Highlight the importance of recognizing the role of spinal arteriovenous malformations (AVM) in patients with Klippel-Trenaunay Syndrome (KTS) presenting with symptoms characteristic of acute myelopathy.

KTS is a rare vascular malformation syndrome characterized by capillary malformations, venous abnormalities, and limb hemihypertrophy. Controversy exists in the literature of whether KTS is associated with spinal AVMs.

26-year-old male with PMH of KTS with congenital right leg hemihypertrophy and radiculopathy presented with sudden lower back pain, right leg weakness and paresthesia. Initial neurological exam was remarkable for right leg monoplegia, absent sensation below the right knee, absent right hallux proprioception, and absent bilateral patellar reflexes. Within hours of arriving at the hospital, the patient had progressive weakness and paresthesias of both legs, decreased rectal tone, and urinary retention.

Emergent MRI T/L with and without gadolinium showed a T12 intramedullary hemorrhage associated with a complex vascular malformation extending from T10-L2. This prompted an emergent spinal angiogram, which confirmed the presence of a complex AVM centered at T10 with intraspinal and extraspinal components, spinal cord venous congestion, and no clear aneurysm. Due to the extent of the malformation and no clear neurointerventional target, there was no acute neurosurgical procedure performed for reversal of the neurological damage. The patient reported improvement of paresthesias with Gabapentin and a trial of Dexamethasone. At the time of discharge to acute rehabilitation, there was minimal improvement in motor strength. The current treatment plan includes a repeat spinal angiogram.

There is limited literature on acute myelopathy due to vascular lesions in patients with known vascular malformation syndromes such as KTS, Parkes-Weber Syndrome, and CLOVES. This case highlights the significance of early consideration of acute hematomyelia due to AVMs to allow for timely neurosurgical intervention and prevention of complications such as permanent paresis.