P061: PERIOPERATIVE CONSIDERATIONS OF JUVENILE MYASTHENIA GRAVIS: A CASE REPORT AND REVIEW OF LITERATURE
Cameron Lambert, DO; Luis Rodriguez, MD; Jackson Memorial Hospital/University of Miami
Introduction: Myasthenia gravis (MG) is a rare autoimmune disorder characterized by a decrement in postsynaptic acetylcholine receptors at the neuromuscular junction secondary to their destruction or inactivation by circulating IgG antibodies. There are four basic strategies in treatment including increasing ACh at NMJs cholinesterase inhibitors, immunosuppression, intravenous immunoglobulins (IVIG), and, specifically in juvenile MG, thymectomies due to the hyperplastic nature of the thymus in this population. Patients with MG are at risk for developing exacerbations of the disease known as a myasthenic crisis with a relative decrease in ACh at the NMJ from their baseline, or a cholinergic crisis produced by an excess of ACh.
Management of pediatric patients with myasthenia gravis depends on a sound understanding of pathophysiology of the disease and the specific pharmacologic interactions of routine anesthetic drugs.
Methods: This paper provides a case report regarding a pediatric patient with juvenile myasthenia gravis in an acute exacerbation undergoing a surgical procedure with applicable review of literature pertaining to the pathophysiology, applied pharmacology, and perioperative considerations in regards to the anesthetic management.
Results: A 12 year-old male with a history of juvenile myasthenia gravis status post thymectomy was admitted for MG exacerbation after missed scheduled IVIG secondary to port malfunction and infection. Patient was scheduled for removal and repeat port placement while in MG exacerbation.
General anesthesia was induced with propofol, fentanyl, and lidocaine. Intubating conditions were achieved appropriately without the presence of a neuromuscular blockade. Sevoflurane and dexmedetomidine were used for maintenance anesthesia. Spontaneous ventilation was maintained and the surgical procedure was successful and uneventful. Patient was safely extubated and recovered appropriately with close monitoring for potential MG exacerbation symptoms.
Discussion: Thorough preoperative assessment and preoptimization is critical in patients with juvenile myasthenia gravis. This includes a full through history of the disease itself, review of relevant labs and exams, and appropriate multidisciplinary approach in order to optimize the patient for surgery, a known exacerbation risk of the disease. A proper preoperative physical exam is key to assess the severity of respiratory and bulbar function to relate to a postoperative exam. Cholinesterase and immunosuppressive drugs should be held the day of surgery and in severe cases pretreatment with IVIG or plasmapheresis can be considered.
Intraoperatively, anesthetic technique is tailored to surgical needs although applied pharmacology to the disease must be considered. Induction for intubation with volatiles or propofol and a short acting opioid is well described in pediatric MG patients and was the method of choice in this case. Neuromuscular blockade is controversial, and is typically avoided due to increased risks of postoperative crises and lower rates of successful extubation. Many antibiotics and cardiac medications are also known to cause exacerbations and should be avoided if possible.
Postoperative planning incorporates the initial multidisciplinary approach to guide recovery. Physical exams should be routine in order to identify potential respiratory compromise. In the event of significant weakness, an edrophinum test can be used to distinguish between a myasthenic or cholinergic crisis to guide management and intubation may be considered.