If epilepsy shows up on MRI

EEG and MRI - a must after the first seizure

How much diagnosis is necessary in children after a first epilepsy-like attack if they are otherwise neurologically normal? In addition to an EEG within the first 24 hours after the attack, blood tests and an MRI are usually recommended. However, many of the abnormalities that are discovered are not relevant for the assessment.

In any case, epilepsy experts agree on EEG examinations - this allows typical epilepsy potentials and focal slowdowns to be determined quickly after the attack. This has now been well documented in studies, reported Professor Bernd Neubauer from the Giessen University Hospital. If such EEG changes are discovered, the risk of a relapse is doubled. With the EEG, however, the point in time is important: the examination has the highest sensitivity in the first 24 hours after the attack. Three days later, the sensitivity is only half as high, said the pediatrician at the neuropediatrics congress in Jena. However: Narrowing the period for the EEG even further does not help. In studies, epilepsy-typical signals could not be detected significantly more frequently three hours after an attack than 24 hours later, according to Neubauer at an event supported by Janssen-Cilag.

Blood tests recommended in children up to three years of age

The situation is less clear with laboratory tests. Studies in both adults and children with the first seizures have only rarely shown deviations in the serum levels of glucose, sodium, potassium and creatinine - if so, then mostly in infants. Neubauer mentioned a study with 160 patients - only in one, namely an infant, was it possible to detect hypoglycemia as the cause of the attack through the blood test. There is so far insufficient data that the serum analysis is helpful in older patients. However: "All the specialist commissions have said that this data is too weak overall, we therefore recommend blood tests at least up to the age of 3," said Neubauer. "I would, however, always do that," added the pediatrician, because one always has to expect surprises when doing blood tests on children.

There is even less evidence of a benefit from lumbar puncture. Neubauer named a study in which twelve percent of children had granulocytosis in the CSF after a first attack - but without a pathogen being detected. But the same applies here: Better safe than sorry. In children in the first year of life, especially in the first six months, a lumbar puncture is generally recommended to rule out an infection, even if there is still no good evidence-based data.

A lumbar puncture is also recommended in infants.

If the blood draw is successful within an hour, even better within 30 minutes of the attack, the prolactin level is informative. "Then you can measure an increase in prolactin in a generalized tonic-clonic seizure, at about 60 percent." In the case of a complex partial seizure, the measurement is less sensitive: Here, such an increase can only be determined in around 45 percent of patients, and it is completely absent in the case of absences. "However, the prolactin values ​​can also rise with syncope. The measurement can only serve to differentiate between psychogenic and grand mal seizures," says Neubauer.

Again, the recommendations for MRI diagnostics are relatively clear: In Germany, an MRI is generally recommended for all children after a first afebrile attack - unless the clinical course clearly suggests idiopathic epilepsy.

The MRI findings are usually less clear, says Neubauer. In studies in which experts were shown blinded MRI images of children after a seizure, abnormalities were found in 30 percent of the children, but only two percent were related to the seizure. In many countries, therefore, there is no general recommendation on MRI. "Whether you recommend an MRI for everyone, even though only two percent need it, is a decision made by the respective health system," says Neubauer.

Reasons for seizures in children

In children who have had a first epilepsy-like attack, idiopathic epilepsies are not the only possible triggers. CNS infections, tumors, hypoglycaemia or syncope can also trigger attacks. Laboratory examinations and an MRI are necessary to clarify this. Seizures that occur within seconds of head trauma and last less than three minutes are usually not at risk of epilepsy.