Delayed Myoclonus and Bilateral Globus Pallidus Lesions Following Organophosphate Poisoning: A Case Report

BACKGROUND Organophosphate-induced delayed neuropathy is a well-known peripheral nervous system manifestation of organophosphate poisoning. However, organophosphate poisoning can also present with delayed central nervous system complications, such as myoclonus. Although peripheral neuropathy has been extensively described in the literature, central nervous system involvement remains relatively underrecognized. Neuroimaging findings in such cases play a crucial role in revealing the underlying toxic injury and structures involved. CASE REPORT A 49-year-old man with organophosphate poisoning recovered from the acute cholinergic phase and intermediate syndrome but developed myoclonus 3 to 4 weeks after organophosphate ingestion. Magnetic resonance imaging (MRI) of the brain showed T2-weighted and FLAIR hyperintensities in the bilateral globus pallidus, suggestive of a toxic insult to the subcortex. The patient received steroids, intravenous immunoglobulin, and symptomatic treatment for myoclonus, with no success. CONCLUSIONS This case highlights a unique complication of myoclonus with brain MRI changes in the setting of organophosphate exposure. The patient recovered from acute cholinergic crisis and intermediate syndrome but developed new-onset neurological deficits during the delayed phase. Such complications can significantly contribute to long-term morbidity and impair quality of life. This report highlights a clinically relevant but underrecognized delayed presentation of organophosphate poisoning. Given the limited number of such reports, this case adds incremental knowledge and helps clinicians recognize similar presentations in practice. Although a causal relationship cannot be definitively established, the temporal association raises the possibility of organophosphate exposure and globus pallidus signal changes in the presence of myoclonus.