Introduction: Patients with multiple sclerosis (MS) frequently develop anorectal dysfunction. The neuromuscular structures of the pelvic floor and the mechanisms of voluntary control over defecation can be compromised by the patchy lesions of MS or secondary to the patient's disability. The involvement of multiple factors limits understanding of the pathophysiology of anorectal dysfunction in MS. Specific neurophysiological tests assess the functionality of the elements of the central and peripheral nervous system involved in anorectal dysfunction.
Aim: To propose a diagnostic protocol of standardised neurophysiological studies of the pelvic floor in order to characterise the pathophysiology of anorectal dysfunction in patients with MS.
Patients and methods: The following studies were conducted on 16 patients with defined MS and who met criteria for constipation or faecal incontinence: external anal sphincter electromyography (EAS-EMG), somatosensory evoked potentials (SSEP) of the internal pudendal nerve, recording of ano-sacral reflexes and pudendal nerve neurography.
Results: The clinical and neurophysiological characteristics were heterogeneous. Nine patients presented constipation; two had isolated faecal incontinence; and five, a combination of both. Abolition or delay in the latency of the SSEP was the most frequent finding (n = 12), followed by the detection of paradoxical contraction (n = 11) and deficient recruitment (n = 8) in the EAS-EMG.
Conclusions: The correct interpretation of each available neurophysiological test and the correlation of the findings as a whole enable us to understand the pathophysiology of anorectal dysfunction. The implementation of a protocol for neuro-physiological studies of the pelvic floor makes it possible to adjust the diagnosis by identifying the central or peripheral nervous lesion determining anorectal dysfunction in patients with MS.
Title: Protocolo de estudios neurofisiologicos del suelo pelvico para la valoracion de la disfuncion anorrectal en pacientes con esclerosis multiple.
Introduccion. Los pacientes con esclerosis multiple (EM) frecuentemente desarrollan disfuncion anorrectal. Las estructuras neuromusculares del suelo pelvico y los mecanismos de control voluntario de la defecacion pueden afectarse por las lesiones parcheadas de la EM o secundarias a la discapacidad del paciente. La implicacion multifactorial limita la comprension de la fisiopatologia de la disfuncion anorrectal en la EM. Tests neurofisiologicos especificos valoran la funcionalidad de los elementos del sistema nervioso central y periferico implicados en las disfunciones anorrectales. Objetivo. Proponer un protocolo diagnostico de estudios neurofisiologicos estandarizados del suelo pelvico para caracterizar la fisiopatologia de la disfuncion anorrectal en los pacientes con EM. Pacientes y metodos. Se realizaron estudios de electromiografia de esfinter anal externo, potenciales evocados somatosensoriales desde el nervio pudendo interno, registro de reflejos sacros anales y neurografia del nervio pudendo a 16 pacientes con EM definida y criterios de estreñimiento o incontinencia fecal. Resultados. Las caracteristicas clinicas y neurofisiologicas fueron heterogeneas. Nueve pacientes presentaron estreñimiento; dos, incontinencia fecal aislada; y cinco, combinacion de ambos. La abolicion o el retraso de la latencia de los potenciales evocados somatosensoriales fue el hallazgo mas frecuente (n = 12), seguido de la deteccion de contraccion paradojica (n = 11) y de reclutamiento deficitario (n = 8) en la electromiografia de esfinter anal externo. Conclusiones. La correcta interpretacion de cada test neurofisiologico disponible y la correlacion de los hallazgos en conjunto permiten comprender la fisiopatologia de la disfuncion anorrectal. La protocolizacion de estudios neurofisiologicos del suelo pelvico permite ajustar el diagnostico al identificar la lesion nerviosa, central o periferica, determinante de disfuncion anorrectal en los pacientes con EM.