Lessons learned about prevalence and growth rates of abdominal aortic aneurysms from a 25-year ultrasound population screening programme

Background

This study aimed to assess how the prevalence and growth rates of small and medium abdominal aortic aneurysms (AAAs) (3·0–5·4 cm) have changed over time in men aged 65 years, and to evaluate long-term outcomes in men whose aortic diameter is 2·6–2·9 cm (subaneurysmal), and below the standard threshold for most surveillance programmes.

Methods

The Gloucestershire Aneurysm Screening Programme (GASP) started in 1990. Men aged 65 years with an aortic diameter of 2·6–5·4 cm, measured by ultrasonography using the inner to inner wall method, were included in surveillance. Aortic diameter growth rates were estimated separately for men who initially had a subaneurysmal aorta, and those who had a small or medium AAA, using mixed-effects models.

Results

Since 1990, 81 150 men had ultrasound screening for AAA (uptake 80·7 per cent), of whom 2795 had an aortic diameter of 2·6–5·4 cm. The prevalence of screen-detected AAA of 3·0 cm or larger decreased from 5·0 per cent in 1991 to 1·3 per cent in 2015. There was no evidence of a change in AAA growth rates during this time. Of men who initially had a subaneurysmal aorta, 57·6 (95 per cent c.i. 54·4 to 60·7) per cent were estimated to develop an AAA of 3·0 cm or larger within 5 years of the initial scan, and 28·0 (24·2 to 31·8) per cent to develop a large AAA (at least 5·5 cm) within 15 years.

Conclusion

The prevalence of screen-detected small and medium AAAs has decreased over the past 25 years, but growth rates have remained similar. Men with a subaneurysmal aorta at age 65 years have a substantial risk of developing a large AAA by the age of 80 years.

Vitamin D supplementation trial in infancy: body composition effects at 3 years of age in a prospective follow-up study from Montréal

BACKGROUND

The impact of vitamin D status on body composition is not well understood.

OBJECTIVES

Evaluate how vitamin D supplementation in infancy affects body composition at 3 years of age.

METHODS

Double-blind randomized trial of 132, 1-month-old healthy, breastfed infants randomly assigned to receive oral vitamin D₃ supplements of 400, 800, 1200 or 1600 IU d^-1 for 11 months. In the present analysis, 87 (66%) returned at 3 years of age. Body composition was measured using dual-energy x-ray absorptiometry and plasma 25-hydroxyvitamin D [25(OH)D] concentrations by liquid chromatography tandem mass spectrometry.

RESULTS

Anthropometry, body composition, diet, activity and demographics were similar across dosage groups at 3 years. Mean 25(OH)D concentration from 1 month to 3 years was higher (P < 0.001) in the 1200 IU group than 800 and 400 IU groups. Children with 25(OH)D concentrations above 75 nmol L^-1 had lower fat mass (~450 g; P = 0.049). In multiple linear regression, mean 25(OH)D was associated with lean mass percent (β = 0.06; CI: 0.00, 0.12; P = 0.042), fat mass (β = -11.29; CI: -22.06, -0.52; P = 0.048) and body fat percent (β = -0.06; CI: -0.12, -0.01; P = 0.045).

CONCLUSIONS

Higher vitamin D status from infancy through to 3 years of age associates with leaner body composition.

Vitamin D supplementation in breastfed infants from Montréal, Canada: 25-hydroxyvitamin D and bone health effects from a follow-up study at 3 years of age

Whether infant vitamin D supplementation may have long-term bone benefits is unclear. In this study, breastfed infants who received vitamin dosages greater than 400 IU/day did not have higher bone mineralization at 3 years. This study provides important data to inform pediatric public health recommendations for vitamin D.

INTRODUCTION

North American health agencies recommend breastfed infants should be supplemented with 400 IU of vitamin D/day to support bone health. Few studies examined the long-term benefits of early life vitamin D supplementation on bone mineralization. The objective of this study was to determine if a dose-response relationship exists between infant vitamin D supplementation, vitamin D status, and bone outcomes at 3 years of age.

METHODS

This was a double-blind randomized trial of 132, 1-month-old healthy, breastfed infants from Montréal, Canada, between 2007 and 2010. In this longitudinal analysis, 87 infants (66 %) returned for follow-up at 3 years of age, between 2010 and 2013. At 1 month of age, participants were randomly assigned to receive oral cholecalciferol (vitamin D3) supplements of 400, 800, 1200, or 1600 IU/day until 12 months of age. Lumbar spine vertebrae 1-4 (LS) bone mineral density (BMD), LS and whole body bone mineral content (BMC), and mineral accretion were measured by dual-energy x-ray absorptiometry at 3 years.

RESULTS

At follow-up, the treatment groups were similar in terms of diet, sun exposure, and demographics. There were no significant differences among the groups in LS or whole body BMC, BMD, or accretion. Although, 25(OH)D concentrations were not different among the groups, higher doses (1200 and 1600 IU/day) achieved higher 25(OH)D area under the curve from 1 to 36 months vs. 400 IU/day.

CONCLUSIONS

This is the first longitudinal follow-up of an infant vitamin D dose-response study which examines bone mineralization at 3 years of age. Dosages higher than 400 IU/day do not appear to provide additional benefits to the bone at follow-up. Larger studies with more ethnically diverse groups are needed to confirm these results.

Prevalence of overweight And Obesity in Canadian Children: A Decade of Progress in the Canadian Community Health and Health Measure Surveys

BACKGROUND: Previous studies using the Canadian Community Health Survey (CCHS) demonstrated an increase in the prevalence of overweight or obesity in Canadian children from 23.3% to 34.7% (1978– 2004) using the new 2010 WHO for Canada Growth Charts.

OBJECTIVES: To better define temporal trends in overweight and obesity status, this study examines additional data from the Canadian Health Measures Survey (CHMS, 2009-2013) by applying current Canadian definitions based on WHO body mass index (BMI) thresholds and recently validated waist-circumference norms from NHANES III (1988-1994). Associations with variables such as family income, parent education and number of parents were also explored over this time frame.

DESIGN/METHODS: Directly measured heights and weights were available for 14,014 children aged 3-19y from the decade 2004 to2013 in CCHS (n=8976)CHMS cycle 2 (n=2578) and CHMS cycle 3 (n= 2460). Z-scores for BMI, height, and weight were based on the 2014 WHO Growth Charts for Canada, including their new extension of weight-for-age beyond 10y. For waist circumference and waist-height ratios, we used new charts from the NHANES III reference population. Inverse probability survey weights were used to account for non-response and under-coverage.

RESULTS: The sex distribution was similar in each survey cycle and ~ 80% were of white race/ethnicity. Using current WHO definitions based on BMI, we observed a decline in the proportion ‘overweight or obese’ from 30.7% (95%CI=29.4–32.0) to 27.0% (25.7–28.3, p&lt;0.001) and a stabilizations in obesity rates at ~13%. Rates of overweight and obesity were higher in boys, non-whites, and older children. These trends persisted after regression adjustment for age, gender, and race-ethnicity. Although declining, median Z-scores for BMI, weight, and height were positive compared to the WHO reference population. Waist-circumference and waist-height ratio Z-scores were negative, with less central adiposity than American children in historic or contemporary NHANES cohorts. Temporal trends in overweight/obesity appear to vary with family income, educational achievement, and immigrant status.

CONCLUSION: After a period of dramatic growth, both BMI-Z-scores and the prevalence of overweight or obesity appear to be declining in in Canadian children, attesting to progress against this important public health challenge.

Increasing Incidence of Optic Nerve Hypoplasia/ Septo-Optic Dysplasia Spectrum: Geographic Clustering in Northern Canada

BACKGROUND: Since optic nerves and pituitary gland are embryologi-cally related, optic nerve hypoplasia (ONH) and septo-optic dysplasia (SOD) represent a clinical spectrum associated with visual impairment, pituitary deficiencies, and severe CNS structural malformations(SODplus). ONH is a leading cause of pediatric blindness in North America; genetic mutations are rarely observed. We recently perceived an increase in the number of children with SOD in our clinic. Similarly, several studies have reported a rise in the incidence of ONH/SOD in other jurisdictions.

OBJECTIVES: Our primary objectives were to examine trends in annual incidence in Manitoba and geographical clustering in our catchment area ofManitoba, NW Ontario and Nunavut.

DESIGN/METHODS: This was a retrospective 1996-2015 chart review from all medical services (Neurology, Ophthalmology, Endocrinology, Genetics) caring for these children to extract information pertaining to anthropometric measures, radiologic findings, parental characteristics, endocrinopathies, and neurologic symptoms. Postal codes were used to assign map co-ordinates and census-based material and social deprivation indices. Numbers of children from Manitoba only were used to calculate annual incidence. From 2010-2014, a Quality Assurance (QA) sub-study identified all pediatric radiology reports containing the words 'optic nerve'; the additional cases of ONH/SOD children not identified by chart review were used to better define the true incidence in Manitoba.

RESULTS: Ninety-three children were identified in our catchment area by chart review; Poisson regression confirmed a striking 1.11-fold annual increase (95%CI=1.07-1.16) or ~800% over two decades. The annual incidence (averaged 2010-2014) reached 53.3 per 100,000 affecting 1 in 1875 live births (chartdata). Including children identified by QA sub-study, the incidence rose to 113.3 per 100,000 live births in Manitoba. These are much higher than previously reported. Most children (~60%) had SODplus. Common presenting or follow-upfeatures were hypoglyce-mia, nystagmus, seizures, and developmental delay (50%); 40% had hormone deficiencies; 80% (75/93) had reduced visual acuity, typically bilateral. Many childrenwere born prematurelywith young (mean 21y: IQR 19-26y), primiparous mothers. Unhealthy maternal lifestyles and severe material deprivation were noted. There wasdisproportionate clustering in Northern Manitoba (3 times the average provincial rate) and in Nunavut.

CONCLUSION: We noted a dramatic rise in the annual incidence of ONH/SOD in Manitoba, NW Ontario and Nunavut, which is much higher than previous reports. This disorderwas strongly associated with poverty in northern communities. The temporal picture was consistent with environmental, nutritional, or toxic etiologies. About half of the children were severely affected with increased morbidity and health care burdens.

Skeletal findings in the first 12 months following initiation of glucocorticoid therapy for pediatric nephrotic syndrome

Incident vertebral fractures and lumbar spine bone mineral density (BMD) were assessed in the 12 months following glucocorticoid initiation in 65 children with nephrotic syndrome. The incidence of vertebral fractures was low at 12 months (6 %) and most patients demonstrated recovery in BMD Z-scores by this time point.

INTRODUCTION

Vertebral fracture (VF) incidence following glucocorticoid (GC) initiation has not been previously reported in pediatric nephrotic syndrome.

METHODS

VF was assessed on radiographs (Genant method); lumbar spine bone mineral density (LS BMD) was evaluated by dual-energy X-ray absorptiometry.

RESULTS

Sixty-five children were followed to 12 months post-GC initiation (median age, 5.4 years; range, 2.3-17.9). Three of 54 children with radiographs (6 %; 95 % confidence interval (CI), 2-15 %) had incident VF at 1 year. The mean LS BMD Z-score was below the healthy average at baseline (mean ± standard deviation (SD), -0.5 ± 1.1; p = 0.001) and at 3 months (-0.6 ± 1.1; p < 0.001), but not at 6 months (-0.3 ± 1.3; p = 0.066) or 12 months (-0.3 ± 1.2; p = 0.066). Mixed effect modeling showed a significant increase in LS BMD Z-scores between 3 and 12 months (0.22 SD; 95 % CI, 0.08 to 0.36; p = 0.003). A subgroup (N = 16; 25 %) had LS BMD Z-scores that were ≤-1.0 at 12 months. In these children, each additional 1,000 mg/m(2) of GC received in the first 3 months was associated with a decrease in LS BMD Z-score by 0.39 at 12 months (95 % CI, -0.71 to -0.07; p = 0.017).

CONCLUSIONS

The incidence of VF at 1 year was low and LS BMD Z-scores improved by 12 months in the majority. Twenty-five percent of children had LS BMD Z-scores ≤-1.0 at 12 months. In these children, LS BMD Z-scores were inversely associated with early GC exposure, despite similar GC exposure compared to the rest of the cohort.

The development of bone mineral lateralization in the arms

Bone mineral content (BMC) is known to be greater in the dominant arm after the age of 8 years. We studied a group of children and found that BMC sidedness gradually increased up to the age of 6 years and then remained stable into late adolescence.

INTRODUCTION

Bone mineral content (BMC) exhibits sidedness in the arms after the age of 8 years, but it is not known whether BMC is greater in the dominant arm from birth or whether lateralization develops in early childhood. To address this, we examined bone mineral status in relation to handedness and age.

METHODS

Subjects (N = 158) were children recently initiating glucocorticoids for underlying disease (leukemia 43 %, rheumatic conditions 39 %, nephrotic syndrome 18 %). Handedness was determined by questionnaire and BMC by dual-energy X-ray absorptiometry.

RESULTS

Median age was 7.2 years (range, 1.5 to 17.0 years), 49 % was male, and the spine BMD Z-score was -0.9 (SD, 1.3). By linear regression, BMC sidedness in the arms was significantly related to age (r = 0.294, p = 0.0005). Breakpoint analysis revealed two lines with a knot at 6.0 years (95 % CI, 4.5-7.5 years). The formula for the first line was: dominant:nondominant arm BMC ratio = 0.029 × age [in years] + 0.850 (r = 0.323, p = 0.017). The slope of the second line was not different from 0 (p = 0.332), while the slopes for the two lines were significantly different (p = 0.027).

CONCLUSIONS

These results show that arm BMC sidedness in this patient group develops up to age 6 years and then remains stable into late adolescence. This temporal profile is consistent with mechanical stimulation of the skeleton in response to asymmetrical muscle use as handedness becomes manifest.

Skeletal findings in children recently initiating glucocorticoids for the treatment of nephrotic syndrome

SUMMARY

Eighty children with nephrotic syndrome underwent lumbar spine densitometry and vertebral morphometry soon after glucocorticoid initiation. We found an inverse relationship between glucocorticoid exposure and spine areal bone mineral density (BMD) Z-score and a low rate of vertebral deformities (8%).

INTRODUCTION

Vertebral fractures are an under-recognized complication of childhood glucocorticoid-treated illnesses. Our goal was to study the relationships among glucocorticoid exposure, lumbar spine areal BMD (LS BMD), and vertebral shape in glucocorticoid-treated children with new-onset nephrotic syndrome.

METHODS

Lateral thoracolumbar spine radiography and LS BMD were performed in 80 children with nephrotic syndrome (median age 4.4 years; 46 boys) within the first 37 days of glucocorticoid therapy. Genant semiquantitative grading was used as the primary method for vertebral morphometry; the algorithm-based qualitative (ABQ) method was used for secondary vertebral deformity analysis.

RESULTS

Six of the 78 children with usable radiographs (8%; 95% confidence interval 4 to 16%) manifested a single Genant grade 1 deformity each. All deformities were mild anterior wedging (two at each of T6, T7, and T8). Four of the 78 children (5%; 95% confidence interval 2 to 13%) showed one ABQ sign of fracture each (loss of endplate parallelism; two children at T6 and two at T8). Two of the children with ABQ signs also had a Genant grade 1 deformity in the same vertebral body. None of the children with a Genant or ABQ deformity reported back pain. An inverse relationship was identified between LS BMD Z-score and glucocorticoid exposure.

CONCLUSIONS

Although we identified an inverse relationship between steroid exposure and LS BMD soon after glucocorticoid initiation for childhood nephrotic syndrome, there was only a low rate of vertebral deformities. The clinical significance of these findings requires further study.

Action of estradiol on epiphyseal growth plate chondrocytes

Estrogen plays an important role in the human growth plate by accelerating growth and promoting epiphyseal fusion in both sexes. Nevertheless, the precise mechanisms responsible for these effects are poorly understood. In the present study, we examined the role of 17beta-estradiol (E2) on cell proliferation and viability, type X collagen synthesis, alkaline phosphatase activity, and matrix calcification in primary cultures of resting, proliferating, and prehypertrophic chondrocytes derived from explants of the bovine fetal epiphyseal growth plate. Growth plate chondrocytes were isolated and separated into maturationally distinct subpopulations, which were cultured for 7-21 days to high density in either (1) serum-free medium, (2) 1 nM thyroid hormone (T3), (3) E2 concentrations ranging from 10(-13) M to 10(-7) M, or (4) a combination of T3 and E2. To compare E2 effects in both sexes, chondrocytes were harvested from 8 fetuses of both sexes. After hormone treatment, cell cultures were analyzed for cell number and viability, collagen type X, alkaline phosphatase (ALP), and matrix calcification. Neither DNA content nor cell viability were affected by the duration or type of hormone treatment. By itself, E2 stimulated maturation of all subpopulations only in pharmacologic doses (10(-7) M). Physiologic E2 concentrations were no different than negative controls treated with ITS (insulin, transferrin, and selenite). Regardless of E2 concentrations, the addition of E2 to 1 nM T3 did not appreciably affect the response to T3 alone, which stimulates maturation of the phenotype. All effects were comparable in both male and female chondrocytes, in all cell subpopulations (maturation stages) and fetuses of varying gestational age. These findings indicate that at physiologic concentrations, the effects of E2 on fetal bovine growth plate chondrocyte appear to be indirect and independent of T3, suggesting that, in vivo, E2 acts in concert with other factors or hormones to induce fusion of the growth plate.

Megestrol acetate promotes euglycemia and appetite in a child with persistent hyperinsulinemic hypoglycemia of infancy

This report describes a successful treatment with megestrol acetate in a child with persistent hyperinsulinemic hypoglycemia of infancy (PHHI). An 8-y-old child with PHHI treated with octreotide had marked impairment of appetite sensation and feeding skills. Within 3 wk of starting megestrol acetate (8 mg/kg/d) to stimulate her appetite, she had a significant improvement. By 1 y postinitiation, she had acquired age-appropriate eating habits. The megestrol acetate caused hyperglycemia, necessitating the discontinuation of all other therapy for her hypoglycemia. Her height growth remained normal but she was found to have asymptomatic adrenal suppression.

CONCLUSION

Megestrol acetate appeared to stimulate appetite and regulate glucose homeostasis in this child with PHHI. Additional studies will be required to document its efficacy and safety in other children with this disorder.

Bisphosphonates in dialysis and transplantation patients: efficacy and safety issues

Bisphosphonates are an old class of compounds. They were used in the 1930s as antiscaling and anticorrosion agents in washing powders and water to prevent the deposition of calcium crystals. Those basic functions were later utilized in an attempt to prevent ectopic calcifications in humans. The early studies demonstrated that bisphosphonates had a strong affinity for bone. That property was first exploited when the compounds were used for "bone scans." Currently, the drugs are used for treatment of hypercalcemic conditions, abnormal bone remodelling, Paget disease, malignancy, and osteoporosis. Bisphosphonates have several important toxicities: acute renal failure, worsening renal function, reduced bone mineralization, and osteomalacia. For those reasons and others, this class of drugs has not yet been approved for use in children or in patients with severe renal insufficiency. The present review covers several aspects of bisphosphonates: molecular structure, routes of administration, pharmacology, mechanisms of action, toxicities, and exceptional uses in children with renal disease.

Multinodular goiter in children

OBJECTIVE

As multinodular goiter (MNG) is an uncommon pediatric disorder, we decided to evaluate the children with this diagnosis at our center to try to delineate better its etiology, the risk of malignancy and appropriate management strategies.

METHODS AND RESULTS

Eighteen patients (12 girls and 6 boys) were the subject of this retrospective review spanning a period of 20 years. All were previously well, except one, and none had had head or neck irradiation. Average age at diagnosis was 12.8 years. Four children belonged to two previously identified kindreds diagnosed with familial MNG. These families had members affected with multiple cases of non-medullary thyroid carcinoma (NMTC). All were euthyroid and had no symptoms. In eight of 18 patients, the clinical examination missed the presence of multiple nodules which were subsequently detected by ultrasound. Twelve patients had tissue diagnosis by fine needle aspirate cytology (FNAC) or surgery. Five of eight patients undergoing surgery had nodular hyperplasia, one had a follicular adenoma and one had a normal thyroid gland on histology. There was one patient with papillary carcinoma combined with nodular hyperplasia. Seven of the patients had evidence of antithyroid autoimmunity.

CONCLUSION

The etiology of pediatric MNG appears multifactorial including autoimmune and familial factors. We believe that previously healthy children can usually be managed conservatively. Ultrasound at the time of diagnosis and in follow up seems beneficial. Familial forms appear to warrant close follow up, given the apparent increased risk of malignancy. The risk of malignancy while low remains real.

Multicompartment urea kinetics in well-dialyzed children

BACKGROUND

We have reported catch-up growth with hemodialysis (HD) of approximately 15 hours/week. Without an equilibrated post-treatment blood urea nitrogen, the variable-volume single-pool (VVSP) model will not account for urea rebound, inflating the estimated HD dose (K(d)t/V). A two-pool model (FVDP) predicts rebound, but requires fixed compartment volumes for the equations to be solvable in closed form, also inflating K(d)t/V.

METHODS

We developed an approximate perturbation solution (WKB method) to a variable volume, two-pool (VVDP) model. Estimated model parameters were compared with the results of equilibrated kinetic studies using measured clearance K(d) (N = 17). Once the model was validated, we re-analyzed 292 kinetic studies from our earlier cohort, which was considered well-dialyzed on the basis of growth rates (N = 12, mean annual change in height standard deviation score +0.31, mean follow-up of 26 months).

RESULTS

For the VVSP, FVDP, and VVDP models, respectively, the mean errors were (1) K(d)t/V, 0.22 +/- 0.07, 0.29 +/- 0.17, 0.06 +/- 0.07 (ANOVA, P < 0.001); (2) urea distribution volume vol/wt (%), -8.2 +/- 4.2, -9.1 +/- 3.0, -2.2 +/- 3.6 (P < 0.001). Sequential studies confirmed reproducibility, with a coefficient of variation < or = 5%. In the earlier cohort, a comparison of the VVSP and VVDP models yielded the following: (1) K(d)t/V, 1.91 +/- 0.35 vs. 1.76 +/- 0.33 (P < 0.001); (2) normalized protein catabolic rate (nPCR, g/kg/day), 1.56 +/- 0.39 vs. 1.52 +/- 0.38 (P < 0.001); and (3) K(d) (whole blood, mL/kg/min), 4.8 +/- 0.9 vs. 4.4 +/- 0.8 (P < 0.001).

CONCLUSION

This VVDP model yields reliable estimates of K(d)t/V and other kinetic parameters using standard blood urea nitrogen sampling. Analysis of patients previously characterized as well-dialyzed on the basis of growth rates clarifies the HD dose needed to sustain normal growth.

Hypercalcemia of the newborn: etiology, evaluation, and management

Hypercalcemia in infants is uncommon but has potentially serious sequelae. This review examines four cases of neonatal hypercalcemia, emphasizing appropriate investigations and treatment of acute and chronic hypercalcemia. The paper provides additional information as to the mechanisms of calcium dysregulation in idiopathic infantile hypercalcemia, Williams syndrome, vitamin D intoxication, and parathyroid and parathyroid-related protein disturbances.

A search for the possible molecular mechanisms of thyroid dysgenesis: sex ratios and associated malformations

Permanent primary congenital hypothyroidism (CH) can be caused by abnormal thyroid differentiation (athyreosis), migration (ectopy), or function (leading to goiter). Goiters follow an autosomal recessive pattern of inheritance, whereas ectopy and athyreosis are considered as a single sporadic entity with a female preponderance. On the other hand, a high prevalence of extrathyroidal malformations has been reported in CH, but without linking specific defects to specific types of CH. On the basis of TSH screening, 273 newborns were referred to an academic pediatric endocrinology clinic in the province of Quebec between 1988 and 1997. Of 230 patients with permanent primary CH who had scintigraphy at diagnosis, 141 had ectopy (104 girls), 36 had athyreosis (21 girls), 42 had goiter (18 girls), 10 (3 girls) had a normal scan, and 1 girl had hemiagenesis. Only in the ectopies was the proportion of girls significantly higher than 0.5 (P<0.001). Isolated cardiac malformations were observed in 7 patients (3.0%), a prevalence 5-fold higher than that in the general population; this was largely due to atrial and ventricular septal defects, which were only observed in ectopy and athyreosis. Our data suggest that the molecular mechanisms that lead to complete absence of thyroid differentiation or defective thyroid migration 1) may be similar, but are modulated by the genetic makeup of the embryo and/or the hormonal milieu of the fetus; and 2) may also be involved in septation of the embryonic heart.

Moderate renal failure in association with prolonged acquired hypothyroidism in children

We evaluated five children with prolonged primary hypothyroidism and noted a significant reduction in renal function (40%), which was reversible with hormonal replacement. This decline was higher than reported in adults and was of sufficient magnitude to warrant altering drug-dosing schedules. Furthermore, patients with moderately reduced renal function should be carefully evaluated for signs and symptoms of hypothyroidism.

Growth during maintenance hemodialysis: impact of enhanced nutrition and clearance

Growth of children during maintenance hemodialysis has been reported to be uniformly poor, with a mean annual loss of 0.4 to 0.8 SD in height. We adopted an intensive program of closely monitored energy and protein intake with dialysis urea clearances exceeding conventional recommendations. Twelve prepubertal or early pubertal children (aged 7 months to 14 years) were monitored for an average of 2.2 years (range 4 to 81 months) while receiving maintenance hemodialysis. These children received an average of 90.6% and 155.9% of their recommended energy and protein nutritional intake, respectively. With a prescribed urea clearance of 5 mL/kg/min, we achieved a mean single treatment urea clearance normalized for total body water of 2.00, a urea reduction ratio of 84.7%, and an average time of hemodialysis of 14.8 h/wk, all well beyond current guidelines. Over the course of dialysis treatment, the improvement in height SD score was+0.31 SD/y (+0.32 excluding the 2 children treated with recombinant human growth hormone). Normal growth was achieved without overt obesity and was associated with normal pubertal growth spurt. These findings suggest that the combination of increased dialysis and adequate nutrition can promote normal growth in children treated with long-term hemodialysis.

The use of pamidronate in three children with renal disease

The successful use of pamidronate, a bisphosphonate, for the treatment of hypercalcemia and/or osteopenia is reported in three children with renal failure or following renal transplant. Patient 1 was an 11-year-old post renal transplant male who received a single dose of i.v. pamidronate (0.5 mg/kg) for the treatment of acute hypercalcemia associated with a pathological fracture and subsequent immobilization. Prompt resolution of the hypercalcemia was seen. He received a second course of pamidronate (0.5 mg/kg per day for 3 days) for the treatment of osteopenia and has had a subsequent 15% increase in lumbar spine bone mineral content (BMC). Patient 2, a 14-year-old male on peritoneal dialysis, presented with symptomatic hypercalcemia associated with tertiary hyperparathyroidism. A single dose of i.v. pamidronate (0.4 mg/kg) was given with prompt resolution and prolonged control of his hypercalcemia. The third patient was a 16-year-old female, also in renal failure on peritoneal dialysis. Her course had been complicated by marked osteopenia. I.v. pamidronate (0.5 mg/kg per dose) was given on 3 successive days before and after renal transplant in an attempt to stabilize her bone mineral density (BMD) around the time of renal transplantation, when additional glucocorticoid was necessary. Her total body BMC and BMD remained stable pre and post transplant. The treatment was effective and well tolerated in all three patients. Hence pamidronate is safe and effective for the management of hypercalcemia and osteopenia in children with renal failure and/or renal transplant.

Cystic thyroid lesions in children

BACKGROUND/PURPOSE

Cystic lesions of the thyroid encompass a wide and heterogeneous group of disease states in children, ranging from benign purely cystic entities to malignant tumors. The purpose of this study was to study both the presentation and management of cystic thyroid lesions in the pediatric population.

METHODS

A retrospective review of all thyroid masses presenting between 1978 and 1996 and found to be purely or partially cystic on ultrasound examination was conducted, looking at presentation, family history, laboratory values, ultrasound scan and radionuclide imaging, and pathological and cytological evaluation.

RESULTS

Twenty-four patients (19 girls, 5 boys) aged 6 to 18 years received the diagnosis of cystic lesions of the thyroid. Of these, 23 presented with painless neck masses, 21 were clinically euthyroid, only one had a single abnormal thyroid function test, only two had mildly positive antithyroid antibody test results, and nearly 30% had a positive family history of thyroid disease. Ultrasonography showed pure cysts in five patients and mixed solid cystic lesions in 19 patients. On scintiscan, six lesions were hot, 13 were cold, three showed normal uptake, and two were mixed. Treatment included either observation, aspiration, cyst sclerosis, surgery, or combinations thereof. Pathological and cytological results included follicular adenoma (n = 9), cystic degeneration (n = 6), multinodular goiter (n = 4), carcinoma (n = 2), branchial cleft cyst (n = 1), and undetermined (n = 2).

CONCLUSIONS

Thyroid cysts are often thought to represent benign degenerative disease. Our study, which is the first in the literature to specifically address thyroid cysts in children, shows that ultrasound scan is useful in evaluating thyroid masses, whereas laboratory and radionuclide are of less value, and that single lesions of mixed echogeneity are likely to represent neoplasms, a significant percentage of which are malignant.

Thyroid abnormalities as a feature of DiGeorge syndrome: a patient report and review of the literature

DiGeorge syndrome or anomaly consists of a developmental field defect which is characterized by congenital absence or hypoplasia of the thymus and parathyroids, as well as facial dysmorphism and congenital heart defects. Other congenital malformations may coexist, in particular, thyroid abnormalities. A case of congenital hypothyroidism and DiGeorge syndrome is reviewed. Necropsy, clinical, and experimental studies also show that thyroid abnormalities may be a feature of DiGeorge syndrome. Although this could be purely coincidental, our case suggests that thyroid gland dysgenesis may be more common than previously thought. Thus, children with the DiGeorge syndrome may be at higher risk for hypothyroidism. Because of this potential association, patients who are considered to have this anomaly should have early newborn thyroid screening.

Congenital hyperthyroidism caused by a solitary toxic adenoma harboring a novel somatic mutation (serine281-->isoleucine) in the extracellular domain of the thyrotropin receptor

Activating somatic mutations in the thyrotropin (TSH) receptor have been identified as a cause of hyperfunctioning thyroid adenomas, and germline mutations have been found in familial nonautoimmune hyperthyroidism and sporadic congenital hyperthyroidism. All mutations reported to date have been located in the transmembrane domain. We now report an example of an activating mutation in the extracellular, TSH-binding domain, found in a male infant with congenital hyperthyroidism due to a toxic adenoma. The pregnancy was remarkable for fetal tachycardia. Scintigraphic studies demonstrated a large nodule in the right lobe, and a hemithyroidectomy was performed at the age of 2 yr. Direct sequencing of the TSH receptor gene revealed a mutation in one allele resulting in a substitution of serine281 by isoleucine (Ser281--> Ile) in the extracellular domain. The mutation was restricted to the adenomatous tissue. Expression of the Ser281--> Ile mutation in vitro revealed an increase in basal cAMP levels. Affinity for TSH was increased by the mutation. These findings demonstrate that activating mutations can also occur in the extracellular domain of the TSH receptor, and support a model in which the extracellular domain serves to restrain receptor function in the absence of TSH or antibody-induced conformational changes.

Ontogeny of hepatic nuclear triiodothyronine receptor isoforms in the rat

We have determined the contribution of the thyroid hormone receptor (TR) isoforms TR alpha 1 and TR beta 1 to the postnatal rise in rat hepatic nuclear T3-binding capacity. In agreement with previous studies, total hepatic nuclear binding capacity rose by about 8-fold from the 19th day of gestation to young adulthood at 2 months of age (0.10 +/- 0.03 to 0.86 +/- 0.17 pmol/mg DNA). The levels of specific TR species were measured by immunoprecipitation of T3-binding activity from hepatic extracts using a panel of antisera directed against specific regions of the TR isoforms. The difference between receptor immunoprecipitated with antibody against TR beta 1 and that precipitated with an antibody against an identical region in both TR beta 1 and TR alpha 1 was tentatively assumed to represent TR alpha 1. TR alpha 1 accounted for virtually all T3-binding activity in fetal liver on gestational day 19 (G19), increased by 2-fold shortly after birth, and remained constant thereafter. TR alpha 1 mRNA, on the other hand, was highest in concentration on G16 and fell by 50-75% in the adult. TR beta 1 was undetectable by immunoprecipitation of hepatic extracts from fetuses on G19. However, Northern analysis showed the presence of TR beta 1 mRNA in the fetal liver, which rose in concentration by 3- to 4-fold in late gestation and then remained constant. The contribution of TR beta 1 to total binding capacity rose to 33% and 40% on postnatal days 15 and 30, respectively, and to 80% in the adult liver. Immunohistochemical analyses of hepatic sections confirmed the presence of very low levels of TR beta 1 in fetal liver as early as G16 and G19, and a sharp rise in TR beta 1 protein concentration in the postnatal period. This indicated that the increase in TR beta 1-binding capacity results from increased TR beta 1 mass. The increase in TR beta 1-binding capacity, thus, is due to increased translational efficiency of the beta 1 mRNA or stabilization of the TR beta 1 protein. The prominence of TR alpha 1 in both rat fetal liver and fetal brain, as previously demonstrated in our laboratory, raises the possibility that this receptor isoform may carry out specialized functions in the fetus and that TR beta 1 subserves still other functions at later stages of development.(ABSTRACT TRUNCATED AT 400 WORDS)

Prediagnostic malakoplakia presenting as a chronic inflammatory mass in the soft tissues of the neck

Malakoplakia presenting in the head and neck is very rare. We present a case of an inflammatory mass in the neck, clinically mimicking actinomycosis in a 67-year-old man. Repeated culture of E. coli and histological and electron microscopic examination of biopsy material showed an infiltration of granular macrophages and intracellular gram negative bacilli, but no classical Michaelis-Gutmann bodies. The clinical and pathological findings and criteria for the diagnosis of malakoplakia are discussed.