To review a rare case of Peyote poisoning and bring awareness.

Peyote is a small spineless cactus that holds sacred significance in southwestern US Native American religious practice. It contains several biologically active alkaloids with hallucinogenic properties when ingested and can cause various neurological and systemic symptoms. Here, we present a case of polyneuropathy accompanied by encephalopathy due to peyote poisoning.

A previously healthy 24-year-old Native American woman presented to an outside facility in northern Arizona with a three-week history of generalized weakness and paresthesia, preceded by two weeks of nausea, vomiting, and severe constipation. Suspected Guillain-Barré Syndrome based on her weakness and areflexia led to a five-day course of IVIG without symptomatic improvement. She was then transferred to our facility for higher level of care. Behavioral changes including social withdrawal, visual hallucinations, and uncharacteristic outbursts were additional symptoms upon her arrival. On examination, she had persistent tachycardia, significant abdominal distension, hypophonia, generalized muscle weakness, hypotonia, absent deep tendon reflexes, and reduced sensation in all modalities. Her CSF analysis revealed a mildly elevated protein level of 62mg/dl with normal WBC and glucose. MRI brain and total spine were unremarkable. With concerns for autoimmune encephalitis with polyneuropathy, she received a three-day course of methylprednisolone, though without improvement. Extensive lab tests for autoimmune, paraneoplastic, toxic/metabolic, and infectious causes were negative. The diagnosis remained elusive until nursing staff discovered that her mother was regularly administering peyote as part of a religious practice.

Peyote may cause a range of adverse effects beyond hallucinations. Systemic symptoms may include tachycardia, nausea, vomiting, constipation, blood pressure fluctuations, fever, and muscle weakness, while polyneuropathy and encephalopathy may be additional neurological symptoms. Although overdosing on peyote is rare, recognizing its clinical presentation is crucial, especially in high-risk and vulnerable patient populations.