Tests for neuropathy

CIDPUSA.ORG

CIDP with IgM MGU monoclonal gammopathies (eg MGUS), most frequently gammopathy of immunoglobulin M (IgM)

Evidence suggests that CIDP with IgM MGUS has specific clinical and electrophysiologic characteristics

Usually predominance of distal weakness with sensory symptoms greater than motor

Multiple sclerosis

Reports describe CNS white matter changes in patients with CIDP

Whether a true association exists between CIDP and multiple sclerosis remains unclear

Systemic lupus erythematosus

Chronic active hepatitis (B or C)

CIDP associated with hepatitis should be differentiated from cryoglobulinemic vasculitis

The latter causes either symmetric distal sensorimotor polyneuropathy or mononeuropathy multiplex but on pathologic examination shows wallerian degeneration and not the segmental demyelination seen in CIDP

Inflammatory bowel disease

CIDP has been described in association with Crohn disease and other inflammatory bowel conditions, although no direct correlation between the two afflictions is known

The mechanism of development of CIDP is presumed to be an autoimmune abnormality that is also causing the primary problem in inflammatory bowel disease, although the details are not known

Increasing evidence supports the suggestion that some patients with diabetes who have severe neuropathy or unusually progressive neuropathy may have CIDP superimposed on their diabetic disorder

Diabetes may predispose patients to CIDP

Known to worsen CIDP

Worsening usually occurs in the third trimester or in the postpartum period

CIDP: Monitoring and Prognosis

Sometimes difficult to assess the activity of a chronic neuropathy

Nerve biopsy can be used to detect active nerve lesions and inflammatory infiltrates

Axonal loss has more long-term prognostic impact than active demyelination or inflammatory infiltrates in demyelinating disorders of the peripheral and central nervous systems

The diagnosis of CIDP is typically based on the clinical presentation, absence of other causes of the neuropathic syndrome, and results of electrodiagnostic studies

Presence of increased cerebrospinal fluid (CSF) protein and demyelinating changes on nerve biopsy are supportive of the diagnosis, but these are not always present

Because of the clinical heterogeneity and the lack of a diagnostic test, various diagnostic criteria have been proposed

In one series of patients all of whom had proximal and distal weakness and in whom 95% of patients had improvement with treatment, only 30% had the classic triad of slow nerve conduction velocity, elevated CSF protein and demyelination on nerve biopsy

American Association of Neurology: Criteria

Developed criteria for the identification of patients with CIDP for research studies

Pathologic criteria

Electrophysiologic criteria: Require 3 demyelinating range abnormalities (either slow conduction velocity, prolonged distal motor latencies or F wave latencies or conduction block) in 2 nerves

Criteria are not sensitive and may miss more than 50 % of patients with CIDP

Specificity approaches 100%

Majority of patients seen in clinical practice fail to meet all of the criteria

Laboratory Studies: CSF

Protein level is increased significantly in 80% of patients

Usually between 50 and 200 mg/dL, but can be higher

10% of patients also have mild lymphocytic pleocytosis (<50 cells) and increased gamma globulin (usually associated with HIV infection)

CBC, sedimentation rate, antinuclear antibody, biochemistry profile, and serum and urine immunoelectrophoresis are necessary to exclude important associated systemic disorders
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