Unclear transient loss of consciousness is a frequent interdisciplinary diagnostic problem. Of particular importance is the distinction between epileptic and non-epileptic events. Our group showed in two previous studies that serum lactate is elevated in epileptic seizures, but mostly not in syncopes, psychogenic non-epileptic seizures and complex partial seizures. These results showed that lactate can be used as a diagnostic marker for the presence of a generalized epileptic seizure.It remains unclear whether a normal serum lactate value is also present in a convulsive syncope as the most important differential diagnosis to generalized epileptic seizures.~So in the present prospective study, the serum lactate concentrations are compared following convulsive and non-convulsive syncopes.~The examinations are carried out in cardiological patients who receive a tipping table examination with the aim of initiating a syncope. The question is whether there is hyperlactatemia following convulsive syncopes. If no elevated serum lactate values were measured after convulsive syncopes, this would additionally indicate the great benefit of the serum lactate value as a diagnostic marker in the generalized epileptic seizure.~In addition, a comparison is made with the parameters creatine kinase, prolactin, pH-value, bicarbonate, sodium and potassium.~If increased serum lactate values are measured following a syncope further venous blood controls are carried out at intervals of 20 minutes within the first hour and then after 90 minutes and 120 minutes until normalization.
The investigators compared the serum lactate, serum prolactin and serum creatine kinase concentrations following convulsive and non-convulsive syncopes. The aim of the study was to investigate their importance as diagnostic markers in transient loss of consciousness.