Erectile dysfunction (ED) refers to the persistent or recurrent inability to achieve or maintain a sufficient penile erection for satisfactory sexual intercourse. It is generally believed that the duration of the disease should be at least 3 months before ED can be diagnosed. Etiology and pathogenesis of erectile dysfunction Etiology: With the development of science and social progress, people’s understanding of ED has deepened. For example, as early as the 15th century, ED was thought to be possessed by the devil; in the 18th century, it was thought to be caused by masturbation; at the beginning of the 19th century, it was also thought that ED were all psychological disorders, and after 1950, it was thought to be behavioral disorders. it was still considered to be related to the decrease in the amount of androgens, the aging of the natural age, and the psychological factors before 1970. Due to the lack of common knowledge about ED, many ED patients carry a heavy burden of thought, affecting normal family life, and also tend to become withdrawn and prone to irritability, which affects interpersonal relationships.After 1970 due to the progress of research on the physiology and pathology of erection, it has been recognized that psychological factors can certainly cause ED, but for the majority of men ED is associated with a number of diseases (hypertension, diabetes mellitus, cardiovascular disease), drugs, trauma and surgery, etc. Because the mechanism of erection is a complete hemodynamic process of penile cavernous smooth muscle relaxation, penile arterial dilatation, increased blood flow and obstruction of venous return, in which any dysfunction or any defect in the structure of the penis may cause and lead to erectile dysfunction. So the causes of erectile dysfunction can be categorized as: Psychological ED: refers to erectile dysfunction caused by psychosomatic factors such as tension, stress, depression, anxiety and marital discord. Organic ED: Vascular causes: including any disease that may lead to reduced blood flow in the penile cavernous artery, such as atherosclerosis, arterial injury, arterial stenosis, pubic arterial shunt and cardiac function abnormalities, etc., or have impediments to venous return to the closed mechanism of the penile leukomalacia, the penile cavernous sinus smooth muscle due to the reduction of the penile venous leakage. Neurological causes: central and peripheral nerve disease or injury can lead to erectile dysfunction. Surgery and trauma: surgery such as major vascular surgery, radical prostatectomy, radical abdominal perineal rectal cancer, and pelvic fracture, lumbar spine compression fracture, or straddle injuries can cause vascular and nerve damage related to penile erection, leading to erectile dysfunction. Endocrine disorders, chronic diseases and long-term use of certain drugs can also cause erectile dysfunction. Diseases of the penis itself: such as sclerosis of the penis (induration of the penis), penile curvature deformity, severe circumcision and foreskin? cephalitis. Mixed ED: refers to erectile dysfunction caused by a combination of psychosomatic factors and organic etiology. In addition, because of the organic ED has not been timely treatment, the patient’s psychological pressure is aggravated, the fear of failure of sexual intercourse, so that the ED treatment tends to be more complicated. Domestic 1 group of 628 cases of ED patients etiological classification of the study showed that: psychological accounted for 39%, organic for 15.8%, mixed accounted for 45.2%. Pathogenesis: classification: according to the pathophysiological mechanism of ED can be divided into 6 categories: psychological erectile dysfunction: about 50% of ED patients, the main reasons are anxiety, depression, tension, husband and wife relationship and lack of sexual attraction or spouse, childhood bad addiction. Endocrine erectile dysfunction: such as hypogonadotropic hypogonadotropic hypogonadism, hypergonadotropic hypogonadism, hyperprolactinemia, Klinefelter syndrome, testicular trauma, thyroid dysfunction and so on. Neurogenic erectile dysfunction: damage to the parasympathetic or somatic nerves emanating from the sacral medulla can cause partial or complete erectile dysfunction. In addition, neurological disorders caused by certain diseases can also cause erectile dysfunction, such as diabetes, chronic alcoholism. Arterial erectile dysfunction: Atherosclerosis of the cavernous arteries of the penis can narrow the lumen, prostate cancer treatment, pelvic fracture and other injuries to the penile arteries, resulting in a decrease in the pressure of blood perfusion and a decrease in blood flow. In addition smoking, hypertension, diabetes can cause arterial lesions. Venous erectile dysfunction: Sometimes despite adequate penile arterial perfusion, excessive venous leakage can cause erectile dysfunction, such as leukomalacia and abnormal cavernous smooth muscle function. Others: pharmacological, usually interfere with the central neuro-endocrine function of penile erection or affect the local neurovascular regulation of drugs prone to induce erectile dysfunction, such as antihypertensives, antidepressants, anticholinergics, estrogens and so on. Usually 2. to 5. is called organic erectile dysfunction. Grading: ED is classified as mild, moderate, or severe. The International Inventory of Erectile Function (IIEF) scale can quantify ED symptoms in a more objective way. Severe ED: IIEF scale score 5-7 points. Moderate ED: IIEF score 8-11. Mild ED: IIEF scale score 12-21. No ED: IIEF scale score ≥ 22. Clinical manifestations of erectile dysfunction Detailed history analysis: should include the following: whether it is a gradual development or sudden, intermittent or persistent; nocturnal penile erection; whether it has suffered a major mental shock; marital status should be to understand the relationship with their spouses, fertility, the purpose of seeking medical treatment. Should also ask what kind of drugs, there is no history of trauma, there is no diabetes or other chronic diseases, there is no masturbation habits and tobacco and alcohol addiction, whether the prostate removal surgery, sterilization surgery or lower abdominal surgery, there is no chronic prostatitis or seminal vesiculitis and so on. Physical examination: general conditions should pay attention to the body type, hair and subcutaneous fat distribution, muscle strength, secondary sexual characteristics, the presence of male breast feminization. This is relevant to suggest the presence of cortisolism, thyroid disease, hyperprolactinism, testicular and other gonadal function abnormalities. The cardiovascular system measures blood pressure and limb pulses, and the disappearance or weakening of femoral and N arterial pulses suggests that there may be abdominal aorta and iliac artery embolism or stenosis. Nervous system focus on the lower back, lower limbs, perineum and penis pain, touch and temperature sensation, penis and toes vibration sensation, bulbocavernosus reflex (when stimulating the glans penis, inserting a finger into the anus should feel the contraction of the anal sphincter) and other changes in the nervous system. External genitalia The size and shape of the penis and the foreskin are abnormal. Should carefully touch the cavernous body of the penis, if there are fibrous plaques, suggesting cavernous sclerosis of the penis. The prepuce, foreskin adhesion or short foreskin tie can affect the normal erectile function; testicular size, texture, with or without syringomyelia, epididymal cysts and varicocele. Huge syringomyelia and hernia can also affect normal sexual intercourse; anal finger test prostate size, texture, nodules and tenderness, anal sphincter tone, etc., for ED patients over 50 years old should pay more attention to anal finger test. Erectile dysfunction examination Laboratory tests: blood, urine routine, fasting blood sugar, high and low density lipoprotein and liver and kidney function. Hormone measurement: including serum testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin (PRL). If low testosterone production is suspected, testosterone levels should be measured twice. Chromosomal tests should be performed if necessary. Other auxiliary tests: nocturnal penile tumescence (NPT): paper tape or Snap-Gauge test: before going to bed at night, the test ring with 3 different tension strips is fixed on the penis, and on the morning of the second day, the tension strip is checked to see if the strip breaks, and accordingly to determine whether there is an erection at night and the hardness of the erection. Penile Hardness Tester: It is the only non-invasive test that can measure the nocturnal swelling of the penis and at the same time reflect the hardness of the penis. Normal parameters: nocturnal erection frequency of 3-6 times, each erection lasts 5-10 min, hardness more than 70%, swelling >2-3 cm. Penile brachial index (PBI): The systolic blood pressure of brachial and dorsal penile arteries were measured with a Doppler ultrasound stethoscope. The ratio of the systolic pressure of the dorsal penile artery to the systolic pressure of the brachial artery is the penile arterial blood pressure index, and if the PBI is >0.75, it is normal; <0.6, it is the insufficiency of penile blood supply. Penile cavernous injection of vasoactive drugs test (intracavernous injection, ICI): vasoactive substances are injected directly into the cavernous body of the penis to induce an erection, and the time, hardness, angle of erection, and duration of the induced erection are used to determine the blood supply and venous return of the penis. Commonly used drugs are: poppy seed 30mg plus phentolamine 0.5~1mg; or prostaglandin El 10~40μg. Penile cavernous angiography: for those who are suspected of having venous fistula. First inject vasoactive substances to induce penile erection, and then quickly inject 30% pantethine glucosamine 30-100ml into the cavernous body, and immediately take positive and lateral X-ray film of the penis. Those with venous fistula can have obvious changes. Selective penile arteriography: Arteriography is the main method of locating and characterizing abnormalities in the penile blood supply, it is an invasive test and is contraindicated in those with severe hypertension, diabetes, myocardial infarction and vasculitis. Neurological examination: Autonomic nerve test: there is no direct examination method, only through the functional status and nerve distribution of organs and systems involved in autonomic neuropathy and their relationship with autonomic nerves to indirectly understand and evaluate their neurological function. Examinations include: heart rate control test, cardiovascular reflex detection test, sympathetic skin response, spongy body electromyography, temperature domain value test, urinary anal reflex. Somatic nervous system examination: including penile biological threshold measurement test, sacral nerve stimulation response, pubic nerve conduction velocity, somatosensory nerve evoked potentials. Color duplex ultrasonography (CDU): a non-invasive examination, high-frequency probe can observe whether there are pathological changes in the penis, 4.5 MHz pulse ranging probe can perform blood flow analysis, determine the blood flow rate, combined with the ICI to observe the penile blood flow before and after the injection, to understand the mechanism of penile arterial blood supply and venous closure. The main parameters are: arterial systolic maximal blood flow rate (PSV) >25cm/s for normal penile arterial blood supply, end-diastolic blood flow rate (EDV) <5cm/s for normal dorsal penile vein closure function, and resistance index (resistance index RI) the average value of 0.99 for normal people. Penile corpus cavernosum manometry (CAVNOMY, CM): It is an effective method for diagnosing venous erectile dysfunction, in which the perfusion flow rate (MF) to maintain erection is directly related to venous fistulae. venous closure can be considered with MF >10 ml/min. Treatment of erectile dysfunction Correction of the relevant factors causing ED, including: change of poor lifestyle and psychosocial factors; sexual skills and sexual knowledge counseling; change of the relevant drugs causing ED; treatment of the relevant organic diseases causing ED, such as androgen deficiency, available androgen supplementation therapy. Direct treatment for ED includes: psychosexual treatment: such as psychosexual therapy or behavioral therapy between couples. Oral medications: Viagra (Sildenafil), Elidel (Vardenafil), and cialis (Tadalafil) are a selective type 5 phosphodiesterase inhibitor, I clinically effective, but contraindicated in combination with nitrates or severe hypotension will occur. Phentolamine is an a-adrenergic receptor blocker with effects on both the sexual center and the periphery, and is suitable for mild and moderate ED applications. Local treatment: penile corpus cavernosum injection of vasoactive drugs, prostaglandin E1 (PGE1), the efficacy of up to 80% or more, but due to invasive, pain, abnormal erection and the formation of localized scarring of the penis after prolonged use, and less use; transurethral administration of medication, Bifar is a local topical PGE. cream, the efficacy of up to 75%, the adverse effects of localized pain and low blood pressure; vacuum constriction device is a device that is used to reduce blood flow through negative pressure. The blood will be inhaled into the penis, and then use a rubber band bound at the root of the penis to block blood reflux, maintain penile erection, the disadvantage is the use of trouble, and penile pain, numbness, bruising, ejaculation disorders and so on. Surgical treatment: including vascular surgery and penile prosthesis, which is only used when all other treatments are ineffective.