Successful treatment of severe infantile hyperekplexia with low-dose clobazam.

We report two cases of severe infantile hyperekplexia successfully treated with low-dose clobazam. The first case presented at 6 weeks of age with multiple episodes consisting of difficulty diapering because of stiffness and loud inspiratory noises followed by breath-holding in inspiration. She was diagnosed with hyperekplexia and started on clonazepam 0.05 mg daily. This was discontinued because of excessive sleepiness. The second case presented at 3 weeks of age with episodes of crying that would change in pitch and then abruptly stop, followed by leg and arm extension and stiffening. On occasion, there was cyanosis, and she received mouth-to-mouth resuscitation. She was diagnosed with hyperekplexia at 9 months of age. Both infants were treated with clobazam (0.25 and 0.3 mg/kg/day respectively), resulting in resolution of symptoms with no side effects. During treatment, both had minimal startle response to various stimuli and have now been successfully weaned from clobazam. Low-dose clobazam is effective in the treatment of hyperekplexia and is well tolerated in infants.