Shuddering attacks as an important differential diagnosis of infantile epilepsy. A video-EEG presentation

Introduction: Shuddering attacks are benign non-epileptic paroxysmal spells of infancy, that can easily be confused with focal epileptic seizures. However, in order to prevent unnecessary diagnostic procedures and parental worries it is necessary to clearly distinguish these episodes from epileptic seizures. In order to illustrate the diagnostic difficulties in such patients we present an impressive case of a 6 months old infant with shuddering attacks.

Case: The patient was presented to the A&E department of our hospital by his worried parents because of series of paroxysmal episodes with sudden flexion of the neck and trunk and adduction of the arms followed by shiver-like movements of the head and sometimes also the trunk. These attacks seemed to occur preferably while eating and were often preceded by myoclonic of the mouth. The patient was staring but seemed alert. The episode usually lasts 5–15 seconds.

While in hospital we were able more than 20 of these episodes, which were initially believed to be focal seizures. However, repeated video-EEG-documentations did not reveal any changes in the EEG other than muscle artefacts. After carefully reviewing current literature we were able to diagnose shuddering attacks. Within a few weeks the attacks resolved spontaneously and the child is developing well.

Conclusion: The pathophysiology is unknown, although a relationship with essential tremor has been postulated. The origin is unclear, but shuddering attacks are not epileptic in nature. Once one has seen a typical case future diagnosis will probably be made straight away as we have experienced just two weeks later in a different case. Further investigations are usually not indicated.