Epilepsy with myoclonic astatic seizures (Doose Syndrome)

Epilepsy with myoclonic astatic seizures typically develops between 1 and 4 years and affects more boys than girls. It accounts for 1-2% of cases of children with epilepsy. The term atonic is also used instead of astatic, meaning loss of tone to describe how the child suddenly drops. The syndrome was formerly called Doose Syndrome.

Causes 

While it is suspected that the cause may be a genetic mutation, this has not yet been established and there is no genetic test available at present.

Characteristics

A variety of seizures may present in this syndrome typically between the second and fourth years of life. These include myoclonic jerks, atonic seizures (drop attacks)  or a combination of these myoclonic-astatic where a jerk is followed by a fall. Some children may have generalized tonic-clonic seizures and some may have absence seizures or staring like episodes with loss of awareness.  About 30% may have a prolonged seizure of some kind at some point whether convulsive or non-convulsive.

Prognosis

Children with myoclonic astatic seizures vary in terms of the outlook for their type of epilepsy. Some 50% will improve on ASM’s but may have ongoing cognitive difficulties. Some children may achieve seizure control with minimal or mild delays in learning. The remaining children will continue to have seizures despite treatment with ASM’s and dietary therapy and will often have more significant learning delays.

Diagnosis

Diagnosis is made by a paediatric neurologist based on EEG results which are typically abnormal and in sleep, the EEG may show spike and wave or poly spike and wave activity. Abnormal activity can arise from both sides of the brain or from the entire brain at once. Other tests and scans, blood tests and  MRI are typically normal.

Treatment

Anti-Seizure Medications

Anti-seizure medicines (ASM’s) used first in treatment include sodium valproate or levetiracetam. If these are not effective then other options may be considered such as the ketogenic diet and other ASM’s such as Ethosuximide, Zonizamide, Clobazam and Topiramate

Ketogenic Diet

The ketogenic diet (KD) is a high-fat, low-carbohydrate diet. There are several variations such as the classical MCT oil diet, low glycaemic index diet and the modified Atkins diet. It is a non-pharmacological treatment and is used in combination with ASM’s. The diet has been effective at reducing seizures and is regarded as safe with side effects being transient and less likely to lead to cognition difficulties and drowsiness.

Emergency treatment

Prolonged or repeated seizures leading to status epilepticus are common in this syndrome, whether it be convulsive or non-convulsive status. Your child’s neurology team will discuss a care plan including the treatment of convulsive status epilepticus with emergency medication or the treatment of non-convulsive status epilepticus or both.

Surgery

Epilepsy surgery may be an option for those children who do not respond to ASM’s or Ketogenic Diet therapy. For children for whom epilepsy surgery is not an option vagus nerve stimulation (VNS) may be considered.

Further Information