¿Qué es el Clonus?
Hola lectores de Tratamientoictus.com. Hoy vamos a hablar del Clonus, un síntoma que aparece en ciertas patologías neurológicas.
La Universidad de Navarra lo define como :
Contracción y relajación muscular alternadas en una sucesión rápida. || Reflejo profundo con respuesta repetitiva (contracciones y relajaciones musculares), que aparece en un grupo muscular al efectuar una extensión brusca y pasiva de los tendones; es característico de las lesiones de la vía piramidal.
Se diferencia del reflejo policinético simple en que de este se obtiene una respuesta repetitiva aplicando una sola vez el estímulo, mientras que el clonus requiere que se mantenga el estímulo.
El siguiente artículo científico lo describe en su abstract como: Clonus is involuntary and rhythmic muscle contractions caused by a permanent lesion in descending motor neurons. Clonus may be found at the ankle, patella, triceps surae, wrist, jaw, biceps brachii. In general, clonus may occur in any muscle with a frequency of 5-8 Hz and the average period of oscillations of the ankle clonus is approximately 160-200 ms. Plantar flexion (PF) comprises 45% of the period, dorsifleksion (DF) comprises 55% of the period. The first beat is always longer, with the time shortening in continuing beats and becoming stable in the 4th or 5th period. The exact mechanism of clonus remains unclear. Two different hypotheses have been asserted regarding the development of clonus. The most widely accepted explanation is that hyperactive stretch reflexes in clonus are caused by self-excitation. Another alternative explanation for clonus is central generator activity that arises as a consequence of appropriate peripheral events and produces rhythmic stimulation of the lower motor neurons. The durations of clonus burst were found longer than the durations of Soleus medium-latency reflex (MLR). There is a similarity in their nature, although the speed and cause of the stretch of triceps surae differ in the MLR and the clonus, and there is a sufficient period of time for group II afferents and for other spinal mechanisms to be involved in the clonus, together with Ia afferents. Clonus can be treated by using baclofen, applying cold, botox or phenol injections. (Boyraz I, Uysal H, Koc B, Sarman H. Clonus: definition, mechanism, treatment.Med Glas (Zenica). 2015 Feb;12(1):19-26.)