The Role of IVIG in Neuromuscular Disease

CLINICAL UPDATE
Source: van der Meche FGA, van Doorn PA. The current place of high-dose immunoglobulins in the treatment of neuromuscular disorders. Muscle Nerve 1997;20:136-147.

Intravenous immunoglobulin (ivig) is a powerful agent in the treatment of a host of neuromuscular conditions.

Inflammatory myopathies: Patients with polymyositis (PM) and dermatomyositis (DM), including children with DM refractory to conventional therapy (e.g., prednisone, azathioprine) have, in open trials, and in one placebo-controlled randomized trial in DM, shown benefit from IVIG. Overall, 75% of patients improved. Despite conflicting reports, inclusion body myositis does not appear to respond (Cherin P, et al. Am J Med 1991;91:162-168; Lang BA, et al. Am J Med 1991;91:169-172; Dalakas MC, et al. N Engl J Med 1993;329:1993-2000; Amato AA, et al. Neurology 1994;44:1516-1518; Dalakas MC, et al. Neurology 1995;45:(S)208 [abstract]).

Immune mediated neuromuscular junctionopathies: Overall response rate to IVIG in myasthenia gravis is approximately 75%, a result comparable to that which follows plasma exchange (PE). Improvement begins in the first week of therapy but lasts only 7-9 weeks. Not all patients respond, and some are refractory both to IVIG and PE. Lambert-Eaton myasthenic syndrome also appears to respond to IVIG, with clinical improvement correlating with reduced levels of P/Q-type calcium-channel antibodies (Cosi V, et al. Acta Neurol Scand 1991;84:81-84; Stricker RB, et al. Arch Neurol 1993;50:837-840; Uchiyama M, et al. Ann NY Acad Sci 1987;505:868-871; Bain PG, et al. Neurology 1996;47:678-683).

Guillain-Barré syndrome: Please refer to "What’s best for GBS?" in the April 1997 issue of Neurology Alert.

Chronic inflammatory demyelinating polyneuropathy (CIDP): Randomized placebo-controlled studies have demonstrated IVIG and prednisone to be equally effective, with a favorable response in about two-thirds of cases. Despite the added cost of IVIG, its simplicity and lack of long-term complications make it preferable to prednisone (van Doorn PA, et al. Neurology 1990;40:209-212; Dyck PJ, et al. Ann Neurol 1994;36:838-845).

Multifocal motor neuropathy (MMN): Placebo-controlled randomized studies have demonstrated that IVIG benefits up to 86% of MMN patients (Azulay J-P, et al. Neurology 1994;44:429-432; van den Berg LH, et al. J Neurol Neurosurg Psychiatry 1995;59:248-252). Improvement appears by the end of the first week of therapy, increases for the first month, but then wanes in subsequent months. Interval therapy may be necessary to maintain the benefit. —mr