Bilateral basal ganglia hyperintensity and cerebellar dysfunction in avermectin poisoning: a case report

Common neurologic signs can be caused by rare conditions. Avermectin poisoning is one of the underreported causes of neurologic syndromes, especially in the agricultural population. It can cause headaches, vomiting, ataxia, and nystagmus. Linking typical magnetic resonance imaging with the proper clinical context could raise suspicion of poisoning, especially when the patient is uncooperative. Recognition of these cases can prevent worsening neurologic symptoms in patients.

We report the case of a 17-year-old Syrian male individual who presented with headache, vomiting, ataxia, and nystagmus. Symptoms began 3 weeks after repeated avermectin exposure (six sessions over 1 month) without a protective shield. The patient had no medical history, and he works as a farmer. After ruling out many potential causes of his presentation through laboratory studies, brain magnetic resonance imaging revealed hyperintensity in the basal ganglia. Eventually, by historical chronological association, he was diagnosed with avermectin-induced pesticide poisoning. He was managed symptomatically and advised to avoid exposure to pesticides. Continued exposure would lead to a very advanced condition. Nevertheless, his condition was stable at the time of hospitalization. After the follow-up, eventually, he improved.

Avermectin poisoning should be suspected in specific groups of patients with occupational exposure to agricultural or pharmaceutical chemicals. A thorough differential diagnosis is required when a patient presents with nonspecific neurological signs. This report is the first to link avermectin poisoning to specific magnetic resonance imaging findings.