From the Guidelines
Prolactin levels can be elevated after seizures, particularly generalized tonic-clonic and complex partial seizures, and measuring serum prolactin can help differentiate epileptic seizures from psychogenic non-epileptic seizures (PNES). When considering the management of prolactin-related issues in patients with seizures, it's essential to prioritize the most recent and highest quality evidence. According to a 2024 study published in Nature Reviews Endocrinology 1, dopamine agonists, such as cabergoline, can reduce pituitary-origin hyperprolactinaemia of any cause. In the context of seizures, prolactin levels can rise due to the disruption of the inhibitory control of dopamine on prolactin release from the pituitary gland. Some key points to consider when evaluating prolactin levels in patients with seizures include:
- Prolactin levels typically elevate within 10-20 minutes post-seizure and return to normal within 2-24 hours
- Measuring serum prolactin can help differentiate epileptic seizures from psychogenic non-epileptic seizures (PNES) with a sensitivity of 60-100% and specificity of 80-100% when measured within 10-20 minutes after the event 1
- Prolactin testing has limitations, including false positives with syncope or acute medical stress, and is not useful for simple partial seizures, absence seizures, or status epilepticus
- For accurate results, blood samples should be collected within 10-20 minutes post-event and compared to baseline levels
- While helpful as a diagnostic tool, prolactin testing should be used alongside clinical evaluation, EEG, and other diagnostic methods rather than as a standalone test for epilepsy diagnosis. It's also important to note that the evaluation and management of reproductive endocrine disorders, including hyperprolactinaemia, in patients with epilepsy may require close cooperation between neurologists and endocrinologists or gynaecologists, as highlighted in a 2002 study published in the Journal of Neurology, Neurosurgery and Psychiatry 1.
From the Research
Prolactin and Seizures
- Prolactin levels may increase as a consequence of epileptic seizures, with a rise seen in approximately 60% of complex partial seizures 2.
- The increase in prolactin levels is caused by the propagation of epileptic activity, usually from the temporal lobe to the hypothalamic-pituitary axis 2.
- Postictal prolactin levels can be used to differentiate between epileptic and psychogenic seizures, as prolactin usually fails to rise after psychogenic seizures 2.
Effect of Seizures on Prolactin Secretion
- Serum prolactin level was significantly increased after seizures, which peaked at 15 min postictal and attained the levels more than 5-fold the baseline in 59 patients 3.
- The changes of hormone levels correlated significantly with the types of seizures 3.
- In repetitive seizures, prolactin may show a decrease in its postictal release, which is more common in status epilepticus, probably as a result of a diminished propagation of ictal activity during the course of status epilepticus 2.
Antiepileptic Drugs and Prolactin Secretion
- Antiepileptic drugs, such as phenytoin, valproate, and carbamazepine, can affect the secretion of prolactin in the pituitary 3.
- The basal prolactin levels in patients with exclusive phenytoin or valproate, and in those with combined administration of carbamazpine, were significantly lower than the control levels 3.
- Traditional Chinese medicine therapies do not affect the secretion of prolactin 3.
Treatment of Hyperprolactinemia
- Hyperprolactinemia can be treated with dopamine agonists, such as bromocriptine and cabergoline, which can normalize prolactin secretion and gonadal function, and can also cause significant tumor shrinkage in a high percentage of cases 4, 5.
- Cabergoline seems to have the most favorable profile, followed by quinagolide, in terms of efficacy and tolerability 4, 5.
- Surgical resection of the prolactinoma is an option for patients who may refuse or do not respond to long-term pharmacological therapy 4, 5.