Involuntary Muscle Spasms

Clonus is a condition that results in involuntary muscle spasms and most commonly affects the muscles at the end of a limb. Clonus can be a condition in itself, or it can be a symptom of another condition.

Clonus mainly affects the knees, ankles, upper and lower arm muscles, and the jaw. These involuntary muscle contractions can make everyday activities quite challenging and even lead to debilitating fatigue.

Clonus is often confused with myoclonus, a condition in which the muscle uncontrollably jerks. A person cannot control clonus and living with it can be quite challenging. Here we will outline the causes, symptoms, tests, and treatments of clonus to help you have a better understanding of the condition.

Clonus causes and symptoms

Clonus is caused by a disconnect of information flowing between the central nervous system and the affected muscles. Clonus most commonly affects muscles at the ends of limbs, including ankles, wrists, etc.

Clonus can also be caused by a medical condition such as multiple sclerosis, Huntington disease, spinal cord and brain injuries, meningitis, stroke, upper motor neuron lesion, spastic paraparesis, subacute sclerosing panencephalitis, Brown-Sequard syndrome, and cerebral palsy. Uncovering the underlying cause of clonus is important to help determine which modes of treatment will yield the greatest success.

The main symptom of clonus is involuntary muscle spasms. These muscle spasms can be sudden, shock-like, intensive, and frequent. Clonus may affect only one muscle or several muscles, and it can spread to different muscle groups. A severe case of clonus can even impair speech or movement.

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