Segmental somatosensory-evoked potentials as a diagnostic tool in chronic inflammatory demyelinating polyneuropathies, and other sensory neuropathies

French recommendations for the management of adult & pediatric chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare autoimmune disorder of the peripheral nervous system, primarily affecting the myelin sheath. The pathophysiology of CIDP is complex, involving both humoral and cellular immunity. The diagnosis of CIDP should be suspected in patients with symmetrical proximal and distal motor weakness and distal sensory symptoms of progressive onset, associated with decreased/abolished tendon reflexes. Treatments include intraveinous immunoglobulins, steroids and plasma exchange, with usually an induction phase followed by a maintenance therapy with progressive weaning. Treatment should be rapidly initiated to prevent axonal degeneration, which may compromise recovery. CIDP outcome is variable, ranging from mild distal paresthesiae to complete loss of ambulation. There have been several breakthroughs in the diagnosis and management of CIDP the past ten years, e.g. discovery of antibodies against the node of Ranvier, contribution of nerve ultrasound and magnetic resonance imaging to diagnosis, and demonstration of subcutaneous immunoglobulins efficiency. This led us to elaborate French recommendations for the management of adult & pediatric CIDP patients. These recommendations include diagnosis assessment, treatment, and follow-up.

Motor chronic inflammatory demyelinating polyneuropathy (CIDP) in 17 patients: Clinical characteristics, electrophysiological study, and response to treatment

Motor chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare and poorly described subtype of CIDP. We aimed to study their clinical and electrophysiological characteristics and response to treatment. From a prospective database of CIDP patients, we included patients with definite or probable CIDP with motor signs and without sensory signs/symptoms at diagnosis. Patients were considered to have pure motor CIDP (PM-CIDP) if sensory conductions were normal or to have motor predominant CIDP (MPred-CIDP) if ≥2 sensory nerve action potential amplitudes were abnormal. Among the 700 patients with CIDP, 17 (2%) were included (PM-CIDP n = 7, MPred-CIDP n = 10); 71% were male, median age at onset was 48 years (range: 13-76 years), 47% had an associated inflammatory or infectious disease or neoplasia. At the more severe disease stage, 94% of patients had upper and lower limb weakness, with distal and proximal weakness in 4 limbs for 56% of them. Three-quarters (75%) responded to intravenous immunoglobulins (IVIg) and four of five patients to corticosteroids including three of three patients with MPred-CIDP. The most frequent conduction abnormalities were conduction blocks (CB, 82%) and F-wave abnormalities (88%). During follow up, 4 of 10 MPred-CIDP patients developed mild sensory symptoms; none with PM-CIDP did so. Patients with PM-CIDP had poorer outcome (median ONLS: 4; range: 22-5) compared to MPred-CIDP (2, range: 0-4; P = .03) at last follow up. This study found a progressive clinical course in the majority of patients with motor CIDP as well as frequent associated diseases, CB, and F-wave abnormalities. Corticosteroids might be considered as a therapeutic option in resistant IVIg patients with MPred-CIDP.

Abnormality of multimodal evoked potentials in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)

Introduction

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease of the peripheral nervous system, sometimes including the central nervous system. The aim of the study was the assessment of the prevalence of central sensory impairment and its reliance on peripheral nerve damage in patients with CIDP.

Material and methods

Multimodal (visual—VEP, brainstem auditory—BAEP, somatosensory—SEP) evoked potentials (EPs) were studied in 24 patients diagnosed with CIDP. The results were compared with neurographic parameters of sensory responses. The control group consisted of 35 healthy volunteers selected with respect to age and sex.

Results

Mean latency of most components of EP were considerably prolonged in patients compared with the control group. There were no correlations between the P100 VEP latency and the peripheral sensory parameters. Statistically significant negative correlations were obtained between BAEP and SEP responses and the amplitude and sensory conduction velocity of peripheral nerves. The inter-latencies were also longer.

Conclusions

The authors indicated to the possibility of central sensory involvement in patients with CIDP, especially based on the prolonged inter-latency of BAEPs with simultaneously confirmed root affection. The severity of central damage correlates with the degree of peripheral nerve impairment.

Comparison of Lewis-Sumner syndrome with chronic inflammatory demyelinating polyradiculoneuropathy patients in a tertiary care centre

BACKGROUND AND PURPOSE

Whether the Lewis-Sumner syndrome (L-SS) is a distinct entity from other types of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP-ot) remains controversial.

METHOD

The clinical/electrophysiological characteristics and long-term outcomes of 45 L-SS and 35 CIDP-ot patients were retrospectively compared.

RESULTS

The CIDP-ot group was composed of 11 patients with a typical CIDP, 17 with a pure sensory form, four with a distal form and three with a pure motor form. In the L-SS group, asymmetric (P < 0.001) and monomelic involvement (P = 0.04) of the upper limbs (P < 0.001) was significantly more frequent; paucisymptomatic forms (Overall Neuropathy Limitations Scale ≤ 1) were less frequent (P < 0.001); electroneuromyography showed that conduction block in intermediate nerve segments was the main demyelinating feature, with frequent F-wave abnormalities on nerves without conduction block (44%). Long-term prognosis was globally poorer in the L-SS group with more frequent aggravation during treatment (P = 0.02), less frequent treatment withdrawal (P = 0.03) and longer time to achieve successful withdrawal (39 vs. 15 months).

CONCLUSIONS

Our study suggests that L-SS patients have a less favourable therapeutic response rate and long-term outcomes. Rapid differentiation of L-SS from other forms of CIDP is important in order to anticipate a more complicated disease course management, with from one side the inefficacy or even harmfulness of corticosteroids and from the other side a difficult weaning procedure. A prospective study is necessary to confirm these results.

Diagnostic usefulness of plexus magnetic resonance imaging in chronic inflammatory demyelinating polyradiculopathy without electrodiagnostic criteria of demyelination

BACKGROUND AND PURPOSE

The usefulness of plexus magnetic resonance imaging (MRI) in the diagnosis of chronic inflammatory demyelinating polyradiculopathy (CIDP) without definite European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) electrodiagnostic criteria is currently unclear.

METHODS

Data from consecutive patients with clinical manifestations suggesting CIDP, with or without (CIDP-D and CIDP-ND, respectively) definite EFNS/PNS electrodiagnostic criteria, and referred for plexus MRI in our imaging centre were retrospectively analysed. An expert committee of neurologists compared the level of suspicion of CIDP in CIDP-ND patients to the blinded/unblinded MRI findings. Plexus MRI was reviewed by a neuroradiologist blinded to the final diagnosis.

RESULTS

In all, 38 patients were assessed with suspected CIDP-ND [7/38 (18%) probable; 13/38 (34%) possible; 18/38 (47%), no EFNS/PNS electrodiagnostic criteria], plus 10 with CIDP-D. Thirty-six of the 38 (95%) fulfilled clinical criteria of CIDP variants, including pure sensory neuropathy in 22/36 (61%). Plexus MRI showed abnormalities in 22/38 (58%) patients including increased nerve signal intensity on T2-weighted images in 22/22 (100%), nerve enlargement in 20/22 (91%) and contrast enhancement in 8/22 (36%). Plexus MRI enabled the expert committee's final diagnosis to be adjusted in 7/38 (18%) patients, and in conjunction with nerve conduction studies was a supportive criterion to classify 7/24 (29%) patients as definite CIDP. MRI abnormalities were more asymmetrical (P = 0.03) and less diffuse (P = 0.1) in CIDP-ND than in CIDP-D.

CONCLUSIONS

Our observations suggest that plexus MRI makes a valuable contribution to the diagnosis of CIDP-ND patients. Further studies are needed to investigate inter-rater reliability of clinical and imaging criteria of CIDP in these patients, and the impact on outcomes.

Utility of somatosensory evoked potentials in the assessment of response to IVIG in a long-lasting case of chronic immune sensory polyradiculopathy

BACKGROUND

Chronic immune sensory polyradiculopathy (CISP) identifies a progressive acquired peripheral dysimmune neuropathy recognized as a chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) variant. We describe a young woman with a thirteen-year history of CISP with a belated variable response to intravenous immunoglobulin (IVIG) and an almost erratic anticipation of symptoms between IVIG cycles. The association of IVIG and corticosteroids, immunosuppressants, plasmapheresis, did not lead to clinical improvement and was characterized by significant side effects. We evaluated a combined clinical and somatosensory evoked potentials (SSEPs) approach aimed to identify possible predictive parameters concerning the effect and duration of each IVIG administration. Neurologic disability was evaluated using INCAT - Overall Disability Sum Score (INCAT-ODSS).

CASE PRESENTATION

A 30-year-old woman presented on 2004 for the subacute onset of asymmetric paresthesias in the lower limbs over the previous six months. The symptoms had been relapsing-remitting during the first four months, followed by a slow progression, resulting in limbs ataxia and a progressive gait disturbance requiring Canadian crutches. Motor and sensory nerve conduction studies and electromyographic evaluation were into normal limits. Median SSEPs were normal, while tibial SSEPs were characterised by the bilateral absence of both lumbar and cortical responses. Cerebrospinal fluid detected an increased protein concentration, while spinal MRI showed a pronounced thickening of the sacral nerve roots, together with a tube-shaped enlargement. These findings led to the diagnosis of CISP and the patient was treated with IVIG reaching a stable remission over the following 9 years. In early 2014, the patient began to show a variable response to treatment with erratic anticipation of sensory disturbances, and a more pronounced walking disability: corticosteroids, plasmapheresis, mycophenolate mofetil and cyclophosphamide were uneffective and burdened by relevant side effects. To better assess the response to IVIG in terms of time-effect, consistency and duration, we have combined a scheduled clinical and SSEPs evaluation during and after each IVIG cycle.

CONCLUSIONS

The correlation between the neurophysiological data and the INCAT-ODSS scores has allowed the modulation of IVIG cycles with a significant reduction of the clinical fluctuations and disability. SSEPs may therefore represent an useful and recommended additional aid for the treatment schedule of this rare clinical form.