Myaesthenia Gravis: An Anaesthetic Challenge

Abstract

Myaesthenia gravis (MG) is a chronic autoimmune neuromuscular disorder characterized by fluctuating skeletal muscle weakness that worsens with exertion and improves after a period of rest Keywords: myasthenia gravis, respiratory muscle weakness, anticholinesterase medicationCase Report A 78year old male, weighing 65kgs, known case of myasthenia gravis (Osserman IIa) presented for cholecystectomy with CBD exploration. He was on tablet. Pyridostigmine 60 mg twice daily. He had been treated conservatively for cholangitis and had undergone endoscopic retrograde cholangio pancreaticography (ERCP) with biliary stenting ten days prior. Other complaints included urinary incontinence (for which he was on tab. Urimax-D once daily) and dyspnoea on exertion (NYHA grade II). General and systemic examination were unremarkable except for pallor and decreased breath-holding time(~12-13seconds).Airway examination revealed anticipated difficult intubation due to heavy jaw, Mallampatti grade III and multiple artificial fixed dentures in both jaws. Routine haematological investigations were within normal limits except haemoglobin 8.0gm%.He had left anterior hemiblock on ECG and moderate obstruction on pulmonary function test (PFT). Chest radiograph revealed increased broncho-vascular markings with few calcific granulomas. Echocardiography showed ejection fraction 55% with diastolic dysfunction and concentric left ventricular hypertrophy. The patient was taken up for surgery after correcting anaemia and optimizing with nebulisations. High risk consent was taken and ICU bed and ventilator were kept available.