PICU nurses are no strangers to the seizing child. There are many causes of seizure disorder in the pediatric population and some are much more common than others. The usual suspects are the infamous and usually not serious febrile seizure, CNS injuries related to prematurity or birth trauma, hydrocephalus and head injury. The manifestations range from staring to lip-smacking, single limb twitches to full-body twitching and jerking. They can be subtle and easily-overlooked at times and absolutely unmistakable at others. This article will look at three more uncommon causes of seizure in pediatric patients where the only similarity is that sufferers have seizures.
Lennox-Gastaut Syndrome
This disorder has a frequency of about 1-4% of childhood epilepsy, has an early onset - often before the age of 2, is 5 times more common in boys and is notoriously hard to treat. Children with LGS have a variety of ictal types, including any combination of generalized tonic-clonic, atypical absence, atonic, massive myoclonic and myotonic-atonic seizure. Any of these can be the basis for status epilepticus. Other features of this syndrome are developmental regression or delay, abnormalities in level of consciousness, cranial nerve dysfunction with associated feeding difficulty, physical developmental delay and behavioural issues. Diagnosis is through EEG, neuroradiologic imaging (MRI preferred) and clinical presentation. A significant number of children with LGS will also have signs that overlap those of West syndrome. Many children with LGS will have appeared to be quite normal for a period of time before the onset of symptoms. The younger the child at onset the more dramatic the cognitive impairment. Cognitive functions most often impaired are reaction time and information processing.
One feature of LGS that affects the majority of patients is persistent, difficult to control seizures. The most concerning of these is the atonic seizure, or "drop attack" where the child just simply falls to the ground unconscious. Mortality (~3%) in LGS is usually related to these and associated head trauma. Some authorities indicate that that between 10 and 56% of LGS patients will experience these. Nearly all of them will experience atypical absence seizures. Tonic seizures can be asymmetrical and will affect roughly half of these children. They're also more likely to experience nonconvulsive status epilepticus. Imagine how that affects their brains.
These children will require a cocktail of anticonvulsant medication at relatively high doses. They may be on a combination of valproic acid, clobazam or clonazepam, vigabatrin, topiramate, lamotrigine and rufinamide... and still seize. In March, 2014 a new extended release topiramate formulation called Qudexy SR was approved by the FDA as an adjunct therapy for LGS patients as young as 2 years old. Unlike the previously approved extended release version called Trokendi XR, this formulation can be removed from the capsule and mixed with soft food. Ketogenic diet is somewhat successful for some children while others are helped by corpus callostomy, vagal nerve stimulation or focal cortical resection. These surgeries are palliative only.
What typically brings these little people into hospital and the PICU after diagnosis is infection. Any illness that upsets the balance in their lives will almost surely send them into status. The most important nursing intervention after timely medication administration for these kiddies is protection from injury. Padded side rails, bed lowered to the lowest possible position, the use of strollers rather than wheelchairs, careful positioning and airway maintenance during seizures are all essential. Including family members in patient care and allowing parents to provide input into best practices as related to their child are also welcomed. They're going to be the experts in this situation.
West Syndrome
Known as infantile spasm. This condition is a triad of infantile spasm, interictal hypsarrhythmia and mental retardation. An apt description of the spasm (no longer used) is salaam seizure: the sudden bowing of the patient's head almost to the knees then relaxation into the upright position again repeated 10-20 times over about 3 minutes and recurring several times each day. Children with this disorder may have one or more structural abnormality in their brains, a congenital disorder such as Trisomy 21, birth trauma or metabolic disorder. However, the single most common cause of West syndrome is tuberous sclerosis. This syndrome accounts for about 2% of childhood epilepsies but about 25% of epilepsies with onset in the first year. There's no gender predilection. Only a small number of these children will have normal or borderline normal cognition. The majority are severely retarded and may also have psychiatric conditions such as autism or hyperactivity. The premature death rate is high, between 5 and 31% before the age of 10. Diagnosis is through laboratory studies for underlying metabolic disorders, neuroradiologic imaging, EEG and lumbar puncture.
Treatment typically involves a variety of medications in the lowest doses effective to diminish seizure activity without deleterious affects on quality of life. Ketogenic diet is sometimes effective as well. Rarely is focal cortical resection required. Children with West syndrome are often deficient in ACTH, so supplementation may be part of the treatment regime, as is prednisone. The most effective anticonvulsant is vigabatrin; some children will also require others such as valproic acid, lamotrigine, topiramate or levetiracetam. As one would expect in children with adrenal insufficiency, any illness that increases physiologic stress will lower the seizure threshold and has the potential to lead to status. As a general rule, basic seizure precautions are enough for these kiddies.
Rasmussen's Encephalitis
Also known as epilepsia partialis continua type II or prolonged partial seizure. This rare disorder is devastating in its effects. At onset it manifests "as a syndrome of continuous focal jerking of a body part occurring over hours, days or even years". (Cockerell et al 1996 and Shorvan 1994) It's defined as partial status epilepticus with simple motor jerks lasting more than an hour with clonic activity limited to one limb or body part - most often in the upper body - and occurring at regular intervals. The disorder is progressive, affecting about 1 in 1,000,000 people, slightly more often in males and usually not seen until the teenage years or older. Seizures may exhibit a Jacksonian spread (gradually moving from one side of the body to the other) and may degenerate into a generalized tonic-clonic seizure. Patients may have other neurological effects such as paresthesia, paresis, visual field defects, aphasia, alterations in level of conscious and dementia. In recent years research has been aimed at autoimmune causes, although a long list of other conditions have been considered to be causative. Diagnosis is based primarily on neuroradiologic imaging and EEG. Mortality is roughly 16%.
Treatment is difficult. Often patients require toxic levels of phenobarbital or phenytoin to decrease seizure activity. Benzodiazepines have a limited role and in severe cases of status, thiopental or pentobarbital coma may be required. IVIG has sometimes been useful and moderately effective in controlling seizure and progression of the disease. Immunosuppression is often initiated with mixed results; high dose IV steroids, biological response modifiers such as rituximab and chemotherapeutics such as cyclophosphamide may be used. Surgically, total hemispherectomy may be used as a last resort. It's not known what initiates the onset of rapid progression but it seems once it begins, it's almost impossible to stop.
Seizure disorders are common, but as we've seen, there are some very uncommon and fascinating causes for these in children. There is much we don't know about the brain and nervous system and we may never fill those gaps. This article serves as a small attempt.
peaq
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thanks! I really enjoyed reading this article, articles of health issues interest me especially on Epilepsy due to three of my 5 children have had it and out grown it. Now two of my grandsons have it both which are very young. the LGS struck me as very familiar to my two year old grandson especially since he seemed pretty much on track developmentally until the seizure activity. He falls so much more than before and also barely says words and when he gets one right we get excited over here. The three year old as well, but before any his first seizure, which landed him in the picu, had delays prior to that so also familiar to his case.
Not looking for medical advice at all just found this interesting and thought maybe my daughter should approach this subject with their neurologist. Not sure if that would make a difference in their medications or treatment plan but figure it can't hurt.
Again very informative article! thank You.