This article elucidates a case report highlighting the perioperative considerations for a patient with Myasthenia Gravis undergoing laparoscopic cholecystectomy. It addresses key concerns in the preoperative, intraoperative, and postoperative periods.

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Myasthenia Gravis

Myasthenia Gravis is an autoimmune neuromuscular disorder characterised by skeletal muscle weakness and fatigue due to impaired neuromuscular transmission. It is caused by autoantibodies targeting acetylcholine receptors or related proteins at the neuromuscular junction. Patients with Myasthenia Gravis are susceptible to neuromuscular blocking agents and other anaesthetic drugs, making perioperative management challenging.

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The Case

A 52-year-old female with Myasthenia Gravis for five years, on pyridostigmine (60 mg thrice daily) and prednisone (5 mg daily), presented with symptomatic gallstone disease. She had stable disease control, no prior myasthenic crisis, and a baseline forced vital capacity (FVC) of 2.5L.

She was scheduled for an elective laparoscopic cholecystectomy (ASA 2). Preoperative evaluation revealed adequate mouth opening (Mallampati class 2), METS >4, and no signs of ptosis, diplopia, dysarthria, or dysphagia. ECG showed sinus rhythm (68 bpm) with mild left ventricular hypertrophy (LVH), and arterial blood gas (ABG) analysis revealed pH 7.4, pCO₂ 47 mmHg, HCO₃ 21 mEq/L, and pO₂ 90 mmHg.

Preoperative Management

Preoperative management included continuing pyridostigmine up to the morning of surgery and administering stress-dose corticosteroids (Hydrocortisone 100 mg IV) due to chronic steroid use. Considering the potential risk of bulbar muscle weakness, preparations were made for difficult airway management, and postoperative ICU admission was planned for close monitoring. A nerve stimulator was ensured for neuromuscular monitoring.

Intraoperative Management

1. Anesthetic Induction

1. After obtaining written and informed consent, standard ASA monitoring (ECG, SpO₂, EtCO₂, NIBP) was applied.
2. The patient was pre-oxygenated for five minutes. Induction was carried out with titrated doses of propofol (1 mg/kg) and fentanyl (2 mcg/kg).
3. Rocuronium (0.3 mg/kg) was administered cautiously for intubation, guided by neuromuscular monitoring to prevent prolonged paralysis.
4. Endotracheal intubation was performed using video laryngoscopy with a size 7.0 endotracheal tube.

2. Maintenance of Anesthesia

1. Anesthesia was maintained with sevoflurane in an oxygen-air mixture, and intraoperative analgesia was provided with intermittent doses of fentanyl and a paracetamol infusion.
2. Neuromuscular monitoring guided muscle relaxant dosing, with sugammadex readily available for complete reversal to avoid postoperative residual weakness.
3. Opioid use was minimised to prevent respiratory depression, and intra-abdominal pressure was kept below 12 mmHg to reduce diaphragmatic splinting.
4. Haemodynamic stability was maintained with adequate fluid management. The surgery lasted 45 minutes, and the intraoperative period was uneventful.

Postoperative Management

1. The patient was extubated in a fully awake state after confirming adequate neuromuscular recovery (TOF ratio > 0.9) and was shifted to the SICU for close monitoring to detect any early signs of respiratory compromise.
2. Supplemental oxygen therapy was provided with continuous SpO₂ monitoring. Postoperative analgesia was managed with multimodal analgesia using IV paracetamol and low-dose opioids as needed, while NSAIDs were avoided due to the risk of steroid-induced gastric mucosal vulnerability.
3. Respiratory monitoring included serial ABG assessments, chest physiotherapy, and incentive spirometry to prevent atelectasis, with non-invasive ventilation (NIV) kept readily available in case of respiratory deterioration.
4. The postoperative course remained uneventful, with the patient hemodynamically stable and showing no signs of myasthenic exacerbation.
5. Oral pyridostigmine was resumed six hours postoperatively, and the patient was discharged on postoperative day three with a planned follow-up.

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Discussion

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Perioperative Concerns in Myasthenia Gravis

Preoperative Concerns

Myasthenia Gravis patients exhibit variable sensitivity to muscle relaxants and anaesthetic agents, necessitating careful titration to prevent excessive neuromuscular blockade. Preoperative pulmonary function tests (PFTs) are crucial for assessing respiratory reserve and predicting the risk of postoperative respiratory failure. Continuing pyridostigmine up to the day of surgery helps maintain neuromuscular function and reduces the risk of perioperative weakness.

Intraoperative Concerns

Non-depolarising neuromuscular blockers (NMBAs) should be administered in reduced doses with continuous neuromuscular monitoring, as Myasthenia Gravis patients are highly sensitive to these agents. Volatile anaesthetics, which have inherent muscle relaxant properties, should be titrated cautiously to avoid excessive respiratory depression. Additionally, laparoscopic surgery-induced pneumoperitoneum can compromise respiratory mechanics, requiring careful intraoperative ventilatory adjustments.

Postoperative Concerns

Extubation should only be attempted after confirming full neuromuscular recovery, ensuring a Train-of-Four (TOF) ratio >0.9 to minimise the risk of postoperative respiratory failure. Myasthenic crisis can be triggered by surgical stress, infections, or incomplete reversal of muscle relaxants, necessitating close monitoring in high-risk cases. Postoperative respiratory support, including non-invasive ventilation (NIV), should be readily available for patients with significant respiratory compromise.

The anaesthetic management of Myasthenia Gravis patients undergoing laparoscopic cholecystectomy requires meticulous preoperative assessment, cautious intraoperative management with neuromuscular monitoring, and vigilant postoperative care. Avoidance of prolonged neuromuscular blockade and ensuring optimal respiratory function are key principles for successful outcomes. A multidisciplinary approach involving anesthesiologists, surgeons, and intensivists ensures patient safety.

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Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr N Chinna Siddeswarappa is an Assistant professor (Anaesthesiology dept.) at Meenakshi Medical College Hospital And Research Institute, Kanchipuram.