The role of postictal laboratory blood analyses in the diagnosis and prognosis of seizures

Abstract

Presently, no postictal laboratory values can definitively prove or rule out the diagnosis of an epileptic seizure. For seizures with unknown causes, simple blood tests can be a valuable aid for quickly defining the etiology, particularly with certain metabolic and toxic encephalopathies. For this reason, CK, electrolytes, creatinine, liver and renal function tests should be measured on at least one occasion. Further research is needed in order to identify new biomarkers that improve the diagnosis and prognosis of seizures and seizure-related complications.

Blood markers of cardiac stress after generalized convulsive seizures

“…It is a negative prognostic stress marker in stroke, sepsis, and AMI . It helps to distinguish between patients with chest pain who need hospitalization and patients who are not immediately threatened . Copeptin levels above a proposed cutoff value of 10 pmol/L were found in 94% of our patients and reached the 30‐fold average baseline level within minutes after the GCS.…”

“…However, elevations of copeptin in the setting of syncope have been described recently, challenging its discriminative value for GCS from episodes of other origins . In this context, it is important to stress that copeptin can be significantly elevated in association with other diseases such as ischemic stroke, subarachnoid hemorrhage, septic shock, and other medical conditions with impaired levels of consciousness or focal neurologic deficits that could possibly be confused with postictal states or postictal Todd phenomenon . Future studies are required to elucidate the sensitivity and specificity of copeptin in the differential diagnosis.…”

“…Notably generalized convulsive seizures (GCS), including focal to bilateral tonic–clonic seizures and generalized‐onset tonic–clonic seizures, put a strain on the cardiovascular system, which may promote cardiac complications such as cardiac arrhythmia, cardiomyopathy, and myocardial infarction . In line with this assumption, previous emergency room (ER) studies have reported troponin elevations after GCS in 6%‐12% and acute myocardial infarction (AMI) in 2% of all cases referred because of GCS . Patients with AMI in association with GCS were older and commonly had a history of coronary artery disease as compared to those without AMI .…”

A potential role of hypophosphatemia for diagnosing convulsive seizures: A case‐control study

“…Phosphate concentration in blood samples collected after TLOC may therefore be useful in clinical practice to assess the likelihood of a GTC seizure episode, especially when phosphatemia is <0.6 mmol·L –1 . In terms of sensitivity and specificity, the value of hypophosphatemia seems roughly similar to other established markers in terms of specificity, whereas its sensitivity seems lower . For CK, a rise of >15 U/L is helpful for distinguishing GTC seizures from syncope, with a sensitivity of 69% and a specificity of 94%, whereas a threshold of 2.3 mmol·L –1 for lactate levels is associated with 73% sensitivity and 97% specificity for GTC seizures versus other TLOC.…”

Epilepsy under my skin?

“…Additionally, supportive was the elevated serum prolactin which has a specificity of 96% and a sensitivity of 62% for epileptic seizures in the context of a syncope 8 14 15. The epileptic seizure disrupts the regulation of the hypothalamus which results in the release of prolactin by the pituitary gland 8. Prolactin levels should be measured as soon as possible as they peak within 10–20 min, but they remain elevated during the first 2 hours 8 14–16.…”