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choco lite BENIGN NEONATAL CONVULSIONS

NEO-NATAL EPILEPSIES

Several type of seizures can occur during the neonatal periode. 

1. Focal Epilepsies

     1.1 Idiopathic

          There is no Partial Idiopathic Epilepsy described in the neonatal period.

     1.2 Symptomatic

          It is conceivable to have a localization related epilepsy secondary to a focal lesion to have its onset in the neonatal period. However because at this age the Seizures are often if not always, both focal and generalized, this category is regrouped in 3.1.

 2. Generalized Epilepsies

     2.1 Idiopathic

          There are 2 syndromes described under the IGE which have their onset in the neonatal period. These are:

          2.1.1. Benign Neonatal Familial Convulsions

          2.1.2. Benign Neonatal Convulsions

     2.2 Symptomatic or Cryptogenic.

     2.3 Symptomatic

          The difference with 2.2  and 2.3 is that in these (2.3)syndromes there is a definite lesion in all cases.

              2.3.1. Without a specific aetiology. There are 2 syndromes described in the neonatal age group.

          2.3.1.1. Early Infantile Myoclonic Encephalopathy ( described by Aicardi )

          2.3.1.2. Infantile Epileptic Encephalopathy of Ohtahara.

              2.3.2. With a specific aetiology. Here we find the Progressive myoclonic epilepsies and in particular the early infantile form of the Ceroid LipoFuscinosis: The Santavuori Syndrome.

 

3. Undetermined Epilepsies.

hallu motion

     3.1. With both partial and generalized Seizures.

          This is where most of the neonatal seizures are going to enter. NB that in this Category of epilepsies (3.) we have lost the previous way of classification between Idiopathic and symptomatic. Therefore there will be both type regrouped under the same heading. 2 main syndromes are described:

          3.1.1. Neonatal Seizures without specific aetiology or with specific aetiology. i.e.. the ones we see after perinatal anoxia as well as the ones we do not know why they are there.  But are excluded the seizures in the context of an acute metabolic imbalance.

 4. Special Syndromes.

     4.1. In relation with a situation. We have here only the seizures in a metabolic context.


  BENIGN NEONATAL SEIZURES

 

Also known as "5th day seizures".

     According to various studies prevalence varies between 4 and 38% of all NNS. It is more likely to be closer to the lower number (4%) than to the upper one.

      Male > females by 62% vs. 38%.

     Onset always between day 1 and day 7

           90%           day 4 and day 6

           97%            day 3 and day 7

     Seizures all ALWAYS clonic, often partial, alternating and or apneic, NEVER tonic. Motor seizures are often lateralised, going from one hemi body to the other, less frequently generalised.

     They last about  1 mn to 3 mn. They are often repeated realizing a status epilepticus. The average length of this status is 20 hours, but can be shorter 92Hrs) or longer (3 days).

     At the onset of the status the baby neurological exam is normal. Then the child becomes drowsy, AED's? and hypotonic. Later the children recover a normal neurological status.

     EEG Intercritical can be normal, discontinue, with focal or multifocal anomalies. But most frequently: "theta pointu alternant".    Dominant Theta activity

              Alternating or discontinue

              Non reacting

              Sharp waves

              Interhemispheric asynergy

              Wake state as well as sleep (both slow and agitated)

     After this status the "theta pointu alternant" can be found until day 12. It will then be possible to diagnose Benign neonatal seizures outside of the status epilepticus. NB: the Theta pointu alternant can be found in status of the neonatal period from other aetiologies eg: Hypocalcaemia, meningitis, I C hemorrhages) and is not specific to the benign neonatal seizures. However it is a GOOD prognostic factor since it always carries a favorable NEUROLOGICAL outcome.ling fluent

     Recorded seizures can be found al over the scalp but are most frequently in the Rolandic area. Occasionally can be unilateral, immediately generalised or secondarily generalized. EEG tracing are spikes or slow waves. There is no post critical flattening (which would be of poor prognosis) and no alpha-like rhythm. There can be clinical seizures without EEG anomalies and EEG critical discharges without clinical seizures.

     During the status many drugs have been tried (PHB, DPH, BZD, Paraldehyde, Chloral, ...) Mot of the times the seizures stop spontaneously and it seems that the AED's do not modify the duration of the status.

     Differential diagnosis: MB imbalance

                             Meningitis

                             Viral infections

                             Malformation

     Pathophysiology. Possibly a deficit in Zinc in the CSF. (Goldberg and Sheehy 1983, Arch. Dis. Child.57, 633-635).

 Summary:

Benign neonatal seizures are very frequent clonic or apneic seizures having their onset around the 5th day of life. A status epilepticus lasts about 20 hours. There is no known aetiology and MB imbalance. Intercritical EEG often shows aspect of "theta pointu alternant". There is no further epilepsy and the neurological outcome is normal.

B. Neonatal Sz

B. Familial NN. Sz

 

No familial cases

AD transmission, 20,q13.2

ONSET

day 2 or 3

day 4 or 5

course

Status for 20 hours

Isolated Sz for up to **weeks

Secondary epilepsy

0.5%

11%

Neurological Anomalies

  more frequent

  less frequent