Neuropediatrics 2011; 42 - VS04
DOI: 10.1055/s-0031-1273968

Postanoxic myoclonus (Lance-Adams syndrome) after near-drowning

A Hahn 1, BA Neubauer 1
  • 1Universitätskinderklinik, Neuropädiatrie, Gießen, Germany

A 16 year-old boy suffered cardiac arrest and cerebral hypoxia despite rapid cardiopulmonary resuscitation after near-drowning. He remained unconscious for about three weeks, and was left with a mild spastic tetraparesis and a persistent intellectual deficit. A few days after regaining consciousness, brief and sometimes violent jerks involving the entire body were first noted. These jerks occurring many times per day were precipitated by voluntary action and aggravated by stress.

A video-polygraphic recording capturing several of these jerks showed a bilateral, mainly proximal myoclonus, lasting 100–200ms. Myoclonic jerks were not registered during rest, but were easily provoked by motor activities (action myoclonus). Epileptic myoclonus was ruled out, since no epileptic discharges time-locked to the EMG-bursts were detected in the EEG, and because jerk-locked back averaging revealed no EEG-spike preceding the EMG-bursts.

Patient's history, clinical observations, and neurophysiological findings fit well with the diagnosis of Lance-Adams syndrome (LAS), which is a rare chronic myoclonic syndrome of presumably cortical origin, that manifests during recovery from cerebral hypoxia. LAS is often difficult to treat and has to be distinguished from myoclonic status epilepticus, which usually occurs within the first 24 hours after hypoxia and which is associated with a very poor prognosis.