Mediziner haben in der Praxis häufig das Problem, echte epileptische Anfälle von ähnlicher Symptomatik bei schwerer Hypoglykämie (z. B. bei Diabetikern) und Migräne zu unterscheiden. Verschiedene Untersuchungen haben gezeigt, dass bei echten epileptischen Anfällen in der Regel erhöhte Prolaktionspiegel vorliegen. Ein Bluttest soll auf dieser Basis eine bessere Unterscheidung ermöglichen.
Without diagnostic equipment, doctors have a hard time telling the difference between the jerking, convulsions, and strange behaviors of an epileptic seizure and similar symptoms that can accompany hypoglycemia, migraine headaches, and small strokes. But recently, researchers in California found that a blood test could help doctors differentiate between some types of epileptic seizures and conditions that imitate epilepsy.
The blood test measures prolactin, a hormone that causes women to lactate when breastfeeding. For years, medical researchers have suspected that epileptic seizures cause a rise in prolactin, in both women and men, but were uncertain how and when a prolactin test might be useful.
To answer these questions, doctors at Stanford University School of Medicine reviewed eight studies on prolactin blood tests involving roughly 300 people known to have epilepsy. The researchers found that an increase in prolactin levels could help diagnose two types of seizures:
- tonic-clonic seizures, marked by jerking motions followed by convulsions, and
- complex partial seizures, where the electrical activity starts in one part of the brain and results in loss of consciousness.
Because prolactin levels in the blood return to normal soon after a seizure, doctors must take blood within 20 to 30 minutes after the symptoms occur. For now, the test is most useful in a hospital setting.
"Doctors who treat epilepsy often have to pose the question: 'Is this epilepsy?' " says study author Robert Fisher, director of the Epilepsy Center at Stanford and editor of Epilepsia, an international journal on epilepsy. "We've long wanted a reliable blood test."
Fisher explained that increases in prolactin don't always accompany some tonic-clonic and complex partial seizures, so there's a risk of false-negative blood tests. Some people, including nursing mothers and people on certain medications, normally have elevated levels of prolactin, so false positives are a concern as well. Further, prolactin levels vary in the body throughout a person's daily wake/sleep cycle. Nevertheless, the blood test could help doctors diagnose epilepsy, especially when more advanced diagnostic techniques like video electroencephalography are not available.
Researchers think that epileptic seizures stop the release of a brain chemical called dopamine from the hypothalamus, a brain structure that controls many of the body's hormones. Since dopamine normally inhibits prolactin, more prolactin gets released into the bloodstream during a seizure.
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Anmerkung von migraeneinformation.de:
Interessant ist insbesondere auch, dass der Test epileptische Anfälle gegenüber Hypoglykämie und Migräne abgrenzen soll. In der Tat kann die Symptomatik sehr ähnlich sein und es ist zu vermuten, dass (verdeckte) Hypoglykämien häufig die gemeinsame Ursache bei den diskutierten Erscheinungen ist.