Drug-induced parkinsonism.

Area of Science:

• Neurology
• Pharmacology

Background:

• Drug-induced parkinsonism (DIP) is a common condition in the elderly, often misdiagnosed as Parkinson's disease (PD) due to overlapping clinical features.
• Neurological deficits from DIP can be severe and persistent, impacting daily activities long after drug cessation.
• Various medications, including antipsychotics, prokinetics, calcium channel blockers, and antiepileptics, can cause DIP.

Purpose of the Study:

• To highlight the diagnostic challenges in differentiating DIP from PD.
• To explore the pathophysiological basis of DIP and its distinction from PD.
• To emphasize the utility of dopamine transporter (DAT) imaging in diagnosing DIP.

Main Methods:

• Review of clinical manifestations and pathophysiology of DIP.
• Comparison of clinical features between DIP and PD.
• Discussion of the role of DAT imaging in differentiating presynaptic parkinsonism.

Main Results:

• Clinical presentation of DIP can mimic PD, including asymmetry and resting tremor in about half of cases.
• DIP results from postsynaptic dopaminergic receptor blockade, leaving presynaptic dopaminergic neurons intact.
• DAT imaging shows normal striatal uptake in DIP, contrasting with the decreased uptake seen in PD.

Conclusions:

• Differentiating DIP from PD is crucial due to potential long-term effects and differing management strategies.
• DAT imaging is a valuable tool for distinguishing DIP from PD by assessing presynaptic dopaminergic integrity.
• Clinicians must exercise caution when prescribing dopaminergic receptor blockers and monitor for parkinsonism.