Successful administration of electroconvulsive therapy in a patient with treatment-resistant schizophrenia and coexisting myasthenia gravis

Sir,

Electroconvulsive therapy (ECT) is an efficacious treatment for resistant schizophrenia.[1] However, the presence of comorbid myasthenia gravis (MG) poses considerable challenge and concerns for administering anesthesia during ECT.[2] To the best of our knowledge, till date, there is only a solitary case reporting the use of ECT in schizophrenia with coexisting MG.[3] Hence, in this case report, we describe successful administration of modified ECT under anesthesia in a patient with treatment-resistant schizophrenia with MG.

CASE REPORT

Ms. A, a 32-year-old female, presented with 5 years of second person commanding auditory hallucinations, delusion of control, and delusion of persecution. She had a poor response on risperidone 6 mg/day for 2 months, olanzapine 15 mg/day for 2 months, and lurasidone 80 mg/day for 4 months. She had a history of hypothyroidism (on thyroxine 75 μg/day) and seropositive (anti-acetylcholinesterase antibody [anti-AChAb] – 21.42 nmol/L [positive >0.4 nmol/L]) generalized MG of 7-year duration. She had undergone thymectomy for MG, and symptoms were under control on oral mycophenolate mofetil 1500 mg/day and pyridostigmine 270 mg/day.

She was diagnosed as having schizophrenia as per the international classification of diseases. Considering the treatment resistance, she was started on clozapine which was increased up to 500 mg/day and later augmented with risperidone 4 mg/day and then aripiprazole 20 mg/day, but the patient continued to have auditory hallucinations (Scale for the Assessment of Positive Symptoms [SAPS]-22, Scale for the Assessment of Negative Symptoms [SANS]-20, and Auditory Hallucinations Rating Scale[4] [AHRS]-34). In view of coexisting MG, noninvasive brain stimulation by inhibiting temporoparietal junction was attempted with transcranial direct current stimulation (10 sessions) and thereafter with repetitive transcranial magnetic stimulation (24 sessions).

As distressing commanding auditory hallucinations persisted despite the above treatments, we considered ECT. A detailed preanesthetic evaluation with bedside pulmonary function testing was conducted to ascertain good pulmonary reserve. Plasma pseudocholinesterase levels and anti-AChAb levels were 11.2 U/ml (normal – 4.65–10.44 U/ml) and 8.8 nmol/L, respectively. This was to ensure remission of MG before administering succinylcholine. During the ECT, precautions were taken to achieve adequate muscle relaxation, and the patient was closely monitored to prevent prolonged apnea. We avoided atropine during ECT to prevent cholinergic crises as the patient was on treatment with physostigmine.

She received nine sessions of modified bifrontal ECT on alternate day, three times a week with a charge of 240 mC (at 1.5 times suprathreshold). Intravenous thiopentone 120 mg and succinylcholine 25 mg were used as anesthetic and muscle relaxing agents, respectively. She showed significant improvement in hallucinations (AHRS-22, SAPS-12, and SANS-20); first five sessions of bimonthly maintenance ECTs were given which reduced to 3 monthly sessions thereafter before stopping ECTs. The patient complained of nausea and dizziness on days of ECT in 7 of the total 17 sessions, which were managed symptomatically. Nausea is one of the common self-limiting side effects following ECT and is probably unrelated to MG[5] and possibly secondary to prolonged fasting or anesthetic procedure. It was symptomatically managed with antiemetics. No other adverse events were noted, and over the next 2 months, neurologist reduced physostigmine to 210 mg/day. In follow-up after 14 months of ECT, the patient's MG is in remission and maintains significant improvement with occasional hallucinations and good functional recovery.

DISCUSSION

To the best of our knowledge, this is the second case report demonstrating successful and safe administration of ECT in a patient with schizophrenia with coexisting MG. Although ECT is an effective augmentation strategy in clozapine-resistant schizophrenia,[1] in view of the risks associated with MG, we did not consider ECT initially. Due to refractory symptoms, ECT under general anesthesia was considered, and the patient had significant reduction in hallucinations. One previous case report described a patient with MG with schizophrenia receiving up to 20 ECT sessions[3] and nine case reports with concomitant other psychiatric disorders.[2] Our report further adds to the existing literature and indicates that with due precautions, ECT can be safely administered in patients with comorbid MG.

While the current case report was in a patient with schizophrenia with comorbid MG, the principles and precautions to be taken during administration of ECT in the patient with MG are applicable to other psychiatric diagnosis as well. The interaction of depolarizing muscle relaxants and acetylcholinesterase inhibitors used for the treatment of MG could lead to prolonged apnea[2] and asystole.[6] However, succinylcholine, a depolarizing neuromuscular blocker, has been shown to be safe if MG is under remission,[7] which was the case in our patient. There is also a risk of precipitating myasthenic crisis with rigorous physical activity occurring during the electroconvulsive therapy if used without adequate muscle relaxation. Ensuring remission of MG before administering succinylcholine, achieving adequate muscle relaxation, close monitoring for prolonged apnea, and avoiding atropine to prevent cholinergic crises during an ongoing anticholinesterase (like pyridostigmine) treatment are recommended while administering ECT in MG.

To summarize, ECT can be safely administered in patients with coexisting MG with due precautions. However, one needs to be cautious in choosing the medications for muscle relaxation during ECT. Succinylcholine appears to be a safe agent for neuromuscular block if MG is under reasonable remission.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.