Medical examination for the assessment of sexual dysfunction should be comprehensive and include all systems potentially involved in the physiology of sexuality. Neurologic examination should include the assessment of genital sensitive function including the research for allodynia, muscle weakness and alterations in muscular tone and the anal wink to document reflex function of the sacral segments.

Physical examination should also be accurately performed as it may reveal potential signs of medical conditions associated to sexual dysfunction. A decline in body hair, gynecomastia and testicular atrophy can signal a decreased sieric androgen level. Scars as signs of prior abdominal surgery, the presence of bruits at the auscultation of femoral pulses may indicate a possible cause of neurovascular dysfunction. Orthostatic hypotension may discover an autonomic nervous system dysfunction. External examination of the penis is also important as it can reveal anatomic abnormalities that can be secondary to diseases (i.e. Peyronie’s disease), trauma or surgery.

Magnetic Resonance Imaging of the brain and entire spinal cord should be performed. Emotional incontinenceectrophysiological examination is based on the bulbocavernosus reflex that may reveal a disruption in either the central sacral reflex center or the pudendal/penile nerves. It should be accompanied by the evoked somatosensory reflex of the pudendal plexus. In the case of erectile dysfunction, nocturnal penile tumescence should also be assessed as a simple and non-invasive method to distinguish psychogenic component of erectile dysfunction (ED). This test can document the preserved nocturnal reflex erection in psychogenic erectile dysfunction (ED). However, it may sometimes give false positive results in patients with purely neurogenic erectile dysfunction (ED). Psychogenic erectile dysfunction generally develops acutely, could be intermittent or present only with selected partners, with the preservation of the ability to masturbate and to achieve morning erections. Most Multiple sclerosis patients with erectile dysfunction continue to have nocturnal erections or erections in response to genital stimulation without being sufficient for sexual intercourse. Organic causes of erectile dysfunction other than Multiple sclerosis include medical conditions such as diabetes mellitus, atherosclerosis, hyper or hypothyroidism, hypertension, uremia, alcoholism, vasculopathy, neuropathy and hypogonadism. In Multiple sclerosis, male patients experiencing erectile dysfunction are generally young and have no other risk factors for erectile dysfunction (ED). On the other hand, all these conditions should be excluded or confirmed, as neurogenic erectile dysfunction is not predicted by any test, and it is diagnosed by exclusion. However, organic and psychogenic erectile dysfunction can coexist and the identification of an organic cause cannot exclude the presence of psychological stressors.

A complete review of medication regimen is crucial to exclude iatrogenic causes of sexual dysfunction. A great variety of symptomatic drugs commonly used in Multiple sclerosis are recognized causes of sexual dysfunction (Table Adverse sexual effects of frequently used symptomatic drugs for multiple sclerosis).

Table Adverse sexual effects of frequently used symptomatic drugs for multiple sclerosis

Symptoms of Multiple sclerosis Treatment Adverse sexual function effects
Spasticity Baclofen Erectile dysfunction
Inability to ejaculate
Tizanidine Urinary frequency
Urinary retention
Dantrolene Decreased libido
Erectile dysfunction
Retrograde ejaculation
Fatigue Amantadine Decreased libido
Pain Tricyclic antidepressants Erectile dysfunction
Ejaculatory impairment
Decreased libido
Valproic acid Erectile dysfunction
Carbamazepine Erectile dysfunction
Gabapentin Erectile dysfunction
Levetiracetam Erectile dysfunction
Lamotrigine Erectile dysfunction
Duloxetine Decreased libido Erectile dysfunction
Ejaculation dysfunction
Depression Selective serotonin reuptake inhibitors Decreased libido
Delayed ejaculation
Venlafaxine Erectile dysfunction

Antispastics can induce several SDs including erectile dysfunction and inability to ejaculate (Baclofen), urinary frequency, urgency, retention and incontinence (Tizanidine), erectile dysfunction, retrograde ejaculation end decreased libido (Dantrolene). Amantadine, the most frequently used drug treatment for fatigue may determine decreased libido. Also anticonvulsants such as carbamazepine or phenytoin may lower serum levels of testosterone and, subsequently, libido. Other anticonvulsant or antidepressant drugs commonly used for the treatment of seizures, depression or neuropathic pain are associated to a large number of adverse sexual side effects including erectile dysfunction, ejaculatory impairment and anorgasmia, decreased libido (tricyclic antidepressants, selective serotonine reuptake inhibitors, venlafaxine), erectile dysfunction (valproic acid, lamotrigine, duloxetine, gabapentin, levetiracetam). A possible treatment strategy could be represented by the tapering of dose and the substitution with alternative agents. A comprehensive review addressing the potential adverse side effects of symptomatic drugs for Multiple sclerosis has been recently published by Fletcher et al..

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