Small penis

Introduction to small penis Micropenis refers to the normal appearance of the penis, the ratio of length to diameter is normal, but the length of the penis 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. basic knowledge The proportion of illness: 0.0032% Susceptible population: adult male Mode of infection: non-infectious Complications: impotence, premature ejaculation

Cause of small penis

(1) Causes of the disease

The causes of small penis are:

1 Hypogonadism with insufficient gonadotropin secretion. 2 gonadotropin excessive secretion of hypogonadism. 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, because there is no gonadotropin-releasing hormone, resulting in less testosterone secretion, resulting in small penis, congenital pituitary body is not developed, part Hypothalamic dysfunction caused by cerebral palsy dysplasia, cerebral bulging occipital dysplasia and cerebellar malformation of dysplasia, etc., are caused by abnormal gonadotropin secretion, which also causes 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, and the specific cause is unclear, mostly various syndromes, such as Kallmann, Padwelli syndrome (Prader-Willi), Lawrence-Moon-Beidel syndrome, etc., often accompanied by multiple malformations, according to studies related to chromosomes, genetic abnormalities, as well as endocrine, biochemical metabolic abnormalities caused by gonadotropin-releasing hormone, luteinizing hormone, etc. Lack of disease.

2. Gonadal dysfunction caused by excessive gonadotropin secretion

In this type of patients, the hypothalamus and pituitary secretion function are normal, but the testicular degeneration changes in the late pregnancy and the testosterone secretion is reduced. The negative gonadotropin secretion is caused by the negative feedback pathway. The cause of the small penis is mainly in the testis itself. Such as congenital testicular absent, testicular insufficiency, etc., some patients with normal testis, but its luteinizing hormone receptor abnormalities, so that can not secrete enough testosterone, in addition to pay attention 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, and can grow in adolescence, the cause is not clear, it is speculated that it may be delayed gonadotropin stimulation in the late embryo. A small number of patients may have abnormal androgen receptors due to decreased testosterone secretion.

Patients with small penis may have sex chromosome abnormalities such as Klinefelter syndrome (47,XXY), multiple X syndrome (48, XXXY and 49, XXXXY), and multiple chromosome (69,XXY triploid) malformations.

(two) pathogenesis

Normal male penis development is completed in the first 12 weeks of the embryonic stage, divided into 3 stages, the first stage is the reproductive nodule stage, the reproductive nodules are gradually extended like hillocks, 8 to 15 mm long, and the second stage is the penis stage. Under the action of dihydrotestosterone (DHT), 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 has a penis length of 38 to 45 mm, and the urethra is completed.

Embryonic development until the 7th to 8th week, the gonads gradually differentiate into testis, and under the stimulation of chorionic gonadotropin (HCG) produced by the placenta, testicular stromal cells (Leydig's cells) produce testosterone, fetal hypothalamus after 4 months of pregnancy Gonadotropin-nelasing hormone (GRH) is secreted to stimulate the production of progesterone (LH) and urinary gonadotropin (FSH) in the anterior pituitary. Under the combined action of HCG, LH and FSH, testis continuously produces testosterone and testosterone. In addition, the conversion to DHT under the action of 5- reductase stimulated the penis to gradually increase, and the small penis was caused by hormone deficiency after 14 weeks of embryo.

Small penis prevention

1, more exercise, maintain a balanced nutrition.

2. Choosing the right underwear is critical.

Traditional underwear is prone to the following:

1) Loose panties are too high to the left or to the right, which may cause the penis to bend to the left or to the right.

2) The penis of the close-fitting underwear is pressed for a long time (especially when sleeping), which tends to cause the penis to be short and curved.

In order to avoid the above situation, it is recommended to pay special attention to avoid, long-term squeeze of the penis scrotum, especially when sleeping at night.

3, eat high-calorie foods, because often eat high-calorie foods, easily lead to obesity.

Small penile complications Complications impotence and premature ejaculation

Associated with male secondary sexual characteristics (pubic hair, mane and beard, voice change, larynx, male genital morphology, etc.) dysplasia or gradual deterioration, mental dysfunction, general weakness, lack of male masculinity; pubic hair sparse, loss of libido, or emergence Impotence, premature ejaculation and other sexual dysfunction problems.

Often complicated by bilateral cryptorchidism, obesity, scrotum and testicular dysplasia and other malformations.

Small penis symptoms common symptoms penis short pain penile erection testicular hypoplasia hypospadias

1. The penis is very small, not in accordance with age, but the appearance is normal, its length to diameter ratio is normal, its length is less than the average length of the normal penis length of 2.5 standard deviations, and some corpus cavernosum dysplasia.

2. Check for no scrotum, testicular small, soft, incomplete or absent deformity.

3. Anal examination refers to the examination of the prostate is smaller than normal.

Small penis examination

Routine examination of karyotype, blood glucose, potassium, sodium determination or growth hormone-related hormone examination and thyroid function test, for LH, FSH, testosterone is low, should be suspected of primary testicular dysfunction, can be human chorionic gonadotropin ( HCG) stimulation test (intramuscular injection of HCG 1000 ~ 1500U, 7 times a day, check serum testosterone within 24 ~ 48h after the last injection), such as testosterone, LH, FSH are <3.45nmol / L, testicular function is insufficient; If testosterone, LH, and FSH are both low, a gonadotropin-releasing hormone stimulation test is performed to identify the function of the pituitary gland.

Imaging examination: those with conditions should take magnetic resonance MRI as a routine examination, mainly to check the presence or absence of hypothalamus and pituitary malformation in the brain. For those with abnormal craniocerebral, attention should be paid to the intersection of the optic nerve, and whether the fourth ventricle and the corpus callosum are abnormal.

Diagnosis of small penis

diagnosis

1. Diagnostic criteria The penis is straightened as far as possible by hand. The distance between the pubic symphysis and the tip of the penis is measured as the length of the penis. When the length of the penis is less than 2.5 standard deviations from the average length of the normal penis, the penis can be diagnosed.

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 chromosome and brain development abnormalities, such as wide eye distance, small mouth, low auricle position, and refers to (toe), multi-finger (toe), etc. At the same time, understand the development of the scrotum and testicular position, number and size.

Differential diagnosis

1, false penile shortness: refers to the penis in non-erectile state, although the length is less than 3cm, but in the erect state can be significantly extended, thickened 2 to 3 times, and does not affect sexual life.

2, latent penis: refers to the penis seems to be short, but when the hand pushes the skin next to the penis, it can reveal the normal size of the penis.

3, Scorpio: the penis is short, and the testicular and male second sexual characteristics are incomplete, the karyotype is 47, XXY and so on.

4, penis scrotum fusion (squat penis): refers to the scrotal skin forward expansion of a thin wrinkled wall to the ventral side of the penis, adult sexual life is a scorpion penis.

5, contraction syndrome: men will feel that their penis is shrinking, or even shrink into the abdomen, resulting in a fear, is a rickety, it is normal, the penis and accessory sexual characteristics are normal.

6, scrotal rubber swelling scrotum excessive swelling, penis buried in it, but a history of filariasis infection, scrotal skin thickening, rough and chapped, sometimes involving the skin of the thigh and lower limbs.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.