Multiple sclerosis: Periop mgmt

Multiple Sclerosis is an autoimmune disease of inflammation, demyelination, and axonal damage to the central nervous system(Pasternak, 2008; Dorotta, 2002). The disease progression may be subacute with relapses and remissions or chronic and progressive. Treatments include corticosteroids, Interferon-beta, glatiramer acetate, azathioprine, and low-dose mexthotrexate. Although exacerbations can be triggered by physical and emotional stress, exacerbations and remissions often occur unpredictably.

In the pre-operative evaluation, a thorough baseline neurologic history and exam should be performed. Patients on corticosteroid therapy should continue therapy and may require stress dosing. General anesthesia is most often used in patients with multiple sclerosis. The anesthesiologist should closely monitor temperature and minimize increases above baseline as even slight increases in body temperature may precipitate a decline in neurologic function postoperatively. In addition, one should usesuccinylcholine judiciously as demyelination and denervationmay increase the risk of succinylcholine-induced hyperkalemia in these patients (Dorotta, 2002).Nondepolarizing neuromuscular blockers are safe to use although patients with multiple sclerosis may have altered sensitivity to these drugs in the setting of baseline limb weakness. They may also have limited ‘physiologic reserve’ (neurologic and respiratory) and be less able to tolerate stressors such as a mild degree of post-operative residual muscle relaxant (Dorotta, 2002). Some multiple sclerosis patients, such as those with baseline weakness or pharyngeal dysfunction, will require extended monitoring and care postoperatively. As in other patients with chronic brain injury, patients with MS may be expected to have some MAC reduction and delayed emergence proportionate to the severity of their disease.

In terms of regional anesthesia, both spinal and epidural anesthesia has been successfully employed in parturients with multiple sclerosis (Perlas, 2005).In some studies, spinal anesthesia has been implicated in postop exacerbations whereas epidural and peripheral nerves blocks have not. One theory is that demyelination of the spinal cord makes it more susceptible to the neurotoxic effects of local anesthetics and the concentration of local anesthetic in the white matter of the spinal cord is higher following a spinal compared to an epidural.There is very little evidence to support or refute the concerns regarding spinal anesthesia(Martucci et al., 2011).

Finally, regardless of anesthetic technique, worsening of multiple sclerosis symptoms is experienced by 20-30% of women in the post-partum period. Whether this is due to a reversal of the pregnancy-induced ‘immunotolerant’ state or other factors is not entirely clear (Dorotta, 2002).