Definition and Incidence
Erectile dysfunction (ED) is defined as the persistent or recurrent inability of man to achieve and/or maintain a sufficient penile erection, both for his own and for the needs of the partner, to lead and manage a successful sexual intercourse. This condition can occur occasionally and without inducing psychological problems or management, but when it is repeated several times and the dysfunctional defect becomes more important for quality and/or quantity then a whole series of problems related to it are activated. Normally it is distinguished:
- Primary Erectile dysfunction – If the man has never been able to achieve or sustain erection due to psychological causes and/or biological
- Secondary Erectile dysfunction – If man who previously could achieve and sustain erections, is no longer able to do so, for organic causes in 90% of cases
The persistent ED is an uncommon problem under 40 years of age. Generally the incidence of ED is about 10% in the Western population, but it reaches 50% in the age between 40 and 70 years, so that about 65% of men aged 70 presents problems of ED, increase mainly due to vascular disorders and that occurs with about 10 years earlier in diabetic men. Unfortunately, the issue is adequately addressed by only a very small part of the men involved, at all ages and especially in young men, both to minimize the problem of fear or shame. This attitude often leads to a worsening of the overall picture that instead could be solved quite easily, if not always quickly, after the accurate diagnosis of the causes.
Numerous physical and psychological factors are involved in normal erectile function, including neurological, vascular and hormonal factors. More simply, the underlying causes of ED can be:
ED is caused by an alteration of the anatomical structure or physiological functioning of the systems involved in the erection process. The most common organic causes are those that affect the vascular system of the erection (atherosclerosis of the arteries of the penis, linked to harmful lifestyles such as smoking, physical inactivity, obesity and/or chronic conditions such as hypertension, diabetes, hyper cholesterolemia that prevents the increase in blood flow necessary to bring and maintain an erection); endocrine diseases, in particular testosterone deficiency; neurological and psychiatric disorders, in particular depression and traumatic injuries of the nerve pathways that carry erectile signals to the penis, which may occur, for example, as a result of spinal trauma of the column or following surgery on organs of the abdomen such as the bladder, prostate, rectum and abdominal aorta.
In the absence of a detectable organic cause, the ED is caused by a central inhibition of the mechanisms of erection, or by a psychological alteration, dependent by cognitive and emotional processes.
When both factors, psychogenic and organic coexist.
In the majority of patients with ED, there is a combination of organic and psychogenic factors. However it is important to note that the etiological classifications are relatively simple. Indeed, the presence of an organic alteration in case of ED does not exclude concomitant psychological causes. On the other hand the non-detection of an organic cause not confirm, by itself, the exclusively psychogenic origin of ED.
Causes of ED
- Vascular Diseases
Arteriosclerosis causes the stiffening and restriction of the arteries, resulting in reduction of blood flow in the vascular network of body, and therefore also in the arteries of supply to the penis. It is related to age and is the cause of impotence in approximately 60% of men with more than 60 years; there are also behavioral conditions that may favor it even in much younger subjects, such as smoking, diabetes, hypertension and hypercholesterolemia.
The deficiency of insulin or its improper use by the body, carries a high level of glucose in the blood, therefore the vessels, especially the small ones, are altered thus reducing the flow of blood and also the conduction of nervous stimuli is altered also preventing the regulatory activity of the nerves that govern the erection.
The use of several drugs, such as those for the treatment of hypertension and cardiovascular disease, antidepressants, tranquilizers and sedatives, directly or indirectly induce the ED, in addition to the constant consumption of alcohol, smoking and drugs that in a medium-long period of time inevitably produce neurovascular injury.
- Endocrine imbalances
They are the less frequent causes (less than 5%) of ED. The deficiency of testosterone, or better of its active form dihydrotestosterone (DHT), not only is very rare, but must be consistent (the blood level of testosterone must be less than 2 ng/ml, and that of DHT less than 30 pg/ml) and in this case can induce the reduction of libido and the resulting erectile response. Even the stable excess of prolactin (over 30 ng/ml) can induce the reduction of the erectile response by a quite complex neural and endocrine mechanism.
- Neurological causes
The lesions of the spinal cord and brain injuries, resulting in the interruption of the control circuits of the erection and sensory stimuli may be responsible for ED. Among these the most frequent are, however, serious diseases such as paraplegia, cerebral infarction, multiple sclerosis, Alzheimer’s and Parkinson ‘s disease.
- Trauma and pelvic surgery
Traumas and surgicery of the lumbosacral and pelvic region can induce injuries to the corresponding spinal cord, to the neural and vascular pelvic networks, with a reduction in blood flow (arterial) and increase in blood flow (venous), so that, in both temporary that definitive way, the ED can occurs.
- Peyronie’s syndrome
It is an infrequent or rare inflammatory condition whose nature is not clear (repeated microtrauma, autoimmune reactions, local metabolic alterations) that produces retroactive cicatricial repairs that make rigid the area of the cavernous body preventing the erectile expansion.
- Venous Insufficiency
When the veins and their system of valves are not able to retain the blood in the penis, the erection is active, but does not remain stable. The reasons for this effect are due to venous lesions caused by various factors both organic and psychodynamic.
- Pelvic congestion
The dysfunctional and inflammatory processes of the pelvic venous network, in particular of recto-sigmoid colon and prostate, induce a congestion of the venous-lymphatic system leading to a circulatory and drainage imbalance so that protective stimuli and mechanisms of inadequate venous sealing are activated that lead to ED or its opposite infarction (persistent erection with thrombosis of the cavernous bodies, priapism), which then evolves into venous insufficiency.
- Psychological causes
Depression, guilt feelings, worries, stress, anxiety contribute to inhibit the erectile response and libido. Frequently this is due to the appearance of ED for one or more of the previous causes, activating the persistent framework of ED by fear for the performance, and triggering a kind of circuit that tends to amplify the real causes of ED.
Anatomy of the Penis
The penis consists of a cylindroid part, the body, and a conoid part, the glans. The main structure of both is vascular type, which is a network of vessels widely communicating between them in which the blood volume and the rigidity of the covering sheath constitute the basic conditions for the erection. The body of the penis consists of two dorsolateral cylindrical bodies, called cavernous bodies (corpora cavernosa), enveloped by a thick sheath of fibrous tissue little elastic or tunica albuginea, and a mid-ventral cylindrical body, called spongious body (corpus spongiosum), in which is placed the penile or spongy urethra. The fibers of the tunica albuginea surrounding the cavernous bodies and join to form a perforated septum that allows these bodies to operate as a single unit .
The cavernous bodies and spongy body of the penis are surrounded by a deep fibrous tissue, Buck’s fascia. The cavernous spongiform tissue form a network of interconnected cavernous spaces, called sinusoidal or lacunar spaces. The epithelial vascular cells cover the cavernous spaces separated by trabeculae, constituted by bundles of smooth muscle fibers, with an extracellular matrix (elastin, collagen, and fibroblasts).
The cavernous bodies are the erectile elements dysfunction, while the urethra, the channel for urine and semen emission, is therefore connected to the bladder and the ejaculatory ducts. The glans is the terminal part of the penis, and has at its top the urethral opening, the meatus which serves for the emission outside of urine and sperm. The skin, with a high elasticity, covers the whole body to the third distal, almost to the glans, then folds up to form the foreskin, which more or less completely covers the glans, and whose vertex is connected ventrally by the frenulum or fillet. The penis is primarily vascularized by internal pudendal artery, which branches into perineal artery and penile artery. The penile artery then divides into the bulbar, urethral, dorsal spongy and cavernous arteries. The cavernous artery enters into the cavernous bodies and runs along the penile body, where it divides into many branches called helicine arteries which open in the cavernous spaces . The blood drains from the penis through the superficial, intermediate and deep veins. These latter drain the blood from the cavernous bodies and the spongious bodies. On the basis of sensory stimuli increases the flow of blood through the cavernous arteries and helicine arteries and this leads to erection.
Physiology of erection
The mechanism of erection is a hemodynamic event that involves both Central Nervous System vascular and the vascular system. It is one of the most sophisticated and complex mechanisms, as well as one of the most perfect of the human body. In fact it provides that a double series of impulses that come from two different areas of the body, the limbic system of the brain, where instinctive impulses arise, and the area of the genitals where arise the sensitive impulses, go simultaneously to activate and deactivate the erection center located in the spinal cord. The stimuli coming from the brain arise from a series of commands coming from the hypothalamus from senses of smell and sight, while those coming from genital apparatus are essentially tactile. While instinctive impulses that are the basis of libido arise from the brain to the centers lumbar and sacral of erection, the other stimuli arise from the nerve fibers connected to the external genitalia, in coordination with each other: in the absence of stimuli by an area, these are compensate by those of the other area.
The physical and psychological stimuli converge on the center of the erection so then move on to the cavernous bodies of the penis, through a circuit that triggers the increase of blood flow (arterial) to the penis and decreases the outflow (venous) from the penis. The two penile arteries carry blood to the two cavernous bodies, while the spongious artery carries it to the penis, so that the increase in the amount clog up the vascular network of the cavernous bodies and glans pumping them: rigidity is due to the delicate balance that is achieved between the increased pressure in the vascular network and the elastic stiffness of the tunica albuginea that covers it. The pressure is also supported by the partial closure for compression and contraction of smooth muscle fibers near the valves of the veins. Simultaneously with the relaxation of the cavernous arteries is also the relaxation of smooth muscle of the cavernous bodies. An adequate blood flow to the penis is therefore the key to making this process work properly.
Biochemical mechanisms of erection
Current knowledge indicates that the relaxation of smooth muscles of the cavernous bodies and the activity of the vascular network necessary for penile erection are also supported by the release of molecules with vasodilatotory actvity. Neurotransmitters are emitted along the circuits of activation and deactivation of the erectile response of the penis; so depending on which of the two activities dominates, it will activate or deactivate the erectile process. Under physiological conditions, one of the main positive mediators of the erectile phenomenon is the nitric oxide (NO), a neurotransmitter originally called endothelium derived releasing factor from the, synthesized from arginine and released from nerve terminals NANC (non- adrenergic non cholinergic), in response to sexual stimulation, and then it spread in the smooth muscle of the cavernous bodies. After spreading to the muscle cells, NO activates the cytosolic enzyme guanylate cyclase, which synthesizes a second messenger, the cyclic guanosine monophosphate (cGMP) from GTP. This intracellular mediator (cGMP) allows the relaxation of smooth muscles of the cavernous bodies, leading to the appearance of penile tumescence and finally erection. The cGMP is then usually hydrolysed by nucleotidic cyclic isoenzymes, called phosphodiesterases (PDEs), which are located in various tissues. In the cavernous body of man, the predominant isozyme of cGMP-specific PDE is the type 5 (PDE5) or 5-phosphodiesterase, which catalyzes the conversion of cGMP to GMP thus ending this activator signal and deactivating the process of vasodilation. Therefore the erectile process is the result of several and very delicate erectile mechanisms that can be reversed also quickly enable or disable it.
Pathophysiology of erection
The relaxation of the smooth muscle of the cavernous body and penile erection depend on a delicate balance between the effects of vasoconstrictors and vasodilators factors. To bring the flaccid penis, tonically contract in the erection state, it is necessary that the relaxation of the smooth muscle of the cavernous body have to exceed a certain threshold level. It has been shown that the basic defect in patients with erectile dysfunction can be, regardless of etiology, an imbalance between the contraction and the ability to smooth muscle relaxation in the cavernous body. If the base tone of smooth muscle of the cavernous body is too high, the maximum relaxation level may not be sufficient to allow the increase of the blood flow required for a normal erection. If the threshold level of smooth muscle relaxation is not reached or is maintained, the resistance to venous outflow will be insufficient. For this reason you can have erections with different degrees of rigidity.
Treatment of Erectile Dysfunction
The therapeutic treatment of ED can be divided into different solutions and must always predict the possible therapies for the organic type related diseases on other organs, genital or otherwise, or other districts: these will be resolved or rebalanced before or simultaneously with the specific treatment for erectile dysfunction.
The general approach should be to advise the patient to reduce smoking and alcohol consumption. The control of diabetic patients should be followed carefully, considering the possibility of changing the drug therapy in progress, even if the transition from one to another antihypertensive drug rarely used to improve erectile dysfunction. It possible to prescribe testosterone in older men with isolated androgen deficiency proven, particularly in patients with impaired libido. However, it is firstly need to exclude the presence of prostate cancer. Young patients with androgen deficiency and those with hyperprolactinaemia should be addressed to an endocrinologist.
- Sexological therapy
Many men develop a ED based on psychological and/or behavioral and/or relational, for reasons that should always be emphasized. In this case it is necessary to intervene through the simple dialectic confrontation, or the teaching of devolution activities and recovery of sensory perceptions of the body, or with appropriate shiatsu-Ayurvedic course for rebalance and relaxation, or with a restoration work of couple communication also, if necessary, delegating therapy to the psychologist. The sexual counseling is an important aspect of any treatment and it is preferable that also the partner is involved. The counseling helps to reassure the couple and alleviate the tension between the partners.
Immunotherapy is based on the administration, through microinjection intradermal, of Fab component of specific antitissular antibody that act on target tissues rebalancing impaired function; schedule of administration depends on the causes that induce erectile dysfunction so as to act on the different components whether neuroendocrine, vascular or penile. The treatment takes at least 3-6 months and choices must be performed by a urologist experienced in such therapy.
- Oral drug therapy
The two main drugs used for oral administration are Sildenafil (Viagra ®) and Yohimbine (Yohimbine®, Yocon®), both non-inducing erection, but supporters of the it. Sildenafil improves and helps to sustain an erection, normally induced, since it inhibits the enzyme 5-fostodiesterasi (PDE5) that degrades cGMP necessary to the maintenance of the biochemical message of erection. This leads to an increase in intracellular levels of the neurotransmitter NO that induces the relaxation of smooth muscle of the cavernous bodies, facilitating the inflow of blood and the subconsequent relaxation of the cavernous bodies. Sildenafil has been approved for the treatment of erectile dysfunction of either organic and psychological causes.
The Yohimbine improves and helps to sustain an erection, normally induced, because it induces the block of the alpha-2 adrenergic receptors thus reducing vasoconstriction.
Vardenafil (Levitra®) is another active drug for the oral therapy of ED: it belongs to the class of PDE5 inhibitors and its activity in vitro has been widely compared respect to that of Sildenafil.
Tadalafil (Cialis®) is another active drug in the oral therapy of ED. It is a molecular variant always belonging to the class of PDE5 inhibitors, but having a chemical structure totally different compared to Sildenafil and Vardenafil, it has a absolutely particular pharmacokinetic action. It has a more prolonged over time action due to a slower metabolism, but retains all the problems typical of Sildenafil and accentuates some risks including that of the erectile persistence which can lead to priapism.
- Auto injecting drug therapy –
The self-injection involves the use of a thin and short needle to inject medication directly into one of the cavernous bodies, just below and laterally the glans; the drug in 10-30 minutes induces erection that can last for many hours. The two main drugs used are prostaglandin E1 (PGE1) or Alprostadil (Caverject®) and Papaverine (Papaverinahe Teofarma®) both induce an erection by relaxing the smooth muscle and thus allowing high blood flow and vasodilation in the cavernous bodies.
- Vacuum devices
These devices have the advantage of being non-invasive and can be effective in all men when other treatments are ineffective or to enhance the results of drug therapy. They usually are devices consisting of a plastic cylinder which is sealed with a gasket at the base of the penis, which is connected to a manual aspirator at the other extreme (from the side of the glans) so as to generate the vacuum in the cylinder around the penis and favor the flow of blood within the cavernous bodies by pressure difference; once the blood has inflated the penis, is the pressure that keeps it inside and the cylinder can be removed leaving a rubber ring at the base of the penis which prevents emptying, but which must be removed maximum after 30 minutes, otherwise the risk of injury from compression and trigger reactions of thrombosis and micro-hemorrhages in the structure of the penis, with the consequent damage. The disadvantages are mainly due to the fact that a certain manual skill is required to use, and a certain period of time to be applied.
- Intracavernous penile prosthesis
These prostheses are indicated when the ED can not be treated or there are not absolutely positive results with the previous treatments even after solving the related diseases; sometimes they represent the only possible solution after demolition surgery for tumors or reparative for pelvic trauma. The types of prostheses currently used are two: the inflatable and malleable prostheses.
The inflatable prostheses consist of two cylindrical chambers connected, with a valve inserted into the scrotum to a tank inserted into the abdomen; it is also used a model that compact the tank and the rooms in a single endocavernous structure. The valve lets the fluid flow from the tank in the rooms that swell causing an erection rigid enough, or it lets the liquid to drain from the prosthesis into the tank restoring the flaccidity.
The malleable prostheses are instead constituted by cylinders with a silicone conoid termination with a metal core, which allow to make more or less rigid the prosthesis, and then to obtain a good rigidity or a discrete flaccidity. It is evident that the penis still maintains a semi-rigid state linked to the presence of the prosthesis.
However in both prosthesis, the consistency of the penis is obviously smaller, even less in those malleable; both leave the glans little turgid being possible its tension only in the case in which the natural blood flow is still a little adequate. The choice of the type of prosthesis depends on many factors, including the cost and the possibility of installation of one or another model.
- Vascular reconstructive surgery
This solution has a very specific indication for surgical risk, for possible damage to the nerve network and the possible formation of scar tissue. In some cases it may be useful the penile revascularization using natural or artificial vascular prostheses that carry the proper and adequate blood flow to the penis; alternatively it is possible to build a bridge between the vessels to the cavernous bodies and an artery derived from the root of the thigh; in particular, the application may be useful in young patients with a specific arterial blockage. In some cases of primary venous insufficiency of the cavernous bodies, as a last therapeutic option, it is possible to proceed to the ligature of insufficient vein at the base of each cavernous body; the success of this intervention is modest and can lead to priapism or instability in the medium-long period.
- Naturopathic therapy
The integrity of erectile function is also strictly dependent on dietary choices and lifestyle. Incorrect nutritional choices, such as too much processed food, too fast and not very digestible diet, lacking in fruit and vegetables are often the basis of ED; also a lifestyle characterized by the excessive or continuous use of alcohol, smoke and drug use, stress and overwork or by an excess of competition is often the basis of ED. These factors may be coexisting thereby amplifying the modest effects derived from other negative conditions. The nutritional rebalancing associated with the change of the lifestyle are the basis of naturopathic therapy and often reconstitute the normal erectile function by ensuring a high benefit even if there are other pathological conditions.
Use of Phytotheray
The use of phytotherapeutic remedies, well selected and properly prepared, it is often useful to integrate drug therapy or as a consolidation treatment when the drug therapy is not necessary. It is important that the phytotherapeutic remedies or herbal medicines are of high quality and adequate preparation. The choice, composition and the dosage must be determined by a doctor or urologist phytotherapist. Among the main phytotherapeutic remedies normally used for the treatment of ED there are: Asian Ginseng, Ginkgo Biloba, Maca, Muira Puama, Guaranà, Damiana, Catuaba.