Prolactin in the diagnosis of epilepsy

The clinical differentiation of epileptic seizures from hysterical pseudo-epileptic seizures is sometimes difficult. The routine inter-ictal electroencephalogram is of limited use in such instances and prolonged electrophysiological monitoring for the detection of ictal changes may not always be feasible, especially in many centres in developing countries. This article focuses on hyperprolactinaemia as a biochemical marker of a recent ictus. It reviews studies that have explored the possibility of utilizing transient post-ictal elevations in serum prolactin as a diagnostic test in aiding the differentiation of epilepsy from hysterical pseudo-epilepticseizures, In the past decade many reports have documented post-ictal elevations in serum prolactin after tonic-clonic and complex partial seizures. Peak prolactin levels were observed 15 to 20 minutes after the ictus and values fell towards baseline within the hour. Evidence from these studies indicates that post-ictal hyperprolactinaemia is caused by involvement of medial temporal structures, especially the amygdala and hippocampus, by ictal discharges and the resultant disruption of tonic dopaminergic inhibition of prolactin release and/or stimulation of serotonin, rather than due to non-specific influences. The factors that affect the specificity, sensitivity and predictive value of post-ictal hyperprolactinaemia as a diagnostic test are discussed and a standard test procedure and definition of test result proposed that would improve its clinical utility. The test is recommended as a simple, relatively inexpensive, highly specific and fairly sensitive aid to diagnosis.