Is prolactin level useful in determining whether my patient with loss of consciousness suffered a seizure?

It depends on the timing of your patient’s presentation!

It is generally held that serum prolactin level peaks within 10-20 min after a generalized tonic-clonic or complex partial seizure and returns to baseline within 2-6 h. Even then, its sensitivity is no more than 50%-60% for these types of seizures.  Elevated PL is also seen in 60%-80% of patients with syncope.1

A report by the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology (2006) concluded that “elevated serum prolactin assay, when measured in the appropriate clinical setting at 10-20 min after a suspected event, is a useful adjunct for the differentiation of generalized tonic-clonic or complex partial seizure from psychogenic non-epileptic seizure among adults or older children (Level B).2 

In contrast, reports of PL increasing for up to 6 h after epileptic seizure or not reaching baseline for 12-18 h can also be found in the literature.3

Although the mechanism for elevation of PL in certain seizures is unknown,  one hypothesis proposes that prolactin is secreted due to the interference with the inhibitory control of hypothalamus by the electrical perturbation of this part of the brain.4  

References

  1. Nass RD, Sassen R, Elger CE. The role of postictal laboratory blood analyses in the diagnosis and prognosis of seizures. Seizure 2017;47:51-65. https://www.ncbi.nlm.nih.gov/pubmed/28288363
  2. Chen DK, So YT, Fisher RS. Is prolactin a clinically useful measure of epilepsy? Epilepsy Currents 2006;6:78-79. https://www.ncbi.nlm.nih.gov/pubmed/16157897
  3. Siniscalchi A, Gallelli L, Mercuri NB, et al. Serum prolactin levels in repetitive temporal epileptic seizures. Eur Rev Med Pharmacol Sci 2008;12:365-368. https://www.ncbi.nlm.nih.gov/pubmed/19146198
  4. Collins WCJ, Lanigan O, Callaghan N. Plasma prolactin concentrations following epileptic and pseudoseizures. J Neurol Neurosurg Psych 1983; 46:505-8. http://jnnp.bmj.com/content/jnnp/46/6/505.full.pdf

 

Is prolactin level useful in determining whether my patient with loss of consciousness suffered a seizure?

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