Bradykinesia (Pediatric) Treatment
In some cases, if a specific metabolic disorder can be identified, a specific treatment may be available. However, the mainstay of treatment for parkinsonism of any cause is the use of oral L-DOPA. L-DOPA is a precursor of dopamine and is converted by the body into dopamine. Dopamine cannot be directly ingested, as it is poorly absorbed by the intestines and rapidly degraded in the blood. In order to deliver as much L-DOPA to the brain as possible, it is usually combined in a pill with another medicine such as carbidopa in the combined medication Sinemet®. Carbidopa inhibits the conversion of L-DOPA to dopamine until the L-DOPA has entered the brain. This increases the effectiveness of L-DOPA, thus lowering the oral dose and decreasing the side effects.
Side effects are mostly due to L-DOPA that is converted to dopamine outside the brain. Side effects include nausea, diarrhea, and low blood pressure. In some cases, an increase in the carbidopa dose helps to counteract this. (Domperidone is an effective alternative but is not currently available in the United States.) Side effects are worse when taken on an empty stomach. Ondansetron may be helpful to treat nausea; but, other more common anti-nausea medicines, including metoclopramide (Reglan®), prochlorperazine (Compazine®), or meclizine (Antivert®) may actually worsen symptoms. L-DOPA is absorbed better when taken with carbohydrates and worse with proteins. If it is taken with a protein meal, both the beneficial effects and the side effects are decreased. Parkinson's disease typically requires increasing doses of L-DOPA over many years, and eventually side effects occur. In contrast, children with dopa-responsive dystonia often have complete resolution of symptoms on very low doses of L-DOPA, with no need to increase the dose over time. Exceptions to this have been reported.
Other medications used for parkinsonism include anticholinergics (trihexyphenidyl, benztropine), dopamine agonists (pramipexole, ropinirole, bromocriptine), amantadine, selegiline, rasagiline, and entacapone. With the exception of the anticholinergics, there is limited experience with the use of these medications in children.
Many adults with idiopathic adult-onset Parkinson's disease have benefited from deep-brain stimulation applied to the internal globus pallidus or the subthalamic nucleus. Whether this procedure will be helpful for children with bradykinesia is not yet known.