Secondary Movement Disorders: Drug‑Related, Systemic, and Neurological Etiologies Across Clinical Spectra

Movement disorders frequently arise as secondary manifestations of systemic, metabolic, toxic, infectious, vascular, autoimmune, and iatrogenic conditions, yet they remain underrecognized in clinical practice. This narrative review aims to provide a comprehensive and clinically oriented overview of secondary movement disorders, emphasizing common and uncommon etiologies, underlying pathophysiological mechanisms, diagnostic challenges, and management considerations. A broad literature review was conducted using PubMed, Scopus, and Google Scholar, focusing on movement disorders associated with medications, stroke, infections, metabolic abnormalities, demyelinating and autoimmune diseases, neurodegenerative conditions, and systemic illnesses. Secondary movement disorders encompass a wide spectrum of hyperkinetic and hypokinetic phenomenologies, including tremor, dystonia, chorea, myoclonus, parkinsonism, ataxia, and mixed syndromes, often reflecting disruption of basal ganglia–thalamo–cortical and cerebellothalamic networks. Drugs—particularly antipsychotics, antiseizure medications, antidepressants, and antiemetics—represent the most frequent cause, while vascular lesions, infections, and metabolic disturbances constitute important and potentially reversible contributors. Neuroimaging and ancillary testing play a pivotal role in identifying secondary etiologies and distinguishing them from primary neurodegenerative or functional disorders. Recognition of secondary movement disorders is essential, as prompt identification and treatment of the underlying cause may lead to symptom resolution or significant improvement. This review highlights the importance of systematic evaluation, interdisciplinary collaboration, and individualized management strategies, reinforcing the concept that movement disorders often reflect multisystem disease rather than isolated motor pathology.