Growth hormone response to clonidine administration for evaluation of autonomic dysfunction in multiple sclerosis patients.

UNLABELLED OBJECTIVES Our objective was to assess the dynamic serum growth hormone (GH) response to clonidine administration in multiple sclerosis patients, looking for a possible biomarker of degenerative process and to correlative with disability. METHODS 21 patients with relapsing remitting multiple sclerosis, who were evaluated clinically by expanded disability status scale (EDSS) score and multiple sclerosis functional composite (MSFC) score and for whom we measured the GH before and one hour after oral clonidine administration.Different cut-off values of EDSS score were chosen for observation of GH serum dynamics after clonidine administration. All patients had normal IGF1 values. RESULTS There was a significant positive correlation between EDSS and time to walk 25 feet (r = 0.5, p = 0.002) and EDSS and nine holes peg tests for dominant and non dominant hands (r = 0.37, p = 0.024 and r = 0.53, p = 0.001, respectively).There was a moderate negative correlation, significant statistically, between EDSS and paced auditory serial additional test (PASAT) (r= -0.36, p= 0.046).4 out of 7 patients with EDSS score over 3.0 failed to increase serum GH levels after clonidine administration, as compared to 4 out of 14 patients with EDSS < 3 (r = 1.6; p=0.02), revealed by means of the Pearson chi square test. CONCLUSION Despite the small number of subjects enrolled in this pilot study, there is a tendency of blunted GH response in patients with more severe physical disability (stated by an increased value of EDSS), suggesting that GH response to clonidine could assess central autonomic dysfunction in MS patients.