Generalized myoclonus following a tarantula spider bite: a case report Mioclonía generalizada tras picadura de tarántula: reporte de un caso Academic Article in Scopus uri icon

abstract

  • Myoclonus, characterized by sudden, involuntary muscle movements, typically arises from several acute neurological insults. This case report introduces a unique instance of generalized myoclonus triggered by a spider bite from a species phyloge-netically linked to tarantulas. A 41-year-old woman presented with sudden jerky movements following a spider bite 2 weeks earlier. Accompanying symptoms included skin lesions, pain, itching, and fever. Examination revealed generalized, action-tri-ggered jerky movements, classified as myoclonus. Despite thorough evaluation, including brain magnetic resonance imaging, electroencephalography, and extensive laboratory tests, no abnormalities were detected except for abnormal electromyogra-phy findings consistent with myoclonus. Excluding infectious, metabolic, and structural causes, the spider bite emerged as the most plausible etiology, involving a spider from the Mygalomorphae suborder. Treatment with clonazepam, trihexyphenidyl, and doxycycline significantly improved myoclonus within 24 h. One month later, the patient remained asymptomatic. This case challenges conventional diagnostic paradigms and underscores the importance of considering unconventional etiologies in cases that defy traditional explanations. In Mexico, only black widow and violinist spiders are recognized for their medical significance. However, this case involved a spider from the Mygalomorphae suborder, which includes tarantulas. Tarantula venom typically induces pain, local tissue necrosis, and, rarely, muscle cramping, with a generally favorable prognosis. The venom consists of low molecular mass compounds, antimicrobial peptides, cysteine-rich neurotoxic peptides, enzymes, and proteins, potentially acting synergistically.This case suggests that components of the Mygalomorphae suborder venom may induce exaggerated responses in sensitive individuals. It offers insights into the complexities of arachnid envenomations and their neurological consequences. © 2024 Instituto Nacional de Neurología y Neurocirugía. Publicado por Permanyer. Este es un artículo open access bajo la licencia CC BY-NC-ND (http://creativecommons.org/licenses/by-nc-nd/4.0/).

publication date

  • January 1, 2025