Peripheral neuropathy: an underdiagnosed cause of erectile dysfunction.

OBJECTIVES

• To assess the prevalence of peripheral neuropathy in patients with erectile dysfunction (ED). • To evaluate the reliability of clinical tests such as the five-item version of the International Index of Erectile Function (IIEF-5) and the Neuropathy Symptom Score (NSS) classification system in predicting the concurrence of peripheral neuropathy.

PATIENTS AND METHODS

• We studied 90 patients who were consecutively recruited from the Department of Andrology of the Central Hospital of Asturias. • Anamnesis included questions about risk factors related to ED. • The severity of ED was classified according to IIEF-5 scores and symptoms of peripheral neuropathy were assessed using the NSS. • Neurophysiological tests included electromyography, nerve conduction studies, evoked potentials from pudendal and tibial nerves as well as bulbocavernosus reflex. • Small fibre function was assessed using quantitative sensory tests and sympathetic skin response. Statistical analysis was performed using the SPSS-11 program.

RESULTS

• Patients with more severe symptoms of peripheral neuropathy showed lower (worse) IIEF-5 scores (P= 0.015) and required more aggressive therapies (P < 0.001). • Neurophysiological exploration confirmed neurological pathology in 68.9% of patients, of whom 7.8% had myelopathy and 61.1% peripheral neuropathy. • Polyneuropathy was found in 37.8% of the patients, of whom 8.9% had pure small fibre polyneuropathy, and pudendal neuropathy was diagnosed in 14.4%. • No association between neurophysiological diagnosis and IIEF-5 score was detected, but a statistical association was found between neuropathy and NSS scores.

CONCLUSIONS

• Up to now, the impact of peripheral neuropathy in the pathogenesis of ED has been underestimated. The combination of anamnesis and an ad hoc neurophysiological protocol showed its high prevalence and provided a more accurate prognosis. • In future, clinical practice should optimize the assessment of pelvic small fibre function.