Diagnosis and Treatment of Chronic Immune-mediated Neuropathies

Intravenous immunoglobulin for treatment of neuromuscular disease

Intravenous immunoglobulin (IVIg) has been widely used in the treatment of autoimmune neuromuscular diseases. Compared to other treatment modalities, such as corticosteroids and chemotherapy for autoimmune disorders, IVIg has relatively few side effects and favorable therapeutic outcomes in certain neuromuscular diseases. There is Class I evidence for IVIg as an initial treatment for patients with Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), and multifocal motor neuropathy. It is as effective as plasma exchange in GBS and CIDP. In myasthenia gravis, IVIg is used for myasthenic crisis and exacerbations, though it is also helpful as maintenance therapy, particularly in patients with a suboptimal response or contraindications to prednisone or other immunosuppressive agents. IVIg has been demonstrated to be beneficial in placebo-controlled, double-blind, randomized studies in dermatomyositis and Lambert-Eaton syndrome. IVIg has also been beneficial in select patients with polymyositis and other autoimmune peripheral neuropathies. Clinical trials in amyotrophic lateral sclerosis, inclusion body myositis, and anti-myelin-associated glycoprotein neuropathy have been negative.

Coincident membranous glomerulonephritis and chronic inflammatory demyelinating polyradiculoneuropathy: Questioning the autoimmunity hypothesis

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and membranous glomerulonephritis (MGN) are both autoimmune disorders that are rarely observed concurrently. We describe a patient who developed MGN nearly 20 years after the onset of CIDP, resulting in a secondary progression of his neuropathy. He responded dramatically to a novel regimen of plasma exchange and methotrexate. We propose a mechanism other than autoimmunity for the coincidence of these disorders and discuss the theoretical superiority of the treatment regimen that he received.

Prevalence and characteristics of immunomediated neuropathies in a group of patients with autoimmune diseases

OBJECTIVE

To determine the prevalence and the clinical-neurophysiological characteristics of immunomediated peripheral neuropathies (PN) in a group of patients with systemic autoimmune diseases.

METHOD

Fifty-nine patients with proved systemic autoimmune diseases were included. Patients underwent clinical examination and nerve conduction studies to diagnose the PN.

RESULTS

Immune PNs were detected in 18 patients (30.5%). Out of the total number of PNs (18), 39% were sensory-motor polyneuropathies, 33% mononeuritis multiplex, 11% pure sensory polyneuropathies, 11% cranial neuropathies, and 6% proximal motor neuropathies, such as the Guillain-Barré syndrome. Nine PNs (50%) appeared at the onset of the connective tissue disorders, and the rest of the cases appeared during the course of the disease. Of the total of PNs detected in this study, only 45% had a previous diagnosis. Vasculitis was the disease that presented more associated PNs. Systemic lupus erythematosus showed the widest range of PN clinical varieties.

CONCLUSIONS

The first national prevalence rate of PNs in patients with systemic autoimmune diseases was provided: 30.5%. No comparative data were found in the international bibliography. Sensory-motor polyneuropathy was the most frequently observed form of PN, followed by mononeuritis multiplex. The NPs appeared with the same frequency both at the onset and during the course of the diseases under study; these predominated at the onset of vasculitis and primary Sjögren syndrome. The compromise of the peripheral nervous system is underdiagnosed.

Vasculitic Neuropathies

BACKGROUND

Systemic vasculitis has been classically categorized as a primary disorder, such as polyarteritis nodosa, Churg-Strauss syndrome, and Wegener granulomatous, or as a secondary process, representing a complication from a connective tissue disorder (eg, rheumatoid vasculitis), infection, medication, or malignancy. Peripheral neuropathy is a well-recognized consequence of systemic vasculitis due to peripheral nerve infarction with Wallerian degeneration. Rarely, neuropathy is the sole manifestation of vasculitis, referred to as nonsystemic vasculitic neuropathy (NSVN). These conditions are defined pathologically by tissue biopsy demonstrating disruption or destruction of the vessel wall with inflammatory cell infiltrates.

REVIEW SUMMARY

The diagnosis of vasculitic neuropathy is straightforward in patients with an established diagnosis of systemic vasculitis and classic features of mononeuritis multiplex. Most patients have clinical features of a subacute, progressive, generalized but asymmetric, painful, sensorimotor polyneuropathy. Laboratory tests often indicate features of systemic inflammation, such as an elevated sedimentation rate or positive anti-neutrophil cytoplasmic antibody, and electrodiagnostic evaluation shows multiple mononeuropathies or a confluent, asymmetric axonal neuropathy. Nerve biopsy is necessary to establish the diagnosis in most cases, particularly in patients with NSVN. This review summarizes the current treatment of vasculitic neuropathy.

CONCLUSION

Long-term immunosuppressive therapy is required in most cases. High-dose prednisone combined with intravenous pulse or oral daily cyclophosphamide is standard initial therapy. In those with NSVN, cyclophosphamide also should be used if prednisone monotherapy is ineffective or the patient relapses with tapering. Other agents, such as azathioprine, methotrexate, intravenous immunoglobulin, mycophenolate mofetil, plasma exchange, and rituximab can be offered to patients who are intolerant or have a contraindication to cyclophosphamide. However, evidence for the benefit of these agents is limited to case reports and small case series.