Myoclonus: Pathophysiology and Treatment Options.

OPINION STATEMENT: Treatment of myoclonus requires an understanding of the physiopathology of the condition. The first step in treatment is to determine if there is an epileptic component to the myoclonus and treat accordingly. Secondly, a review of medications (e.g., opiates) and comorbidities (e.g., hepatic or renal failure) is required to establish the possibility of iatrogenic and reversible conditions. Once those are eliminated, delineation between cortical, cortico-subcortical, subcortical, brainstem, and spinal generators can determine the first-line treatment. Cortical myoclonus can be treated with levetiracetam, valproic acid, and clonazepam as first-line agents. Phenytoin and carbamazepine may paradoxically worsen myoclonus. Subcortical and brainstem myoclonus can be treated with clonazepam as a first-line agent, but levetiracetam and valproic acid can be tried as well. L-5-Hydroxytryptophan and sodium oxybate are agents used for refractory cases. Spinal myoclonus does not respond to anti-epileptic drugs, and clonazepam is a first-line agent. Botulinum toxin treatment can be useful for focal cases of spinal myoclonus. The etiology of propriospinal myoclonus is controversial, and a functional etiology is suspected in most cases. Treatment can include clonazepam, levetiracetam, baclofen, valproate, carbamazepine, and zonisamide. Functional myoclonus requires multimodal and multidisciplinary treatment that may include psychotropic drugs and physical and occupational therapy. Close collaboration between neurologists and psychiatrists is required for effective treatment. Finally, deep brain stimulation targeting the globus pallidus pars-interna bilaterally has been used in myoclonus-dystonia when pharmacological treatments have been exhausted.