Pattern of sensory conduction in Guillain-Barre Syndrome

This study in undertaken to evaluate the pattern of sensory conduction abnormalities in Guillain-Barre (GB) Syndrome. Thirty six patients with GB Syndrome following clinical and CSF examination were subjected to motor conduction studies of median, ulnar and paroneal nerves including F wave latencies and sensory conduction studies of median, ulnar and sural nerves bilaterally. Motor conduction abnormalities were seen in 32 out of 36 patients (83%) and were seen more frequently in the lower limbs than upper. Median sensory conduction was abnormal more frequently than ulnar (21 Vs 17 patients). Median sensory conduction was abnormal in 21, ulnar in 17 and sural in 10 patients. In all the patients having abnormal ulnar sensory conduction, median sensory conductions were also abnormal. The patients with abnormal sural conductions had abnormal median sensory conductions in all except one patient. A pattern of normal sural with abnormal median sensory conductions was present in 12 patients. Both sural and median sensory conductions were abnormal in 9 patients and both normal in 14 patients. One patient had abnormal sural conduction with normal median sensory conduction but he had underlying diabetes. A similar pattern was found in relation to ulnar and sural sensory conductions although it was less frequent and less specific. The discordance of sural and median sensory conduction is important in GB Syndrome. Normal sural conductions with abnormal median sensory conductions is suggestive of GB Syndrome in the presence of an appropriate clinical setting, but a reverse pattern should alert an underlying polyneuropathy.