Is electroconvulsive therapy safe in multiple sclerosis?

To the Editor

Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating disease with accompanying neurological symptoms and an increased prevalence of mood disorders, including bipolar disorder (Palm et al., 2014). Electroconvulsive therapy (ECT) is a well-established treatment for mood disorders but is infrequently administered to MS patients due to a perceived risk of worsening MS lesions (Urban-Kowalczyk et al., 2014). We present a case of MS and bipolar depression which responded well to ECT with no complications and discuss the safety of ECT in MS.

Mrs M is a 61-year-old woman with a well-established history of bipolar disorder and a 26-year history of secondary progressive MS managed with glatiramer and baclofen. After an acute flare of MS, she had a depressive relapse that was difficult to treat, resulting in polypharmacy (paroxetine, agomelatine, lithium and olanzapine). Given the severity of her depressive episode and emergence of psychotropic side effects, she was admitted for consideration of ECT after medication rationalisation. She received 10 bifrontal treatments to good effect. She was initially hyperkalaemic and thus administered rocuronium with sugammadex reversal for muscle relaxation to avoid suxamethonium-induced hyperkalaemia, which is more pronounced in MS (Fitzsimons et al., 2007). Throughout her admission, there was no worsening of neurological symptoms or baseline cognition.

ECT might not be favoured in MS due to anaesthetic complications and potential neurological deterioration. Suxamethonium, the traditional muscle relaxant used in ECT, is associated with a higher risk of hyperkalaemia in MS and thus a non-depolarising muscle relaxant is preferred (Fitzsimons et al., 2007). For Mrs M, rocuronium was chosen for its fast onset of action, with specific and predictable reversal by sugammadex.

Despite a perceived concern that ECT in the setting of MS can worsen neurological symptoms, the risk is low and the mechanism unknown (Urban-Kowalczyk et al., 2014). Of the 21 cases published, 80% experienced no neurological deterioration. Palm et al. (2014) report four patients developing neurological complications including localised muscle weakness, gait disturbances, transient hemiparesis and delirium. Only two patients did not respond to ECT.

ECT is a safe and effective treatment option in MS patients with bipolar depression and should be utilised earlier in the treatment course, reducing the potential for polypharmacy. When considering ECT in MS, suxamethonium may not be appropriate given the increased risk of hyperkalaemia. A safe alternative to consider is rocuronium with sugammadex reversal.