Sexual activity for men usually requires the co-ordination of arousal, penile erection and orgasm including ejaculation, along with the many other emotional and relationship components that are integral for satisfaction. Direct disruption of nerve pathways controlling erection and ejaculation are common.
Erectile dysfunction
An erection occurs when there is relaxation of the muscle cells in the wall of the penile blood vessels and the erectile tissue, leading to the penis filling with blood. Relaxation of these muscle cells is initiated by nitric oxide (NO) release from nerves coming from the lower spinal cord. The messages transmitted by these nerves usually arise in the brain and pass down to the lower spinal cord.
Erectile dysfunction (ED) is the commonest sexual dysfunction in men and usually is due to disease of the vascular or neurological systems, but psychosexual influences are also important. ED can have a major impact on self-esteem, relationships and general well-being.
In men with MS, lesions in the spinal cord that interfere with the passage of nerve impulses from the brain may cause ED. The limited studies of men with MS indicate that ED is a frequent symptom, often affecting younger men and sometimes affecting fertility.
Ejaculatory dysfunction
At ejaculation there is widespread muscle contraction in the pelvic area that leads to expulsion of the semen and much of the sensation associated with the broader response of orgasm.
These responses are also triggered by nerve impulses that traverse the spinal cord from important brain centres.
Often, delayed ejaculation and complete failure of ejaculation (anejaculation) are caused by disruption of the nerve pathways and may be part of a broader orgasmic failure.
Ejaculatory disturbances also occur in MS, although there is less information about the prevalence. Anti-depressant medications (see page 16) that may be used in MS often cause ejaculatory problems as a side-effect. Some men with MS may develop premature ejaculation because of anxiety about their disease.
Sexual desire
Testosterone is active in several brain centres important for sexual thoughts and desire (libido) and low levels are associated with depression and obesity, both of which can relate to MS. Frequently, desire is affected by factors other than the direct physical component of the disease, and this is particularly so in MS where other physical and psychological factors, such as fatigue, may play a major role.
Clinical assessment
Not all men with ED (or even health professionals) find it easy to talk about sex, and they may not raise this distressing issue. It is important to note that sexual dysfunction is diagnosed by taking a careful history; there are no diagnostic tests. Men with MS may have other causes of sexual dysfunction and the assessment should take this into account. Simple blood tests to exclude diabetes, high cholesterol and testosterone deficiency are recommended. Careful assessment of the impact of medications and substance use is important.
| The importance of assessing both the man with MS and his partner cannot be over-emphasised, particularly if initial treatment is not successful. This will require more developed skills that not all doctors will have.
Treating erectile dysfunction
The neurologist or MS nurse should ask men with MS if they are having erectile dysfunction. If they do, the impact of this important disorder needs to be assessed and, if it is considered significant, a full range of treatment options should be discussed. Treatment is usually erectionpromoting medications rather than treating the underlying disorder. However, consideration should always be given to improving potentially reversible aspects. Drugs used to modify MS progression also could help. The most commonly used medications act to enhance the relaxation of muscle cells in the penis. Sildenafil, tadalafil and vardenafil all act in this way through a similar mechanism. They are safe, well-tolerated medications and observation of their use in MS and spinal cord injury confirm a high efficacy, with about three-quarters of men experiencing satisfactory outcomes. Education about how to achieve the best results is the most important aspect of the use of these medications. They need to be taken at least half an hour before sex, but some couples find the idea of premeditating their sexual experience offputting, and this often interferes with treatment. Normal sexual stimulation is required to initiate the erection, therefore the couple needs to be in the mood for sex. Apprehension about the outcome may result in less than optimal results for the first few doses. Persistence, medical review and re-instruction are important for successful results.
Adverse effects
These drugs can cause mild headaches, flushing, nasal congestion, indigestion and muscle aches, but these adverse effects usually do not preclude their use. When sildenafil was launched, much was said of possible adverse cardiac effects and this still worries some men and their partners. There is a potentially harmful reaction with all these drugs when used with nitrates (mainly used to treat angina), and men with active heart disease, for whom the level of physical activity during sexual intercourse is potentially dangerous, should use these drugs with caution.
Alternative ED treatments
If these drugs do not work or cannot be safely used, injecting drugs into the penis or the use of mechanical aides may be helpful. Prostaglandin E1 can be injected directly into the penis. This relaxes the muscle cells and usually induces a hard, lasting erection. Significant dexterity and common sense are essential for self-injection. Penile pain, nodular scarring within the erectile bodies and unduly prolonged erection may occur. The dosing regimen prescribed must be followed
strictly. Some men with partial ED can obtain a good erection using a penile ring, usually combined with a vacuum device. The latter draws more blood into the penis while the ring, applied after blood flow into the penis is sufficient, reduces blood flow out of the penis. If all else fails, a penile prosthesis can be implanted so that cylinders implanted into the shaft of the penis can be filled from a fluid reservoir placed in the scrotum.
Treatment of ejaculatory disorders and low
desire Unlike ED, there is no medication that acts directly to improve ejaculatory problems or low desire. Emphasis will be on optimising physical and emotional well-being. The ED drugs are often tried where there is difficulty achieving ejaculation and orgasm, as there is often a degree of ED as well. In addition, there is usually heightened stimulation with a harder erection. Different positions help some men to be more stimulated and some benefit from mechanical assistance, for example using a vibrator. Couples should be reassured that satisfying sex can be achieved without full erection and penetration, and that partner satisfaction can be achieved by a variety of stimulating techniques.
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