Demonstration of autonomic dysfunction in traumatic brachial plexus injury using quantitative sudomotor axon reflex test: Preliminary results.

OBJECTIVE: To objectively document autonomic dysfunction in the affected arm with traumatic brachial plexus injury (TBPI) using quantitative sudomotor axon reflex test (QSART). MATERIALS AND METHODS: Patients with TBPI presenting to the neurosurgical outpatient department from August 2013 to November 2014 were included in the study. The QSART was administered to each patient with prior informed consent detailing the procedure. A total of 20 patients with TBPI were included in the study. The age, sex, mode of injury, date of injury, side of injury, and type of injury (pan brachial plexus vs preserved distal function) were recorded. The presence of any pain was also recorded. The injuries were also grouped as preganglionic and postganglionic injuries based on clinical, electroneuromyography (ENMG) and magnetic resonance imaging (MRI) findings. The results of the test for the affected and normal limb were recorded and analyzed with appropriate statistical tests to determine any significant differences. RESULTS: The study included 20 patients, with their age ranging from 15 to 50 years. Out of the 20 patients, one was female and the rest 19 were males. Seven (35%) of the injuries were complete (pan brachial plexus) and 13 (65%) were incomplete (preserved distal function). All patients had preganglionic TBPI. There was no evidence of any statistically significant difference between the affected and normal arm for total sweat volume (P = 0.20) and latency period (P = 0.42). However, the average mean values for the same were lower in the affected arm as compared to the normal. The baseline sweat output (P = 0.010), however, was significantly lower in the affected arm as compared to the normal arm. CONCLUSION: QSART has demonstrated reduced baseline sweat output in the affected arm in patients with TBPI. This indicates the presence of autonomic dysfunction in the injured arm.