Short penis

Introduction The small penis (micropenis) refers to the normal length to diameter ratio of the penis appearance, but the length of the penis body is less than 2.5 standard deviations above the average length of the normal penis. The length of the penis refers to the straightening of the penis head as much as possible, which is equivalent to the distance from the top of the penis to the pubic symphysis when the penis is fully erect. Adults generally have a penis relaxation length of less than 3 cm for a small penis. In order to avoid the occurrence of small penis, it is recommended that male friends in adolescence pay special attention to avoid squeezing the penis and scrotum for a long time, especially when sleeping at night.

Cause

(1) Causes of the disease:

The causes of small penis are: 1 hypogonadism of insufficient gonadotropin secretion; 2 hypogonadal hypertrophy of gonadal dysfunction; 3 primary small penis.

1. Hypogonadism with insufficient gonadotropin secretion:

(1) Abnormal brain tissue structure: children without brain malformation have no hypothalamic secretion function even if the pituitary gland develops normally due to the absence of gonadotropin-releasing hormone, resulting in less testosterone secretion, resulting in a small penis congenital pituitary gland not developing part of cerebral corpus dysplasia Hypothalamic dysfunction, cerebral bulging of the occipital cerebral bulge, and cerebellar malformation, such as cerebellar malformation, are caused by insufficient gonadotropin secretion and cause multiple malformations in other systems.

(2) Congenital gonadotropin-releasing hormone deficiency without brain tissue abnormalities: small penis caused by such causes is more common than the former. The specific cause is unclear. Various syndromes such as Kallmann Padwell syndrome (Prader-Willi) Lawrence-Moon-Beidel syndrome is often accompanied by multiple malformations. It is related to chromosomal gene abnormalities and deficiencies of gonadotropin-releasing hormone luteinizing hormone caused by abnormal endocrine biochemical metabolism.

2. Gonadal dysfunction with excessive gonadotropin secretion:

The hypothalamic pituitary secretion function of these patients is normal only in the late pregnancy, the testicular degeneration changes and the testosterone secretion is reduced. The negative feedback pathway leads to the excessive secretion of gonadotropin, which causes the small penis mainly in the testicle itself such as congenital testis. Some patients, such as testicular insufficiency, have normal testicular but their luteinizing hormone receptor abnormalities can not secrete enough testosterone. In addition, attention should be paid to gender abnormalities.

3. Primary small penis:

In addition to the above reasons, there are a small number of patients with hypothalamic-pituitary-testicular axis hormone secretion but there is a small penile malformation to adolescence and more growth causes are not clear. It is speculated that the late gonadotropin stimulation may delay the transient testosterone secretion. There are also a small number of patients who may be abnormal for androgen receptors.

Penile patients may have sex chromosome abnormalities such as Klinefelter syndrome (47XXY) multiple X syndrome (48XXXY and 49XXXXY) multichromosome (69XXY triploid) malformation.

(2) Pathogenesis:

Normal male penile development is completed in the first 12 weeks of the embryonic stage. The first stage is the genital nodule. The reproductive nodules gradually prolong. Similar to the small mound length 8 to 15 mm. The second stage is the penile stage in dihydrotestosterone (DHT). Under the action of the penis, the penis continues to grow in a cylindrical shape with a length of about 16 to 38 mm. The urethral groove extends to the penis head. The third stage penis length is 38 to 45 mm. Embryonic development until the 7th to 8th week, the gonads gradually differentiate into testis and stimulate the chorionic gonadotropin (HCG) produced by the placenta. Leydig's cells produce testosterone. After 4 months of pregnancy, the fetal hypothalamus secretes gonads. Hormone releasing hormone (gonadotropin-nelasing hormone GRH) stimulates the production of luteinizing hormone (LH) and urinary gonadotropin (FSH) in the anterior pituitary. Under the combined action of HCGLH and FSH, the testes continuously produce testosterone testosterone and are transformed by 5-alpha reductase. DHT stimulated the penis to gradually increase the small penis due to hormone deficiency caused by the embryo 14 weeks later.

an examination

Related inspection

Penis check

symptom:

1. The penis is small and does not match the age, but the appearance is normal. The length to diameter ratio is normal. The length is less than the average length of the normal penis length of 2.5 standard deviations or more.

2. Check: no scrotal testicles with small soft insufficiency or lack of deformity.

3. Anal examination: The prostate is smaller than normal.

diagnosis:

1. Diagnostic criteria: Straighten the penis as far as possible to measure the distance between the pubic symphysis to the tip of the penis head. If the length of the penis is less than 2.5 standard deviations from the average length of the normal penis, the penis length can be diagnosed as a small penis.

2. Physical examination: In addition to measuring the length of the penis, attention should also be paid to the presence or absence of signs related to chromosomal brain dysplasia such as low eye distance, small mouth, auricular position, and multi-finger (toe), etc. The number and size of testicular positions.

Check the test:

Routine examination of karyotype blood potassium and sodium determination or growth hormone-related hormone examination and thyroid function test for LHFSH testosterone should be suspected of primary testicular hypofunction can be human chorionic gonadotropin (HCG) stimulation test (intramuscular injection every other day) HCG 1000 ~ 1500U a total of 7 times after the last injection 24 to 48h check serum testosterone) such as testosterone LHFSH <3.45nmol / L testicular function is insufficient; such as testosterone LHFSH are low, then gonadotropin-releasing hormone stimulation test to identify Pituitary function.

Imaging examination: those with conditions should use magnetic resonance MRI as a routine examination to check the presence or absence of hypothalamic pituitary malformation in the brain. Patients with craniocerebral abnormalities should pay attention to whether the optic nerve intersects the fourth ventricle and the corpus callosum.

Differential diagnosis

Identification of symptoms that are easily confused with penis:

1 False penis shortness: refers to the penis in the non-erectile state, although the length is less than 3cm, but in the erect state, it can significantly increase the thickness of 2 to 3 times and does not affect sexual life.

2 latent penis: refers to the penis seems to be short, but the hand can push the skin next to the penis to expose the normal size of the penis.

3 days: the penis is short and the testicular and male second sexual characteristics are incompletely karyotype 47XXY.

4 penis scrotum fusion (squat penis): refers to the scrotal skin forward expansion of a thin wrinkled wall to the penis ventral adulthood after the impact of sexual life is a scorpion-shaped penis.

5 Systolic disease: Men will feel that their penis is shrinking or even shrinking into the abdomen to produce a kind of fear. It is a rickety. When the disease does not occur, the penis and accessory characteristics of normal people are normal.

6. Scrotal rubber swelling: excessive swelling of the scrotum is buried in the penis but there is a history of filariasis infection. Scrotal skin thickening and rough cleft palate sometimes involving the skin of the thigh and lower limbs.

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