Erectile dysfunction (ED) in diabetes is multifactorial. So far, the impact of neuropathy has not been well determined. This study was performed to assess the frequency of abnormal neurophysiological tests in patients with ED due to diabetes compared to patients with ED due to nondiabetic neuropathies in order to estimate the contribution of neuropathy in diabetic ED. Forty-nine men with ED were studied. We classified ED as 'diabetic" 'neuropathic' or 'ED of other origin'. 26.6% of the men fulfilled the criteria of diabetic ED, 42.9% had neuropathic ED. In every patient history taking, a questionnaire focusing on autonomic symptoms other than ED, clinical examination, nerve conduction studies (NCS), sphincter ani electromyography (EMG), heart rate variability testing (HRV) and quantitative sensory testing (QST) was performed. Vascular function was assessed by the intracavernosal prostaglandin El (PGE1) injection test. The frequency of abnormal results in diabetic and neuropathic patients was compared. Vascular function was abnormal in only one patient with diabetic ED and three patients with neuropathic ED. Both groups had similar frequencies of autonomic symptoms other than ED (64% in diabetic vs. 64% in neuropathic patients), abnormal EMG (33% vs. 40%) and abnormal QST (vibratory perception 83% vs. 84%, cold perception 9% vs. 19%, warm perception 42% vs. 43%). Abnormal clinical findings (50% vs. 33%), NCS (75% vs. 50%) and HRV (39% vs. 25%) were slightly, but not significantly more frequent in men with diabetic ED than neuropathic ED. The tests indicating neuropathy showed abnormalities in men with diabetic ED as frequently as in men with neuropathic ED. Some tests even suggested neuropathy more often in diabetic than in neuropathic ED. The findings support the hypothesis that neuropathy contributes significantly to the pathophysiology of ED in diabetes mellitus. [Neurol Res 2001; 23: 651-654]
Keywords: Pathophysiology of diabetic erectile dysfunction; neuropathy; vasculopathy; nerve conduction studies; quantitative sensory testing
INTRODUCTION
Diabetic men frequently present with erectile dysfunction (ED)1. ED may even be the first symptom of diabetes mellitus2. ED is defined as the persistent inability to obtain or maintain an erection to permit satisfactory sexual performance3. ED may be due to various causes such as neuropathy, cavernosal arterial insufficiency, corporal veno-occlusive dysfunction, endocrine abnormalities, or psychogenic etiology4-7.
The impact of neuropathy on diabetic ED has not been well established as yet, and it is unclear whether angiopathy of the genital vasculature or dysfunction of the nerves supplying the genitalia is the predominant pathophysiological factor of diabetic ED6-8. Assuming primary vascular changes to be the major pathophysiological factor in diabetic ED, one would expect a higher frequency of neuropathic findings in patients with ED, caused by a neuropathy without accompanying vasculopathy, than in diabetic ED. If neuropathy, on the other hand, was the major pathophysiological factor in diabetic ED, frequencies of abnormal findings suggestive of neuropathy should be similar in patients with diabetic ED and patients with purely neuropathic ED.
To clarify this issue and to estimate the impact of neuropathy on the pathogenesis of diabetic ED, we studied diabetic men with ED and men with ED caused by other neuropathies not affecting the vasculature, and we compared the frequency of clinical symptoms and neurophysiological abnormalities indicating neuropathy in both groups.
PATIENTS AND METHODS
Forty-nine patients (age 23-70 years, mean 52.3 years) with ED participated in the study. All men were referred to our department without prior selection.
CONCLUSION
The tests indicating neuropathy showed abnormal results in men with ED due to diabetes as frequently as in men with ED due to other neuropathies. Some of our tests, such as clinical signs of polyneuropathy, nerve conduction studies and heart rate variability studies, even suggested that neuropathy is slightly more frequent in diabetic than in neuropathic ED. The findings support the hypothesis that neuropathy is a major contributing factor in the pathophysiology of ED in diabetes mellitus. To refine the evaluation of the pathophysiology of ED and improve therapeutical decisions, an extended neurological work-up, including neurophysiological assessment of myelinated and unmyelinated nerve fibers, should be part of the diagnostic procedures used in diabetic patients with erectile dysfunction.
REFERENCES
1 McCulloch DK, Campbell IW, Wu FC, Prescott RI, Clarke BF. The prevalence of diabetic impotence. Diabetologia 1980; 18: 279-283
2 Deutsch S, Sherman L. Previously unrecognized diabetes mellitus in sexually impotent men. JAMA 1980; 244: 2430
3 NIH Consensus Conference. Impotence. NIH Consensus Development Panel on Impotence. JAMA 1993; 270: 83-90
4 el-Bayoumi M, el-Sherbini 0, Mostafa M. Impotence in diabetics: Organic versus psychogenic factors. Urology 1984; 24: 459-463 5 McCulloch DK, Young RJ, Prescott RJ, Campbell IW, Clarke BF.
The natural history of impotence in diabetic men. Diabetologia 1984; 26: 437-440
6 Hakim LS, Goldstein I. Diabetic sexual dysfunction. Endocrin Metab Clin N Am 1996; 25: 379-400
7 Hilz Mj, Hecht M, Kolsch C. Erektile Dysfunktion. Akt Neurol 2000; 27:1-12
8 Dunsmuir WD, Holmes SAV. The aetiology and management of erectile, ejaculatory and fertility problems in men with diabetes mellitus. Diabetic Med 1996; 13: 700-708
9 Ludin HP. Elektromyographie, Thieme, 1992
10 Fowler CJ. Electrophysiologic evaluation of sexual dysfunction. In: Low PA, ed. Clinical Autonomic Disorders, Boston: Little, Brown and Co., 1992: pp. 279-285
11 Goldberg JM, Lindblom U. Standardised method of determining vibratory perception thresholds for diagnosis and screening in neurological investigation. J Neurol Neurosurg Psychiatry 1979; 42:793-803
12 Hilz MJ, Glorius S, Beric A. Thermal perception thresholds: Influence of determination paradigm and reference temperature. J Neurol Sci 1995; 129: 135-140
13 Hilz MJ, Axelrod FB, Hermann K, Haertl U, Deutsch M, Neundorfer B. Normative values of vibratory perception in 530 children, juveniles and adults aged 3-79 years. J Neurol Sci 1998; 159:219-225
14 Hilz MJ, Stemper B, Axelrod FB, Kolodny EH, Neundorfer B. Quantitative thermal perception testing in adults. J Clin Neurophysiol 1999; 16: 462-471
15 Nisen HO, Larsen A, Lindstrom BL, Ruutu ML, Virtanen JM, Alfthan OS. Cardiovascular reflexes in the neurological evaluation of impotence. Br J Urol 1993; 71: 199-203
16 Akselrod S, Gordon D, Obel FA, Shannon DC, Barger AC, Chen RJ. Power spectrum analysis of heart rate fluctuation: A quantitative probe of beat-to-beat cardiovascular control. Science 1981; 213: 220-222
17 Pomeranz B, Macaulay RJB, Caudill MA, Kutz I, Adam D, Gordon D, et al. Assessment of autonomic function in humans by heart rate spectral analysis. Am I Physiol 1985; 248: Hi 51-Hl 53
18 Ewing DJ, Campball IW, Murray A, Neilson JM, Clarke BF. Immediate heart rate response to standing: Simple test of autonomic neuropathy in diabetes. Br Med J 1978; 1: 145-147
19 Saul JP. Beat-to-beat variations of heart rate reflect modulation of cardiac autonomic outflow. News Physiol Sci 1990; 5: 32-37
20 Malliani A, Pagani M, Lombardi F, Cerutti S. Cardiovascular neural regulation explored in the frequency domain. Circulation 1991; 84: 482-492
21 Goldstein B, Woolf PD, DeKing D, DeLong Dj, Cox C, Kempsky MH. Heart rate power spectrum and plasma catecholamine levels after postural change and cold pressor test. Pediatr Res 1994; 36: 358-363
22 Stein PK, Bosner MS, Kleiger RE, Conger BM. Heart rate variability: A measure of cardiac autonomic tone. Am Heart J 1994; 127: 1376-1381
23 Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology: Heart rate variability: Standards of measurement, physiological interpretation, and clinical use. Circulation 1996; 93: 1043-1065
24 Ziegler D, Dannehl K, Muhlen H, Spuler M, Cries FA. Prevalence of cardiovascular autonomic dysfunction assessed by spectral analysis, vector analysis and standard tests of heart rate variation and blood pressure responses at various stages of diabetic neuropathy. Diabetic Med 1992; 9: 806-814
25 Khan MA, Thompson CS, Sullivan ME, Jeremy JY, Mikhailidis DP, Morgan RJ. The role of prostaglandins in the etiology and treatment of erectile dysfunction. Prostaglandins, Leukot Essent Fatty Acids 1999; 60: 169-174
26 Virag R, Bouilly P, Frydman D. Is impotence an arterial disorder? A study of arterial risk factors in 440 impotent men. Lancet 1985; 1: 181-184
27 Benvenuti F, Boncinelli L, Vignoli GC. Male sexual impotence in diabetes mellitus: Vasculogenic versus neurogenic factors. Neurourol Urodyn 1993; 12: 145-151
28 Wang CJ, Shen SY, Wu CC, Huang CH, Chiang CP. Penile blood flow study in diabetic impotence. Urol Int 1993; 50: 209-212
29 Faerman I, Glocer L, Fox D, Jadzinsky MN, Rapaport M. Impotence of diabetes: Histological studies of the autonomic nervous fibers of the corpora cavernosa in impotent diabetic males. Diabetes 1974; 23: 971-976
30 Lincoln J, Crowe R, Backlay PF, Pryor JP, Lumley JSP, Burnstock G. Changes in the vipergic, cholinergic and adrenergic innervation of human penile tissue in diabetic and nondiabetic impotent males. J Urol 1987; 137: 1053-1059
31 Saenz-de-Tejada I, Goldstein 1, Azadzoi K, Krane RJ, Cohen RA. Impaired neurogenic and endothelium-mediated relaxation of penile smooth muscle from diabetic men with impotence. N Engl J Med 1989; 320: 1025-1030
32 Fowler CJ, Ali Z, Kirby RS, Pryor JP. The value of testing for unmyelinated fiber sensory neuropathy in diabetic impotence. Br] Urol 1988; 61: 63-67
33 Dyck PJ. Quantitating severity of neuropathy. In: Dyck PJ, ed. Peripheral Neuropathy, 3rd edn, Philadelphia: Saunders, 1993: pp.686-697
34 Vardi Y, Sprecher E, Kanter Y, Livne PM, Hemli JA, Yamitzki D. Polyneuropathy in impotence. Intj Impot Res 1996; 8: 65-68
35 Thomas P, Thomlinson D. Diabetic and hypoglycemic neuropathy. In: Dyck P, Thomas P, eds. Peripheral Neuropathy, Philadelphia: Saunders, 1993: pp. 1219-1250
Martin J. Hecht, B. Neundorfer, F. Kiesewetter* and Max J. Hilz
Department of Neurology, *Department of Dermatology, University of Erlangen-Nuremberg, Erlangen, Germany
Correspondence and reprint requests to: Professor Dr Max J. Hilz, Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany.
[max.hilz@neuro.med.uni-erlangen.de] Accepted for publication March 2001.
Copyright Forefront Publishing Group Sep 2001
Provided by ProQuest Information and Learning Company. All rights Reserved
Contact
Home
A
Dandy-Walker syndrome