Case Report Myoclonic status misdiagnosed as movement disorders in Rett syndrome: A video-polygraphic study Giuseppe d’Orsi * , Vincenzo Demaio, Mauro G. Minervini Epilepsy Center, Neurological Unit, Casa Divina Provvidenza, Opera Don Uva, Via Bovio 78, 70052 Bisceglie (BAT), Italy article info Article history: Received 10 February 2009 Revised 23 March 2009 Accepted 25 March 2009 Available online 23 April 2009 Keywords: Rett syndrome Myoclonic status Movement disorders Video-polygraphy Levetiracetam abstract Myoclonic jerks and myoclonic status (MS) are sometimes difficult to distinguish clinically from move- ment disorders such as hand stereotypies, tremor, and dystonia in Rett syndrome. We describe a rare and complete video-polygraphic study of a girl with Rett syndrome (MECP2 mutation) and MS misdiag- nosed as movement disorders and disclosed after video-polygraphic recordings. Corresponding to closely recurring activity of diffuse spike and polyspikes–wave-type paroxysms, rhythmic and, especially, arrhythmic myoclonias, usually asymmetrical and asynchronous, involving mainly right muscle deltoid and rarely followed by an inhibitory phenomenon, appeared. The MS improved and, most importantly, disappeared after the use of levetiracetam, with an evident antimyoclonic efficacy and a marked improvement of daily life for the patient and her caregivers. The difficulty in differentiating some typical nonepileptic behavioral features and movement disorders of patients with Rett syndrome from seizures was overcome using prolonged video-polygraphic recordings in our case. Ó 2009 Elsevier Inc. All rights reserved. 1. Introduction Recently, Caraballo et al. [1] described the electroclinical fea- tures of myoclonic status (MS) in nonprogressive encephalopathies as characterized by the recurrence of long-lasting status associated with absences and myoclonias, mixed with other abnormal move- ments; the etiology is mainly genetic (Angelman syndrome and 4p syndrome) and developmental cortical malformations. Of seven patients with epilepsy and Rett syndrome (RTT) with a proven MECP2 mutation, we report a rare and complete video-polygraphic study of a girl whose clinical manifestations and polygraphic fea- tures were compatible with MS and were misdiagnosed as move- ment disorders. 2. Case study The patient was an 8-year-old girl with a psychomotor develop- ment that was normal until the age of 12 months, but then pro- gress stagnated, and it became difficult to get in touch with her. From the age of 18 months, she developed movement disorders, including hand stereotypies, tremor, and dystonia; moreover, the child experienced paroxysmal episodes of hyperventilation and ap- nea during wakefulness. She became severely retarded with autis- tic traits and, at the age of 2, was diagnosed as having RTT with a truncating nonsense mutation in the MECP2 gene. When she was 3 and 4, during nocturnal sleep, she had repetitive generalized tonic– clonic seizures, resistant to rectal diazepam. Focal seizures (brief loss of contact) also started at age 4, and the decision was made to initiate treatment with carbamazepine (200 mg/day), which she tolerated well, resulting in a 3-year seizure-free period. At the age of 7, she was admitted to our epilepsy center because her condition had insidiously deteriorated: the parents noticed progressive deterioration of contact, and the child had become more and more ataxic with jerks in the extremities, predominantly asymmetrical and asynchronous, misdiagnosed as movement dis- orders and nonepileptic behavioral features. In fact, subcontinuous myoclonic jerks were intermingled with hand stereotypies, tremor, and dystonia, and a firm diagnosis of MS could be established using prolonged video-polygraphic recordings (polygraphic parameters: EEG; electromyographic activity from right and left deltoid mus- cles, right and left flexor and extensor hand muscles, right and left tibialis anterior muscles; ECG; thoracic respiration). The EEG showed closely recurring activity of diffuse spike and polyspike– wave-type paroxysms, involving mainly the anterior regions, inter- mingled with multifocal spikes, occasionally resulting in spike– wave complexes, predominant in frontocentral regions. From the electromyographic point of view, corresponding to the diffuse par- oxysms, rhythmic and, especially, arrhythmic myoclonias, usually asymmetrical and asynchronous, involving mainly right deltoid muscle and rarely followed by an inhibitory phenomenon, ap- peared (Fig. 1). Because myoclonic jerks were intermingled with movement disorders, and especially with hand stereotypies, the 1525-5050/$ - see front matter Ó 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.yebeh.2009.03.033 * Corresponding author. Fax: +39 080 3367418. E-mail address: giudorsi@yahoo.it (G. d’Orsi). Epilepsy & Behavior 15 (2009) 260–262 Contents lists available at ScienceDirect Epilepsy & Behavior journal homepage: www.elsevier.com/locate/yebeh