The recent accessibility of video electroencephalography (EEG) monitoring has reduced interest in the use of prolactin in distinguishing epileptic seizures from psychogenic nonepileptic seizures. However, a serum marker continues to be clinically useful when video EEG is not available. The American Academy of Neurology (AAN) has released evidence-based recommendations for the use of serum prolactin tests in differentiating between epileptic and nonepileptic seizures. The report was published in the September 2005 issue of Neurology.
The AAN developed the following practice recommendations for physicians considering a laboratory blood test to diagnose epileptic seizures:
When measured in appropriate clinical settings at 10 to 20 minutes after a suspected event, elevated serum prolactin levels are useful in distinguishing generalized tonic-clonic seizures or complex partial seizures from psychogenic nonepileptic seizures in adults and older children.
Serum prolactin levels should be representative of the baseline prolactin level when measured more than six hours after a suspected episode.
Serum prolactin assay is not useful in distinguishing seizure from syncope.
Serum prolactin assay has not been established in the assessment of status epilepticus, repetitive seizures, or neonatal seizures.
The AAN also made the following recommendations for future research on serum prolactin assays:
Additional research should be done to provide a more accurate standardization of sex-specific prolactin threshold values.
Studies should evaluate the usefulness of an out-patient prolactin kit that could be kept in the patient’s home to document capillary prolactin changes shortly after seizure episodes.
Studies should determine what prolactin changes occur after other seizure imitators that may affect the hypothalamic-pituitary axis (e.g., migraines, transient ischemic attacks, cardiac arrhythmias).
Prospective studies of postictal prolactin measures in neonates and young children are needed.
Additional data are needed to interpret prolactin values after status epilepticus and repetitive seizures.