|Ahead of print
Anesthetic management for functional hemispherectomy in a patient of Rasmussen’s encephalitis: A case report
Shalvi Mahajan, Aparna Depuru, Vinitha Narayan, Kirandeep Kaur
Department of Anesthesia and Intensive Care, Postgraduate Institute of Medical Education and Research, Chandigarh, India
|Date of Submission||19-Oct-2021|
|Date of Decision||05-Jan-2022|
|Date of Acceptance||24-Jan-2022|
|Date of Web Publication||30-Jan-2023|
Department of Anesthesia and Intensive Care, Postgraduate Institute of Medical Education and Research, Chandigarh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Rasmussen’s encephalitis (RE) is a rare inflammatory neurological disease, characterized by frequent and severe seizures, loss of motor skills and speech, hemiparesis (weakness on one side of the body), encephalitis (inflammation of the brain), and dementia. It is characterized by refractory epilepsy and progressive atrophy of one cerebral hemisphere. Here, we report a successful anesthetic management of a child with RE scheduled for functional hemispherectomy.
Keywords: Functional hemispherectomy, Rasmussen’s encephalitis, refractory epilepsy
| Introduction|| |
Theodore Rasmussen, a neurosurgeon, and his co-workers in the late 1950s described bizarre seizure disorder with unknown etiology as Rasmussen’s encephalitis (RE) for the first time. RE is a progressive disease characterized by pharmaco-resistant focal epilepsy later on progressing to epilepsia partialis continua (EPC), progressive hemiplegia, speech disturbances (dominant language area), hemianopia, and cognitive decline, with unihemispheric brain atrophy. We report a successful anesthetic management of a child with RE scheduled for functional hemispherectomy.
| Case Report|| |
A 6-year-old right-handed male child weighing 25 kg presented with chief complaints of continuous jerky movements on the right side of body for the last 2 years, refractory to multiple anti-epileptic drugs (AEDs). The antiepileptics include tablet form of lacosamide 50 mg, brivaracetam 25 mg, phenobarbitone 30 mg, levetiracetam 250 mg, sodium valproate 250 mg, carbamazepine 200 mg, and phenytoin 50 mg. All AEDs were given twice a day except carbamazepine and phenytoin which are taken thrice a day. Consequently, 24-lead electroencephalogram (EEG) monitoring for seizure episodes and magnetic resonance imaging (MRI) of brain were carried out. The child had shown a positive response to lacosamide in the form of reduction of EPC at the time of sleeping on EEG. MRI of brain showed left brain atrophy in frontal and temporal lobes and hyperintense signals [Figure 1]. Based on clinical features and MRI of brain, diagnosis of RE was made. Hence, left fronto-temporo-parietal craniotomy and functional hemispherectomy were planned.
|Figure 1: T2-weighted magnetic resonance image of the brain showing diffuse left cerebral hemisphere atrophy marked in fronto-parietal lobes with prominent extra-axial cerebrospinal fluid spaces and lateral ventricle|
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On examination, the child was conscious, well-oriented, and had continuous jerky movements on the right side of the body. There were no signs suggestive of raised intracranial pressure or cranial nerve deficits. Rest of the systemic examination was within normal limits including the airway assessment. Laboratory examination was within normal limits.
The child was assigned the American Society of Anesthesiology Physical Status (ASA PS)-3 category. Written informed consent was taken from the parents, and they were also counseled regarding risks associated with the surgery and the post-operative course.
The patient was kept nil per oral from midnight as per the ASA standard guidelines. All AEDs were continued till morning of the surgery. On arrival to pre-operative area, the child’s vitals were recorded and the patient was premedicated with intravenous (IV) midazolam 1 mg after securing 20G IV cannula.
The temperature of the operation theater was kept around 24°C. The child was connected to multi-parameter monitors: electrocardiography, non-invasive blood pressure, oxygen saturation (Spo2), neuromuscular monitoring (NMT), capnometry (ETCO2), and temperature. The baseline vitals were noted, and 0.9% saline was given as IV fluid. Anesthesia was induced with morphine 2.5 mg and propofol 40 mg. After ensuring loss of consciousness, NMT monitoring was initiated and atracurium 12.5 mg was administered. When the train of four count was zero, trachea was intubated with a 5.0 mm internal diameter cuffed endotracheal tube. Afterwards, invasive arterial line with 22G cannula was established in the left radial artery for continuous blood pressure monitoring. Anesthesia was maintained with sevoflurane [1.0 minimum alveolar concentration (MAC)] in a mixture of oxygen/nitrous oxide, along with intermittent atracurium bolus based on NMT monitoring. Intraoperatively, IV lacosamide 50 mg and levetiracetam 250 mg were administered. Intraoperatively, 1200 mL of IV crystalloid was administered and there was 150 mL of blood loss. The surgery lasted for 4 h. At the end of the surgery, the patient was shifted to the neurosurgery intensive care unit. The child was extubated the next day. During post-operative course, seizure frequency decreased and right-sided hemiplegia (power 2/5) developed. After a week, he was discharged from the hospital with five AEDs. On 6-month follow-up, AEDs were further tapered down to four AEDs with reduced doses and right-sided limb power improved to 3/5 with physiotherapy.
| Discussion|| |
The reported incidence of RE in children is 2.4 in 10 million. The median age of onset is 6 years and less than 10% of the cases are seen in adulthood. The occurrence of bilateral disease is debatable. Diagnosis of RE is based on clinical, radiological, and pathological criteria.
The main anesthetic concerns are pediatric age, neurosurgical procedure, and pharmaco-resistant epilepsy with multiple anti-epileptics. The goals of neuroanesthesia revolve around avoidance of hypoxia, hypercapnia, hypocapnia, hypotension, hypoglycemia, electrolyte disturbances, and timely administration of anti-epileptics.
Routine pediatric pre-operative evaluation begins with the establishment of good rapport with the child and parents. In addition, documentation of pre-operative neurological deficits, knowledge of all anti-epileptic agents, evaluation of pre-operative investigations—hemogram, coagulogram, serum electrolytes, renal and liver function, any previous surgery, IV access, need for post-operative mechanical ventilation—are important. Counseling of patient regarding the procedure and also post-operative complications is must.
Premedication in children should be aimed at both pharmacological and non-pharmacological methods. Anti-anxiety drugs should be administered in the pre-operative area under supervision as multiple anti-epileptics may cause sedation.
Induction of anesthesia in the pediatric population involves inhalational induction and less commonly, IV induction. Most commonly used inhalational agents (IAs) are sevoflurane and halothane. Halothane has potent anti-convulsant property, though in modern anesthesia practice, its role is obsolete. With sevoflurane induction, one should avoid concentration above 1.5 MAC and hypocapnia. Uptake and distribution of IAs are rapid due to the increased respiratory rate and distribution of higher proportion of cardiac output to brain and heart. Hence, a careful watch on hemodynamics, especially bradycardia, is crucial. For IV induction, propofol or thiopentone may be used. Ketamine and etomidate are best avoided. Etomidate is proconvulsant at clinical doses, although, at higher doses, it confers anti-convulsant property. Maintenance of anesthesia can be achieved safely with total IV anesthesia with propofol and fentanyl or IAs with nitrous oxide. At lower MAC, nitrous oxide is not proconvulsant.
For perioperative analgesia, opioids other than meperidine and tramadol may be used. Normeperidine, a metabolite of meperidine, is a proconvulsant. Seizure activity was noticed with tramadol due to increase in serotonin levels.
AEDs should be continued in the perioperative period. During intraoperative seizure, the motor component may go unnoticed owing to myorelaxants unless EEG monitoring is present. However, abnormal cerebral activity during intraoperative seizure necessitates administration of intraoperative AEDs. Also, pediatric population has low blood volume and if excessive blood loss occurs, optimal blood levels of AEDs may fall which, in turn, demands AEDs supplementation.
Chronic administration of phenytoin and carbamazepine (>7 days) results in faster hepatic clearance due to enzymatic metabolism of opioids and myorelaxants such as vecuronium and rocuronium. Hoffman elimination of atracurium and cis-atracurium allows its safer use in patients with multiple AEDs, but the metabolite laudanosine has been postulated to be proconvulsant (although no reported case in humans). Hence, interaction between AEDs and myorelaxant mandates use of NMT intraoperatively as done in the indexed case. The NMT should be done on non-hemiplegic limb due to the presence of higher acetylcholine receptor density of lower motor nerve units innervated by dysfunctional or non-functional upper motor neurons in hemiplegic limb. Consequently, resistance to non-depolarizing myorelaxants along with overdosing of normal neuromuscular units occurs.
The aim of fluid management in pediatric neurosurgical patients is optimization of pre-load to replete fluid deficits related to fasting, urine output, insensible losses, and replacement of intraoperative blood loss. Normovolemia and normotension using isotonic non-glucose containing crystalloids area well-established norm to maintain adequate cardiac output. During craniotomy, significant blood loss can occur in infants and children, so the maximum allowable blood loss should be calculated prior to surgery. There is no specific threshold for blood transfusion. Hence, blood replacement following fluid replacement should be individualized based on pre-operative hemoglobin, dynamic hemodynamics parameters (pulse pressure variation), and acid–base measurements (lactate levels and base deficit).
Maintenance of normothermia during anesthesia is of supreme importance. Hypothermia has been associated with delayed emergence, altered pharmacokinetics, and poor tissue perfusion. Forced air warming blankets and IV fluid warmers should be routinely used, and the patient should be kept covered as much as possible. The operating room temperature should be raised during skin preparation and before draping.
Intraoperative complications pertinent to neurosurgery are blood loss, venous air embolism (VAE), and intraoperative seizures. Large craniectomy for hemispherectomy can cause massive blood loss and tearing of venous sinuses. Also, a slight head-up position to facilitate surgery decreases superior sagittal sinus pressure, thus increasing the likelihood of VAE. Hence, vigilant end-tidal carbon dioxide monitoring is important.
The complications which can be seen in the post-operative period are persistent seizures, hydrocephalus, hemiplegia, hemianopia, aseptic meningeal reaction (fever, headache, neck stiffness lasting for a week or so without any microbiological source), and post-operative nausea and vomiting. Intensive care monitoring, appropriate fluid management, good post-operative analgesia, and continuation of AEDs as per the need should be provided. Dopamine antagonists such as haloperidol and metoclopramide should be avoided due to the extrapyramidal side effects which can be confused with seizure activity.
Very sparse literature is available regarding the anesthetic management of such rare cases. To the best of our knowledge, only an abstract on a case series of RE was noted which was done by Khandelwal et al.
| Conclusion|| |
RE has childhood presentation. Pediatric anesthesia concerns along with polypharmacy and various drug interactions are important. Therefore, it necessitates a proper pre-operative assessment, careful administration of anesthetic drugs, and intraoperative continuation of the AEDs. Further studies are required in this realm which may be difficult due to the rarity of the disease.
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Conflicts of interest
There are no conflicts of interest.
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