P11.66.A Immune checkpoint inhibitors related peripheral nerve disorders: clinical and electrophysiological particularities

Background

The immune-checkpoint inhibitors (ICIs) announced a new era in cancer treatment allowing long-term survival in advanced cancers. However, immune related adverse events impose treatment limitations being one of the main challenges when dealing with ICI treated patients. Neurologic toxicities have unique presentations and can progress rapidly, requiring prompt recognition. Among them, ICI-related peripheral nerve disorders are highly heterogeneous, profoundly debilitating, and insufficiently explored.

Material and Methods

We reviewed the clinical and electrodiagnostic features of a retrospective cohort of patients hospitalized in our centre for ICI related neuropathies. We applied the EFNS 2021 electrodiagnostic criteria for neuropathies and we researched the outcome according to the treatment received.

Results

We included 16 patients: 4 men and 12 women, median age 61 years (31-72) treated by anti-PD1 monotherapy (10) or antiCTLA4-antiPD1 combination (6). Median delay from ICIs initiation to neuropathy symptoms was 58,5 days (4 cycles), it seemed lower in combination group (median 33,5 days vs 81,5 days in monotherapy patients p=0,02). Half of patients presented with concurrent non-neurological irAE. CSF was inflammatory in 56% of cases, pleocytosis was seen in 57% of these. Cranial nerve involvement was rare (3/16) the most frequent phenotype was demyelinating polyneuropathy fulfilling EFNS 2021 EMG criteria in 10 cases. The other 6 presented with non-length dependent sensory neuropathy, (3) dysautonomic neuropathy (1) or sensory motor neuropathy with incomplete EFNS 2021 EMG criteria (2). ICI treatment was stopped, and steroids were the first line of treatment for all patients. However, 12/16 patients received additional iv immunoglobulin. Supplementary immunomodulation (cyclophosphamide, tocilizumab) was required in 2 cases. 75% of patients improved within a median of 4.5 months, median decrease in mRS was 2 points. Noteworthy, the rechallenge by antiPD1 monotherapy was proposed in 4 patients with a single neuropathy relapse.

Conclusion

Our series expand the knowledge on the clinical and electrophysiological phenotype of ICI related neuropathies improving their recognition in clinical practice. Moreover, our findings argue for the benefit of adding iv immunoglobulin to steroids as a first line treatment for different phenotypes of ICI related neuropathies.

French Society of ENT (SFORL) guidelines. Management of acute Bell's palsy

AQFThe authors present the guidelines of the French Society of ENT and Head and Neck Surgery (SFORL) regarding the management of Bell's palsy in adults. After a literature review by a multidisciplinary workgroup, guidelines were drawn up based on retrieved articles and group-members' experience, then read over by an independent group to edit the final version. Guidelines were graded A, B, C or "expert opinion" according to decreasing level of evidence. Thorough ENT and neurological clinical examination is recommended in all patients presenting with peripheral facial palsy to confirm diagnosis of Bell's palsy. MRI with gadolinium enhancement should explore the entire course of the facial nerve, if possible within the first month. ENMG should be performed to assess prognosis for recovery. In confirmed Bell's palsy, corticosteroid therapy should be implemented as early as possible (ideally within 72h) at a dose of 1mg/kg/day for 7-10 days. Antiviral therapy should be associated to steroids in patients with severe and early-onset disease and in Ramsay-Hunt syndrome. Isolated antiviral therapy is not recommended. To date, there is no evidence that surgical facial nerve decompression provides benefit.

Focal myositis: A review

Amongst the heterogeneous group of inflammatory myopathies, focal myositis stands as a rare and benign dysimmune disease. Although it can be associated with root and/or nerve lesions, traumatic muscle lesions and autoimmune diseases, its triggering factors remain poorly understood. Defined as an isolated inflammatory pseudotumour usually restricted to one skeletal muscle, clinical presentation of focal myositis is that of a rapidly growing solitary mass within a single muscle, usually in the lower limbs. Electromyography shows spontaneous activity associated with a myopathic pattern. MRI reveals a contrast enhanced enlarged muscle appearing hyper-intense on FAT-SAT T2 weighted images. Adjacent structures are spared and there are no calcifications. Serum creatine kinase (CK) levels are usually moderately augmented and biological markers of systemic inflammation are absent in most cases. Pathological histological features include marked variation in fibre size, inflammatory infiltrates mostly composed of T CD4+ lymphocytes and macrophages, degenerating/regenerating fibres and interstitial fibrosis. Differential diagnoses are numerous and include myositis of other origin with focal onset. Steroid treatment should be reserved for patients who present with major pain, nerve lesions, associated autoimmune disease, or elevated C reactive protein or CK.

Antibodies to clustered acetylcholine receptor: expanding the phenotype

BACKGROUND AND PURPOSE

To provide a detailed phenotypical description of seronegative patients with generalized myasthenia gravis and antibodies to clustered acetylcholine receptors (AChRs) and to assess their frequency amongst a French seronegative generalized myasthenia gravis (SNMG) population.

METHODS

A French SNMG database was created and the sera from the 37 patients included in it were analysed by immunofluorescence of cell-based assays using cotransfection of AChR subunit genes together with rapsyn to densely cluster the AChRs.

RESULTS

Sixteen per cent (n = 6) of the SNMG patients were found to have antibodies to clustered AChR. They presented either with early onset MG and thymic hyperplasia, late onset MG and thymic involution, or thymoma associated MG. They responded well to cholinesterase inhibitors and immunosuppressants.

CONCLUSIONS

Patients with antibodies to clustered AChR account for a significant proportion of SNMG patients and resemble patients with AChR antibodies detected by standard radio-immunoprecipitation.

[Distal hereditary motor neuropathy]

INTRODUCTION

Distal hereditary motor neuropathy (dHMN), also known as spinal muscular atrophy, represents a group of clinically and genetically heterogeneous diseases caused by degenerations of spinal motor neurons and leading to distal muscle weakness and wasting. Nerve conduction studies reveal a pure motor axonopathy and needle examination shows chronic denervation.

STATE OF ART

dHMN were initially subdivided into seven subtypes according to mode of inheritance, age at onset, and clinical evolution. Recent studies have shown that these subtypes are still heterogeneous at the molecular genetic level and novel clinical and genetic entities have been characterized. To date, mutations in 11 different genes have been identified for autosomal-dominant, autosomal-recessive, and X-linked recessive dHMN. Most of the genes encode protein involved in housekeeping functions, endosomal trafficking, axonal transport, translation synthesis, RNA processing, oxidative stress response and apoptosis.

PERSPECTIVES

The pathophysiological mechanisms underlying dHMN seem to be related to the "length-dependent" death of motor neurons of the anterior horn of the spinal cord, likely because their large axons have higher metabolic requirements for maintenance.

CONCLUSION

dHMN remain heterogeneous at the clinical and molecular genetic level. The molecular pathomechanisms explaining why mutations in these ubiquitously expressed housekeeping genes result in the selective involvement of spinal motor neurons remain to be unravelled.