Abstract:

Infantile epilepsy surgery is rarely performed due to complexities associated with it however presently unique chance of alleviating catastrophic seizures so also preserving the cognitive development of the child. High volume epilepsy surgery centers or tertiary centers equipped with advanced equipment’s should take up infantile surgeries. Here we describe 6 months old baby presenting with infantile catastrophic epilepsy and recurrent status epilepticus with parieto occipital dysplasia which was managed surgically. We also review literature and state of evidence on infantile epilepsy surgeries.

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Image Dysplasia

Introduction:

Surgical treatment of epilepsy is now a standard of care in drug resistant epilepsies and is associated with good seizure control along with improved learning, development and quality of life in pediatric patients(l), however infantile epilepsy surgeries are very rarely performed (2). Infantile period is very crucial as brain development happens at high pace necessitating aggressive treatment for seizure control to ensure proper brain development. Infantile epilepsies pose challenge of proper diagnosis, identifying surgical substrate and treatment for optimal outcomes, but encouraging results are reported from various high-volume epilepsy surgery centers (1-4).

We describe our experience with 6 months old baby boy presented with drug resistant epilepsy and recurrent status epilepticus, who underwent surgical work up and treatment. With this case, we discuss the various intricacies associated with infantile epilepsy surgeries, methodologies of work up, surgical details and outcomes along and present literature review of commonly neglected aspect of catastrophic infantile epilepsies.

Case Report

We present a six months old male child, first issue of non-consanguineous marriage born at full term by cesarean section. He cried immediately after birth with normal APGAR scores and did not require any post-natal Intensive care. He started having seizures since 1 and 1/2 month of age. Typical seizures started with behavioral arrest, cessation of pre ictal activities, staring looks followed by right beating nystagmoid movements. These events lasted for 1-2 minutes with complete post ictal recovery. Initially seizure frequency was 4-5 per day. He was admitted and evaluated at our hospital. Routine biochemistry and metabolic screen was normal. Electroencephalogram (EEG) showed left temporo-occipital epileptiform activity, which was almost continuous throughout the sleep record. All the seizures were having electrophysiological correlate originating from Left posterior temporal and occipital region. He was started on phenytoin and levetiracetam, which controlled his seizures hence he was discharged from the hospital.

 

He was asymptomatic for next two months. His development was appropriate for his age. He started having recurrent seizures with increase in frequency of 10-14 per day with clusters lasting or 3 hours and more. He was then subsequently tried on Clobazam, Oxcarbazepine, topiramate and lacosamide for next two months. As seizures continued, he was referred for pre surgical evaluation

PET Scans showing Left posterior quadrant Hypo metabolism

Pre-Surgical work up

VEEG was done and it captured multiple seizures within three hours of recording. His clinical semiology and ictal EEG (Figure 1) confirms the onset of seizures from left occipitotemporal region. Magnetic resonance imaging (MRI) under epilepsy protocol (Figure 2) showed left temporooccipital sub hemispheric cortical dysplasia. Ictal PET study (Figure 3) showed diffuse area of hypometabolism in left occipito-temporal region. Ictal PET and MRI were Co-registered for better accuracy and abnormality was posterior to central sulcus. All data is reviewed and discussed in weekly epilepsy pre-surgical meeting with multi-disciplinary team consisting of pediatric epileptologist, pediatric neurologist, epilepsy surgeon, neuroradiologist, nuclear medicine consultant, neuropsychologist and social worker. After discussion plan for left temporo-parieto-occipital disconnection was made and discussed with parents.

Surgical steps included neuro¹ navigation guided appropriately shaped craniotomy followed by baseline electrocorticography and somatosensory evoked potentials for confirmation of motor strip aided by neuronavigation guided confirmation of other landmarks. Extensive amygdalar resection done at first followed by disconnection of temporal stem along the superior temporal gyrus beneath insula. Same line of disconnection continued upward behind the post central gyrus till sagittal sinus to disconnect parietal lobe and occipiral lobe till corpus callosum. Posterior disconnection done along with hippocampal outflow tract sectioning was performed to achieve completion of temporo parieto occipital disconnection.

Patient was put on ventilator elective y hours and weaned off next day. On postoperative day 2, patient developed right hemiparesis, w recovered in next 24 hours without any sequel Rest of the hospital stay was uneventful and patient discharged from the hospital on Day 12 was seizure free at discharge and postoperative EEG showed persistent spikes in left parietal an temporal areas. He was again evaluated at months after surgery and enjoys complete seizure freedom so far.

Discussion:

Infantile epilepsies one of the difficult to manage due to diagnostic challenges, considerable expertise needed to interpret EEGs and identifying various syndromes, which are prevalent in infantile period (5). There is considerable overlap of benign epilepsy syndromes, genetic epilepsies and symptomatic epilepsies in infantile period, thus identifying symptomatic epilepsy is another challenge. Although epilepsy surgeries are established standard of care for drug resistant epilepsy, proving drug resistance in infantile period is difficult task and the term catastrophic substrate positive epilepsy appears better for management purpose (3, 6-8). MRI remains the crucial investigation in deciding substrate positive epilepsy and surgical plan; however, myelination patterns of brain in infantile period pose a challenge in identifying the dysplastic cortical malformation and its extent with certainty (8). Here PET scan proves to be of great significance, which identifies area of decreased metabolism delineating possible functional deficits zone (7, 8). Multimodality imaging, co-registrations and electrophysiological data often can offer a rational surgical hypothesis, which can be executed with safety (3, 7, 8).

Outcomes of infantile epilepsy surgery is encouraging and ranges between 60% – 80% from various centers across pathologies (3, 8, 9). Hemimegelencepphaly has little worse outcomes than focal dysplasias as far as seizure outcome is concerned. Our patient is seizure free for last 7 months after surgery and his drug requirement has halved down. He has also shown improvement in achieving developmental milestones. Cognitive development remains most important aspect in proposing early surgical intervention.

Most of the infantile surgeries are for large dysplasia or hemimegencephaly, which are mostly hemispherotomy and major disconnections (10). Surgery on infant brain is delicate and maximum allowable blood loss is often the restriction on the operating surgeon. Dorfer et al in their series of 4 hemispherotomies at median age of 2.9 months patients, reported intraoperative transfusion in all kids, with median volume of transfusion 435 ml (9). Similarly, Cleveland clinic group in their series of 15 patients reported blood loss as most common complication with all the kid requiring blood transfusion and average 63% of blood volume was replaced preoperatively (7).In our patient, preoperative hemoglobin was 7.5 hence preoperative transfusion was given to achieve 9.5 gm % and intraoperative transfusion was not needed. Hence geared up anesthetist team support along with good intensive care are major surgeries. Kumar et al reported one mortality due to status epilepticus post operatively in their series of 25 infants and asserted that complications are common in this age group still favored early surgical intervention for catastrophic epilepsies (3). Neurological deficits are uncommon as reported by most of the reported series and plausible explanation could be optimal neuroplasticity of infantile brain. In our patient, no paucity of right sided movement was observed on day 2 which reverted back to normal by 4^th day.

Once the surgical plan is decided, timing of surgery is crucial factor. Potential risks of early surgery are to be balanced against preserving the normal brain development. High volume developed epilepsy surgery centers operates kids as early as two months (3, 6, 7, 9).

These patients always present with catastrophic epilepsies with recurrent status epilepticus and hospital admissions. Mortality associated with these admissions is found to be higher than surgical mortality in high volume centers with experienced surgeons. Also, surgical treatment offers long-term solutions, early discharge from the hospital and prevents further admissions hence decreasing the burden on resources.

Conclusion

Surgical management of catastrophic substrate positive epilepsies leads to good seizure outcome with acceptable complications. It provide hope to preserve normal brain development. It also reduces further ICU admissions, hospitalizations reducing financial burden on parents.

Epilepsy surgery in catastrophic infantile Book Appointment 

Source: Indian journal of pediatric neurology 2017 July (Vol – 5): 11-15