الجمعة، 30 يوليو 2010

Treatment

Treatment depends on the cause. Testosterone supplements may be used for cases due to hormonal deficiency. However, the cause is more usually lack of adequate penile blood supply as a result of damage to inner walls of blood vessels. This damage is more frequent in older men, and often associated with disease, in particular diabetes.
Treatments (with the exception of testosterone supplementation, where effective) work on a temporary basis: they enable an erection to be attained and maintained long enough for intercourse, but do not permanently improve the underlying condition.
ED can in many cases be treated by drugs taken orally, injected, or as penile suppositories. These drugs increase the efficacy of nitric oxide, which dilates the blood vessels of corpora cavernosa. When oral drugs or suppositories fail, injections into the erectile tissue of the penile shaft are extremely effective but occasionally cause priapism.[citation needed]
Exercise, particularly aerobic exercise is an effective cheap treatment for erectile dysfunction.[23][non-primary source needed]
When pharmacological methods fail, a purpose-designed external vacuum pump can be used to attain erection, with a separate compression ring fitted to the penis to maintain it. These pumps should be distinguished from other penis pumps (supplied without compression rings) which, rather than being used for temporary treatment of impotence, are claimed to increase penis length if used frequently, or vibrate as an aid to masturbation. More drastically, inflatable or rigid penile implants may be fitted surgically. Implants are irreversible and costly.[citation needed]
All these mechanical methods are based on simple principles of hydraulics and mechanics and are quite reliable, but have their disadvantages. In a few cases there is a vascular problem which can be treated surgically.[citation needed]
Counselling is often a consideration, both where a psychological cause is suspected or must be ruled out, or to assist in management of any distress.[citation needed]
[edit]Medications
The cyclic nucleotide phosphodiesterases constitute a group of enzymes that catalyse the hydrolysis of the cyclic nucleotides cyclic AMP and cyclic GMP. They exist in different molecular forms and are unevenly distributed throughout the body.
One of the forms of phosphodiesterase is termed PDE5. 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 specific phosphodiesterase type 5 causes the smooth muscle of the arteries in the penis to relax, allowing the corpus cavernosum to fill with blood.[citation needed]
These medications work when there is sexual stimulation. Depending on the treatment, it will need to be taken 20 minutes to 1 hour before sex and the period of time over which it works can vary between 3 hours and up to 36 hours.[citation needed]
Alprostadil
Alprostadil can be injected into the penis or inserted using a special applicator - usually just before sexual intercourse.[citation needed]
Alprostadil has also become available in some countries as a topical cream (under the brand name Befar),[24] and preliminary studies have shown a clinical efficacy of up to 83%.[25][non-primary source needed]
Androskat
Androskat is a mixture of papaverine and phentolamine injected into the penis before sexual intercourse. It does not require refrigeration.[citation needed]
[edit]Surgery
Main article: Penile prosthesis
Often, as a last resort if other treatments have failed, the most common procedure is prosthetic implants which involves the insertion of artificial rods into the penis.[26][unreliable source?]
[edit]Devices
Vacuum Therapy
Main article: penis pump
These work by placing the penis in a vacuum cylinder device.[27][not in citation given] The device helps draw blood into the penis by applying negative pressure. A tension ring is applied at the base of the penis to help maintain the erection.[27][not in citation given] This type of device is sometimes referred to as penis pump and may be used just prior to sexual intercourse. Several types of FDA approved vacuum therapy devices are available with a doctor's prescription.
[edit]Alternative medicine
Numerous alternative therapies are used to improve sexual function. Some include: niacin, zinc, ginseng root, ginkgo. None of these however have been recognized as effective by the FDA.[28][clarification needed] While zinc deficiency may be a cause of lower testosterone levels in hemodialysis patients, which may benefit from zinc supplementation,[29][dead link][non-primary source needed] such supplements have no effect on the testosterone levels of healthy males who consume a zinc-sufficient diet

Other

Penile biothesiometry
This test uses electromagnetic vibration to evaluate sensitivity and nerve function in the glans and shaft of the penis. A decreased perception of vibration may indicate nerve damage in the pelvic area, which can lead to impotence.[citation needed]
Penile Angiogram
Invasive test - allows visualization of the circulation in the penis and is used during the repair of a priapism.[citation needed]
Dynamic Infusion Cavernosometry
(Abbreviated DICC) technique in which fluid is pumped into the penis at a known rate and pressure. It gives a measurement of the vascular pressure in the corpus cavernosum during an erection. To do this test, a vasodilator like prostaglandin E-1 is injected to measure the rate of infusion required to get a rigid erection and to help find how severe the venous leak is.[citation needed]
Corpus Cavernosometry
Cavernosography measurement of the vascular pressure in the corpus cavernosum. Saline is infused under pressure into the corpus cavernosum with a butterfly needle, and the flow rate needed to maintain an erection indicates the degree of venous leakage. The leaking veins responsible may be visualised by infusing a mixture of saline and x ray contrast medium and performing a cavernosogram.[22]
Digital Subtraction Angiography
In DSA, the images are acquired digitally. The computer creates a mask from lower-contrast x-rays of the same area and digitally isolates the blood vessels (this is done manually through darkroom masking with traditional angiography).[citation needed]
Magnetic resonance angiography (MRA)
This is similar to magnetic resonance imaging. Magnetic resonance angiography uses magnetic fields and radio waves to provide detailed images of the blood vessels. Doctors may inject a "contrast agent" into the patient's bloodstream that causes vascular tissues to stand out against other tissues. The contrast agent provides for enhanced information regarding blood supply and vascular anomalies. Aside from the IV used to introduce the contrast material into the bloodstream, magnetic resonance angiography is noninvasive and painless

Nocturnal penile tumescence

Nocturnal penile tumescence (NPT)
It is normal for a man to have five to six erections during sleep, especially during rapid eye movement (REM). Their absence may indicate a problem with nerve function or blood supply in the penis. There are two methods for measuring changes in penile rigidity and circumference during nocturnal erection: snap gauge and strain gauge. A significant proportion of men who have no sexual dysfunction nonetheless do not have regular nocturnal erections. Thus presence of NPT tends to signify physically functional systems, but absence of NPT may be ambiguous and not rule out either cause

Penile nerves function

Penile nerves function
Tests such as the bulbocavernosus reflex test are used to determine if there is sufficient nerve sensation in the penis. The physician squeezes the glans (head) of the penis, which immediately causes the anus to contract if nerve function is normal. A physician measures the latency between squeeze and contraction by observing the anal sphincter or by feeling it with a gloved finger inserted past the anus. Specific nerve tests are used in patients with suspected nerve damage as a result of diabetes or nerve disease

Diagnosis

Duplex ultrasound
Duplex ultrasound is used to evaluate blood flow, venous leak, signs of atherosclerosis, and scarring or calcification of erectile tissue. Injecting prostaglandin, a hormone-like stimulator produced in the body, induces erection. Ultrasound is then used to see vascular dilation and measure penile blood pressure. Measurements are compared to those taken when the penis is flaccid

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 or emotional 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 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. Restriction of blood flow can arise from impaired endothelial function due to the usual causes associated with coronary artery disease, but can also be caused by prolonged exposure to bright light.

Causes

Erectile dysfunction (ED, "male impotence ") is a sexual dysfunction characterized by the inability to develop or maintain an erection of the penis sufficient for satisfactory sexual performance
(1)
Drugs (anti-depressants (SSRIs) and nicotine are most common. A study entitled “Drug-induced male sexual dysfunction” concluded that of the 12 most commonly prescribed medications on the market today, 8 of those medications list impotence as a side effect of the drug.[citation needed][dated info] Other drugs such as
alcohol, cocaine, and heroin negatively impact male sexual libido
(2)
Neurogenic Disorders (spinal cord and brain injuries, nerve disorders such as Parkinson's disease, Alzheimer's disease, multiple sclerosis, and stroke
(3)
Hormonal Disorders (pituitary gland tumor; low or abnormally high levels of the hormone testosterone

And much much more