Morvan syndrome (MvS) is a rare constellation of neurological symptoms with peripheral nerve hyper-excitability, autonomic instability, and encephalopathy. It is an auto-immune disease with antibodies against voltage-gated potassium channel complex (VGKC). Here, we are describing our experience of successful anesthetic management of a patient with MvS scheduled for right upper limb debridement.
An 83-year-old male patient was scheduled for debridement because of cellulitis of the right upper limb. He was a known case of MvS with fronto-temporal dementia with a right middle cerebral artery (MCA) infarct with left-sided hemiparesis.
Pre-operatively, the patient was drowsy and irritable, with a Glasgow coma scale (GCS) of 11 (E3V3M5). He was taking IV diltiazem 30 mg three times a day for rate control because of atrial fibrillation, and tablet dabigatran 110 mg for MCA infarction. Transthoracic echocardiography (TTE) revealed a 60% left ventricular ejection fraction (LVEF) with grade 3 diastolic dysfunction.
All standard ASA monitors were attached to the patient in the operating room, emergency cardiac drugs were arranged, and defibrillator pads were placed on the patient's chest. The patient was sedated with fentanyl and etomidate, and after achieving the desired level of anesthesia, a size 4 gel was inserted. Air, oxygen, and sevoflurane were used to maintain anesthesia. The procedure lasted 70 minutes and was uneventful. Post-operative analgesia was given in the form of paracetamol 1 gm intravenously thrice a day.
MvS is a rare neuromyotonia disorder that was first described in 1890 by Augustine Marie Morvan. It is distinguished by hyper-activity of the central, autonomic, and peripheral nervous systems. The etiology is either auto-immune or the result of a para-neoplastic syndrome. Patients with auto-immune etiology are more commonly associated with thymoma and have very good clinical responses to immuno-therapy.
There is a scarcity of literature on the safe administration of anesthesia in a patient with MvS, with only two case reports published to date depicting its anesthetic management. The most common intra-operative concerns are spontaneous laryngeal spasms caused by neuromyotonia and hyper-excitability caused by potassium channel abnormalities. As many of these patients are usually associated with thymoma, auto-antibodies against the acetylcholine receptor (AChR) can cause variable responsiveness to non-depolarizing neuro-muscular blockade. Thus, we decided to avoid muscle relaxants in our patient. Brachial plexus nerve block could be the procedure of choice if the patient was not on an oral anti-coagulant.
Thus, we can conclude that with vigilance, a multi-disciplinary approach, and thoughtful pharmacologic administration, the anesthesiologist can minimize intra-operative risks in MvS while facilitating safe surgical practice.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
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