Judging by the number of pseudoseizure patients admitted to the epileptic laboratories, nobody is particularly adept at telling true from false. Oh's Manual admits that there is occasionally no clinical way to distinguiah between them, and thus EEG testing must be embarked upon, to everybody's embarrassement and dissatisfaction.

Features of a pseudoseizure

  • Variability in the character of seizures between events
  • Non-sustained convulsive movement - "on and off"
  • Resistance to eye opening
  • Gaze aversion - they will not look at you!
  • Rapid resporation of normal cognition following the convulsive episode

Features of a "genuine seizure"

  • Pupils are dilated
  • Reflexes are brisk, exaggerated
  • Dulled cognition in the post-ictal period

The value of prolactin levels

Though much is made of prolactin levels in discriminating true from false seizures, perhaps it is without a lot of backing evidence. For example, one such article draws some information from 36 patients, of whom 18 had pseudoseizures. At least in this study, the prolactin level was consistently elevated in the "true" epileptics. The peak levels were about 10-15 minutes after the seizure, and this peak is typically 2-3 times the upper reference range. It is thought that the seizure needs to be generalised in order to trigger a prolactin release (i.e. it needs to cross the midline of the brain, so as to involve the hypothalamus which is in turn responsible for the inhibition of prolactin release). At least in the abovementioned study, the patients with partial seizures did not experience a very large prolactin elevation.

 

References

Oh's Intensive Care manual:

Chapter 49   (pp. 549) Disorders  of  consciousness  by Balasubramanian  Venkatesh

Chapter   50   (pp. 560) Status  epilepticus  by Helen  I  Opdam

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