P126. Identification by ultrasound of a cervical nerve root edema caused by vertebral artery loop

Abstract Ultrasound is an excellent modality in imaging of peripheral nerves ( Lawande et al., 2014 , Suk et al., 2013 ). Although it is a well-established technique its use is not a first-line diagnostic tool in patients with brachialgias. In this case we report of a 44 years old male, who suffered for years from brachialgia of fluctuating intensity of the right arm. A lax humerus articulation of the same arm was diagnosed in the childhood and treated surgically. Actually the patient reported pain mainly in the C6 dermatome, but also shoulder area (C5). He associated these symptoms with a varicella zoster virus (VZV) affection of the shoulder some weeks ago. Cerebral spinal fluid (CSF) examination showed an altered cell count (11 cells/ μ L). Viral Plexus neuritis was suggested and antiviral therapy was started. Not congruent were the neurological status ( Miller et al., 2000 ) and the electrophysiological examination of the periphery nerves, both within normal limits. The further results from the CSF suggested no acute viral infection and showed residual post infectious state with elevated IgG-Antibodies for VZV. As part of the further differential diagnosis a sonography of the cervical roots and brachial plexus was realized. It showed an edema of the cervical root C6 and in less degree of C5 and C7. Furthermore the patient had a dominant right vertebral artery (V1 diameter 5,2 mm vs. 1,9 mm of the left side) with coiling in V2-segment next to the affected roots. The MRI of the right plexus and MR-angiography confirmed the diagnosis and showed the elongated vertebral artery with a loop with contact to the affected roots. We suggest that the edema is due to the pulsatile contact of the vertebral artery, concordant to a reported intermittent pulsatile pain of the shoulder and right thumb, combined with a chronic intrathecal irritation, which explains the elevated cell count in the CFS. Conclusion There are few case reports ( Hoon Soo et al., 2010 , Ahmed et al., 2014 ) describing a vertebral loop as origin of radiculopathy but we could not find reports of ultrasound of peripheral nerves for this diagnose. We postulate that routine ultrasound as preliminary evaluation of cervical roots and plexus of patients with brachialgias and diffuse arm pain symptoms could help to improve the diagnostic precision with this high definition and low cost methodology with no adverse events for the patients.