Parkinsonism
Parkinsonism is a clinical syndrome characterised by tremor, muscle rigidity, slowness of movement (bradykinesia), and postural instability. It is not a single disease but a group of conditions that share these motor features. Parkinson’s disease is the most common cause, but parkinsonism can also be triggered by certain medicines, vascular changes in the brain, or rarer neurodegenerative disorders.
Key points
- Reduced dopamine activity in a brain region called the basal ganglia disrupts smooth, coordinated movement in every form of this syndrome.
- Certain medicines, particularly antipsychotics, can trigger identical symptoms by blocking dopamine receptors, which usually settle once the drug responsible is stopped.
- Procyclidine, an anticholinergic, helps ease tremor and rigidity by rebalancing disrupted signals, though it works less well for slowed movement itself.
What causes parkinsonism
The common thread in all forms of parkinsonism is disruption to the brain circuits that regulate smooth, coordinated movement, usually involving reduced dopamine activity in the basal ganglia. In Parkinson’s disease this happens because dopamine-producing neurones gradually degenerate. Drug-induced parkinsonism, which is particularly relevant where antipsychotics and antiemetics are widely used in hospital settings, arises when medicines block dopamine receptors directly, producing identical symptoms that typically resolve once the causative drug is stopped.
Managing symptoms
Treatment depends on the underlying cause. When drug-induced parkinsonism is confirmed, the offending medicine is reviewed first. For symptoms that require direct management, anticholinergic agents such as procyclidine are used to rebalance the neurotransmitter signals disrupted in the motor pathways. Procyclidine is particularly useful for tremor and muscle stiffness rather than bradykinesia. A neurology specialist will typically guide ongoing therapy, adjust dosing, and monitor for any side effects over time.