Comparison of ultrasound findings in Guillain-Barre syndrome and chronic inflammatory demyelinating polyneuropathy for differential diagnosis.

Background: Peripheral nerve ultrasound (US) has been used as a promising diagnosing technique for peripheral nerve disorders. This study aimed to compare the US findings of Guillain-Barre syndrome (GBS) with chronic inflammatory demyelinating polyneuropathy (CIDP). Methods: This case-control study was done on 25 patients with GBS at 3 weeks after onset of disease and 25 patients with CIDP. Demographic information and US results of median nerve at 2 points, ulnar nerve at 3 points, and tibial and peroneal nerves were collected. Results: Left median nerve diameter in patients with CIDP with the mean of 0.141 ± 0.047 was more than GBS group with the mean of 0.095 ± 0.034 (P < 0.001). Both sides of median nerve diameter in patients with CIDP were higher than patients with GBS (P < 0.050), but in the left side, it was more in patients with CIDP (P = 0.003). Conclusion: The diameter and circumference of median, ulnar, and tibial nerves in forearm and elbow of patients with CIDP are more than patients with GBS; therefore, it may be possible to use US findings based on these differences in diagnosis and differentiation of the two diseases.