Symptoms of Spinal Arteriovenous Malformations
Spinal AVMs most commonly present with progressive motor weakness and sensory disturbances, though acute neurological deterioration from hemorrhage can occur in up to 50% of cases.
Primary Clinical Presentations
Progressive Neurological Decline (Most Common)
Progressive spastic paraparesis is the hallmark presentation, developing insidiously over months to years as venous congestion and ischemia damage the spinal cord 1, 2.
Lower motor neuron involvement occurs in 95% of patients, manifesting as muscle weakness, atrophy, and fasciculations across multiple myotomes—often more widespread than the actual lesion location 2.
Sensory disturbances are typically the earliest complaint, presenting as paresthesias, numbness, or dysesthesias in a non-dermatomal distribution that progresses over time 2.
Bladder and bowel dysfunction develops as the myelopathy advances, reflecting involvement of autonomic pathways 1.
Acute Hemorrhagic Presentation
Sudden-onset paraplegia or quadriparesis can occur during physical exertion or spontaneously when the AVM ruptures, representing a neurological emergency 3.
Acute back or neck pain often accompanies hemorrhage, with rapid neurological deterioration over minutes to hours 3.
Hemorrhage occurs in approximately 50% of spinal AVM patients, similar to intracranial AVMs, and represents the most devastating presentation 4.
Specific Symptom Patterns by Location
Cervical Spinal AVMs
Tetraparesis with upper and lower extremity weakness is characteristic of cervical lesions 1.
Respiratory compromise may occur with high cervical lesions affecting the phrenic nerve 1.
Thoracic Spinal AVMs
Progressive paraparesis with lower extremity weakness predominates 1, 4.
Sensory level may be identified on examination, though often does not correlate precisely with the AVM location 2.
Conus Medullaris AVMs
Early bladder and bowel dysfunction is more prominent with conus lesions 5.
Saddle anesthesia and lower extremity weakness develop as the lesion progresses 5.
Critical Diagnostic Pitfalls
The location of symptoms frequently does not match the anatomical location of the AVM, because venous congestion and inadequate drainage affect spinal cord segments remote from the actual shunt 2. This discrepancy can delay diagnosis if clinicians rely solely on symptom localization.
Initial complaints are nonspecific and variable, making early diagnosis challenging—patients may present with vague sensory complaints or mild weakness that progresses insidiously before the diagnosis is considered 2.
Pathological spontaneous activity on EMG across multiple myotomes is a key electrophysiological finding that should raise suspicion for spinal AVM, especially when combined with abnormal sensory-evoked potentials but normal peripheral nerve conduction 2.
Temporal Pattern Recognition
Symptoms typically progress in a stepwise or gradually worsening pattern over months to years, reflecting recurrent microhemorrhages or progressive venous hypertension 2.
Acute deterioration superimposed on chronic symptoms suggests hemorrhage in a patient with previously undiagnosed spinal AVM 1, 3.
Exercise-induced symptom exacerbation can occur, as increased cardiac output and blood pressure may precipitate hemorrhage or worsen venous congestion 3.
Key Clinical Features Distinguishing Spinal from Intracranial AVMs
Unlike intracranial AVMs where hemorrhage (50-60%) and seizures (20-25%) dominate the presentation 6, spinal AVMs present predominantly with progressive myelopathy and lower motor neuron signs rather than seizures or headaches 2, 5.
Early diagnosis before progression to severe paraplegia is essential, as outcomes are significantly better when treatment occurs before irreversible spinal cord damage develops 2.