| Congenital hypothyroidism (CH), namely cretinism, caused by all factors contributing to the thyroid hormone secreting decreasingly, resulting in profound alterations of mental capacities, neurological functions, and metabolic processes, is a common endocrine disease. Mental retardation, motor deficits, deafness, lethargy, and slowed metabolism are all characteristic in subjects affected by congenital hypothyroidism. The expectations of 80% of patients with CH achieving a mental development within normality in the children detected by the neonatal screening is a fact confirmed by many authors. It's difficult to be detected only by symptoms of the patients because of secrete clinical features, so mental retardation, motor deficits, deafness, lethargy, and slowed metabolism are all developing in subjects affected by congenital hypothyroidism. It is a proven fact that early diagnosis and treatment of this problem prevents mental retardation, which has led to the design and utilization of methods of systematic detection in the newly born. The Newborn Screening program was developed in the early 1970s to prevent mental retardation by early detection of congenital hypothyroidism. Current methods of screening are the primary thyrotropin(thyroid stimulating hormone, TSH) screening alone.In Zhejiang province the screening program for CH was initiated from 1999. The screening method was time-resolved fluoroimmunoassay for TSH on filter paper spots. If diagnosed, the infants would be received substitute treatment with levothyroxine as early as possible and follow-up for certain interval. In our research, we got the neonatal screening data from October 1999 to September 2002. The aim of theinvestigation was to achieve the data of CH among the lively newborns in Zhejiang province and to get the best treatment dosage of levothyroxine (L-T4).Objects and MethodsPart 1 Neonatal screening for congenital hypothyroidism in ZhejiangprovinceObjectsPart of lively newborns that were given birth in all locality hospitals (Ningbo city excepted) all over the province from Oct. 1,1999 to Sep.30,2002. MethodsTSH screening for CH was done from 1999 to 2002 in neonates of 48-72 hours age. Three drops of blood were taken from heels of newborns to the filter papers. All specimens of dried blood on filter paper taken from newborn babies were stored in icebox at 4 ℃ after being naturally dried and sent to our laboratory by mail. The values of TSH were measured by time-resolved fiuoroimmunoassay. The criteria for requesting repeat specimens, diagnosis and follow-up were uniform. Infants withelevated TSH level of greater than 9 u U/ml were recalled for tests of serum total triiodothyronine(TT3), total thyroxine(TT4) and TSH by chemiluminesence. The infants would be diagnosed as CH if they has not only the clinical features as lethargy, slowed metabolism, constipation, and too long time jaundice etc, but also the elevated TSH level, decreased levels of TT3, TT4. We would give them the tablets oflevothyroxine. If it's only found elevated TSH level in the individual, we wouldfollow-up it in 15 days to get the true diagnosis.Part 2 The low initial dose of levothyroxine for treatment ofcongenital hypothyroidismObjects138 infants (60 males and 78 females) affected congenital hypothyroidism diagnosed in our newborn screening center were initially treated from average 29.3 days (SD 6.6). Methods138 newborns with primary CH were divided into 3 groups according to their biochemical levels of TT4: l)sub-clinical CH group (TT4>54 nmol/L), 2) slight CH group (TT4 <54 nmol/L), 3) severe CH group (TT4<54 nmol/L and TT3 <1.2 nmol/L). Starting levothyroxine dose was 3.5±1.0(u g/kg.d) for mild CH group, 4.3±0.7(u g/kg.d) for moderate CH group and 4.7±0.6( u g/kg.d) for severe CH group. Follow-up evaluation was carried out at 1,2 and 3 months of age by measuring serum levels of TT3 , TT4 and TSH. When clinical signs and symptoms eliminated and serum levels of TT3, TT4 and TSH normalized, the time was...
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