Malignant Hyperthermia and Muscular Dystrophies

Anesthetic Approach for a Pediatric Patient With Facioscapulohumeral Muscular Dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) belongs to the group of rare diseases known as muscular dystrophies. Patients with muscular dystrophies face a heightened risk of intraoperative complications, including severe hyperkalemia and acute rhabdomyolysis. This case report outlines the anesthetic approach employed for a pediatric patient diagnosed with FSHD undergoing a planned exploratory tympanotomy. To the best of our knowledge, it is the first documented case in the literature detailing pediatric general anesthesia in a patient with FSHD, with the additional use of neuromuscular blockade reversal with sugammadex.

Association of a novel dystrophin (DMD) genetic nonsense variant in a cat with X-linked muscular dystrophy with a mild clinical course

X-linked muscular dystrophy in cats (FXMD) is an uncommon disease, with few reports describing its pathogenic genetic variants. A 9-year-old castrated male domestic shorthair cat was presented with persistent muscle swelling and breathing difficulty from 3 years of age. Serum activity of alanine aminotransferase, aspartate transaminase, and creatine kinase were abnormally high. Physical and neurological examinations showed muscle swelling in the neck and proximal limb, slow gait, and occasional breathing difficulties. Electromyography showed pseudomyotonic discharges and complex repetitive discharges with a "dive-bomber" sound. Histopathology revealed muscle necrosis and regeneration. Whole-genome sequencing identified a novel and unique hemizygous nonsense genetic variant, c.8333G > A in dystrophin (DMD), potentially causing a premature termination codon (p.Trp2778Ter). Based on a combination of clinical and histological findings and the presence of the DMD nonsense genetic variant, this case was considered FXMD, which showed mild clinical signs and long-term survival, even though immunohistochemical characterization was lacking.

Guidelines for inhaled sedation in the ICU

INTRODUCTION AND OBJECTIVES

Sedation is used in intensive care units (ICU) to improve comfort and tolerance during mechanical ventilation, invasive interventions, and nursing care. In recent years, the use of inhalation anaesthetics for this purpose has increased. Our objective was to obtain and summarise the best evidence on inhaled sedation in adult patients in the ICU, and use this to help physicians choose the most appropriate approach in terms of the impact of sedation on clinical outcomes and the risk-benefit of the chosen strategy.

METHODOLOGY

Given the overall lack of literature and scientific evidence on various aspects of inhaled sedation in the ICU, we decided to use a Delphi method to achieve consensus among a group of 17 expert panellists. The processes was conducted over a 12-month period between 2022 and 2023, and followed the recommendations of the CREDES guidelines.

RESULTS

The results of the Delphi survey form the basis of these 39 recommendations - 23 with a strong consensus and 15 with a weak consensus.

CONCLUSION

The use of inhaled sedation in the ICU is a reliable and appropriate option in a wide variety of clinical scenarios. However, there are numerous aspects of the technique that require further study.

[Trigger-free anesthesia : Indications and safe application]

The safe anesthesiological care of patients with neuromuscular diseases poses a particular challenge for anesthetists. Only a small group of muscle diseases and syndromes are associated with an increased risk of malignant hyperthermia and therefore require trigger-free anesthetic procedures avoiding volatile anesthetics and succinylcholine. These diseases are frequently associated with mutations in the RYR1, CACNA1S or STAC-3 genes. In other neuromuscular diseases, anesthetic-induced rhabdomyolysis can occur. Therefore, volatile anesthetics should be avoided in these patients in addition to the contraindication for succinylcholine. In other neuromuscular diseases the risk of a propofol infusion syndrome or myotonic crises can be elevated or the duration of the effect of non-depolarizing muscle relaxants can be changed in an incalculable way. In every case an individual anesthetic aproach including the avoidance of potential pharmacological or non-pharmacological triggers is essential for the safety of the patients.

Anticipation Avoids Adversity: Anesthetic Management of a Case of Facioscapulohumeral Dystrophy (FSHD)

Patients with muscular dystrophies, especially those pauci-symptomatic presenting for surgery pose a complex problem for the anesthesiologist in preparing, optimizing and performing anesthesia. A myriad of complications including cardiac, respiratory, rhabdomyolysis, hyperkalemia, increased sensitivity to muscle relaxants etc., influence the anesthetic technique and recovery. Preoperative identification and appropriate choice of anesthesia technique can prevent most of the adverse events during anesthesia. We present a case of facioscapulohumeral dystrophy (FSHD) presenting for emergency appendectomy. Preoperative investigations and lung function were adequate. The patient underwent general anesthesia with propofol, cisatarcurium, and remifentanil and was maintained on total IV anesthesia for the duration of surgery. Continuous neuromuscular monitoring was carried out at two sites and the patient responded normally to intubating dose of cisatracurium and subsequent top-up doses, showing no increased sensitivity or need for dose reduction. The patient was hemodynamically stable with propofol and remifentanil infusions, with inhalational agents purposefully avoided. The patient was reversed with anticholinesterase and good train-of-four (TOF) ratio (>90%) was ensured before being shifted to recovery. The patient had a further uneventful course in the hospital.

European Neuromuscular Centre consensus statement on anaesthesia in patients with neuromuscular disorders

BACKGROUND AND PURPOSE

Patients with neuromuscular conditions are at increased risk of suffering perioperative complications related to anaesthesia. There is currently little specific anaesthetic guidance concerning these patients. Here, we present the European Neuromuscular Centre (ENMC) consensus statement on anaesthesia in patients with neuromuscular disorders as formulated during the 259th ENMC Workshop on Anaesthesia in Neuromuscular Disorders.

METHODS

International experts in the field of (paediatric) anaesthesia, neurology, and genetics were invited to participate in the ENMC workshop. A literature search was conducted in PubMed and Embase, the main findings of which were disseminated to the participants and presented during the workshop. Depending on specific expertise, participants presented the existing evidence and their expert opinion concerning anaesthetic management in six specific groups of myopathies and neuromuscular junction disorders. The consensus statement was prepared according to the AGREE II (Appraisal of Guidelines for Research & Evaluation) reporting checklist. The level of evidence has been adapted according to the SIGN (Scottish Intercollegiate Guidelines Network) grading system. The final consensus statement was subjected to a modified Delphi process.

RESULTS

A set of general recommendations valid for the anaesthetic management of patients with neuromuscular disorders in general have been formulated. Specific recommendations were formulated for (i) neuromuscular junction disorders, (ii) muscle channelopathies (nondystrophic myotonia and periodic paralysis), (iii) myotonic dystrophy (types 1 and 2), (iv) muscular dystrophies, (v) congenital myopathies and congenital dystrophies, and (vi) mitochondrial and metabolic myopathies.

CONCLUSIONS

This ENMC consensus statement summarizes the most important considerations for planning and performing anaesthesia in patients with neuromuscular disorders.

Risk of malignant hyperthermia in patients carrying a variant in the skeletal muscle ryanodine receptor 1 gene

Malignant hyperthermia is a life-threatening disorder, which can be prevented by avoiding certain anesthetic agents. Pathogenic variants in the skeletal muscle ryanodine receptor 1-gene are linked to malignant hyperthermia. We retrospectively studied 15 patients who presented to our clinic with symptoms of muscle dysfunction (weakness, myalgia or cramps) and were later found to have a variant in the skeletal muscle ryanodine receptor 1-gene. Symptoms, creatine kinase levels, electromyography, muscle biopsy and in vitro contracture test results were reviewed. Six out of the eleven patients, with a variant of unknown significance in the skeletal muscle ryanodine receptor 1-gene, had a positive in vitro contracture test, indicating malignant hyperthermia susceptibility. In one patient, with two variants of unknown significance, both variants were required to express the malignant hyperthermia-susceptibility trait. Neurologists should consider screening the skeletal muscle ryanodine receptor 1-gene in patients with myalgia or cramps, even when few to no abnormalities on ancillary testing.

Management of patients susceptible to malignant hyperthermia: A surgeon's perspective

OBJECTIVES

Malignant hyperthermia (MH) susceptibility caries broad implications for the care of pediatric surgical patients. While precautions must often be taken for only a vague family history, two options exist to assess MH-susceptibility. We evaluate the use of MH precautions and susceptibility testing at a freestanding children's hospital.

METHODS

This single institution retrospective cohort study identified patients of any age who received general anesthetics utilizing MH precautions over a five-year period. The electronic medical record was further queried for patients diagnosed with MH. The indication for MH precautions and uses of susceptibility testing are assessed. Secondary outcomes included a diagnosis of bona fide MH.

RESULTS

A total of 125 patients received 174 anesthetics with MH precautions at a mean age of 114 months (0-363 months). Otolaryngology was the procedural service most frequently involved in the care of the cohort (n = 45; 26%). A reported personal or family history of MH (n = 102; 59%) was the most common indication for precautions, followed by muscular dystrophy (n = 29; 17%). No MH events occurred in the cohort and further review of ICD-9 and -10 diagnosis codes found no MH diagnoses. No study subjects received muscle biopsy and contracture testing and only 5 (4%) underwent genetic testing for genomic variants known to cause MH susceptibility. A case example is given to highlight the implications of a reported MH history.

CONCLUSION

Otolaryngologists should maintain a familiarity with the precautions necessary to manage patients at risk for MH and MH-like reactions. Without an accessible test to rule out susceptibility, surgeons must rely on a careful history to appropriately utilize precautions. An inappropriate label of "MH-susceptible" may result in decreased access to care and treatment delays.

Mapping the current evidence on the anesthetic management of adult patients with neuromuscular disorders-a scoping review

PURPOSE

Patients with neuromuscular disorders (NMDs) are at increased risk of perioperative complications. The objective of this scoping review was to examine emerging evidence from published studies, case reports, and review articles on anesthetic management of patients with NMDs, following the methodological frame for scoping reviews.

SOURCES

We searched PubMed and EMBASE for articles published between 1 January 2000 and 14 July 2021.

PRINCIPAL FINDINGS

Three prospective and 21 retrospective studies on altered pharmacokinetics and pharmacodynamics of neuromuscular blocking agents (NMBA) in NMD patients were included. Furthermore, 168 case reports/series reporting 212 anesthetics in 197 patients were included. These studies showed that preanesthetic neuromuscular monitoring can be used for precise NMBA dosing in myasthenia gravis patients. Sugammadex was associated with fewer postoperative myasthenic crises. Perioperative complications were not associated with specific anesthetic agents. Case reports/series showed that in 32% (67/212) of anesthetics, at least one complication was reported. Unexpected intensive care unit admission was a frequently reported complication. Patients with a complicated disease course may have had a higher use of succinylcholine (unadjusted relative risk, 0.13; 95% confidence interval [CI], 0.20 to 0.86) and volatile anesthetics (adjusted odds ratio [OR], 0.38; 95% CI, 0.20 to 0.73; P = 0.004).

CONCLUSION

Evidence on the anesthetic management and perioperative complications of patients with NMDs is mainly based on small retrospective studies and case reports. Further clinical trials or large retrospective studies are required to investigate the choice of safe anesthetic agents. Main areas of interest are the potential benefits of neuromuscular monitoring and sugammadex and the risks possibly associated with volatile anesthetics and succinylcholine.

Facioscapulohumeral muscular dystrophy-Reproductive counseling, pregnancy, and delivery in a complex multigenetic disease

Reproductive counseling in facioscapulohumeral muscular dystrophy (FSHD) can be challenging due to the complexity of its underlying genetic mechanisms and due to incomplete penetrance of the disease. Full understanding of the genetic causes and potential inheritance patterns of both distinct FSHD types is essential: FSHD1 is an autosomal dominantly inherited repeat disorder, whereas FSHD2 is a digenic disorder. This has become even more relevant now that prenatal diagnosis and preimplantation genetic diagnosis options are available for FSHD1. Pregnancy and delivery outcomes in FSHD are usually favorable, but clinicians should be aware of the risks. We aim to provide clinicians with case-based strategies for reproductive counseling in FSHD, as well as recommendations for pregnancy and delivery.

TRPC3, but not TRPC1, as a good therapeutic target for standalone or complementary treatment of DMD

Background

Duchenne muscular dystrophy (DMD) is an X-linked inherited disease caused by mutations in the gene encoding dystrophin that leads to a severe and ultimately life limiting muscle-wasting condition. Recombinant adeno-associated vector (rAAV)-based gene therapy is promising, but the size of the full-length dystrophin cDNA exceeds the packaging capacity of a rAAV. Alternative or complementary strategies that could treat DMD patients are thus needed. Intracellular calcium overload due to a sarcolemma permeability to calcium (SPCa) increase is an early and critical step of the DMD pathogenesis. We assessed herein whether TRPC1 and TRPC3 calcium channels may be involved in skeletal muscle SPCa alterations and could represent therapeutic targets to treat DMD.

Methods

All experiments were conducted in the DMD^mdx rat, an animal model that closely reproduces the human DMD disease. We measured the cytosolic calcium concentration ([Ca²⁺]_c) and SPCa in EDL (Extensor Digitorum Longus) muscle fibers from age-matched WT and DMD^mdx rats of 1.5 to 7 months old. TRPC1 and TRPC3 expressions were measured in the EDL muscles at both the mRNA and protein levels, by RT-qPCR, western blot and immunocytofluorescence analysis.

Results

As expected from the malignant hyperthermia like episodes observed in several DMD^mdx rats, calcium homeostasis alterations were confirmed by measurements of early increases in [Ca²⁺]_c and SPCa in muscle fibers. TRPC3 and TRPC1 protein levels were increased in DMD^mdx rats. This was observed as soon as 1.5 months of age for TRPC3 but only at 7 months of age for TRPC1. A slight but reliable shift of the TRPC3 apparent molecular weight was observed in DMD^mdx rat muscles. Intracellular localization of both channels was not altered. We thus focused our attention on TRPC3. Application of Pyr10, a specific inhibitor of TRPC3, abolished the differences between SPCa values measured in WT and DMD^mdx. Finally, we showed that a rAAV-microdystrophin based treatment induced a high microdystrophin expression but only partial prevention of calcium homeostasis alterations, skeletal muscle force and TRPC3 protein increase.

Conclusions

All together our results show that correcting TRPC3 channel expression and/or activity appear to be a promising approach as a single or as a rAAV-based complementary therapy to treat DMD.

Osmotic Demyelination Syndrome due to Rhabdomyolysis and Hyperosmolar Hyperglycemic Syndrome following Cardiogenic Shock

Osmotic demyelination syndrome (ODS) is a relatively rare disease that causes rapid demyelination, resulting in pontine and central nervous system damage with various symptoms, including impaired consciousness. It often occurs when hyponatremia is rapidly corrected. However, it can also occur when a normonatremic patient suddenly develops hypernatremia. A 51-year-old man developed cardiogenic shock with impaired consciousness, hyperCKemia, hypernatremia, and hyperglycemia. Osmotic demyelination syndrome secondary to rhabdomyolysis and hyperosmolar hyperglycemic syndrome was suspected. The patient's fluid volume decreased because of osmotic diuresis caused by hyperglycemia, and the blood sodium level increased rapidly. The latter resulted in ODS, which in turn resulted in a prolonged disturbance of consciousness, from which he has not yet recovered. ODS has been reported as a serious complication of rapid correction of hyponatremia, although it also occurs when normonatremia leads to hypernatremia. This disease is difficult to diagnose, as magnetic resonance imaging (MRI) of the brain is often unremarkable several weeks after its onset. This case of ODS occurred when normonatremia led to hypernatremia, as a result of rhabdomyolysis and hyperosmolar hyperglycemic syndrome. Diagnosis was made based on the MRI brain findings.

Anesthesia management in a pediatric patient with Becker muscular dystrophy undergoing laparoscopic surgery: A case report

BACKGROUND

Patients with Becker muscular dystrophy (BMD) have a high risk of developing hyperkalemia, rhabdomyolysis, and malignant hyperthermia when exposed to volatile anesthetics and depolarizing muscle relaxants. Patients with BMD are also prone to respiratory depression after general anesthesia. Thus, it is extremely challenging for anesthesiologists to manage anesthesia in BMD patients, particularly in pediatric BMD patients. Here, we present successful anesthesia management using transversus abdominis plane block (TAPB) combined with total intravenous anesthesia (TIVA) in a pediatric BMD patient undergoing laparoscopic inguinal hernia repair.

CASE SUMMARY

A 2-year-old boy, weighing 15 kg, with BMD, was scheduled for laparoscopic inguinal hernia repair. TIVA was used for induction, and continuous infusions of short-acting intravenous anesthetics combined with TAPB were performed for anesthesia maintenance. Moreover, TAPB provided good postoperative analgesia. The patient underwent uneventful surgery and anesthesia, and over the 17 mo follow-up period showed no anesthesia-induced complications.

CONCLUSION

TAPB combined with TIVA, using short-acting intravenous anesthetic agents, can provide safe and effective anesthesia management in pediatric BMD patients undergoing short-term abdominal surgery.

General anesthesia with remimazolam in a patient with mitochondrial encephalomyopathy: a case report

Background

Systemic anesthetic management of patients with mitochondrial disease requires careful preoperative preparation to administer adequate anesthesia and address potential disease-related complications. The appropriate general anesthetic agents to use in these patients remain controversial.

Case presentation

A 54-year-old woman (height, 145 cm; weight, 43 kg) diagnosed with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes underwent elective cochlear implantation. Infusions of intravenous remimazolam and remifentanil guided by patient state index monitoring were used for anesthesia induction and maintenance. Neither lactic acidosis nor prolonged muscle relaxation occurred in the perioperative period. At the end of surgery, flumazenil was administered to antagonize sedation, which rapidly resulted in consciousness.

Conclusions

Remimazolam administration and reversal with flumazenil were successfully used for general anesthesia in a patient with mitochondrial disease.

A case report of malignant hyperthermia in a patient with myotonic dystrophy type I: A CARE-compliant article

RATIONALE

Several hereditary myopathies that can predispose to malignant hyperthermia (MH) are reported. However, the risk of MH in myotonic dystrophy type I (DM1) has been suggested equal to general population, although the evidence is limited to only a few case reports.

PATIENT CONCERNS

We encountered a rare case of MH during anesthesia induction with sevoflurane in a male adolescent with previously undiagnosed DM1.

DIAGNOSES

After the event, genetic testing revealed the presence of a previously unknown heterozygous missense mutation in ryanodine receptor 1 (RYR1) associated with MH (c.6898T > C; p.ser2300Pro). Concomitantly, the patient was diagnosed with DM1 with abnormal cytosine-thymine-guanine triplet expansion in the DMPK gene.

INTERVENTIONS

Dantrolene was administered to treat the hypermetabolic manifestations in 20 minutes after the identification of MH.

OUTCOMES

The patient was successfully treated and discharged without any complications. Laboratory abnormalities were recovered to baseline at postoperative 4 days.

LESSONS

The authors suggest that possible MH susceptibility in DM1 patients may be refocused. Genetic testing can be a screening tool for MH susceptibility in these population, prior to receiving general anesthesia.

Effects of estimated glomerular filtration rate and diabetes mellitus on the effect of insulin for treating hyperkalemia during anesthesia

PURPOSE

We analyzed the effectiveness of insulin for treating hyperkalemia (≥ 5 mEq/L) during anesthesia and the effects of the estimated glomerular filtration rate (eGFR) and diabetes mellitus (DM) on the insulin treatment.

METHODS

Patients 18 years of age and older who received intravenous insulin lispro for hyperkalemia under general anesthesia between January 2010 and March 2020 were enrolled. We performed three propensity score matching analyses according to eGFR stages (eGFR ≥ 60 vs. 30 ≤ eGFR < 60 and eGFR ≥ 60 vs. eGFR < 30 mL/min/1.73 m²) and DM status.

RESULTS

The study included 475 patients. For patients with hyperkalemia during surgery, the odds ratios [ORs] of failure to decrease potassium (K⁺) after insulin treatment were higher in patients with eGFR < 30 mL/min/1.73 m² (adjusted OR 3.24; 95% confidence interval 1.38-7.64; P = 0.007) than in patients with eGFR ≥ 60 mL/min/1.73 m². There was no significant difference in the ORs of patients with 30 ≤ eGFR < 60 mL/min/1.73 m² and DM.

CONCLUSION

The patients with a low eGFR had a higher incidence of K⁺ not decreasing after insulin treatment. Periodic assessment of K⁺ may be required during anesthesia.

Thyroid storm after mitral valve repair in a patient with Becker muscular dystrophy

A 40-year-old male with Becker muscular dystrophy presented with severe mitral regurgitation and underwent mitral valve repair. Following the surgery, the patient became tachycardic and developed a continuous high-grade fever and hyperbilirubinemia. The patient's condition worsened and we eventually tested his thyroid levels and discovered abnormally high thyroid levels. After diagnosing a severe thyroid storm, the patient was treated with oral administration of Lugol's iodine and thiamazole, as well as an intravenous steroid, which led to an immediate improvement of symptoms. The incidence of thyroid storm after open-heart surgery is extremely rare but highly life-threatening if unrecognized.

Pediatric Ambulatory Anesthesia Challenges

Ambulatory surgery in the pediatric population can be similar to adult ambulatory with a few different challenges. Success is best determined by appropriate preoperative screening. Issues common in pediatrics are the respiratory infection, asthma, congenital heart disease and syndromes, as well as sleep apnea. Risk factors for adverse respiratory events and patient transfer differ from adults as do data for rapid discharge.

The clinical management of neuromuscular disorders in intensive care

Life-threatening neuromuscular disorders affect a small, but growing group of patients in the intensive care unit who present special management problems, as well as great therapeutic opportunities. In inflammatory conditions, a cure is often possible, and for chronic, genetic or degenerative conditions, achieving the previous level of function is the target. Neuromuscular experts and intensivists need to cooperate closely to achieve the best possible outcomes. They need to acquire a very specific set of skills, including both a thorough understanding of the mechanics of ventilation as well as familiarity with the diagnostic categories of genetic and of autoimmune diseases. This review of the clinical management of adult neuromuscular disease in the ICU aims to provide an overview of the most important conditions encountered in the ICU and a practical approach to their diagnosis, monitoring, and treatment.

Neuromuscular problems in the ICU

PURPOSE OF REVIEW

Patients with acute life-threatening neuromuscular disease require close cooperation between neuromuscular and intensive care specialists to achieve the best possible outcomes. The problems encountered by these patients are different from those in traditional neuromuscular practice, and neurologists consulting in the ICU need a specific skill set to provide useful guidance. However, outcomes can be very good if treatment is instituted effectively. This review aims to provide an overview of the most important neuromuscular conditions encountered in the ICU and enable a practical approach to patient management.

RECENT FINDINGS

New research has provided improved knowledge of the impact of acute neuromuscular failure on the mechanics of respiration, on the categories of neuromuscular disease in the ICU, and on the main factors influencing outcomes. Pitfalls and risks in ICU treatment are better understood.

SUMMARY

Evidence-based algorithms for monitoring and treatment have been developed. These advances enhance the role of the neuromuscular specialist in acute care. The principles of best practice are discussed in this review.

Case Report of Cardiac Arrest After Succinylcholine in a Child With Muscle-Eye-Brain Disease

Muscle-eye-brain disease is a rare autosomal recessive disorder characterized by congenital muscular dystrophy, ocular abnormalities, and brain malformation. We report an intraoperative hyperkalemic cardiac arrest following the administration of succinylcholine in a child with muscle-eye-brain disease. The disease was diagnosed only after this event. Our experience suggests that preoperative determinations of serum concentrations of lactate and creatine kinase may be useful if clinical signs consistent with myopathy are present.

Malignant Hyperthermia Susceptibility and Related Diseases

This review identifies disease states associated with malignant hyperthermia susceptibility based on genotypic and phenotypic findings, and a framework is established for clinicians to identify a potentially malignant hyperthermia–susceptible patient.

Rocuronium-induced neuromuscular block and sugammadex in pediatric patient with duchenne muscular dystrophy: A case Report

INTRODUCTION

Anesthetic management of patients with Duchenne muscular dystrophy (DMD) is complicated because these patients are more sensitive to nondepolarizing neuromuscular blocking agents (NMBAs) and are vulnerable to postoperative complications, such as postoperative residual curarization and respiratory failure. Sugammadex is a new reversal agent for aminosteroidal NMBAs, but its safety in children is controversial.

CLINICAL FEATURES

An 11-year-old boy with DMD underwent general anesthesia for a percutaneous nephrolithotomy. We used rocuronium bromide and sugammadex to reverse the deep neuromuscular block. Reversal of neuromuscular block was done 15 minutes after administration of 2 mg/kg of sugammadex. The patient's recovery from anesthesia was uneventful, and he was discharged to the postoperative recovery ward.

CONCLUSION

A delayed recovery was achieved, but no adverse events were observed, such as recurarization or hypersensitivity to sugammadex. We report safe use of 2 mg/kg of sugammadex to reverse a deep neuromuscular block in a child with DMD.

Case Report: Red Urine After Day Care Strabismus Surgery

In the absence of surgery on the urinary tract, the emission of red urine after anesthesia should be considered as a diagnostic emergency because it can be a sign of hematuria, hemoglobinuria, blood transfusion reaction, significant myoglobinuria, or porphyria.This case describes the management of a 12-year-old boy who presented red urine at the day care unit after strabismus surgery.

Combined Right Ventricular Outflow Tract Epicardial and Endocardial Late Potential Ablation for Treatment of Brugada Storm: A Case Report and Review of the Literature

A 34-year-old man with Brugada syndrome (BrS) presented with electrical storm, manifested as multiple appropriate shocks from his implantable cardioverter-defibrillator over a period of 7 hours. He had not tolerated prior treatment with quinidine, and had self-discontinued cilostazol citing persistent palpitations. After stabilization with intravenous isoproterenol, an electrophysiology study was performed but no spontaneous or induced ventricular ectopic beats were identified. A three-dimensional (3D) endocardial electro-anatomic map of the right ventricular outflow tract (RVOT), pulmonic valve, and pulmonary artery, as well as a 3D epicardial map of the RVOT, were created. Low voltage, complex, fractionated electrograms and late potentials were targeted for irrigated radiofrequency ablation both endocardially and epicardially. Post-procedure, he was maintained on cilostazol (referring clinician preference), and has had no further ventricular tachyarrhythmia episodes over the past forty-one months. We propose that this novel ablation strategy may be useful for acute management of selected patients with BrS.

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.

Neuromuscular conditions associated with malignant hyperthermia in paediatric patients: A 25-year retrospective study

Malignant Hyperthermia (MH) is a rare pharmacogenetic syndrome that can be fatal and the risk of MH in non RYR1-related disorders is unknown. We conducted a retrospective study to determine the prevalence of neuromuscular disorders among patients with MH at our centre. Patients who were admitted to the Hospital for Sick Children during the study period of January 1, 1990 to April 1, 2015 with a CK level > 8000 IU/L, or who received dantrolene, or who had a clinical diagnosis of MH were included. Medical records of 166 patients who met the inclusion criteria were reviewed and 13 patients were identified with MH-like reactions. Nine patients were classified as having true MH after review of the anaesthesia record and genetic testing results were available for 7 patients, 5 of whom had mutations in RYR1. Of the four patients who had severe reactions to anaesthesia but did not meet the criteria for true MH, two had Duchenne muscular dystrophy (DMD). In this retrospective study over 25 years, RYR1 mutations were the most common cause of MH in our cohort, and of these, one third had an underlying neuromuscular diagnosis. Genetic testing of RYR1 is indicated for all patients with MH, and anaesthetic precautions should be considered for any child with symptoms of neuromuscular disease.

Imperatives for DUCHENNE MD: a Simplified Guide to Comprehensive Care for Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a progressive, life-limiting muscle-wasting disease. Although no curative treatment is yet available, comprehensive multidisciplinary care has increased life expectancy significantly in recent decades. An international consensus care publication in 2010 outlined best-practice care, which includes corticosteroid treatment, respiratory, cardiac, orthopedic and rehabilitative interventions to address disease manifestations. While disease specialists are largely aware of these care standards, local physicians responsible for the day-to-day care of patients and families may be less familiar. To facilitate optimal care, a one-page document has been generated from published care recommendations, summarizing the key elements of comprehensive care for people living with DMD ("Imperatives for Duchenne muscular dystrophy). This document was developed through an international collaboration between Parent Project Muscular Dystrophy (PPMD), United Parent Projects Muscular Dystrophy (UPPMD) and TREAT-NMD.

Update on neuromuscular disorders in pediatric orthopaedics: Duchenne muscular dystrophy, myelomeningocele, and cerebral palsy

The purpose of this seminar was to review a large range of lower extremity and neuromuscular disorders. Because of the diversity of the topics covered, including clubfoot and vertical talus treatment, management of Legg-Calve-Perthes disease, and limb lengthening in dwarfism, this review will focus on the neuromuscular subsection reviewing the current management of the muscular dystrophies, myelomeningocele, and cerebral palsy.

Pharmacologic management of Duchenne muscular dystrophy: target identification and preclinical trials

Duchenne muscular dystrophy (DMD) is an X-linked human disorder in which absence of the protein dystrophin causes degeneration of skeletal and cardiac muscle. For the sake of treatment development, over and above definitive genetic and cell-based therapies, there is considerable interest in drugs that target downstream disease mechanisms. Drug candidates have typically been chosen based on the nature of pathologic lesions and presumed underlying mechanisms and then tested in animal models. Mammalian dystrophinopathies have been characterized in mice (mdx mouse) and dogs (golden retriever muscular dystrophy [GRMD]). Despite promising results in the mdx mouse, some therapies have not shown efficacy in DMD. Although the GRMD model offers a higher hurdle for translation, dogs have primarily been used to test genetic and cellular therapies where there is greater risk. Failed translation of animal studies to DMD raises questions about the propriety of methods and models used to identify drug targets and test efficacy of pharmacologic intervention. The mdx mouse and GRMD dog are genetically homologous to DMD but not necessarily analogous. Subcellular species differences are undoubtedly magnified at the whole-body level in clinical trials. This problem is compounded by disparate cultures in clinical trials and preclinical studies, pointing to a need for greater rigor and transparency in animal experiments. Molecular assays such as mRNA arrays and genome-wide association studies allow identification of genetic drug targets more closely tied to disease pathogenesis. Genes in which polymorphisms have been directly linked to DMD disease progression, as with osteopontin, are particularly attractive targets.

The kalaemic and neuromuscular effects of succinylcholine in centronuclear myopathy: A pilot investigation in a canine model

BACKGROUND

Myopathies are generally considered to increase the risk for succinylcholine-induced hyperkalaemia and may affect the duration of action of neuromuscular blockers. Centronuclear (myotubular) myopathy (CNM) is congenital and produces various degrees of muscular weakness and associated complications such as respiratory failure. The effects of succinylcholine and the potentially lethal consequences of hyperkalaemia on patients with CNM are unknown due to its rarity. One source of information is the dog, as CNM occurs naturally in dogs. Because of its remarkable similarity with the disease in man, canine CNM can serve as a model to further our knowledge of the effects of succinylcholine.

OBJECTIVES

We examined the kalaemic and neuromuscular effects of succinylcholine in dogs with and without autosomal-recessive CNM.

DESIGN

A prospective, experimental study.

SETTING

Anaesthesiology laboratory, College of Veterinary Medicine, Cornell University, New York, USA.

PATIENTS

Six dogs with autosomal-recessive CNM and six control dogs.

INTERVENTIONS

Dogs received succinylcholine 0.3 mg kg during isoflurane anaesthesia.

MAIN OUTCOME MEASURES

Whole blood potassium concentration was measured 5 min before and after succinylcholine administration. Neuromuscular function was measured with acceleromyography and single twitch stimulation.

RESULTS

All dogs recovered uneventfully from anaesthesia. The increase in potassium concentration [mean (SD)] following succinylcholine was similar between groups: CNM 0.5 (0.4) mmol l and control 0.7 (0.4) mmol l (P = 0.47). Recovery of the single twitch to 25, 75 and 90% was longer in the CNM group (all P < 0.001); 90% recovery took 35.5 (1.18) min for the CNM group and 23.3 (1.68) min for the control group.

CONCLUSION

CNM did not exacerbate the increase in blood potassium that is ordinarily seen with succinylcholine. Recovery from succinylcholine was nearly 50% longer in dogs with CNM. Although our sample size is too small to evaluate the incidence of succinylcholine-induced hyperkalaemia, extrapolation of these findings suggests that increased duration of action should be expected if succinylcholine is given to a patient with autosomal-recessive CNM.

Malignant hyperthermia in a 3-year-old child with microstomia

Freeman-Sheldon syndrome is a congenital disorder that has been suggested to be associated with malignant hyperthermia. Clinical features of the Freeman-Sheldon syndrome include flexion contractures and characteristic facial features, including microstomia and a whistling shape to the lips. We report a case of malignant hyperthermia in a 3-year-old girl with microstomia but no other features of Freeman-Sheldon syndrome. The purpose of this report was to review the diagnosis and treatment of malignant hyperthermia as craniofacial surgeons have an increased exposure to this rare and potentially fatal condition.

The preoperative neurological evaluation

Neurological diseases are prevalent in the general population, and the neurohospitalist has an important role to play in the preoperative planning for patients with and at risk for developing neurological disease. The neurohospitalist can provide patients and their families as well as anesthesiologists, surgeons, hospitalists, and other providers guidance in particular to the patient's neurological disease and those he or she is at risk for. Here we present considerations and guidance for the neurohospitalist providing preoperative consultation for the neurological patient with or at risk of disturbances of consciousness, cerebrovascular and carotid disease, epilepsy, neuromuscular disease, and Parkinson disease.

Rhabdomyolysis: review of the literature

Rhabdomyolysis is a serious and potentially life threatening condition. Although consensus criteria for rhabdomyolysis is lacking, a reasonable definition is elevation of serum creatine kinase activity of at least 10 times the upper limit of normal followed by a rapid decrease of the sCK level to (near) normal values. The clinical presentation can vary widely, classical features are myalgia, weakness and pigmenturia. However, this classic triad is seen in less than 10% of patients. Acute renal failure due to acute tubular necrosis as a result of mechanical obstruction by myoglobin is the most common complication, in particular if sCK is >16.000 IU/l, which may be as high as 100,000 IU/l. Mortality rate is approximately 10% and significantly higher in patients with acute renal failure. Timely recognition of rhabdomyolysis is key for treatment. In the acute phase, treatment should be aimed at preserving renal function, resolving compartment syndrome, restoring metabolic derangements, and volume replacement. Most patients experience only one episode of rhabdomyolysis, mostly by substance abuse, medication, trauma or epileptic seizures. In case of recurrent rhabdomyolysis, a history of exercise intolerance or a positive family history for neuromuscular disorders, further investigations are needed to identify the underlying, often genetic, disorder. We propose a diagnostic algorithm for use in clinical practice.

Pediatric ambulatory anesthesia

Pediatric patients often undergo anesthesia for ambulatory procedures. This article discusses several common preoperative dilemmas, including whether to postpone anesthesia when a child has an upper respiratory infection, whether to test young women for pregnancy, which children require overnight admission for apnea monitoring, and the effectiveness of nonpharmacological techniques for reducing anxiety. Medication issues covered include the risks of anesthetic agents in children with undiagnosed weakness, the use of remifentanil for tracheal intubation, and perioperative dosing of rectal acetaminophen. The relative merits of caudal and dorsal penile nerve block for pain after circumcision are also discussed.