The Link Between Multiple Sclerosis and Erectile Dysfunction

Erectile dysfunction (ED) is one of the most common symptoms of multiple sclerosis (MS) in men, affecting 23 percent to 91 percent of men. MS is a disease characterized by the progressive damage of nerves. When nerves associated with the erectile response are involved, ED can occur or worsen, leading to impaired stimulation and/or arousal.

Types of Erectile Dysfunction

Erectile dysfunction is a common medical condition which can affect men of any age but is more common in those over 65. ED may be caused by any number of health or lifestyles factors, including stress, high blood pressure, obesity, diabetes, excessive alcohol use, and certain medications.

By the age of 40, approximately 40 percent of men may be affected by ED irrespective of MS. That rate can increase to nearly 70 percent by the age of 70. The way in which ED affects men can vary and include:

• Inconsistent ability to achieve an erection
• Dissatisfaction with size or rigidity of erection
• Having erections of short duration
• Requiring excessive time and/or stimulation to achieve erection

Causes Associated With MS

Erections occur when signals from the brain cause the muscles of the penis to relax, allowing blood to flow into two chambers on the underside of the penis. The increased blood supply causes the penis to swell and become rigid.

Erections happen in response to either sexual arousal or the physical stimulation of the penis. These are important distinctions as they involve two different neurophysiological mechanisms:

• Erections that occur in response to erotic thoughts, touch, or visual cues are processed by the brain and travel down the spinal cord to trigger an erection.
• Erections that happen as a result of genital stimulation use nerves in the lower part of the spinal cord and basically bypass the brain.

Why is this important? In MS, nerve damage is caused by a process called demyelination wherein the immune system attacks and strips away the insulating membrane surrounding a nerve called the myelin sheath. When this happens, the lines of communication between nerves can be severely affected.

Depending on where the demyelination occurs, the cause and symptoms of ED can vary. Some men, for example, may be able to achieve an erection in response to physical but not erotic stimulation, or vice versa. This seems especially true for younger men with MS who have no other known contributing factors to ED.

In other cases, the impairment may be more pronounced. In such case, MS may either be the primary cause or simply a secondary factor compounding an existing problem.

Diagnosis in Men With MS

Erection problems can be disheartening for men and ones that can be difficult to discuss even with a spouse or doctor.

But it's important to remember that ED in men with MS goes well beyond getting a prescription for Viagra or Cialis. Investigations should include a review of your MS-related symptoms, your current treatment, and any psychological difficulties you may be experiencing in association with your disease. Among the factors to consider:

• If there is reduced sensation of the penis or difficulty in achieving ejaculation (both of which may inform how MS is affecting erectile function)
• If you are experiencing urinary leakage during intercourse
• If there are psychological factors related to mood or self-esteem that need to be addressed separately to the physiological symptoms
• If MS symptoms such as fatigue or spasticity may be contributing
• If antidepressant use, common in ED, is causing or contributing to ED
• If anticholinergics, used to treat ​urinary problems, may also be a problem

Treatment Options

By reviewing all of these factors, doctors may offer MS-specific treatment that can either supplement or be used in place standard ED medications.

These may include instructions on alternative forms of stimulation, such as vibrators, to overcome impaired arousal. Abnormal sensations or spasm may be controlled with the use of medication. Intermittent catheterization or medications may also be used to control urinary leakage.

As an alternative to oral ED drugs, injectable medications such as alprostadil, papaverine, and phentolamine can often enhance erection by causing the dilation of blood vessels in the penis. Penile implants are also gaining increasing acceptance by men for whom other options have failed.