硬不出起来是什么原因
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Aetiology of erectile dysfunction
Normal erectile function requires the coordination of psychological,hormonal,neurological,vascular,and cavernosal factors. Alteration in any one of these factors is sufficient to cause erectile dysfunction. Not uncommonly,a combination of factors is involved.
# Chronic systemic illness
Diabetes mellitus,heart disease,and hypertension are all commonly associated with erectile dysfunction. Results from the Massachusetts male aging study showed that the age adjusted prevalence of complete impotence was 28% in treated diabetic patients,39% in those with treated heart disease,and 15% in men taking antihypertensive treatment. The prevalence in the whole study population was 9.6%. Complete impotence has also been observed to increase with the severity of depression; almost 90% of severely depressed men report complete impotence. Peripheral vascular disease leading to insufficient arterial blood supply is another common cause. In addition,an association between low plasma concentrations of high density lipoprotein and erectile dysfunction has been found. Other diseases such as peptic ulcer,arthritis,and allergy are also associated with an increased prevalence of erectile dysfunction.
# Hormonal factors
The role of testosterone in erectile dysfunction is not clear. Some men continue to achieve erection even after castration. The fall in free serum testosterone and increases in concentrations of sex hormone binding globulin with aging may be associated with loss of libido and reduced frequency of erection,but restoration of normal testosterone concentrations does not usually improve sexual function. Patients with hyperprolactinaemia,frequently associated with low testosterone values,can develop low libido and erectile dysfunction by unknown mechanisms. Testosterone replacement treatment,without correction of concurrent hyperprolactinaemia,does not resolve erectile dysfunction associated with hyperprolactinaemia.
# Local conditions
Poor blood supply as a result of congenital malformations or trauma is a less common cause of erectile dysfunction that can affect the young male. Peyronie’s disease is a specific condition of the penis in which the development of fibrous plaques in the tunica albuginea,sometimes extending into the erectile tissue,may cause pain (in the early inflammatory stage) and penile deviation,making coitus impossible. Inability to retain pressurised blood in the corpus cavernosum follows disruption of the veno-occlusive mechanism,which can be caused by Peyronie’s disease,congenital,or the result of trauma or surgery.
# Drug induced erectile dysfunction
Around 25% of erectile failure seen in clinic patients is caused by medication. Erectile dysfunction may affect 10-20% of patients taking thiazide diuretics,and to a lesser extent,patients who are using β blocking drugs. This may be a result of reduced perfusion pressure,as blood pressure falls in response to the medication,or probably a direct (but unknown) effect on smooth muscle. Further support for this mechanism comes from the observation that treatment of hypertension with the α adrenergic receptor blockers is not associated with erectile failure,and possibly even enhances pre-existing poor sexual function,despite lowering arterial blood pressure.
Erectile dysfunction commonly complicates antidepressant treatment with both monoamine oxidase inhibitors and tricyclic antidepressants. Benzodiazepines and selective serotonin reuptake inhibitors have been reported to cause erectile failure,decreased libido,or ejaculatory problems.,Cimetidine,digoxin,and metoclopramide cause erectile dysfunction,as do anabolic steroids,either through a direct effect on penile tissues or through suppression of normal androgen production.
Up to 75% of patients in alcohol rehabilitation programmes have erectile dysfunction. In chronic alcohol abusers erectile failure may be the result of a combination of psychogenic and organic factors (for example,neuropathy).
# Psychogenic causes
Psychogenic influences are the most likely causes of intermittent erectile failure in young men. Anxiety about “performance” may result in inhibitory sympathetic nervous system activity,and anticipatory anxiety can make the condition self perpetuating. A psychogenic component is often present in older men,secondary to an organic cause. Underlying relationship problems are a common cause of erectile failure and this possibility should be explored in men of all ages.","department":"
