Idiopathic delayed puberty

Introduction to idiopathic puberty Boys are over 14 years old, girls are over 13 years and a half, and no adolescent performance is delayed (publishedpuberty). The main manifestation of the boy is that the testicular volume does not increase and the girl's breasts are not developed. Normal people from the second sexual characteristics to adult characteristics usually take 4 to 5 years, such as puberty to genital development more than 5 years, or stop development for 2 years, known as idiopathic puberty delay. basic knowledge The proportion of illness: 0.002%-0.005% (more common in men, due to lack of sex hormones) Susceptible people: no specific population Mode of infection: non-infectious Complications: Diabetic nephropathy Bronchial asthma

Delayed etiology of idiopathic puberty

(1) Causes of the disease

The etiology of delayed puberty is often divided into temporary gonadotropin and sex hormone secretion disorders, hypothalamic-pituitary lesions caused by gonadotropin secretion disorders and hypogonadal dysfunction caused by puberty development delays, of which the former are most common .

1. Temporary gonadotropin and sex hormone secretion disorders

(1) Malnutrition or chronic wasting diseases: such as tuberculosis, diabetes, chronic liver disease, intestinal malabsorption syndrome, bronchial asthma, etc., affecting the development of the nervous system and body organs, so that the patient's age has reached adolescence, but the bone age is It indicates that the systemic development is far behind the normal age of the same age and does not have a systemic basis for gonadal development.

(2) Normal physiological variation: the age at which puberty begins, the rate of development, the age of maturity, and the degree of development have large individual differences, not only between races, but also between men and women, that is, under normal circumstances, the same Gender, same race, and different general environmental conditions, regardless of gender, both precocious, average and late maturity, the reasons may be genetic, nutritional, emotional and other environments, Socioeconomic factors, etc., can also be familial or sporadic.

(3) Others: patients with growth hormone deficiency have delayed growth, delayed bone age, and often accompanied by delayed development of gonads, which are similar to delayed constitutional puberty, thyroid hormone deficiency and hyperprolactinemia, or long-term application of cortisone preparations. It is possible to inhibit the secretion of sex hormones and cause delay in puberty.

2. Delay in puberty caused by hypothalamic-pituitary lesions

(1) Kallmann syndrome: is a hereditary disease, often manifested as autosomal dominant inheritance or X-interlock with recessive inheritance, patients with pituitary gonadotropin hypoxia, often accompanied by brain olfactory dysplasia and middle Dysplasia, resulting in loss of smell, cleft palate, cleft lip and so on.

(2) Single gonadotropin deficiency: may be a sporadic appearance or a hereditary disease.

(3) partial gonadotropin deficiency: manifested as LH secretion deficiency, FSH secretion is normal, androgen is low, sperm development is blocked.

(4) Pituitary function is low or partial low: pituitary tumors, or saddle saddle parasitic tumors, pituitary invasive diseases, radiation therapy, trauma, surgery can lead to hypopituitarism.

3. Delay in puberty caused by hypogonadism

(1) Turner syndrome: It is a kind of gonadal dysplasia caused by sex chromosome deficiency or abnormality. The incidence rate of female is about 1/2500. The patient's phenotype is female, sexual development is not developed, no fertility, short stature, neck brace and so on.

(2) hereditary sex hormone synthesis disorder and peripheral insufficiency: often accompanied by abnormal sexual differentiation, a typical example is 17-hydroxylase deficiency, androgen synthesis is incomplete or partially insensitive, the patient's breast can develop, but there is a primary The amenorrhea and pubic hair are not developed.

(3) Acquired primary hypogonadism: such as trauma, chemotherapy, radiation, infection may lead to obstruction of gonadal development, affecting the synthesis of gonadal hormone and the production of germ cells.

(4) Gonadal developmental disorders.

(two) pathogenesis

Idiopathic puberty delay is the opposite of idiopathic true homosexual precocious puberty. It is a physiological variation of normal growth and development. There is no sign of secondary sexual development when the age exceeds the normal puberty start age of 2.5 SD. The growth rate is also slowed down, however, these children are not familial short stature, the age of puberty initiation is not delayed, the cause of this disease is unknown, the growth rate of patients with delayed idiopathic puberty is slowed down, plasma GH levels and GH are excited The triggering response of factor or GHRH is reduced, but exogenous testosterone or E2 is given, or once puberty is initiated, growth rate and GH secretion return to normal. Therefore, the cause may be temporary and functional deficiency of GH, gonadotropin. The effect on the testis or ovary requires the involvement of GH. When the GH level is relatively reduced (assuming that the IGF-1 in the gonad is also reduced accordingly), the testicular or ovarian response to gonadotropin is impaired and puberty cannot be initiated as scheduled.

Idiopathic puberty delayed prevention

1. During adolescence, care should be taken to protect the reproductive organs from damage caused by improper exercise testicles; to avoid strong radiation exposure, and not to wear tight pants for a long time.

2. Vitamin A intake reduction is one of the reasons for delayed puberty, need to supplement vitamin A and iron.

3. Long-term puberty delay affects bone mineralization and increases the risk of fractures in adulthood. Therefore, there are indications for short-term treatment of sex hormones to promote puberty initiation.

Idiopathic puberty delayed complications Complications Diabetic nephropathy Bronchial asthma

Malnutrition or chronic wasting diseases: such as tuberculosis, diabetes, chronic liver disease, intestinal malabsorption syndrome, bronchial asthma, etc., affecting the development of the nervous system and body organs, so that the patient's age has reached puberty, but the bone age indicates systemic development. The situation lags far behind the normal age of the same age and does not have a systemic basis for gonadal development.

Idiopathic puberty delayed symptoms Common symptoms Gonadal dysplasia Bone age Delayed cleft lip rupture Lip cleft palate Adolescent chest development slow

The child's growth is stagnant, the height is shorter than that of the same age, and the bone age is backward, but the growth rate is consistent with the bone age, and the adrenocortical function is delayed, which is different from the child with isolated gonadotropin deficiency. Adrenal cortical function is on schedule, there is no sign of secondary sexual development, plasma gonadotropin and sex hormones stay at the level of prepubertal children, often have a delayed family history of puberty, father 14 to 18 years of puberty only start or mother Breast development or menarche age is delayed. In addition, other aspects of the body develop normally. Both testes have fallen into the scrotum, there are no hypospadias, no olfactory loss, no congenital somatic deformity, plasma LH, FSH and testosterone or E2 levels. Lower than the same age children, but comparable to the bone age of the child, the response of LH to GnRH excitability reflects the degree of maturity of the hypothalamic-pituitary axis. The response of children with delayed puberty is the same as that of normal prepubertal children. Or no response, if the stimulation of 100g GnRH intravenous bolus, plasma LH peak>2.OU / L, the child in 1 There will be puberty initiation during the year, and a few of the patients with delayed puberty are normal. Most of them may not reach the expected height. The reason may be that the growth of the spine in these patients is lower than that in the normal start of puberty. Some people think that most of these patients are concurrently There is a family short stature.

Idiopathic puberty delay check

1. Endocrine hormone test FSH, LH: If the puberty is delayed due to gonadal dysplasia, FSH, LH is significantly increased, T, E2 is decreased; lower hypothalamic-pituitary function is lower, then FSH, LH decline, TSH, F, The PRL examination is meaningful for the diagnosis of hypothyroidism, Cushing's syndrome, and prolactin-induced puberty delay.

2. Growth hormone challenge test: It is important for growth retardation caused by delayed developmental delay and growth retardation caused by growth hormone deficiency, because the former can promote growth as long as induced development, while the latter requires treatment of growth hormone. If necessary, a growth hormone challenge test or an LHRH challenge test is required.

3. GnRH challenge test: In the case of hypothalamic lesions, GnRH test may appear, suggesting that pituitary secretion of gonadotropin cells is still normal, but according to our experience, most of them should be treated with GnRH for 5-7 days before GnRH test. More obvious, caused by pituitary lesions, GnRH stimulation test response is poor.

4. CT or MRI: When clinical clues suggest hypothalamic-pituitary lesions, CT or MRI is of greater value.

5. Vision, visual field examination: help to determine whether the tumor oppresses the optic nerve.

6. B-ultrasound: For girls, you can understand the development of the ovaries and uterus.

7. Testicular biopsy: Generally used less, can determine whether germ cell differentiation is normal.

8. Bone age: In patients with low gonadotropin function, bone age is relatively low, physical and pituitary function is low, and bone age is more obvious.

Idiopathic puberty delayed diagnosis

Diagnostic criteria

1. There is still no sign of secondary sexual development after the boy is 14 years old or 13 years old.

2. The growth is slow, the bone age is behind the actual age, and the height is shorter than that of the same age, but it is equivalent to the bone age.

3. Adrenal cortical function is initially delayed.

4. There are many family history of delayed puberty.

5. LH, FSH and testosterone E2 levels and LH response to GnRH excitement stayed in prepubertal state.

6. Exclude pubertal delay caused by other lesions.

Differential diagnosis

Delayed puberty caused by other lesions has two categories: high gonadotropin hypogonadism and low gonadotropin hypogonadism. The former lesions are in the gonads, including testicular or ovarian hypoplasia or failure caused by various causes. The common feature is that plasma LH and FSH levels are significantly increased, so it is not difficult to identify, the latter lesions in the hypothalamus (such as Kallmann syndrome) or pituitary (such as pituitary or supra-sacral tumors, etc.).

Although these lesions all cause a decrease in the levels of LH and FSH, the degree of reduction and the degree of response to GnRH are heterogeneous, that is, the extent of pituitary damage is different, in addition, the performance of primary disease (such as tumor) It is not difficult to identify. Kallmann syndrome has olfactory dysfunction or loss, and it is easy to identify. No olfactory loss is difficult to identify. There is no clinically effective trial to delay idiopathic puberty and olfactory loss. The diagnosis of Kalman syndrome is established. The conventional method is to divide the line with 18 years old, that is, patients who have not started adolescence at the age of 18, can be diagnosed as Kalman syndrome or idiopathic hypogonadotropin hypogonadism. .

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