IV immunoglobulin (IVIG), which is composed of >95% immunoglobulin G (IgG) with lesser amounts of IgA and negligible amounts of IgM, is used to treat a variety of immune-mediated neurological disorders. However, the degree of evidence supporting the use of IVIG varies based on the neurological disorder.
The American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM), a professional organization that works to ensure quality neuromuscular (NM) and electrodiagnostic care for all patients, recently updated its 2009 consensus statement on the use of IVIG in the treatment of NM disorders.
A systematic review was performed using Ovid MEDLINE, Ovid Embase, and Ovid Cochrane Central Register of Controlled Trials searching from January 1, 2008, through July 19, 2021 (and updated again in November 2022) for randomized, controlled trials on the use of IVIG in the management of various NM disorders, including adult Guillain Barre syndrome (GBS), pediatric GBS, Miller-Fisher Syndrome (MFS; a rare variant of GBS), chronic inflammatory demyelinating polyneuropathy (CIDP; a progressive weakness and reduced senses in the extremities due to damage to the myelin sheath), multifocal motor neuropathy (MMN; rare, acquired progressive muscle disorder characterized by asymmetric weakness in the hands without sensory problems), paraproteinemic neuropathy (PPN; monoclonal gammopathy of unknown significance), chronic autoimmune large fiber neuropathy (which manifests as loss of joint position and vibration sense and sensory ataxia), and small fiber neuropathy (SFN; e.g., diabetic neuropathy that presents as dysautonomia and may involve sweating, disturbances in vision and in the cardiovascular, gastrointestinal, and genitourinary systems).
The AANEM also searched for randomized, controlled trials on the use of IVIG in the management of myasthenia gravis (MG), Lambert-Easton myasthenic syndrome (LEMS; a rare disorder of the NM junction), dermatomyositis (an inflammatory condition characterized by muscle weakness and a distinctive rash), inclusion body myositis (IBM; an inflammatory myopathy characterized by chronic, progressive muscle inflammation and weakness initially presenting with involvement of the finger flexors and quadricep muscle and causing marked dysphagia that is diagnosed by antibodies against cytosolic 5'-nucleotidase IA), necrotizing autoimmune myopathy (NAM; which is characterized by myofiber necrosis and myositis-specific antibodies and is associated with necrotizing myopathy from statins), polymyositis (which is now being reclassified into other myopathies), postpolio syndrome (PPS), dysautonomia, diabetic lumbosacral radiculoplexopathy (DLRP; an asymmetric lower extremity neuropathy resulting from ischemia and microvasculitis seen in patients with diabetes), idiopathic brachial plexopathy (or neuralgic amyotrophy; an inflammatory disorder of the brachial plexus), and Stiff-person syndrome (SPS; autoimmune neurological disorder associated with muscle stiffness and painful spasms).
For NM disorders that were not included in the 2009 consensus statement, a search was performed from January 1990 through July 19, 2021, with an update in November 2022. A review was also conducted of clinical studies incorporated into the 2009 consensus statement, and only those that constituted class I or class II evidence were included.
When data are available, the consensus compares IVIG to plasma exchange, corticosteroids, and/or placebo. It also discusses adverse events (AEs), which may depend on the brand of IVIG administered, rate of infusion, dose, history of adverse events to previous infusions, or on certain comorbidities, including postural tachycardia syndrome. AEs may range from mild (e.g., headache, fatigue, dizziness, flu-like symptoms to serious (e.g., renal failure, hypotension, aseptic meningitis, hemolytic anemia, and encephalopathy).
The consensus statement concluded that IVIG is beneficial in adult GBS, pediatric GBS (but plasma exchange may be more effective in rapidly progressing disease), CIDP, MMN, MG exacerbations, LEMS, dermatomyositis, and SPS.
There was insufficient evidence to recommend the use of IVIG in MFS, PPN, chronic autoimmune large fiber neuropathy, dysautonomia, DLRP, and idiopathic brachial plexopathy. While there is insufficient evidence for the use of IVIG in NAM, due to its aggressive nature and recommendations for use in an international consensus guideline, IVIG is considered second-line in statin-induced NAM.
IVIG is either not effective or there is insufficient evidence in SFN, depending on the etiology of the neuropathy. IVIG is not recommended for IBM and PPS.
As pharmacists continue to deal with IVIG drug shortages, they should be a familiar with the appropriate use of IVIG in NM disorders to appropriately advise on which patients would benefit most from the limited supply of the immunological agent.
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