Pseudobloqueo de conducci車n en vasculitis aislada del sistema nervioso perif谷rico Pseudo-conduction block in nonsystemic vasculitic neuropath

作者：R M Pabon; L Gila; J Urriza; L Imirizaldu

来源：Anales del Sistema Sanitario de Navarra, 2009.

• Vasculitis
• Mononeuropatia multiple
• Electromiografia
• Biopsia de nervio sural
• Degeneracion walleriana
• Vasculitis
• Mononeuritis multiplex
• Electromyography
• Sural nerve biopsy
• Wallerian degeneration

Fundamento. La vasculitis aislada del sistema nervioso perif谷rico (VASNP) afecta selectivamente a los vasa nervorum, expres芍ndose generalmente como una mononeuropat赤a m迆ltiple. Presentamos un caso de VASNP confirmado histol車gicamente, destacando los hallazgos neurofisiol車gicos en fase aguda. Observaci車n cl赤nica. Mujer de 36 a os con parestesias y debilidad en mano derecha seguidas de paresia para la dorsiflexi車n del pie izquierdo. El primer estudio neurofisiol車gico mostraba amplitud reducida del potencial motor del mediano derecho con est赤mulos proximales. Un segundo estudio mostraba signos de lesi車n axonal en varios nervios, incluyendo el mediano derecho. Conclusiones. La lesi車n isqu谷mica aguda de un nervio puede dar lugar a un patr車n electroneurogr芍fico de bloqueo de conducci車n, como en el mediano derecho del caso descrito. Este fen車meno es conocido como %26quot;pseudobloqueo%26quot;, dado su car芍cter transitorio, con evoluci車n a un patr車n de neuropat赤a axonal. La sospecha de VASNP requiere estudios neurofisiol車gicos seriados para una correcta tipificaci車n de los patrones lesionales. Introduction. Nonsystemic vasculitic neuropathy (NSVN) is an inflammatory disorder of the vasa nervorum which usually is expressed as a mononeuritis multiplex. We present a patient with NSVN with histological confirmination focused on the neurophysiological findings at the early stages. Case report. A 36 years-old woman presented with paresthesia and weakness in her right hand followed by left footdrop. The first neurophysiologic examination showed low amplitude of the right median nerve (RMN) CMAP with proximal stimulation. A second examination showed signs of axonal damage in several nerves, including the RMN. Conclusions. The acute ischemic damage of a nerve can give a pattern of conduction block in the electroneurographic study as in the RMN of the presented case. This phenomenon is referred as %26quot;pseudo-conduction block%26quot;, since it is transient and evolves towards a definite pattern of axonal neuropathy. When a vasculitic neuropathy is suspected, repeated neurophysiologic studies are necessary in order to ensure a proper (appropriate) characterization of the lesional patterns.