Penile erection is managed by two mechanisms: the reflex erection, which is achieved by directly touching the penile shaft, and 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 cases, an intact neural system is required for a successful and complete erection. Stimulation of the 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. Spinal cord injury causes sexual dysfunction including ED. 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.
Cosgrove et al reported a higher rate of sexual dysfunction in veterans with posttraumatic stress disorder (PTSD) than in veterans who did not develop this problem.  The domains on the International Index of Erectile Function (IIEF) questionnaire that demonstrated the most change included overall sexual satisfaction and erectile function. [43, 44] Men with PTSD should be evaluated and treated if they have sexual dysfunction.
When pills don’t work, an ED implant offers hope. Penile implants are custom-fitted devices that are surgically implanted to allow you to obtain an erection when desired. They are undetectable to the naked eye, so no one will know you have one unless you tell them. The Titan® penile implant from Coloplast produces a totally natural, controlled and spontaneous erection that will restore your confidence, relationships and pleasure.
While impotence may be the presenting symptom of vascular disease, in neurologic disease impotence generally occurs in the setting of an obvious nervous system disorder, typically in patients known to have spinal cord pathology or neuropathy. Impotent patients should be questioned about decreased genital sensation, which would suggest diabetic, alcoholic, or other forms of neuropathy; weakness, which may accompany multiple sclerosis or spinal cord tumors; and back pain, bowel, and bladder symptoms, which raise concern for cauda equina syndrome. A careful drug history is important in the evaluation of impotence. Drugs that cause impotence (Table 187.3) generally do so by interfering with neurotransmission.
An initial approach to medical therapy should consider reversible medical problems that may contribute to erectile dysfunction. Included in this should be assessment of the possibility of medication-induced erectile dysfunction with consideration for reduction of polypharmacy and/or substitution of medications with lower probability of inducing erectile dysfunction.
There are no formal tests to diagnose erectile dysfunction. Some blood tests are generally done to exclude underlying disease, such as hypogonadism and prolactinoma. Impotence is also related to generally poor physical health, poor dietary habits, obesity, and most specifically cardiovascular disease such as coronary artery disease and peripheral vascular disease. Therefore, a thorough physical examination is helpful, in particular the simple search for a previously undetected groin hernia since it can affect sexual functions in men and is easily curable.
#9 Smokers hell. Bad stimulants such as smoking cigarettes may be having a negative impact on more than just your lungs. That’s right, smoking may lead to a lazy penis. One study shows that 40% of men that suffer from erectile dysfunction are smokers. The good news is that 75% of men reported erectile issues disappear after quitting smoking. What better motivation to quit smoking than having amazing sex? [Read: How to keep an erection up for longer in 20 ways]
Me and my boyfriend have been together almost two years, and he has only said "I love you" about a dozen times. I know he loves me by his actions but I would still like to hear the words. I have tried talking to him about it but he also isn't one for talking about anything that could possibly be uncomfortable. Sometimes this really makes me insecure, especially since I tell him daily I love him. Other times I feel like I am just being silly and that actions speak louder than words. What should I do?
Other hormone levels: Measurement of other hormones beside testosterone (luteinizing hormone [LH], prolactin level, and cortisol level) may provide clues to other underlying causes of testosterone deficiency and erectile problems, such as pituitary disease or adrenal gland abnormalities. Doctors may check thyroid levels in some individuals as both hypothyroidism (low thyroid function) and hyperthyroidism (overactive thyroid function) can contribute to erectile dysfunction.
Heart disease isn't the only risk. ED is also a predictor of stroke, because when the arteries are narrowed there is more chance of a blood clot, which can spread to the brain. It is also a common complication of diabetes. But embarrassment stops people seeking help, says Jackson. "We need to encourage men to talk to their spouses about this problem, instead of making an excuse to avoid sex.
If you have symptoms of ED, it’s important to check with your doctor before trying any treatments on your own. This is because ED can be a sign of other health problems. For instance, heart disease or high cholesterol could cause ED symptoms. With a diagnosis, your doctor could recommend a number of steps that would likely improve both your heart health and your ED. These steps include lowering your cholesterol, reducing your weight, or taking medications to unclog your blood vessels.
You're right that this should be a last resort, but Paduch also agrees that sometimes a little confidence can help you get back on track. The thing is, you should only take an ED medicine if it's prescribed by your doctor (otherwise you'll miss out on the important medical info you should know before you take it). Another option is an l-arginine supplement, which can increase nitric oxide and blood flow.
This is one of many types of constricting devices placed at the base of the penis to diminish venous outflow and improve the quality and duration of the erection. This is particularly useful in men who have a venous leak and are only able to obtain partial erections that they are unable to maintain. These constricting devices may be used in conjunction with oral agents, injection therapy, and vacuum devices.
Prostaglandins (alprostadil): Alprostadil can be injected into the penis or inserted as a pellet through the urethra. It causes an erection without sexual stimulation that usually lasts about 60 minutes. The danger with this method is that too high a dose can cause priapism, an erection that won't go away. This condition requires immediate medical attention as it can cause serious bruising, bleeding, pain and permanent penile damage. Once the doctor is sure of the right dose, the man can self-inject at home.
Exercise and lifestyle modifications may improve erectile function. Weight loss may help by decreasing inflammation, increasing testosterone, and improving self-esteem. Patients should be educated to increase activity, reduce weight, and stop smoking, as these efforts can improve or restore erectile function in men without comorbidities. Precise glycemic control in diabetic patients and pharmacologic treatment of hypertension may be important in preventing or reducing sexual dysfunction. 
Qaseem, A., Snow, V., Denberg, T. D., Casey, D. E., Forciea, M. A., Owens, D. K., & Shekelle, P. (2009). Hormonal testing and pharmacologic treatment of erectile dysfunction: A clinical practice guideline from the American College of Physicians. Annals of internal medicine, 151(9), 639-649. Retrieved from http://annals.org/aim/article/745155/hormonal-testing-pharmacologic-treatment-erectile-dysfunction-clinical-practice-guideline-from