Transcranial Doppler sonography in a patient with Ehlers-Danlos syndrome: case report

Ehlers-Danlos syndrome is of special interest because of the risk of formation of intracranial aneurysms. The reason is increased elasticity of the vessel wall, which can influence the waveform of the transcranial doppler signal.

A patient with Ehlers-Danlos syndrome Type IV and an aneurysm of the left middle cerebral artery was studied with transcranial doppler sonography. Compared with a reference group of 29 volunteers, there was no difference in blood flow velocity in the middle cerebral and anterior cerebral arteries on both sides. The pulsatility index, however, was lower compared to the pulsatility index of the reference group (right middle cerebral artery, 0.69 versus 0.89; left middle cerebral artery, 0.58 versus 0.87; right anterior cerebral artery, 0.66 versus 0.94; left anterior cerebral artery, 0.68 versus 0.88). There was no difference in blood pressure during examination between the described patient and the reference group.

Under the concept of an increased elasticity of the vessel wall, a decreased flow resistance can be expected, which is represented by a decreased pulsatility of the blood flow waveform. It might be possible that in patients with Ehlers-Danlos syndrome, intracranial arteries that show a very low pulsatility index run a high risk to develop an aneurysm.