Baclofen Toxicity Presenting as Generalized Myoclonus and Choreoathetosis Without Altered Consciousness in the Setting of Acute-on-chronic Kidney Disease
Shivaansh Aggarwal1, Soroush Kakawand1, Evan Mooney1, Sarah Durica1
1University of Oklahoma Health Sciences Center
Objective:
To highlight that baclofen toxicity can present primarily with hyperkinetic movements, without impaired consciousness
Background:
Baclofen is renally cleared, and neurotoxicity in chronic kidney disease (CKD) is well described, often presenting with encephalopathy. Involuntary hyperkinetic movements without altered mental status are rarely reported.
Design/Methods:
A 65-year-old man with CKD (baseline serum creatinine 2.27), ischemic cardiomyopathy, and atrial fibrillation presented with hematemesis and acute kidney injury (serum creatinine 3.7). He had been prescribed baclofen 10 mg three times daily two months earlier for back pain. The patient reported subtle fidgeting movements for ~6 months, but two days prior to admission he developed abrupt, disabling abnormal movements. The clinical examination revealed multifocal asynchronous jerks of the limbs consistent with positive and negative myoclonus. He also had involuntary, non-rhythmic, flowing, and writhing movements of the arms, legs, and the face, consistent with choreoathetosis. Movements were distractible, suppressible, absent during sleep, and interfered with gait and daily function. Mental status was preserved. CT head showed chronic right parietal encephalomalacia without acute changes.
Results:
Given worsening renal function and ongoing baclofen use, baclofen toxicity was considered likely, despite preserved mentation. The movements improved dramatically within 24 hours of hemodialysis and discontinuation of baclofen, with only mild baseline movements persisting.
Conclusions:
Baclofen toxicity can mimic primary movement disorders and can present with acute onset of generalized myoclonus and choreoathetosis even in the absence of encephalopathy. Although baclofen-induced neurotoxicity characteristically presents with altered mental status, clinicians should maintain high suspicion for it in patients with renal injury and other suggestive symptoms. Prompt recognition is critical, as symptoms are rapidly reversible with dialysis.
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