Iatrogenic iodine as a cause of hypothyroidism in infants with end-stage renal failure.
Between 1996 and 2005, two of seven infants in our unit on overnight continuous-cycle peritoneal dialysis (CCPD) acquired hypothyroidism following normal thyroid function on neonatal screening. Case 1 had posterior urethral valves, commenced CCPD at day 29, and developed hypothyroidism requiring treatment at 3 months: TSH 258 micro/l (ref.: 0.3-3.8), total thyroxine 74 nmol/l (ref.: 77-159). Plasma iodine concentration was 7.44 micromol/l (ref.: 0.23-0.68). Iodine concentrations in peritoneal dialysis (PD) fluid were found to be higher at the end of the first cycle (11.4 micromol/l) than at the end of the twelfth cycle (1.55 micromol/l). Case 2 had posterior urethral valves, commenced CCPD on day 4 and was diagnosed with hypothyroidism following a prolonged jaundice screen. Thyroxine replacement was stopped 2 months after a renal transplant. A third child commenced CCPD on day 2 and had high plasma iodine concentrations at 8 weeks (5.79 micromol/l). He had borderline thyroid function, not requiring replacement. Our hypothesis is that these infants developed hypothyroidism as a consequence of iodine exposure via the Wolff-Chaikoff effect. Iodine levels were higher in the PD fluid than in plasma. This suggests that povidine-iodine 10% in the PD cap may be the source of the high plasma iodine levels.
Brough
Richard
R
Department of Nephrology, Royal Liverpool Children's Hospital -- Alder Hey, UK. richardbrough@gmail.com
Jones
Caroline
C
D003287:Contrast Media / Q000009:adverse effects; D006801:Humans; D007037:Hypothyroidism / Q000209:etiology*; D007223:Infant; D007455:Iodine / Q000009:adverse effects*; D007472:Iohexol / Q000009:adverse effects; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000628:therapy*; D008297:Male; D010530:Peritoneal Dialysis / Q000009:adverse effects* / Q000295:instrumentation
D003287:Contrast Media; D007472:Iohexol; D007455:Iodine