Cathodal opening tetanus is a medical term used to describe the sustained muscular contraction resulting from the application of an electrical current. It occurs specifically when a cathode (negative electrode) is placed near a nerve or muscle fiber, and the current is delivered in a series of rapid pulses.
In this phenomenon, the electrical stimulation initially causes a brief contraction of the muscles as the passive response to the depolarization of the nerve or muscle fiber. However, instead of relaxing, the muscles continue to sustain a contracted state due to the continuous electrical pulses that follow, resulting in rhythmic and sustained muscle contractions.
The tetanic contractions experienced during cathodal opening tetanus are notable for their regular, high-frequency pattern, which distinguishes them from other forms of muscle spasms or contractions. This pattern is induced by the repetitive stimulation of the muscles, essentially overwhelming the normal ability of the muscles to relax between contractions.
Cathodal opening tetanus can occur as a result of various conditions or interventions involving the application of electrical currents. It is often observed during electroconvulsive therapy (ECT), a psychiatric treatment that utilizes controlled electric shocks to induce therapeutic seizures. This form of tetanus can also be induced experimentally in laboratory settings to study muscular response to electrical stimulation.
Although cathodal opening tetanus can be uncomfortable or even painful, it is generally reversible once the electrical stimulation ceases. However, in some rare cases, it may cause complications such as muscle fatigue or injury, requiring appropriate medical attention.
