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Pseudomyotonia of the Striated Urethral Sphincter
0022-534 7/83/1302-0512$02.00/0
Vol. 130, September Printed in U.S.A.
THE JOURNAL OF UROLOGY
Copyright © 1983 by The Williams & Wilkins Co.
PSEUDOMYOTONIA OF THE STRIATED URETHRAL SPHINCTER DOMENICO POTENZONI, GIULIO JUVARRA, LUIGI BETTON!
AND
GIORGIO STAGNI
From the Division of Urology and Neurological Clinic, University of Parma, Parma, Italy
ABSTRACT
Pseudomyotonic discharges of the striated urethral sphincter are infrequent findings. We herein report on 9 patients with dissimilar anatomical-clinical conditions. In some patients a definite neurological lesion was ascertained, whereas in the remaining patients no neurological impairment could be determined clinically and instrumentally. The possibility of spontaneous resolution of the phenomenon is an interesting clinical feature. Pseudomyotonia is an electromyographic term that describes spontaneous, high frequency and short duration discharges, generally constant as to frequency and voltage, and showing an abrupt start and finish. Pseudomyotonic discharges can be registered easily by concentric needle electrodes on a common electromyograph but they are not detectable by integrated electromyographs, such as those used routinely in urodynamics laboratories. Pseudomyotonic discharges may occur during bladder filling and voiding. Conversely, true myotonia is characterized by spontaneous discharges variable as to frequency and voltage, with a progressive increase towards the climax, followed by a slow decrease. Therefore, the 2 findings are easily distinguishable. Pseudomyotonic potentials are not limited to urologic conditions and have been observed in patients with neurogenic and myopathic lesions. In urology pseudomyotonia has been reported in patients with myelodysplasia 2 and in 5 patients with neurogenic bladder in whom the upper or lower motor neurons were involved. 3 On the basis of such observations a neurogenic etiology usually has been hypothesized. However, Butler reported pseudomyotonic discharges in 3 patients with stress incontinence without detectable neuropathic conditions and defined them as signs of sphincteric neuropathy of an undefined nature. 4
lesion was found. Voluntary muscle impairment was not detected. Group 4 included 2 young women with postpartum vesico-urethrovaginal fistulas who showed no neuropathic or myopathic signs. DISCUSSION
One cannot consider spontaneous potentials as only a technical artifact. In electromyographic practice short pseudomyotonic discharges owing to needle-electrode trauma occasionally may be registered as an expression of a physiological reaction. In such cases, in fact, spontaneous activity ceases rapidly and is not repeatable. Pseudomyotonic potentials have never been observed as occasional findings within the context of normal patterns, since they have never been reported in electromyography studies of normal muscles. On the contrary, these are potentials described always as features of a neuromuscular lesion. In our patients pseudomyotonia was associated with urological symptoms. Whether a neurogenic or myopathic etiology
CLINICAL MATERIAL
Of >600 urodynamic evaluations pseudomyotonia of the striated urethral sphincter was detected in 9 women with different anatomical-clinical conditions (figs. 1 and 2, and table). Electromyography was performed during and within a few days after urodynamic evaluation in all cases. The patients were divided into 4 groups. Group 1 consisted of 3 women with multiple sclerosis, 1 of whom still required further diagnostic study, who demonstrated alterations of the urethral sphincter and detrusor muscle of a definite neurogenic basis. Group 2 included 2 women with pseudomyotonic discharges that were not connected with detrusor muscle alterations at urodynamic evaluation but who had peculiar anatomical conditions that suggested a neurogenic etiology. One patient had a small spinal cord cyst (Tl2) and a normal functional urethral length with an increased maximum pressure, while 1 had spina bifida (L5) and a completely normal finding (the clinical diagnosis was giggle incontinence). In both cases no clinical or electromyographic abnormality was evident. N eurologically, the anal sphincter and conduction velocity of the posterior tibial nerve were all within normal limits. Group 3 consisted of 2 patients with stress incontinence and descensus anterior of mild degree. Both patients previously had undergone a subtotal hysterectomy for benign lesions. The detrusor was normal at urodynamic evaluation. No clinical or electromyographic evidence of a central or peripheral nervous system Accepted for publication January 14, 1983. 512
_J500JJV 200msec Frn. 1. Single pseudomyotonic discharge from urethral striated sphincter in 59-year-old woman with stress incontinence caused by cystocele. Tracing was obtained 5 days after cystomanometry by means of concentric needle electrode and Medelec electromyograph MS6 with AA6 MkIII amplifier. Recording was printed on Kodak linagraph direct print paper type 1801.
__J5001N 500msec Frn. 2. Double pseudomyotonic discharge from urethral striated sphincter in 17-year-old woman with cervico-urethrovaginal fistula 2 months postpartum. Shorter duration discharge begins contemporarily and then overlaps second, longer discharge. Tracing was obtained 5 days after cystomanometry by means of concentric needle electrode and Medelec electromyograph MS6 with AA6 MkIII amplifier. Recording was printed on Kodak linagraph direct print paper type 1801.
PSEUDOMYOTONIA OF STRIATED URETHRAL SPHINCTER Pt.-Age
Main Symptoms
SM-26 IL-48 FA-36
Urge incontinence Urgency Urge incontinence
GE-11 GP-21
Enuresis Giggle incontinence
PE-48 CB-59
Stress incontinence Stress incontinence
CM-17 AE-18
Incontinence Incontinence
Clinical Diagnosis Group I Multiple sclerosis Multiple sclerosis Multiple sclerosis (probable) Group2 Spinal cord cyst (T12) Spina bifida (L5) Group3 Cystourethrocele Cystocele Group4 Cervico-urethrovaginal fistula Cervico-urethrovaginal fistula
should be considered still is a matter of dispute. In regard to urological conditions pseudomyotonic discharges have been considered as an expression of neurogenic damage owing to the fact that functional impairment of the neurogenic type always was found previously. The etiology in our series is variable, including cases in which a definite central or peripheral nervous system lesion could be ascertained and those in which no sign of a neurogenic or myopathic lesion was detected. On this basis a definite site of a lesion responsible for pseudomyotonic discharges cannot be postulated. Perhaps muscle biopsy with histochemical techniques might provide some qualitative and somewhat quantitative information about primary damage of the muscle fiber itself and/or its nerve supply. Nevertheless, the muscle structures involved are so minute and delicate that they render such an investigation almost impossible in clinical practice. Also noteworthy is the temporal evolution of pseudomyotonia in 2 of our patients suffering from postpartum vesicovaginal fistulas and cystourethrocele, respectively. After surgical treatment, partial urine retention occurred in both patients consistently with pseudomyotonic potentials. Electromyography findings had returned to normal spontaneously and contemporary normalization of voiding had been obtained 3 and 4 months later, respectively. These examples suggest that pseudomyotonia should be defined only as a pathological manifestation of anatomical-functional structures involved with voiding until further studies can clarify its origin. REFERENCES 1. Goodgold, J. and Eberstein, A.: Electrodiagnosis of Neuromuscular
Diseases, 2nd ed. Baltimore: The Williams & Wilkins Co., pp. 146-168, 1977.
2. Chantraine, A., Lloyd, K. and Swinyard, C. A.: The sphincter ani externus in spina bifida and myelomeningocele. J. Urol., 95: 250, 1966. 3. DiBenedetto, M. and Yalla, S. V.: Electrodiagnosis of striated urethral sphincter dysfunction. J. Urol., 122: 361, 1979. 4. Butler, W. J.: Pseudomyotonia of the periurethral sphincter in women with urinary incontinence. J. Urol., 122: 838, 1979. EDITORIAL COMMENTS In our experience we have observed pseudomyotonic discharges (short duration and constant frequency) as well as myotonic discharges (longer duration and decremental frequency) using needle electrodes in various perinea! muscles. Since most of these discharges have been observed in other normal patients we have never attached much significance to this finding. However, I agree with the authors that this is not an artifactual finding. When the cases available in the literature were reviewed it was found that all were women who had suffered pelvic trauma (that is multiple births, vesicovaginal fistula and pelvic surgery). Thus, I believe that if there is any significance to these findings they are indicative of muscle trauma, especially in cases without neurologic disease. With regard to therapeutic implications, I believe that the safest course to follow, until the significance of this finding is clarified, is to proceed with surgical repair using the accepted indications. However, it is prudent to warn the patient that the results may be less than optimal because of muscle weakness.
Mike B. Siroky Department of Urology Boston University School of Medicine Boston, Massachusetts These authors indicate correctly that concentric needle electromyography occasionally will reveal the presence of pseudomyotonic discharges, also known as complex repetitive discharges. These findings should alert the examiner to the possibility of an occult neurologic lesion involving the pudenda! nerve or a myopathic process involving the striated muscles of the pelvic floor. We have encountered pseudomyotonic discharges in a variety of nonneurologic conditions, including recurrent urinary tract infections in women, urethral syndrome, abacterial prostatitis and after pelvic surgery. It is likely that any local inflammatory lesion that affects the nerve or muscle may result in the appearance of these bizarre electromyographic potentials. However, further studies are required to ascertain their true significance. It is important to distinguish pseudomyotonic discharges from myotonia. In the latter condition the discharges have a crescendo-decrescendo pattern that produces a characteristic "dive-bomber" sound via the loud speaker.
Jerry G. Blaiuas Department of Urology Columbia-Presbyterian Medical Center New York, New York
Vol. 130, September Printed in U.S.A.
THE JOURNAL OF UROLOGY
Copyright © 1983 by The Williams & Wilkins Co.
PSEUDOMYOTONIA OF THE STRIATED URETHRAL SPHINCTER DOMENICO POTENZONI, GIULIO JUVARRA, LUIGI BETTON!
AND
GIORGIO STAGNI
From the Division of Urology and Neurological Clinic, University of Parma, Parma, Italy
ABSTRACT
Pseudomyotonic discharges of the striated urethral sphincter are infrequent findings. We herein report on 9 patients with dissimilar anatomical-clinical conditions. In some patients a definite neurological lesion was ascertained, whereas in the remaining patients no neurological impairment could be determined clinically and instrumentally. The possibility of spontaneous resolution of the phenomenon is an interesting clinical feature. Pseudomyotonia is an electromyographic term that describes spontaneous, high frequency and short duration discharges, generally constant as to frequency and voltage, and showing an abrupt start and finish. Pseudomyotonic discharges can be registered easily by concentric needle electrodes on a common electromyograph but they are not detectable by integrated electromyographs, such as those used routinely in urodynamics laboratories. Pseudomyotonic discharges may occur during bladder filling and voiding. Conversely, true myotonia is characterized by spontaneous discharges variable as to frequency and voltage, with a progressive increase towards the climax, followed by a slow decrease. Therefore, the 2 findings are easily distinguishable. Pseudomyotonic potentials are not limited to urologic conditions and have been observed in patients with neurogenic and myopathic lesions. In urology pseudomyotonia has been reported in patients with myelodysplasia 2 and in 5 patients with neurogenic bladder in whom the upper or lower motor neurons were involved. 3 On the basis of such observations a neurogenic etiology usually has been hypothesized. However, Butler reported pseudomyotonic discharges in 3 patients with stress incontinence without detectable neuropathic conditions and defined them as signs of sphincteric neuropathy of an undefined nature. 4
lesion was found. Voluntary muscle impairment was not detected. Group 4 included 2 young women with postpartum vesico-urethrovaginal fistulas who showed no neuropathic or myopathic signs. DISCUSSION
One cannot consider spontaneous potentials as only a technical artifact. In electromyographic practice short pseudomyotonic discharges owing to needle-electrode trauma occasionally may be registered as an expression of a physiological reaction. In such cases, in fact, spontaneous activity ceases rapidly and is not repeatable. Pseudomyotonic potentials have never been observed as occasional findings within the context of normal patterns, since they have never been reported in electromyography studies of normal muscles. On the contrary, these are potentials described always as features of a neuromuscular lesion. In our patients pseudomyotonia was associated with urological symptoms. Whether a neurogenic or myopathic etiology
CLINICAL MATERIAL
Of >600 urodynamic evaluations pseudomyotonia of the striated urethral sphincter was detected in 9 women with different anatomical-clinical conditions (figs. 1 and 2, and table). Electromyography was performed during and within a few days after urodynamic evaluation in all cases. The patients were divided into 4 groups. Group 1 consisted of 3 women with multiple sclerosis, 1 of whom still required further diagnostic study, who demonstrated alterations of the urethral sphincter and detrusor muscle of a definite neurogenic basis. Group 2 included 2 women with pseudomyotonic discharges that were not connected with detrusor muscle alterations at urodynamic evaluation but who had peculiar anatomical conditions that suggested a neurogenic etiology. One patient had a small spinal cord cyst (Tl2) and a normal functional urethral length with an increased maximum pressure, while 1 had spina bifida (L5) and a completely normal finding (the clinical diagnosis was giggle incontinence). In both cases no clinical or electromyographic abnormality was evident. N eurologically, the anal sphincter and conduction velocity of the posterior tibial nerve were all within normal limits. Group 3 consisted of 2 patients with stress incontinence and descensus anterior of mild degree. Both patients previously had undergone a subtotal hysterectomy for benign lesions. The detrusor was normal at urodynamic evaluation. No clinical or electromyographic evidence of a central or peripheral nervous system Accepted for publication January 14, 1983. 512
_J500JJV 200msec Frn. 1. Single pseudomyotonic discharge from urethral striated sphincter in 59-year-old woman with stress incontinence caused by cystocele. Tracing was obtained 5 days after cystomanometry by means of concentric needle electrode and Medelec electromyograph MS6 with AA6 MkIII amplifier. Recording was printed on Kodak linagraph direct print paper type 1801.
__J5001N 500msec Frn. 2. Double pseudomyotonic discharge from urethral striated sphincter in 17-year-old woman with cervico-urethrovaginal fistula 2 months postpartum. Shorter duration discharge begins contemporarily and then overlaps second, longer discharge. Tracing was obtained 5 days after cystomanometry by means of concentric needle electrode and Medelec electromyograph MS6 with AA6 MkIII amplifier. Recording was printed on Kodak linagraph direct print paper type 1801.
PSEUDOMYOTONIA OF STRIATED URETHRAL SPHINCTER Pt.-Age
Main Symptoms
SM-26 IL-48 FA-36
Urge incontinence Urgency Urge incontinence
GE-11 GP-21
Enuresis Giggle incontinence
PE-48 CB-59
Stress incontinence Stress incontinence
CM-17 AE-18
Incontinence Incontinence
Clinical Diagnosis Group I Multiple sclerosis Multiple sclerosis Multiple sclerosis (probable) Group2 Spinal cord cyst (T12) Spina bifida (L5) Group3 Cystourethrocele Cystocele Group4 Cervico-urethrovaginal fistula Cervico-urethrovaginal fistula
should be considered still is a matter of dispute. In regard to urological conditions pseudomyotonic discharges have been considered as an expression of neurogenic damage owing to the fact that functional impairment of the neurogenic type always was found previously. The etiology in our series is variable, including cases in which a definite central or peripheral nervous system lesion could be ascertained and those in which no sign of a neurogenic or myopathic lesion was detected. On this basis a definite site of a lesion responsible for pseudomyotonic discharges cannot be postulated. Perhaps muscle biopsy with histochemical techniques might provide some qualitative and somewhat quantitative information about primary damage of the muscle fiber itself and/or its nerve supply. Nevertheless, the muscle structures involved are so minute and delicate that they render such an investigation almost impossible in clinical practice. Also noteworthy is the temporal evolution of pseudomyotonia in 2 of our patients suffering from postpartum vesicovaginal fistulas and cystourethrocele, respectively. After surgical treatment, partial urine retention occurred in both patients consistently with pseudomyotonic potentials. Electromyography findings had returned to normal spontaneously and contemporary normalization of voiding had been obtained 3 and 4 months later, respectively. These examples suggest that pseudomyotonia should be defined only as a pathological manifestation of anatomical-functional structures involved with voiding until further studies can clarify its origin. REFERENCES 1. Goodgold, J. and Eberstein, A.: Electrodiagnosis of Neuromuscular
Diseases, 2nd ed. Baltimore: The Williams & Wilkins Co., pp. 146-168, 1977.
2. Chantraine, A., Lloyd, K. and Swinyard, C. A.: The sphincter ani externus in spina bifida and myelomeningocele. J. Urol., 95: 250, 1966. 3. DiBenedetto, M. and Yalla, S. V.: Electrodiagnosis of striated urethral sphincter dysfunction. J. Urol., 122: 361, 1979. 4. Butler, W. J.: Pseudomyotonia of the periurethral sphincter in women with urinary incontinence. J. Urol., 122: 838, 1979. EDITORIAL COMMENTS In our experience we have observed pseudomyotonic discharges (short duration and constant frequency) as well as myotonic discharges (longer duration and decremental frequency) using needle electrodes in various perinea! muscles. Since most of these discharges have been observed in other normal patients we have never attached much significance to this finding. However, I agree with the authors that this is not an artifactual finding. When the cases available in the literature were reviewed it was found that all were women who had suffered pelvic trauma (that is multiple births, vesicovaginal fistula and pelvic surgery). Thus, I believe that if there is any significance to these findings they are indicative of muscle trauma, especially in cases without neurologic disease. With regard to therapeutic implications, I believe that the safest course to follow, until the significance of this finding is clarified, is to proceed with surgical repair using the accepted indications. However, it is prudent to warn the patient that the results may be less than optimal because of muscle weakness.
Mike B. Siroky Department of Urology Boston University School of Medicine Boston, Massachusetts These authors indicate correctly that concentric needle electromyography occasionally will reveal the presence of pseudomyotonic discharges, also known as complex repetitive discharges. These findings should alert the examiner to the possibility of an occult neurologic lesion involving the pudenda! nerve or a myopathic process involving the striated muscles of the pelvic floor. We have encountered pseudomyotonic discharges in a variety of nonneurologic conditions, including recurrent urinary tract infections in women, urethral syndrome, abacterial prostatitis and after pelvic surgery. It is likely that any local inflammatory lesion that affects the nerve or muscle may result in the appearance of these bizarre electromyographic potentials. However, further studies are required to ascertain their true significance. It is important to distinguish pseudomyotonic discharges from myotonia. In the latter condition the discharges have a crescendo-decrescendo pattern that produces a characteristic "dive-bomber" sound via the loud speaker.
Jerry G. Blaiuas Department of Urology Columbia-Presbyterian Medical Center New York, New York