Acute Motor Conduction Block Neuropathy After Initiation of Omalizumab: Case Report and Literature Review for Possible Causality.

Background: Omalizumab is an established therapy for allergic conditions, yet its neurological effects remain underexplored compared to other biological agents.

Case Description: A 45-year-old male with asthma developed acute quadriparesis one week after receiving the first dose of omalizumab. Electrophysiological studies have shown partial motor conduction block in multiple nerves, with reduced CMAP amplitudes and absent F-waves in others. CSF showed cyto-albuminous dissociation. The diagnosis was a variant of Guillain-Barré syndrome. Despite intravenous immunoglobulin (IVIG) therapy, the patient experienced persistent neuropathic symptoms.

Discussion: The patient presented with acute quadriparesis devoid of sensory or cranial nerve involvement, suggestive of a variant of Guillain-Barré syndrome (GBS) known as acute motor conduction block neuropathy (AMCBN). Electrophysiological studies have indicated conduction block without demyelination, implicating axonal degeneration. Despite negative findings for common etiologies, the temporal association between omalizumab administration and symptom onset suggests a potential link, supported by criteria for drug-induced illness. Conflicting evidence exists regarding omalizumab's neurological effects, with proposed mechanisms including autoimmune reactions and mast cell dysfunction. Comparisons to TNF-α antagonists highlight similar neuropathy patterns, indicating a need for further research to clarify omalizumab's neurotoxicity.

Conclusion: In conclusion, while omalizumab holds promise for allergic conditions, including chronic urticaria, its potential impact on peripheral nerves necessitates vigilance among clinicians. Further studies are imperative to ascertain the risk-benefit profile and elucidate underlying mechanisms and risk factors of neurological complications associated with omalizumab therapy.