Spinal dural arteriovenous fistula (SDAVF) can lead to spinal cord edema and myelitis, and early unspecific symptoms could cause it to be mistaken with demyelinating diseases such as multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD), according to two recent case reports published in the Journal of Cerebrovascular and Endovascular Neurosurgery.
Patients with SDAVF experience drainage of an arteriovenous malformation into the perimedullary venous plexus, thus causing blood flow congestion and medullary edema. Although angiography is the diagnostic tool of choice in SDAVF, MRI findings such as enlarged pial flow void around the spinal cord on T2W can, in combination with other clinical findings, help reach a diagnosis.
“Since there is a limitation in obtaining detailed images in the [emergency room (ER)], it is easy to misdiagnose as other diseases if the radiologic findings are not obvious,” the authors wrote.
The first case involved a 67-year-old man with a previous history of recurrent transient neurological deficits dating back several years. The patient visited the ER after presenting quadriparesis, voiding abnormalities, and sensory changes since the day before.
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A full neurological physical exam revealed intact cranial nerve function, right dominant quadriparesis, and right-sided hypoesthesia below the T10 dermatome. The cerebrospinal fluid examination was remarkable for elevated proteins; pleocytosis was not present.
A spine MRI showed a high intramedullary signal that extended from the cervicomedullary junction to the T1 spinal cord; during this initial assessment, physicians failed to recognize vessel flow anomalies.
Mainly due to the previous episodes of neurological deficits, the attending physicians considered NMOSD and MS as the more likely diagnoses and initiated corticosteroid therapy. However, following the radiology consult the next day, the patient was diagnosed with SDAVF and underwent embolization therapy with a positive outcome.
The second case involved a 53-year-old man with a 4-day history of paraparesis, dysphagia, dysarthria, and paresthesia below the T6 dermatome. Laboratory tests showed leukocytosis with an unremarkable cerebrospinal fluid study. The only abnormal finding in the MRI was a high signal change in the lower medulla.
The patient was considered to have either MS or NMOSD and received steroid pulse therapy for 5 days. Due to poor response to treatment, a second MRI was performed, revealing an enhancing serpentine vessel in the ventral and dorsal surfaces of the spinal cord. SDAVF was confirmed with conventional angiography, and the patient underwent embolization therapy with a positive response.
“SDAVF has an ambiguous clinical feature with characteristic MRI findings; its diagnosis should be accompanied by careful examination and clinical experience,” the authors concluded.
Kim N, Kim H, Kim H, Park J. Congestive myelopathy due to spinal dural arteriovenous fistula mimicking CNS demyelinating disease. J Cerebrovasc Endovasc Neurosurg. Published online July 29, 2022. doi:10.7461/jcen.2022.e2021.11.003