Symptoms of Spinal Arteriovenous Malformations
Spinal AVMs most commonly present with progressive myelopathy characterized by gradual weakness, lower motor neuron signs (atrophy, fasciculations), and sensory disturbances—not with seizures or headaches like their intracranial counterparts. 1
Primary Clinical Presentations
Progressive Neurological Decline (Most Common)
- Gradual motor weakness affecting both upper and lower extremities, with a particularly high incidence (95%) of lower motor neuron involvement including widespread distribution across multiple myotomes 2
- Sensory disturbances as initial nonspecific complaints, often preceding motor symptoms 2
- Progressive spastic paraparesis developing over time as venous hypertensive myelopathy worsens 3, 4
Acute Presentations
- Sudden quadriparesis or paraplegia, particularly during physical exertion when hemorrhage occurs 3, 5
- Acute neurological decline from hemorrhagic events, present in approximately 50% of patients at some point in their disease course 3, 6
Specific Neurological Findings
Motor System Involvement
- Both upper and lower motor neuron signs are characteristic, distinguishing spinal AVMs from purely upper motor neuron conditions 2
- Tetraparesis when cervical lesions are involved 3
- Paraplegia in thoracic or conus medullaris locations 3
- Muscle atrophy and fasciculations from anterior horn cell dysfunction 1, 2
Sensory Abnormalities
- Pathological sensory-evoked potentials after tibial nerve stimulation, while sural nerve conduction velocities remain normal, indicating sparing of sensory ganglia but involvement of central pathways 2
- Sensory level deficits that may not correlate anatomically with the actual AVM location, as symptoms result from venous congestion rather than the shunt location itself 2
Key Clinical Distinctions from Intracranial AVMs
Spinal AVMs do NOT typically present with:
- Seizures (common in 20-25% of intracranial AVMs) 1
- Headaches (present in 15% of intracranial AVMs) 1
- Pulsatile tinnitus 7
Critical Diagnostic Pitfall
The anatomical location of the AVM frequently does not match the spinal level of clinical symptoms because inadequate venous drainage and venous hypertension—not the shunt itself—drive symptomatology. 2 This discrepancy can mislead clinicians if they rely solely on symptom localization rather than comprehensive spinal imaging.
Pathophysiology Underlying Symptoms
The symptom pattern reflects venous hypertensive myelopathy rather than direct mass effect. 4, 2 The venous drainage system becomes overwhelmed by shunted blood volume, causing:
- Chronic venous congestion
- Spinal cord ischemia from impaired perfusion
- Progressive neuronal damage affecting both gray and white matter 2
Timing and Progression
- Initial complaints are nonspecific and variable, making early diagnosis challenging 3, 2
- Symptoms progress gradually in most cases, though acute deterioration can occur with hemorrhage 3, 4
- Early diagnosis before severe deficits develop is essential, as outcomes are significantly better when treatment occurs before progression to paraplegia 2