Peri-Sylvian Fissure Developmental Venous Anomaly

Abstract

A 9-year-old male presented to the Children's Colorado Emergency Department (ED) after losing consciousness and falling face-first onto a sidewalk while being escorted from a 4th of July parade. He had a mild headache and nausea that worsened as the parade progressed. En route to the hospital, his temperature was 105℉ and he had a tonic-clonic seizure. He had had a head injury one week prior. He had been jumping on a trampoline with siblings when his sister landed on his head. There was no loss of consciousness and he denied headache or nausea afterward. Computed tomography (CT) of his head (not shown) had been reportedly negative. By the time he arrived at the ED this time, he was awake but still had a headache and nausea. On examination, he had nuchal rigidity with gait ataxia and positive Romberg testing. Head CT (Fig. 1A) showed a focal linear hyperdensity in the region of the left Sylvian fissure. There was concern for subarachnoid hemorrhage (SAH) given his two recent head injuries. Later, the same hyperdensity was retrospectively noted on his previous CT. Subsequent magnetic resonance imaging with angiography (MRI/MRA) (Fig. 1B) revealed the hyperdensity to be a large left temporal lobe developmental venous anomaly (DVA). There was no aneurysm. By the next morning, the patient's symptoms and findings had all resolved. It was thought that he had suffered acute hyperthermia. Developmental venous anomalies of the brain are congenital abnormalities that arise from incomplete development of the venous system. They can be found in up to 2.6 % of autopsy studies and are thought to be harmless. They can be associated with sporadic cerebral cavernous malformations. Rare cases of hemorrhage have been reported, but usually in association with cavernous malformations. As DVAs provide venous drainage to the brain, it is important not to damage them during resection of cavernous malformations. The Sylvian fissure is a common place for both posttraumatic and aneurysmal SAH. Sometimes, after trauma, it is unclear whether SAH resulted from the trauma or from aneurysmal rupture. As shown in this report, however, hyperdensity in the region of the Sylvian fissure on CT may not represent SAH. In certain circumstances, if further imaging is being contemplated to search for the source of SAH, providers may consider MRI/MRA with contrast versus CT or catheter angiography, as other lesions will be better seen on MR imaging.