阳痿
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勃起障碍也叫阳痿，男性性功能障碍的一种，指阴茎不能勃起或保持勃起状态来完成性交，但是可能会射精。产生原因有很多，而且很多可以进行治疗。
阳痿有功能性阳痿和器质性阳痿之分，症状是阴茎勃起功能障碍，不能勃起，勃起但是不够坚硬持久。完成不了性交过程。
由于涉及个人隐私，长期以来，这个话题是一个禁忌，充斥着流言。从十九世纪三十年代开始，民间开始大量涉及治愈的广告。在十九世纪九十年代，由于枸橼酸西地那非（伟哥，威而刚）的发明，引发了新一轮的民间的关注。
目录 |
[编辑] 医学症状
勃起障碍的表现是不能保持勃起状态。如果在睡觉时有勃起或晨坚现象，是心理性勃起障碍，如果没有就是器质性勃起障碍，通常是心脏血管疾病。糖尿病也有可能导致勃起障碍，是由于引发了神经疾病和末梢血液循環不良所造成。尿毒症患者亦有一半以上有勃起功能障礙。
[编辑] 医学诊断
没有诊断勃起障碍的一般方法，一些血液檢驗只能查出一些器质性的疾病，比如糖尿病、性腺机能减退和泌乳刺激素過多症。
[编辑] 临床诊断方法
治疗方法有很多，对于功能性阳痿，可以通过心理治疗恢复，主要是解除性交紧张的心理状态。或者用局部注射血管扩张药物的方法达到心理治疗的目的。对于顽固的阳痿可以采取假体植入手术。
[编辑] 超声波双重扫描
超声波双重扫描可以检测血流量、静脉渗漏、前列腺素、动脉硬化和勃起组织损伤或石灰化。把前列腺激素（体内产生的类激素），注入体内，使阴茎勃起，然后用超声波测量血管膨胀和阴茎血压，把这些数据同阴茎疲软后的数据相比较。
[编辑] 阴茎神经功能
球海绵体肌反射测试可以检查阴茎功能，内科医师积压龟头，如果神经功能正常，则肛门就会收缩。医师将戴手套的手指插入比较挤压前后肛门收缩反应的时间。还有特殊的神经测试，看患者因为糖尿病或神经疾病引发的神经损伤。
[编辑] 夜晚阴茎勃起(NPT)
男人夜里睡眠中通常会有五到六次的勃起，特别是在眼睛迅速转动的时刻（REM--rapid eye movement）。如果没有就说明有神经疾病或血液供给问题。有两种方法可以测量阴茎硬度和直径，就是外径规测量和变形测量。
[编辑] Penile biothesiometry
This test uses electromagnetic vibration to evaluate sensitivity and nerve function in the glands and shaft of the penis. A decreased perception of vibration may indicate nerve damage in the pelvic area, which can lead to impotence.
[编辑] Pathophysiology
Penile erection is managed by two different mechanisms. The first one is the reflex erection, which is achieved by directly touching the penile shaft. The second is the psychogenic erection, which is achieved by erotic stimuli. The former uses the peripheral nerves and the lower parts of the spinal cord, whereas the latter uses the limbic system of the brain. In both conditions an intact neural system is required for a successful and complete erection. Stimulation of penile shaft by the nervous system leads to the secretion of nitric oxide (NO), which causes the relaxation of smooth muscles of corpora cavernosa (the main erectile tissue of penis), and subsequently penile erection. Additionally, adequate levels of testosterone (produced by the testes) and an intact pituitary gland are required for the development of a healthy male erectile system. As can be understood from the mechanisms of a normal erection, impotence may develop due to hormonal deficiency, disorders of the neural system, lack of adequate penile blood supply or psychological problems.
A few causes of impotence may be iatrogenic (medically caused). Various antihypertensives (medications intended to control high blood pressure) and some drugs that modify central nervous system response may inhibit erection by denying blood supply or by altering nerve activity. Surgical intervention for a number of different conditions may remove anatomical structures necessary to erection, damage nerves, or impair blood supply.
[编辑] Treatment
Treatment depends on the cause. Testosterone supplements may be used for cases with hormonal deficiency. However, usually the cause is lack of adequate penile blood supply as a result of age-dependent damage of inner walls of blood vessels. Previously, medical substances (e.g. apomorphine) were directly injected into the erectile tissue of penile shaft to treat impotence. In some cases refractory to the medical treatment, a penile implant (penile prosthesis) could be advised. After the discovery of orally active agents that increase the efficacy of NO, which dilates the blood vessels of corpora cavernosa, more conservative methods started to be used.
[编辑] PDE5 Inhibitors
The prescription PDE5 inhibitors sildenafil (Viagra®), vardenafil (Levitra®) and tadalafil (Cialis®) are prescription drugs which are taken orally. They work by blocking the action of PDE5, which causes cGMP to degrade. cGMP causes the smooth muscle of the arteries in the penis to relax, allowing the corpus cavernosum to fill with blood.
[编辑] PT-141
The experimental drug PT-141 does not act on the vascular system like the former compounds but increases sexual desire and drive in male as well as female. It is applied as a nasal spray PT-141 and works by activation of melanocortin receptors in the brain. It is awaiting FDA approval.
[编辑] Ginseng
A double-blind study appears to show evidence that ginseng is better than placebo: see the ginseng article for links and more details.
[编辑] Enzyte
Enzyte is a product that has been advertised by saturation coverage on television channels such as Court-TV. However, the Center for Science in the Public Interest (CSPI) has filed a complaint with the Federal Trade Commission (FTC) about Enzyte for deceptive advertising. It is manufactured by Berkeley Nutritionals, which is alleged to be the subject of an investigation by the Attorney General of Ohio and the defendant in class-action lawsuits.
Enzyte is a supplement that claims to increase the frequency of erections of the male penis or libido. Commercials for Enzyte are shown regularly on television. These commercials feature a man named Bob who never stops smiling, apparently because he had taken Enzyte and improved the size of his sex organs. The commercials are riddled with symbolic phallic imagery, e.g. golf clubs, remarkably tall glasses of iced tea, and a hose spraying barely a trickle of water (carried by someone who doesn't use Enzyte).
The effectiveness of Enzyte is in dispute. Some medical professionals in fact advise against taking Enzyte, saying that it can lead to damage. The Center for Science in the Public Interest have urged the Federal Trade Commission to disallow further television advertising for Enzyte due to a lack of proper studies supporting claims. Enzyte maker Berkeley Premium Nutraceuticals, Inc., is currently under a class action lawsuit for false advertising.
Enzyte is said to contain: Tribulus terrestris; Yohimbe Extract; Niacin; Epimedium; Avena sativa; Zinc Oxide; Maca; Muira Pauma; Ginkgo biloba; L-Arginine; Saw Palmetto. Other ingredients: gelatin, rice bran, oat fiber, magnesium stearate, silicon dioxide.
[编辑] 历史
Dr. John R. Brinkley began a fad for finding cures for male impotence during the 1930s. He used the medium of radio to achieve the same kind of advertising boom to treat the same kind of symptoms.
In the 1930s the American radio airwaves were bombarded with such advertising, first from domestic stations and then upon action by the American Medical Association the media blitz was shifted to superpower Mexican border-blasters.
[编辑] 参考书目
- Cheitlin MD, Hutter AM Jr, Brindis RG, Ganz P, Kaul S, Russell RO Jr, Zusman RM. ACC/AHA expert consensus document. Use of sildenafil (Viagra) in patients with cardiovascular disease. American College of Cardiology/American Heart Association. J Am Coll Cardiol. 1999 Jan;33(1):273-82. Fulltext. PMID 9935041.
[编辑] 外部链接
- PDE5 inhibitors:
- Home Page for Viagra and prescribing information (PDF)
- Official Levitra website
- Pfizer Pharmaceutical (Company website) - manufacturer of Viagra;
- FDA Web Site for Viagra Consumer Information
- Viagra Misunderstood Article describing what Viagra feels like
- FDA's Consumer Information
- Enzyte Company website
- Enzyte investigation reported on CBS-TV news site
- Erectile Dysfunction Primer
