Diagnosis of atypical forms of chronic inflammatory demyelinating polyradiculoneuropathy: a practical overview based on some case studies

Usefulness and prognostic value of diagnostic tests in patients with possible chronic inflammatory demyelinating polyradiculoneuropathy

INTRODUCTION/AIMS

Recent guidelines define chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and possible CIDP. The aims of our study were to evaluate the value of diagnostic tests to support the diagnosis of CIDP in patients with possible CIDP and to identify prognostic factors of therapeutic success.

METHODS

We conducted an observational retrospective two-center study between 2014 and 2019. We selected patients with a clinical presentation suggesting CIDP, but whose electrodiagnostic (EDX) test results did not meet the EFNS/PNS 2021 criteria. We analyzed epidemiologic and clinical features, axonal loss on EDX, cerebrospinal fluid (CSF), somatosensory evoked potentials (SSEPs), plexus magnetic resonance imaging (MRI), nerve biopsy, and therapeutic response.

RESULTS

We selected 75 patients, among whom 30 (40%) responded to treatment. The positivity rates of CSF analysis, MRI and SSEPs were not influenced by the clinical presentation or by the delay between symptom onset and medical assessment. A high protein level in CSF, female gender, and a relapsing-remitting course predicted the therapeutic response.

DISCUSSION

It is important to properly diagnose suspected CIDP not meeting EFNS/PNS 2021 EDX criteria by using supportive criteria. Specific epidemiological factors and a raised CSF protein level predict a response to treatment. Further prospective studies are needed to improve diagnosis and the prognostic value of diagnostic tests in CIDP.

Focal chronic inflammatory demyelinating polyradiculoneuropathy: Onset, course, and distinct features

Focal chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is defined as involving the brachial or lumbosacral plexus, or one or more peripheral nerves in one upper or one lower limb (monomelic distribution). However, other auto-immune neuropathies such as Lewis-Sumner syndrome (LSS) and multifocal motor neuropathy (MMN) can also have a focal onset. From a retrospective cohort of 30 focal CIDP patients with a monomelic onset dating back at least 2 years, we distinguished patients with plexus involvement (focal demyelinating plexus neuropathy [F-PN], n = 18) from those with sensory or sensorimotor (F-SMN, n = 7), or purely motor (F-MN, n = 5) impairment located in one or several peripheral nerves. Few (39%) F-PN patients had motor nerve conduction abnormalities, but the majority showed proximal conduction abnormalities in somatosensory evoked potentials (80%), and all had focal hypertrophy and/or increased short tau inversion recovery image signal intensity on plexus MRI. Impairment remained monomelic in most (94%) F-PN patients, whereas abnormalities developed in other limbs in 57% of F-SMN, and 40% of F-MN patients (P = .015). The prognosis of F-PN patients was significantly better: none had an ONLS score > 2 at the final follow-up visit, vs 43% of F-SMN patients and 40% of F-MN patients (P = .026). Our findings from a large cohort of focal CIDP patients confirm the existence of different entities that are typically categorized under this one term: on the one hand, patients with a focal plexus neuropathy and on the other, patients with monomelic sensori-motor or motor involvement of peripheral nerves. These two last subgroups appeared to be more likely to evolve to LSS or MMN phenotype, when F-PN patients have a more distinctive long-term, focal, benign course.

Chronic inflammatory axonal polyneuropathy

OBJECTIVES

Chronic inflammatory axonal polyneuropathy (CIAP) is defined on the basis of the clinical, electrophysiological and nerve biopsy findings and therapeutic responses of 'immunotherapy responding chronic axonal polyneuropathy (IR-CAP)'.

METHODS

The diagnosis of IR-CAP was made when all of three of the following mandatory criterion were met: (1) acquired, chronic progressive or relapsing symmetrical or asymmetrical polyneuropathy with duration of progression >2 months; (2) electrophysiological evidence of axonal neuropathy in at least two nerves without any evidence of 'strict criteria of demyelination'; and (3) definite responsiveness to immunotherapy.

RESULTS

Thirty-three patients with IR-CAP showed similar clinical features of chronic inflammatory demyelinating polyneuropathy (CIDP) except 'motor neuropathy subtype'. High spinal fluid protein was found in 27/32 (78%) cases. 'Inflammatory axonal neuropathy' was proven in 14 (45%) of 31 sural nerve biopsies.

DISCUSSIONS

IR-CAP could well be 'axonal CIDP' in view of clinical similarity, but not proven as yet. Thus, IR-CAP is best described as CIAP, a distinct entity that deserves its recognition in view of responsiveness to immunotherapy.

CONCLUSION

Diagnosis of CIAP can be made by additional documentation of 'inflammation' by high spinal fluid protein or nerve biopsy in addition to the first two diagnostic criteria of IR-CAP.

Chronic immune sensory polyradiculopathy (CISP): First juvenile case description

In its typical presentation, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) occurs more often in old males as a progressive/recurrent motor and sensory nerve dysfunction with tendon areflexia. However, CIDP has also atypical clinical presentations, including pure sensory neuropathies, among which chronic immune sensory polyradiculopathy (CISP) accounts for only 0.5% of all CIDP, with no juvenile cases reported as yet. A 17-year-old girl presented for a progressive sensory ataxia and hands clumsiness. Diffuse tendon areflexia and hypokinaesthesia were observed. Motor and sensory nerve conduction studies were normal. F-waves were normal in median nerves and elongated in tibial nerves. H-reflex and somatosensory evoked potentials (SSEP) were absent. CSF normal cellularity with hyperproteinorrachia was found. Paraneoplastic, metabolic, and paraproteinemic neuropathies were excluded. A diagnosis of CISP has been made based on the presence of pure sensory symptoms in a polyneuropathic distribution, normal peripheral nerve conduction studies, and two supportive criteria (SSEP and CSF). Our paper describes the first CISP case in the pediatric age. We confirm SSEP and CSF as useful complementary tests for this diagnosis also at this age and suggest that clinicians should consider CISP in the spectrum of sporadic sensory ataxias of the pediatric age. We also suggest that in the presence of normal F-wave and peripheral motor nerve conduction, an absent H-reflex can further substantiate SSEPs in the diagnosis of CISP. Intravenous immunoglobulins were rapidly effective and safe.

[Chronic dysimmune hypertrophic plexopathy as a variant of atypical chronic inflammatory demyelinating polyneuropathy]

The authors report the clinical case of a 7-year-old child with gradual development in left leg weakness considering by the neurologist as the unknown lesion of the sciatic nerve. According to the results of clinical and instrumental examinations, the diagnosis was established as a focal form of chronic inflammatory demyelinating polyneuropathy (CIDP). The dysimmune cause of the disease was confirmed by MRI of the lumbosacral plexus with contrast enhancement of neural structures and response to therapy with high-dose intravenous immunoglobulin in combination with corticosteroids.

Nerve ultrasound and magnetic resonance imaging in the diagnosis of neuropathy

PURPOSE OF REVIEW

This review summarizes the most relevant developments in the fields of nerve ultrasound and MRI in the diagnosis of treatable inflammatory neuropathies over the last 18 months.

RECENT FINDINGS

MRI and nerve ultrasound can accurately identify potentially treatable neuropathies and thereby help to improve diagnosis. Advanced MRI techniques also show potential to dissect pathophysiology. The apparent mismatch between nerve function and morphology is not surprising and reflects different dimensions of the disease process in neuropathies.

SUMMARY

MRI and nerve ultrasound have become useful tools in the diagnosis of inflammatory neuropathies. VIDEO ABSTRACT.

A comparative study of brachial plexus sonography and magnetic resonance imaging in chronic inflammatory demyelinating neuropathy and multifocal motor neuropathy

BACKGROUND AND PURPOSE

To compare the performance of neuroimaging techniques, i.e. high-resolution ultrasound (HRUS) and magnetic resonance imaging (MRI), when applied to the brachial plexus, as part of the diagnostic work-up of chronic inflammatory demyelinating neuropathy (CIDP) and multifocal motor neuropathy (MMN).

METHODS

Fifty-one incident, treatment-naive patients with CIDP (n = 23) or MMN (n = 28) underwent imaging of the brachial plexus using (i) a standardized MRI protocol to assess enlargement or T2 hyperintensity and (ii) bilateral HRUS to determine the extent of nerve (root) enlargement.

RESULTS

We found enlargement of the brachial plexus in 19/51 (37%) and T2 hyperintensity in 29/51 (57%) patients with MRI and enlargement in 37/51 (73%) patients with HRUS. Abnormal results were only found in 6/51 (12%) patients with MRI and 12/51 (24%) patients with HRUS. A combination of the two imaging techniques identified 42/51 (83%) patients. We found no association between age, disease duration or Medical Research Council sum-score and sonographic nerve size, MRI enlargement or presence of T2 hyperintensity.

CONCLUSIONS

Brachial plexus sonography could complement MRI in the diagnostic work-up of patients with suspected CIDP and MMN. Our results indicate that combined imaging studies may add value to the current diagnostic consensus criteria for chronic inflammatory neuropathies.

Intravenous immunoglobulin: pharmacological properties and use in polyneuropathies

INTRODUCTION

Intravenous immunoglobulin (IVIg) is increasingly used for the treatment of autoimmune and systemic inflammatory diseases with both licensed and off-label indications. The mechanism of action is complex and not fully understood, involving the neutralization of pathological antibodies, Fc receptor blockade, complement inhibition, immunoregulation of dendritic cells, B cells and T cells and the modulation of apoptosis. Areas covered: First, this review describes the pharmacological properties of IVIg, including the composition, mechanism of action, and adverse events. The second part gives an overview of some of the immune-mediated polyneuropathies, with special focus on the pathomechanism and clinical trials assessing the efficacy of IVIg. A literature search on PubMed was performed using the terms IVIg, IVIg preparations, side effects, mechanism of action, clinical trials, GBS, CIDP. Expert opinion: Challenges associated with IVIg therapy and the treatment possibilities for immune-mediated polyneuropathies are discussed. The availability of IVIg is limited, the expenses are high, and, in several diseases, a chronic therapy is necessary to maintain the immunomodulatory effect. The better understanding of the mechanism of action of IVIg could open the possibility of the development of disease-specific, targeted immune therapies.