The Use of Intrathecal Baclofen Therapy for Myoclonus in a Patient With Lance Adams Syndrome

Abstract

Myoclonus is a movement disorder characterized by the sudden onset of jerking, “shock-like” involuntary movements that may be triggered by voluntary movement or sensorystimulation. Lance Adams syndrome (LAS) is a type of myoclonus associated with hypoxicinjury to the brain. It was initially described by Lance and Adams in 1963 in a series of 4patients in whom action myoclonus developed as sequelae of hypoxic encephalopathy [1].Since that initial description, more than 100 cases have been reported in medical literature;however, LAS remains a rare condition.When myoclonus is secondary to hypoxic events, it can occur as 2 variants [2]: (1) acuteposthypoxic myoclonus (PHM), which usually occurs within 24 hours of the insult and ischaracterized by generalized myoclonus and poor prognosis; and (2) chronic PHM or LAS,which begins after a delay of generally a few days to a month and manifests predominatelyas action myoclonus. The presence of LAS adds significantly to the functional decline andreduction in quality of life in patients with anoxic brain injury because it causes additionaldifficulties with motor control, dexterity, and pain.Therapeutic options for persons with PHM are scarce and usually unsuccessful. Multiplepharmacologic treatments have been suggested, including clonazepam, levetiracetam, andlevodopa [2]. Baclofen also has been used in both experimental models [3] and in humans[4,5] with promising results.Theuseofintrathecalbaclofen(ITB)therapyinpatientswithposthypoxicmyoclonushasnotbeendescribedintheliteraturetoourknowledge.WepresentacaseofPHMthatimprovedwiththe use of ITB therapy.