic syrinx 1
• Consider complete spine imaging - isolated thoracic syrinx cannot be reliably predicted clinically and may extend rostrally 2

Important Caveats

Common pitfalls to avoid:

• Do not assume the thoracic syrinx is causing the headache - look for alternative explanations first 1, 2
• Do not miss Chiari malformation - this is present in the majority of syringomyelia cases and is the actual cause of headache 1, 2
• Recognize that thoracic syrinx typically causes motor/sensory deficits in the lower extremities and trunk, not headache 4, 3
• Be aware that syrinxes predominantly at thoracic levels are associated with spinal arachnoiditis and present with paraparesis or tetraparesis, not headache 3

The clinical presentation of isolated thoracic syrinx shows great heterogeneity, but headache is not a characteristic feature 2. When headache coexists with thoracic syrinx, investigate for Chiari malformation, CSF leak, or other intracranial pathology as the true etiology 1, 2.