THE RARE CASE OF A MALE WITH GROWTH FAILURE AND PRECOCIOUS PUBERTY
AACE ePoster Library. Rohrs H. 05/13/15; 97809; 1082
Dr. Henry Rohrs
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Abstract
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An 8 year 2 month old male was referred for evaluation of growth failure. He had been growing along the 25th percentile on the height growth curve until 1.5 years ago when his growth velocity slowed and he deviated to the 1st percentile (-2.18 SD) (Figure 1). He had mild constipation and long history of dry skin. Skeletal age was 6.5 years. On exam, he was at the 1st percentile for height and the 31st percentile for weight, had a palpable thyroid, Tanner 1 pubic hair, and 6 mL testicle on the left and 6 mL testicle on the right.
Knowing that there is only one cause of precocious puberty associated with growth failure and delayed skeletal age, thyroid studies and antibodies were performed revealing TSH > 150 mIU/L, free T4 0.5 ng/dL, thyroid peroxidase antibodies 958 IU/mL (<35), and thyroglobulin antibodies 458 IU/mL (<20). Testosterone was 5 ng/dL, FSH 3.98 mIU/mL, and LH 0.15 mIU/mL. He was started on low dose levothyroxine 25 mcg daily and gradually increased to normalize free T4 and TSH. Constipation and dry skin resolved and he lost 3.5 pounds during the first month of treatment with family stating he looked less “swollen”. Most recent follow up was when patient was 8 years and 6 months, height had increased to 3rd percentile (-1.84 SD) with interval growth velocity of 11.1 cm/year since diagnosis and treatment (Figure 2). His genital exam showed Tanner 1 pubic hair and now 4.5 mL testicles bilaterally.
Van Wyk-Grumbach syndrome is characterized by primary hypothyroidism, delayed skeletal age, and pseudoprecocious puberty. The exact mechanism is debated, but one of the most accepted theories proposes that TSH and FSH share a common B subunit and the markedly elevated TSH that occurs in longstanding primary hypothyroidism is thought to directly stimulate the FSH receptor. This would explain our patient’s increased testicular volume without enlarged phallus or development of pubic hair, while having prepubertal gonadotropins and testosterone. The stimulation of Sertoli cells would cause the increase in testicular volume, but lack of stimulation of the Leydig cells would not result in testosterone production. With treatment of the long standing hypothyroidism, the TSH is reduced and subsequently testicular volume decreased without continued stimulation.
In the rare instance that a child is found to have precocious puberty with presence of growth failure and delayed skeletal age, primary hypothyroidism should be considered and thyroid function tests should be obtained. Treating the hypothyroidism with levothyroxine will prevent further progression of puberty, while restoring normal growth velocity.
Knowing that there is only one cause of precocious puberty associated with growth failure and delayed skeletal age, thyroid studies and antibodies were performed revealing TSH > 150 mIU/L, free T4 0.5 ng/dL, thyroid peroxidase antibodies 958 IU/mL (<35), and thyroglobulin antibodies 458 IU/mL (<20). Testosterone was 5 ng/dL, FSH 3.98 mIU/mL, and LH 0.15 mIU/mL. He was started on low dose levothyroxine 25 mcg daily and gradually increased to normalize free T4 and TSH. Constipation and dry skin resolved and he lost 3.5 pounds during the first month of treatment with family stating he looked less “swollen”. Most recent follow up was when patient was 8 years and 6 months, height had increased to 3rd percentile (-1.84 SD) with interval growth velocity of 11.1 cm/year since diagnosis and treatment (Figure 2). His genital exam showed Tanner 1 pubic hair and now 4.5 mL testicles bilaterally.
Van Wyk-Grumbach syndrome is characterized by primary hypothyroidism, delayed skeletal age, and pseudoprecocious puberty. The exact mechanism is debated, but one of the most accepted theories proposes that TSH and FSH share a common B subunit and the markedly elevated TSH that occurs in longstanding primary hypothyroidism is thought to directly stimulate the FSH receptor. This would explain our patient’s increased testicular volume without enlarged phallus or development of pubic hair, while having prepubertal gonadotropins and testosterone. The stimulation of Sertoli cells would cause the increase in testicular volume, but lack of stimulation of the Leydig cells would not result in testosterone production. With treatment of the long standing hypothyroidism, the TSH is reduced and subsequently testicular volume decreased without continued stimulation.
In the rare instance that a child is found to have precocious puberty with presence of growth failure and delayed skeletal age, primary hypothyroidism should be considered and thyroid function tests should be obtained. Treating the hypothyroidism with levothyroxine will prevent further progression of puberty, while restoring normal growth velocity.
An 8 year 2 month old male was referred for evaluation of growth failure. He had been growing along the 25th percentile on the height growth curve until 1.5 years ago when his growth velocity slowed and he deviated to the 1st percentile (-2.18 SD) (Figure 1). He had mild constipation and long history of dry skin. Skeletal age was 6.5 years. On exam, he was at the 1st percentile for height and the 31st percentile for weight, had a palpable thyroid, Tanner 1 pubic hair, and 6 mL testicle on the left and 6 mL testicle on the right.
Knowing that there is only one cause of precocious puberty associated with growth failure and delayed skeletal age, thyroid studies and antibodies were performed revealing TSH > 150 mIU/L, free T4 0.5 ng/dL, thyroid peroxidase antibodies 958 IU/mL (<35), and thyroglobulin antibodies 458 IU/mL (<20). Testosterone was 5 ng/dL, FSH 3.98 mIU/mL, and LH 0.15 mIU/mL. He was started on low dose levothyroxine 25 mcg daily and gradually increased to normalize free T4 and TSH. Constipation and dry skin resolved and he lost 3.5 pounds during the first month of treatment with family stating he looked less “swollen”. Most recent follow up was when patient was 8 years and 6 months, height had increased to 3rd percentile (-1.84 SD) with interval growth velocity of 11.1 cm/year since diagnosis and treatment (Figure 2). His genital exam showed Tanner 1 pubic hair and now 4.5 mL testicles bilaterally.
Van Wyk-Grumbach syndrome is characterized by primary hypothyroidism, delayed skeletal age, and pseudoprecocious puberty. The exact mechanism is debated, but one of the most accepted theories proposes that TSH and FSH share a common B subunit and the markedly elevated TSH that occurs in longstanding primary hypothyroidism is thought to directly stimulate the FSH receptor. This would explain our patient’s increased testicular volume without enlarged phallus or development of pubic hair, while having prepubertal gonadotropins and testosterone. The stimulation of Sertoli cells would cause the increase in testicular volume, but lack of stimulation of the Leydig cells would not result in testosterone production. With treatment of the long standing hypothyroidism, the TSH is reduced and subsequently testicular volume decreased without continued stimulation.
In the rare instance that a child is found to have precocious puberty with presence of growth failure and delayed skeletal age, primary hypothyroidism should be considered and thyroid function tests should be obtained. Treating the hypothyroidism with levothyroxine will prevent further progression of puberty, while restoring normal growth velocity.
Knowing that there is only one cause of precocious puberty associated with growth failure and delayed skeletal age, thyroid studies and antibodies were performed revealing TSH > 150 mIU/L, free T4 0.5 ng/dL, thyroid peroxidase antibodies 958 IU/mL (<35), and thyroglobulin antibodies 458 IU/mL (<20). Testosterone was 5 ng/dL, FSH 3.98 mIU/mL, and LH 0.15 mIU/mL. He was started on low dose levothyroxine 25 mcg daily and gradually increased to normalize free T4 and TSH. Constipation and dry skin resolved and he lost 3.5 pounds during the first month of treatment with family stating he looked less “swollen”. Most recent follow up was when patient was 8 years and 6 months, height had increased to 3rd percentile (-1.84 SD) with interval growth velocity of 11.1 cm/year since diagnosis and treatment (Figure 2). His genital exam showed Tanner 1 pubic hair and now 4.5 mL testicles bilaterally.
Van Wyk-Grumbach syndrome is characterized by primary hypothyroidism, delayed skeletal age, and pseudoprecocious puberty. The exact mechanism is debated, but one of the most accepted theories proposes that TSH and FSH share a common B subunit and the markedly elevated TSH that occurs in longstanding primary hypothyroidism is thought to directly stimulate the FSH receptor. This would explain our patient’s increased testicular volume without enlarged phallus or development of pubic hair, while having prepubertal gonadotropins and testosterone. The stimulation of Sertoli cells would cause the increase in testicular volume, but lack of stimulation of the Leydig cells would not result in testosterone production. With treatment of the long standing hypothyroidism, the TSH is reduced and subsequently testicular volume decreased without continued stimulation.
In the rare instance that a child is found to have precocious puberty with presence of growth failure and delayed skeletal age, primary hypothyroidism should be considered and thyroid function tests should be obtained. Treating the hypothyroidism with levothyroxine will prevent further progression of puberty, while restoring normal growth velocity.
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