Bradykinesia (Pediatric) Workup
It is important for the diagnosing physician to look for reversible or treatable causes of parkinsonism. If there is any possibility of exposure to a toxin, heavy metal, carbon monoxide, or medication, this needs to be investigated. An MRI of the brain is important in order to look for a tumor or stroke. An MRI may also show if there is degeneration in other areas of the brain, such as the cerebellum or brainstem.
When there is difficulty differentiating juvenile Parkinson's disease from dopa-responsive dystonia, it may be helpful to perform a phenylalanine-loading test or lumbar puncture with measurements of dopamine and other neurotransmitters and metabolites. These tests may help to identify a specific metabolic disorder. An important element of the diagnosis is observing the changes in the symptoms with time, and whether or not there is a response to treatment with L-DOPA.
In some cases, it is helpful to obtain a PET scan which can look for the presence or absence of cells that make dopamine, or cells that respond to dopamine. This may help to distinguish whether the problem is "pre-synaptic" (the cells that make dopamine) or "post-synaptic" (the cells that respond to dopamine). If the disorder is post-synaptic, then the child is less likely to respond to treatment with dopamine and similar medications.