Anaesthetic considerations in paediatric myasthenia gravis

Ketamine-Dexmedetomidine Sedation in the Management of a Child With Generalized Refractory Myasthenia Gravis and Respiratory Insufficiency: Case Report

Myasthenia gravis (MG) is a rare autoimmune disease characterized by muscle weakness and fatigability that can be generalized with respiratory muscle involvement. The anaesthetic management of these patients poses significant challenges not only because of the nature of the disease and its possible interactions with anaesthetic drugs but also because of the risk of developing a life-threatening myasthenic crisis. We report the case of a child with generalized refractory MG and pneumonia, worsening his chronic respiratory insufficiency, proposed for an urgent thoracocentesis and chest drain placement, that was successfully managed under sedation with ketamine and dexmedetomidine, allowing to avoid a general anaesthesia, preserve the patient's respiratory drive, and protect his airway. The present report highlights the potential applicability of this novel drug association in MG patients, regarding its safety and efficacy in maintaining respiratory drive and haemodynamic stability in these patients.

Congenital Myasthenic Syndrome With Malignant Hyperthermia Susceptibility in a Child Undergoing Adenotonsillectomy for Obstructive Sleep Apnea: A Case Report

Congenital myasthenic syndromes are rare genetic diseases involving pathologic proteins in the neuromuscular junction. Malignant hyperthermia susceptibility is a genetic disorder involving a hypermetabolic response to volatile anesthetics and depolarizing neuromuscular blocking agents. We present the first reported case of a 3-year-old boy with both congenital myasthenic syndrome and malignant hyperthermia susceptibility, resulting from a mutation in the ryanodine receptor type 1 gene, who underwent an adenotonsillectomy for severe obstructive sleep apnea. We discuss the anesthetic challenges in navigating these 3 comorbidities in the setting of airway surgery.

Myasthenia Gravis and Crisis: Evaluation and Management in the Emergency Department

BACKGROUND

Myasthenia gravis (MG) is an uncommon autoimmune disorder affecting the neuromuscular junction and manifesting as muscle weakness. A multitude of stressors can exacerbate MG. When symptoms are exacerbated, muscle weakness can be severe enough to result in respiratory failure, a condition known as myasthenic crisis (MC).

OBJECTIVE

This review discusses risk factors, diagnosis, management, and iatrogenic avoidance of MC.

DISCUSSION

MC can affect any age, ethnicity, or sex and can be precipitated with any stressor, infection being the most common. MC is a clinical diagnosis defined by respiratory failure caused by exacerbation of MG. Muscle weakness can involve any voluntary muscle. MC can be differentiated from other neuromuscular junction diseases by the presence of normal reflexes, normal sensation, lack of autonomic symptoms, lack of fasciculations, and worsening weakness with repetitive motion. Treatment should target the inciting event and airway support. All acetylcholinesterase inhibitors should be avoided in crisis, including edrophonium testing and corticosteroids initially. Respiratory support can begin with noninvasive positive-pressure ventilation, as this has been successful even in patients with bulbar weakness. If intubation is necessary, consider avoiding paralytics or use a reduced dose of nondepolarizing agents.

CONCLUSIONS

MC should be in the differential of any patient with muscular weakness and respiratory compromise. Emergency department management of MC should focus on ruling out infection and respiratory support. Strong consideration should be given to beginning with noninvasive positive-pressure ventilation for ventilatory support. Corticosteroids, depolarizing paralytics, and acetylcholinesterase inhibitors should be avoided in patients with MC in the emergency department.

Sevoflurane and thoracic epidural anesthesia for trans-sternal thymectomy in a child with juvenile myasthenia gravis

Literature on anesthetic management of juvenile myasthenia gravis (JMG) for thymectomy is limited. Recently, use of inhalational agents and total intravenous anesthesia with propofol and remifentanyl has been reported. All these techniques individually or in combination have been tried to avoid the use of muscle relaxant. We report successful use of sevoflurane as sole anesthetic agent for intubation and in combination with thoracic epidural anesthesia for intraoperative anesthetic management in a 5-year-old child with JMG.