Do Not Forget Nephrotic Syndrome as a Cause of Increased Requirement of Levothyroxine Replacement Therapy

Nephrotic syndrome increases L -thyroxine requirements because of urinary loss of free and protein-bound thyroid hormones. We report 2 hypothyroid patients referred to us because of high serum TSH, even though the L -thyroxine daily dose was maintained at appropriate levels or was increased. The cause of nephrotic syndrome was multiple myeloma in Received: December 12, 2014 Accepted after revision: February 24, 2015 Published online: May 28, 2015 Roberto Vita Endocrinology, Department of Clinical and Experimental Medicine University of Messina, Viale Gazzi, Padiglione H, 4 piano IT–98125 Messina (Italy) E-Mail roberto.vita @ yahoo.it © 2015 European Thyroid Association Published by S. Karger AG, Basel 2235–0640/15/0042–0138$39.50/0 www.karger.com/etj What Is Known about This Topic? • Nephrotic syndrome may trigger the onset of hypothyroidism or aggravate preexisting hypothyroidism, with subsequent increased requirements of the L -thyroxine dose because of urinary loss of free and protein-bound thyroid hormones. What Does This Case Report Add? • This case report provides detailed information on 2 cases of augmented L -thyroxine replacement because of nephrotic syndrome. In both cases, symptoms were initially supposed to be due to hypothyroidism. D ow nl oa de d by : 54 .1 91 .4 0. 80 9 /1 7/ 20 17 4 :3 7: 47 A M