1043-3155 Pediatr Neurol Briefs pedneurbriefs Pediatr Neurol Briefs Pediatric Neurology Briefs Pediatr Neurol Briefs 2166-6482 1043-3155 2166-3155 Pediatric Neurology Briefs Publishers Chicago, IL, USA PNB-6-57 10.15844/pedneurbriefs-6-8-1 Congenital Familial Disorders Neurology Pediatrics Nervous System Diseases Child Development Brain Diseases Neurosurgery Child Infant Hyperekplexia; Response to Clonazepam http://orcid.org/0000-0002-0173-7931 Millichap J. Gordon MD 1 2 * Division of Neurology, Children's Memorial Hospital, Chicago, IL Departments of Pediatrics and Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL Correspondence: Dr. J. Gordon Millichap, E-mail: jgmillichap@northwestern.edu 08 1992 01 07 2016 6 8 57 58 Copyright: © 1992 The Author(s) 1992 This work is licensed under the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Startle disease, or hyperekplexia: response to clonazepam and assignment of the gene (STHE) to chromosome 5q by linkage analysis

Sixteen patients, including 1 neonate, in a large 5 generation family with hyperekplexia (startle disease or congenital stiff-man syndrome) were treated with clonazepam at the University of Texas Health Science Center, San Antonio, TX.

 Hyperekplexia Clonazepam Aspiration Pneumonia

Sixteen patients, including 1 neonate, in a large 5 generation family with hyperekplexia (startle disease or congenital stiff-man syndrome) were treated with clonazepam at the University of Texas Health Science Center, San Antonio, TX. All showed dramatic and sustained improvement. Clonazepam was introduced at a dose of 0.5 mg (0.125 - 0.25 mg for children at bedtime). The total daily dose in children did not exceed 1.5 mg and increases of .125 to .25 mg were made every third day until the symptoms improved. [1]

COMMENT. Hyperekplexia is a distinctive clinical syndrome of hypertonia and exaggerated startle responses that is inherited as an autosomal dominant. This familial form of hyperekplexia responds to clonazepam whereas the less frequent nonfamilial form sometimes fails to respond. A late onset variant with symptoms arising in adolescence responded dramatically to valproate and was not benefited by clonazepam. [2]

Of 15 patients with hyperekplexia identified in 3 families at the Departments of Neurology and Pediatrics, Wayne State University School of Medicine, Detroit, MI, 3 infants died unexpectedly during the neonatal period. Patients treated with clonazepam (0.1-0.2 mg/kg/day) had no serious apneic episodes and startle reflexes induced by nose tapping were diminished [3]. Hyperekplexia is included in the differential diagnosis of neonates with apnea, aspiration pneumonia, episodic muscular rigidity and near miss SIDS. Nose tapping to elicit the hyperekplexic startle response should be included in the routine examination of newborns. See Ped Neurol Briefs May 1991; 5:36. The primary pysiological abnormality in hyperekplexia involves spinal as well as brainstem hyperexcitability. [4]

 Ryan SG Sherman SL Terry JC Sparkes RS Torres MC Mackey RW Startle disease, or hyperekplexia: response to clonazepam and assignment of the gene (STHE) to chromosome 5q by linkage analysis Ann Neurol 1992 Jun 31 6 663 666 10.1002/ana.410310615 1355335 Andermann F Keene DL Andermann E Quesney LF Startle disease or hyperekplexia: further delineation of the syndrome Brain 1980 Dec 103 4 985 997 10.1093/brain/103.4.985 6777025 Nigro MA Lim HCN Hyperekplexia and sudden neonatal death Pediatr Neurol 1992 May-Jun 8 3 221 225 10.1016/0887-8994(92)90073-8 1622521 Matsumoto J Fuhr P Nigro M Hallett M Physiological abnormalities in hereditary hyperekplexia Ann Neurol 1992 Jul 32 1 41 50 10.1002/ana.410320108 1642471