Iodine, thyroid function, and very low birth weight infants.

OBJECTIVE: Research was undertaken to test two hypotheses. First, during the early neonatal period, thyroid function of very low birth weight (VLBW) infants is suppressed by exposure to iodine-containing antiseptic solutions and/or iodized contrast media. Second, this suppression is more pronounced in small for gestational age (SGA) infants. METHODS: Urinary iodine concentration and thyroid function measurements were obtained prospectively from 44 VLBW infants with gestational ages at birth of 30 +/- 2.3 weeks and weights of 1223 +/- 231 g. Eleven of these infants were SGA. The infants were grouped according to iodine exposure: 18 infants had no increased exposure and served as control infants; 9 infants were exposed to an iodine-containing antiseptic (povidone iodine); 12 infants were exposed to an iodized contrast medium (iopamidol); and 5 infants were exposed to both agents. Urinary iodine and serum free triiodothyronine, free thyroxine, and thyrotropin were measured on days 1, 7, 14, 21, and 28 of life. RESULTS: During the period of maximum exposure (days 1 to 7), the concentration of iodine in the urine of study infants was 2 to 4 orders of magnitude greater than that in the urine of control infants (123 +/- 141 micrograms/L). During the subsequent 3 weeks, levels of urinary iodine in study infants returned to levels that were not significantly different from controls. On day 7 of life, iodine-exposed infants had a significantly higher mean thyrotropin level than control infants, whereas on day 28, free triiodothyronine and thyroxine levels were lower. Of the 26 iodine-exposed infants, 6 had transient hyperthyrotropinemia and 2 had transient hypothyroidism. When exposed to iodine, SGA infants had more labile thyroid function than normally grown iodine-exposed or control infants. These SGA infants had significantly lower levels of thyroid hormones in umbilical cord blood, increased production of thyroid hormones on day 14 of life, and lower levels again at 1 month. CONCLUSION: In VLBW infants, the use of iodine-containing antiseptic solutions and iodized contrast media results in massive uptake of iodine that is associated with alterations in thyroid function. It is reasonable to suggest that, whenever possible, iodized products should be avoided in VLBW infants, because their routine use results in exposure to excessive loads of iodine, which can be associated with hyperthyrotropinemia and hypothyroidism.

Ex novo episodes of acute glomerulonephritis and Guillain-Barré syndrome: a case report.

A nine-year-old girl had several ex novo episodes of acute glomerulonephritis with clinical evidence of rapid progression in two of them. Guillain-Barré syndrome was diagnosed 10 days after the second episode of acute glomerulonephritis. Two renal biopsies (performed at about a four-year interval) gave morphological evidence of new episodes of acute glomerulonephritis. To our knowledge this is the first report of an association between ex novo episodes of acute glomerulonephritis and Guillain-Barré syndrome.

Growth evaluation in children with acute renal failure of unknown etiology.

We performed a retrospective study on 47 children over 1 year of age with severe acute renal failure (ARF) treated with hemodialysis (HD) at our Center from 1978 to 1986 in order to evaluate the diagnostic and prognostic value of growth indexes at hospital admission as a criterion to distinguish cases of ARF without previous chronic renal failure (CRF) from cases in which CRF was not previously diagnosed. The age of the patients ranged from 17 months to 13 years. The cause of ARF was identified in 41 children; 5 of them remained on HD for different reasons (hemolytic uremic syndrome with arteriolar involvement in 3 cases; renal vein thrombosis in 1; endoextracapillary glomerulonephritis in 1). No apparent cause of ARF was found in the other 6 children who remained on chronic HD. A careful history showed that these 6 children had had uremic symptoms for many years. When height was expressed as height standard deviation score (HSDS), the 6 children with ARF of unknown etiology showed significantly lower HSDS values compared with the other 41 children in whom a cause of ARF was diagnosed (p less than 0.001). In conclusion, growth failure in children requiring HD for ARF of unknown etiology is an important criterion that suggests a previously undiagnosed CRF and thus consequently a negative long-term prognosis.