Multifactorial anticholinergic toxicity-like presentation and malignant parkinsonism in Perry syndrome.

Perry syndrome is a rare autosomal dominant neurodegenerative disorder characterized by parkinsonism, depression, weight loss, and central hypoventilation. Early diagnosis is challenging because presentations are heterogeneous. A 51-year-old man presented with hyperthermia, impaired consciousness, tachycardia, and gastrointestinal hypomotility suggestive of anticholinergic toxicity. Despite therapeutic fesoterodine levels, he developed hypercapnia requiring mechanical ventilation and later exhibited rigidity with marked creatine kinase elevation, consistent with malignant parkinsonism. Dopamine transporter imaging demonstrated presynaptic dopaminergic loss, and follow-up magnetic resonance imaging revealed bilateral globus pallidus and substantia nigra hyperintensities. Family history was informative, and genetic testing confirmed a DCTN1 mutation. The presentation was multifactorial, reflecting an interaction between therapeutic anticholinergic exposure, reduced cholinergic reserve related to Perry syndrome, endogenous dopaminergic deficiency, and systemic stress. Early recognition is crucial because central hypoventilation may lead to life-threatening respiratory failure.