[The role of TSH psychological and somatic changes in thyroid dysfunctions]

The characteristic psychic and somatic features found in patients with overt hyper- or hypothyroidism are usually attributed to elevated or diminished levels, respectively, of thyroid hormones. This concept does not sufficiently explain our previous investigations in which the same symptoms, albeit attenuated, were also seen in patients suffering from so-called latent disturbances of thyroid function. This state of disorder, however, exhibits normal concentrations of peripheral thyroid hormones. Only the response of thyroid-stimulating hormone (TSH) to thyrotropin-releasing hormone (TRH) stimulation is in accordance with the behaviour of the overt thyroid dysfunction and enables its differentiation from the euthyroid state. In this context, we investigated the question as to whether pathologic signs in thyroid disorders are correlated to alterations of peripheral thyroid hormones or to changes in the hypothalamus pituitary axis. Therefore, we investigated two groups of ten patients each who suffered from latent hyper- or hypothyroidism, respectively, and ten euthyroid controls. All were matched from sex and age. Endocrine function was estimated by TRH testing, TT3, TT4 and thyroxine binding globulin (TBG). Psychologic testing was performed by questionnaires concerning subjective somatic symptoms, emotional disturbances, psychomotoric performance, cognitive impairment and personality. Patients with latent hyperthyroidism were more subject to somatic symptoms and affective complaints than were those who had latent hypothyroidism. As compared with controls, there were significant differences in exhaustion and pain in the limbs and heart. In terms of affective complaints, patients were more depressive, anxious, touchy and irritable; their personalities showed a higher degree of emotional lability, excitement and irritability.(ABSTRACT TRUNCATED AT 250 WORDS)

[Dementia in hypothyroidism]

Hypothyroidism is one of the most frequent causes of potentially reversible dementia. According to present knowledge, symptoms of mental impairment begin insidiously and show a slow progression. They may precede the typical somatic manifestations of thyroid dysfunction. Almost complete remission of dementia may be expected from hormone substitution when the diagnosis is established early. The pathogenetic mechanisms which may have important implications for other forms of dementia are still imperfectly understood.

Does breast-feeding protect the hypothyroid infant whose condition is diagnosed by newborn screening?

Neuropsychological abilities at 1, 3, 5, and 6 years of age were compared in 107 children with congenital hypothyroidism identified by newborn screening who had been either breast-fed or formula fed during infancy. The thyroxine level was significantly higher in breast-fed children than formula-fed children at 1 and 2 months of age, but the level was not higher later during the first year of life. Controlling for parent IQ, socioeconomic status, and dose level, no differences in overall neuropsychological functioning were observed. Children with ectopic glands showed a significant advantage with breast-feeding on several tasks at 3 years of age. These results signify that thyroxine levels in infancy from breast-feeding are not necessarily reflected in improved intellectual functioning later in childhood.

Elementary school performance of children with congenital hypothyroidism. New England Congenital Hypothyroidism Collaborative

The aim of this study was to determine whether hypothyroid children treated early as a result of diagnosis after neonatal screening progressed normally in school. The New England Congenital Hypothyroidism Collaborative studied 72 of its patients at the ages of 9 or 10 years after they had completed 3 years of schooling beyond kindergarten. Control subjects were 96 classmates of the same sex and age as the patients and 32 siblings of appropriate age for the testing. Intelligence quotients (IQs) were measured by the Wechsler Intelligence Scale for Children-Revised abbreviated to five items, and school achievement by the Peabody Individual Achievement Test. In addition, a series of neuropsychologic tests was administered to both patients and control subjects. Educational histories were obtained from the parents for 74 patients, 87 of their siblings, 96 classmates, and 96 siblings of the classmates. The IQ of the control subjects (mean +/- SEM) was 109 +/- 1.2 versus 106 +/- 1.4 for the patients. The mean overall achievement score was 109 +/- 0.93 for the control subjects and 108 +/- 1.3 for the patients. These differences are not statistically significant. The regression lines relating overall Peabody Individual Achievement Test scores or subtests thereof to IQ did not differ among the patients and the control groups. Within the groups the regression lines for IQ and the different subtests of school achievement were also identical. The percentages of children repeating a grade, needing extra tutoring, or in special classes were the same for patients and control groups. We conclude that children with hypothyroidism have no apparent specific impediments to learning unrelated to intelligence.

Depression in primary hypothyroidism masquerading as inadequate or excessive L-thyroxine consumption

Depression may occasionally be a presenting feature of primary hypothyroidism but the influence of psychological illness upon L-thyroxine compliance in hypothyroidism has not been specifically addressed. We report six patients with primary hypothyroidism in whom repeated thyroid function tests implied that they were not taking their L-thyroxine as prescribed. The eventual recognition of underlying depression and its treatment led to appropriate treatment with thyroxine as evidenced by clinical euthyroidism and normal thyroid function tests.

Multivariate analysis of psychomotor development in congenital hypothyroidism

In the Finnish programme of screening for congenital hypothyroidism (CHT), thyroid replacement therapy is started very early (at a median age of 6 days). Our experience with the first 50 patients detected by this programme confirms that clinically relevant mental retardation is avoided by early therapy. But some intrauterine damage is inevitable and its degree correlates with the severity of the CHT. Age at the start of therapy, in our narrow range, did not appear to influence the outcome, as we found only a paradoxical positive correlation between the two. Our results suggest that thyroid hormone is transferred from the mother to her hypothyroid child during delivery.

Evaluation and characterization of the hypothyroid hyt/hyt mouse. I: Somatic and behavioral studies

Mice homozygous for the autosomal-recessive gene hypothyroid (hyt) had congenital hypothyroidism of fetal onset after 15 days postconception. Neonatal hyt/hyt mice had reduced serum thyroxine ranging from 1/5 to 1/6 of normal as well as significantly delayed somatic and behavioral development. Delayed somatic development included retarded eye opening and ear raising, and reduced body length and body weight. The hyt/hyt animals compared to their normal littermates demonstrated delayed reflexive behavior and abnormal motor and adaptive behavior. The somatic and behavioral measures clearly distinguished hyt/hyt animals from their normal littermates even without T4 determination. The somatic and reflexive behavioral abnormalities in the hyt/hyt mouse were similar to other rodent models of human congenital hypothyroidism. The hyt/hyt mouse provided an ideal model for exploring the effect of severe primary inherited hypothyroidism related to deficient autonomous fetal thyroid function and was consistent with the hypothesis that thyroid hormone deficit in utero and in the early neonatal period significantly altered functional development.

Behavioral modifications in relation to hypothyroidism and hyperthyroidism in adult rats

1. Behavioural experiments were carried out on adult rats made hypothyroid and hyperthyroid. The hypothyroid rats in an "open field" situation reduced the number of squares crossed and boluses defecated, the hyperthyroid rats reduced the number of squares crossed. A swimming endurance was conducted to evaluate the physical resistance of the rats: only hypothyroidism affected the performance. 2. Two operant tests were studied: a) an "extinction" trial (60 min), in which the rats trained in a fixed ratio schedule (FR 1:10), were no longer rewarded with pellets of food and b) the "reversal" test in which the contingency for food delivery was switched four times from one lever, where responses were previously reinforced, to the other lever where responses had no programmed consequences. 3. Both hypo and hyperthyroid conditions caused a lower rate of responses during the "extinction" trial, while in the "reversal" test only hyperthyroid rats showed improved performances. 4. Our data clearly demonstrate behavioural changes in adult hypothyroid and hyperthyroid rats.

Psychological depressive symptoms in grade II hypothyroidism in a nursing home

In an effort to explore the relationship between Grade II hypothyroidism and depressive symptoms, 16 nursing home residents with normal free thyroxine index and elevated basal thyrotropin (thyroid-stimulating hormone; TSH) levels were matched for age, sex, nursing level of care, and certain medications with a control group who had normal basal TSH levels. The Geriatric Depression Scale (GDS) was administered to all participants. Basal TSH elevation was not associated with increased psychological depressive symptoms on the GDS.

Intellectual outcome in children with fetal hypothyroidism

Eighty children with congenital hypothyroidism detected by newborn screening were grouped for presence of fetal hypothyroidism using skeletal maturity at the time of diagnosis as the index. Forty-five children with bone age less than 36 weeks were assigned to the delayed group; 35 with bone age 37 weeks to term were assigned to the nondelayed group. Although most children with athyrosis were found in the delayed group, the groups did not differ in birth weight, hormone levels, or family background. Assessments of intellectual and behavioral characteristics at 1, 2, 3, 4, and 5 years of age revealed that, although children in the delayed group performed within the normal range, their scores were significantly lower than those of the nondelayed group from age 2 years on. Perceptual-motor, visuospatial, and language areas were most affected. There were no differences in behavior or temperamental characteristics.

Altered responsiveness to ambiental stimuli in altered thyroidal states

Hypothyroidal rats produced by low iodine diet or propylthiouracyl (PTU) were less active in the open field and received fewer food reinforcements than controls in a lever press situation at both 22 degrees C and 1 degree C. The hypothyroid rats also pressed less when heat was the reinforcer. On the other hand, hyperthyroidal rats produced by thyroid powder ingestion showed reduced emotionality in the open field. Acute exposure to cold failed to increase their alimentary or heat reinforced behavior. The results suggest that hypothyroidism produces a general inattention to the environment. This is found whether the environmental stimulus is an opportunity to explore, access to food or the availability of external heat.

Four-year follow-up of psychological reactions to false positive screening tests for congenital hypothyroidism

Thirty-two families were investigated four years after a false alarm in the neonatal screening of their newborns. Sixteen of the families showed signs of persistent anxiety 6-12 months after the screening. Thirteen of them still show anxiety after 4 years. Of the 16 without anxiety at 6-12 months, 6 show signs of anxiety now. This persistent anxiety may be related to the initial psychological trauma of the false positive screening result. Thus, 19 of the 32 families have not completely integrated their experience. Twenty-four children were psychologically evaluated. Eight families refused to have their children examined. Twelve of the children showed disturbed behavior, 10 of these have parents who show unsatisfactory integration. Medical measures have psychological side-effects, which may be interpreted as iatrogenic. However, the effects of an external stress depend on the individual's susceptibility to it and abilities to cope with it and use external support available.

A comparison between the neurological and intellectual abnormalities in children and adults with congenital hypothyroidism

Standardised intellectual, motor and behavioural tests have been undertaken in a group of 73 children and 43 adults with congenital hypothyroidism in a regional study in the north of England. These provide comprehensive data with which to compare the results of studies of children diagnosed by screening and indicate the degree of abnormalities persisting into adult life in those patients diagnosed before screening was introduced. The mean IQ scores of the hypothyroid children and adults were 1-2 standard deviations (SD) below the population means. Longitudinal IQ data indicate persistence of intellectual abnormalities, though there was an increase in IQ score in several patients. The mean motor scores were reduced by 1-2 SD in the children and 1-3 SD in the adults. Behavioural problems and personality difficulties mainly of a neurotic nature also persisted into adult life.

Aspects of congenital hypothyroidism

This article describes aspects of congenital hypothyroidism, outlining retrospective studies and indicating the effects on development in childhood of the deficiency of thyroid hormone in early life. The intellectual problems persist into adult life and are associated with motor and behavioural abnormalities, causing social difficulties to many of the patients. Prospective screening and early treatment have resolved many of these difficulties but treatment must be given appropriately to ensure adequate progress.

Early treated hypothyroidism: development at 3 years

Eighty children from the North West and North East Thames Regional Health Authorities who had been identified as having congenital hypothyroidism either by neonatal screening (76 cases) or by clinical symptoms (four) were seen for psychological assessments at 1 (60 cases), 3 (58), and/or 5 (20) years of age. Almost all the children's scores were in the normal range, and comparisons with matched controls suggested that they were doing only slightly less well than normal children in overall development. They were significantly slower, however, on a motor skills task. Moreover, a low initial serum thyroxine and triiodothyronine value, considerable delay in initial bone age, and an absence of thyroid tissue on isotope scan seemed to be associated with a somewhat poorer prognosis.