Anesthetic management of a patient with MERRF syndrome

Regional anesthesia in pediatric patients with preexisting neurological disease

Preexisting neurological disease in pediatric patients presents unique challenges to the anesthesiologist. In-depth knowledge of the disease processes and awareness of sequalae that uniquely influence the risks and benefits of anesthetics are needed to make informed decisions. Because these vulnerable populations are often susceptible to perioperative airway or cardiopulmonary complications, the use of regional anesthesia can be advantageous. However, these clinical conditions already involve compromised neural tissue and, as such, create additional concern that regional anesthesia may result in new or worsened deficits. The following discussion is not intended to be a full review of each disease process, but rather provides a concise, yet thorough, discussion of the available literature on regional anesthesia in the more common, but still rare, pediatric neurological disorders. We aim to provide a framework for pediatric anesthesiologists to reengage in a healthy discussion about the risks and benefits of utilizing regional anesthesia in this vulnerable population.

Perioperative Management of an Adult Patient With Myoclonic Epilepsy With Ragged Red Fibers Syndrome: A Case Report

Myoclonic epilepsy with ragged red fibers (MERRF) syndrome is a rare mitochondrial disease potentially associated with increased sensitivity to anesthesia and metabolic decompensation. We present the perioperative management in a 59-year-old man with MERRF scheduled for lipomatosis cure under general anesthesia (GA). Following a reduced fasting period, the patient had an uneventful balanced GA with propofol, sevoflurane, and rocuronium. The patient did not present metabolic decompensation nor malignant hyperthermia but prolonged neuromuscular blockade. Propofol and sevoflurane may be used in asymptomatic MERRF adult patients. Such patients present high risk of residual neuromuscular blockade that should be monitored and reversed.

Pharmacotherapeutic management of epilepsy in MERRF syndrome

INTRODUCTION

Epilepsy is a prominent feature of myoclonic epilepsy with ragged-red fibers (MERRF)-syndrome. The most frequent seizure type is myoclonic seizures, of which the treatment is challenging and empiric.

AREAS COVERED

Herein, the author summarises and discusses previous and recent findings of antiepileptic drug (AED) treatment in MERRF-syndrome.

EXPERT OPINION

MERRF-syndrome is a predominantly maternally inherited, multisystem mitochondrial disorder caused by pathogenic variants predominantly of the mitochondrial DNA (mtDNA). Canonical clinical features of MERRF include myoclonus, epilepsy, ataxia, and myopathy. Additionally, other manifestations in the CNS, peripheral nerves, eyes, ears, heart, gastrointestinal tract, and endocrine organs may occur (MERRF-plus). Today, MERRF is considered rather as myoclonic ataxia than as myoclonic epilepsy. Genotypically, MERRF is due to mutations in 13 mtDNA-located genes and 1 nDNA-located gene. According to the modified Smith-score, the strongest gene-disease relationship exists for MT-TK, MT-TL1, and POLG1. Epilepsy is the second most frequent phenotypic feature of MERRF. Seizure-types associated with MERRF include focal myoclonic, focal clonic, and focal atonic seizures, generalized myoclonic, tonic-clonic, atonic, and myoclonic-atonic seizures, or typical absences. Treatment of myoclonic epilepsy relies on expert judgments recommending levetiracetam, together with clonazepam, or topiramate, zonisamide, or piracetam in monotherapy as the first line AEDs.

MERRF Classification: Implications for Diagnosis and Clinical Trials

BACKGROUND

Given the etiologic heterogeneity of disease classification using clinical phenomenology, we employed contemporary criteria to classify variants associated with myoclonic epilepsy with ragged-red fibers (MERRF) syndrome and to assess the strength of evidence of gene-disease associations. Standardized approaches are used to clarify the definition of MERRF, which is essential for patient diagnosis, patient classification, and clinical trial design.

METHODS

Systematic literature and database search with application of standardized assessment of gene-disease relationships using modified Smith criteria and of variants reported to be associated with MERRF using modified Yarham criteria.

RESULTS

Review of available evidence supports a gene-disease association for two MT-tRNAs and for POLG. Using modified Smith criteria, definitive evidence of a MERRF gene-disease association is identified for MT-TK. Strong gene-disease evidence is present for MT-TL1 and POLG. Functional assays that directly associate variants with oxidative phosphorylation impairment were critical to mtDNA variant classification. In silico analysis was of limited utility to the assessment of individual MT-tRNA variants. With the use of contemporary classification criteria, several mtDNA variants previously reported as pathogenic or possibly pathogenic are reclassified as neutral variants.

CONCLUSIONS

MERRF is primarily an MT-TK disease, with pathogenic variants in this gene accounting for ~90% of MERRF patients. Although MERRF is phenotypically and genotypically heterogeneous, myoclonic epilepsy is the clinical feature that distinguishes MERRF from other categories of mitochondrial disorders. Given its low frequency in mitochondrial disorders, myoclonic epilepsy is not explained simply by an impairment of cellular energetics. Although MERRF phenocopies can occur in other genes, additional data are needed to establish a MERRF disease-gene association. This approach to MERRF emphasizes standardized classification rather than clinical phenomenology, thus improving patient diagnosis and clinical trial design.

A review of anaesthetic outcomes in patients with genetically confirmed mitochondrial disorders

Mitochondrial disorders are a clinically and biochemically diverse group of disorders which may involve multiple organ systems. General anaesthesia (GA) poses a potential risk of decompensation in children with mitochondrial disorders, and there is little guidance for anaesthetists and other clinicians regarding the optimal anaesthetic agents and perioperative management to provide to patients with mitochondrial disease[15]. The aim of this review was to document adverse events and perioperative complications from GA in patients with genetically confirmed mitochondrial disorders. A retrospective chart review of patients with genetically confirmed mitochondrial disorders who had undergone GA was undertaken. The indication for GA, anaesthetic agents utilised, length of admission and post anaesthetic complications were documented and analysed. Twenty-six patients with genetically proven mitochondrial disease underwent 65 GAs. Thirty-four (52%), received propofol as their induction agent. Thirty-three (51%) patients received sevoflurane for the maintenance of anaesthesia, while 8 (12%) received isoflurane and 24 (37%) received propofol. The duration of most GAs was short with 57 (87%) lasting less than 1 h. Perioperative complications occurred in five patients while under GA including ST segment depression, hypotension and metabolic acidosis in one. All five patients were stabilised successfully and none required ICU admission as a consequence of their perioperative complications. The duration of hospital stay post GA was <24 h in 25 (38%) patients.

CONCLUSION

No relationship between choice of anaesthetic agent and subsequent perioperative complication was observed. It is likely that individual optimisation on a case-by-case basis is more important overall than choice of any one particular technique. What is Known: • General anaesthesia (GA) poses a potential risk of decompensation in children with mitochondrial disorders. • There is a great diversity in the anaesthetic approaches undertaken in this cohort, and little guidance exists for anaesthetists and other clinicians regarding the optimal anaesthetic agents and perioperative management to provide to patients with mitochondrial disease. What is New: • In this study of 26 patients with genetically confirmed mitochondrial disease who underwent 65 GAs, no relationship between choice of anaesthetic agent and subsequent perioperative complication was observed • It is likely that individual optimisation on a case-by-case basis is more important overall than choice of any one particular technique.

Anesthetic management of 877 pediatric patients undergoing muscle biopsy for neuromuscular disorders: a 20-year review

BACKGROUND

The objectives are to review the anesthetic management and anesthetic-related adverse events in patients undergoing muscle biopsy for a broad spectrum of neuromuscular disorders (NMD).

AIM

The study aims to assess the hypothesis that perceived awareness of potential anesthesia-induced hyperkalemia and MH in patients with NMD reduces the frequency of such events.

METHODS

A 20-year retrospective review of 877 consecutive patients undergoing muscle biopsy to establish diagnoses of NMD has been performed. Patients were categorized prebiopsy into six groups: M (myopathy and muscular dystrophy), MM (mitochondrial or metabolic myopathy), N (neurodegenerative, peripheral neuropathy or spinal muscular atrophy disorder), D (dermatomyositis), C (cardiomyopathy), or S (seizure disorder). Data were collected for demographics, anesthetic management, pre- and postoperative anesthesia-induced muscle injury, postbiopsy histopathologic diagnosis, and concordance comparisons between pre- and postbiopsy diagnoses.

RESULTS

There were 513 males (58.5%) and 364 females (41.5%) (1.4:1) with 137 individuals (15.6%) operated on under 1 year of age and two-thirds by 6 years of age. NMD diagnosis was reached in 409 (46.6%) while 468 (53.4%) had no specific pathology. No patients exhibited signs of anesthesia-induced muscle injury (malignant hyperthermia, rhabdomyolysis, cardiac arrest, or postoperative deterioration of weakness). MM was the largest group pre biopsy (367, 41.8%). Anesthetic agents were: nitrous oxide in 657 (74.9%); volatile agents in 139 (15.8%); intravenous agents in 836 (95.3%) (primarily propofol, midazolam, and fentanyl); nondepolarizing muscle relaxants in 404 (46.1%); and regional anesthesia in 112 (12.8%) [most commonly spinal anesthesia in 80 (71.4%)]. Comparing preoperative diagnostic category with postoperative diagnosis, there was a concordance of 78% (319/409) between the two for cases with a definitive diagnosis and 89.7% (787/877) for all cases.

CONCLUSIONS

In this retrospective study, no patient exhibited signs or symptoms of hyperkalemia or MH probably because the incidence is very low and becomes even less likely due to the selection of the various anesthetic agents and strategies administered.

Late-Emerging Lethal Exacerbation of Cardiomyopathy in a Patient with Mitochondrial Myopathy After Total Hip Arthroplasty: A Case Report

CASE

Mitochondrial myopathy comprises heterogeneous neuromuscular disorders caused by mitochondrial dysfunction. Acute exacerbation of mitochondrial myopathy infrequently occurs sequentially after perioperative stress. We present an unusual case of a late-emerging and lethal exacerbation of mitochondrial myopathy after total hip arthroplasty. Despite special attention paid to perioperative control, the patient's condition drastically deteriorated on postoperative day thirteen, and she died later as a result of cardiomyopathy.

CONCLUSION

When performing surgery on a patient with mitochondrial myopathy, the merits of surgery must always surpass the possible grave risk of this condition.

Perioperative management of the paediatric patient with coexisting neuromuscular disease

Children with neuromuscular diseases present a wide range of clinical manifestations and clinical implications for the anaesthesiologist. Neuromuscular diseases in children affect muscle strength by either directly weakening the muscle fibrils or indirectly by a degenerative nerve supply and weak neuromuscular junction. Of the more than 200 neuromuscular disorders known, the vast majority are genetic in origin. This review focuses on four of the more common neuromuscular disorders with emphasis on their pathophysiology and clinical implications for anaesthesiologists: malignant hyperthermia, the muscular dystrophies (Duchenne's, Becker's, and Emery-Dreifuss), mitochondrial disorders, and cerebral palsy.

Successful left hemihepatectomy and perioperative management of a patient with biliary cystadenocarcinoma, complicated with MELAS syndrome: report of a case

Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-like syndrome (MELAS) is a rare, fetal disease caused by a mutation in mitochondrial DNA that leads to impaired oxidative metabolism in skeletal muscle, the central nervous system, and liver function. This report presents the case of a 50-year-old woman with biliary cystadenocarcinoma complicated by MELAS who underwent a successful left hemihepatectomy. In this case, the diagnostic key for the malignant tumor was an (18)F-fluorodeoxyglucose positron emission tomography study, which was useful even in a patient with MELAS, which causes abnormal glucose metabolism. The perioperative management of such patients includes special precautions to prevent lactic acidosis and deterioration of the reserved liver function after a hepatectomy, since the mitochondrial function in MELAS patients is abnormal. The patient in this report has remained free of liver dysfunctions and cancer recurrence for 2 years following the hepatectomy. This is the first report of a successful major hepatectomy for a patient with MELAS.

Drug management in emergent liver transplantation of mitochondrial disorder carriers: review of the literature

BACKGROUND

Mitochondrial respiratory-chain disorders (MRCD) lead to progressive disabling of neurological and cellular conditions that involve muscles, brain, kidney, and liver dysfunction. Affected individuals may need surgery, including orthotopic liver transplantation (OLT). Surgery poses anesthesia challenges because of the prolonged use of anesthetic drugs and sedatives, which may inhibit oxidative phosphorylation, mimic mitochondrial cytopathic disorders, or unveil them ex novo.

MATERIALS AND METHODS

We conducted a multilingual PubMed search of surgical and non-surgical anesthesia reports between the years 1992 and 2008, where anesthetic drugs were used in MRCD patients, especially for those undergoing urgent OLTs.

RESULTS

There were 51 case reports of 210 anesthesia and critical care interventions in patients with MRCD, a large part of them were children. Data pertaining to the safe usage of anesthesia and perioperative drugs were limited and conflicting. We found no article that addressed the issue of perioperative handling of urgent OLT in MRCD patients. We therefore suggest our own - although limited - experience for such occasions.

CONCLUSION

There are no randomized, controlled, trial-based indications regarding safe anesthetic drugs to be used perioperatively in MRCD carriers. Consultation among geneticists, anesthesiologists, intensivists, and surgeons is essential in patients with known/suspected metabolic syndrome for planning appropriate perioperative care.

Mitochondrial disorders and general anaesthesia: a case series and review

Patients with mitochondrial disease are at risk of metabolic decompensation and often require general anaesthesia (GA) as part of their diagnostic work up and subsequent management. However, the evidence base for the use of GA is limited and inconclusive. We have documented the practice and outcome in the use of GA in paediatric patients with mitochondrial disease using a retrospective case review study of 38 mitochondrial patients who had undergone 58 anaesthetics within the regional metabolic service for the period 1989-2005. A variety of anaesthetic agents were used and the pattern of use reflects that seen in standard paediatric practice. There were no episodes of malignant hyperthermia and no documented intraoperative events attributable to the GA. Three postoperative adverse events were noted; one episode of hypovolaemia, one episode of acute on chronic renal failure, and one episode of metabolic decompensation 12 h post-muscle biopsy. Despite theoretical concern about this group of patients, adverse events after GA are rare and in most cases unrelated to the anaesthesia. Further prospective studies of GA in mitochondrial disease are required to create evidence-based clinical guidelines for safe practice.

Anesthesia-related morbidity and mortality after surgery for muscle biopsy in children with mitochondrial defects

BACKGROUND

Children with mitochondrial defects (MD) may have an increased risk for cardiorespiratory and neurological complications from anesthesia. The aim of this study was to determine the incidence of perioperative complications and adverse events in children with MD.

METHODS

We performed a retrospective review of the anesthesia, surgical and medical records of 155 children up to 10 years who underwent a diagnostic surgical muscle biopsy for suspected mitochondrial and muscle disorders between 1999 and 2003. The data of the 122 patients where a definite MD diagnosis was found were analyzed. Anesthesia was conducted according to the discretion of the attending staff. In children with MD the activity of the different complexes of the oxidative phosphorylation system was measured.

RESULTS

From the preoperative assessment, signs of encephalopathy were most frequent (n = 93), followed by muscle weakness (n = 32), lactic acidosis (n = 15), cardiomyopathy and/or conduction defects (n = 10) and chronic respiratory problems (n = 7). The mean age of the children with MD was 32.4 months (SD = 26.9). The mean duration of anesthesia was 36.0 min (SD = 12.6) and the mean length of stay in the recovery room was 33.0 min (SD = 24.0). There were no major changes in heart rate or blood pressure which required pharmacological intervention during anesthesia or postanesthesia care unit (PACU) stay. A short episode of SpO2 <80% with airway obstruction occurred once in the PACU. Biochemical analysis in the children with a MD showed an isolated deficiency of one of the five protein complexes of oxidative phosphorylation in 42 children, a combination of complex deficiencies in 41 and no definite localization in 39 children.

CONCLUSION

With standard preoperative assessment, monitoring and anesthesia management, there were no major peroperative and postoperative anesthesia-related complications in children undergoing surgical muscle biopsy with a MD diagnosis.