Parkinson disease practice parameters
A comprehensive set of evidence-based practice parameters on Parkinson disease (PD) care were presented April 2, 2006, at the 58th annual meeting of the American Academy of Neurology (AAN) in San Diego. The aim of the practice parameters is to assist neurologists in "making the correct diagnosis as early as possible, making the best use of time-tested and effective therapies to improve motor function, and treating depression, psychosis, and dementia," said William J. Weiner, MD, professor and chair of the Department of Neurology at the University of Maryland School of Medicine in Baltimore.The practice parameters were authored by the Quality Standards Subcommittee of the AAN, which included Weiner. They appear as 4 distinct articles in the April 2006 issue of Neurology and cover topics related to screening for PD, prognosis, therapy, and screening and management of PD-associated psychiatric illnesses. Some key points follow.IDENTIFYING DISEASE EARLYThe AAN subcommittee concluded that clinical features of early-stage disease that may distinguish PD from other parkinsonian disorders include:- History of falls.- Poor response to levodopa.- Symmetry at onset.- Rapid progression.- Lack of tremor.- Dysautonomia.Although the subcommittee conceded that insufficient evidence exists on whether the following measures provide an advantage over clinical diagnostic criteria for PD, it recommended levodopa or apomorphine challenge tests to clarify the diagnosis and olfaction testing to differentiate PD from progressive supranuclear palsy or corticobasal degeneration.Electrooculography, single photon emission computed tomography, and growth hormone stimulation with clonidine were deemed probably not useful in making a differential diagnosis.PROGNOSTIC INDICATORSOnce a PD diagnosis has been established, features that augur a poor prognosis include:- Older age at onset.- Rigidity or hypokinesia as an initial symptom.- Male sex.- Presence of PD-associated comorbidities.- Decreased response to dopamine.Older age at onset, presence of comorbidities, and male sex are predictive of rapid motor decline, and older age at onset and rigidity or hypokinesia are predictive of rapid cognitive decline. Older age, dementia, and decreased response to dopamine are predictive of nursing home placement and decreased survival.RECOMMENDED INTERVENTIONSRecommended therapeutic agents to reduce motor fluctuations include:- Entacapone.- Rasagiline (Agilect).- Pramipexole (Mirapex).- Ropinirole (Requip).- Tolcapone (Tasmar) (monitor for hepatotoxity).- Pergolide (Permax) (monitor for valvular fibrosis).Of these, the subcommittee regarded entacapone and rasagiline as the best choices for reducing off-time motor fluctuations. Amantadine was noted as possibly the best therapeutic candidate for reducing dyskinesias.The subcommittee also deemed the use of deep brain stimulation of the subthalamic nucleus useful in improving motor function, dyskinesias, and need for medication. Good outcome was predicated on positive preoperative response to levodopa.PSYCHIATRIC SYMPTOMSThe subcommittee recommended that the Beck Inventory and Hamilton Depression Rate Scale be used to screen for depression in patients with PD, adding that the Montgomery-Asberg Depression Rating Scale also may be valuable. In screening for dementia in these patients, the Mini Mental State Examination and the Cambridge Cognitive Examination were recommended. The subcommittee forwent making recommendations about screening for psychosis.Although not the first choice for treating depression in patients with PD, the subcommittee concluded that amitriptyline could be considered, adding that insufficient evidence exists to make definitive recommendations on preferred agents for this indication. For dementia, the subcommittee recommended donepezil (Aricept) or rivastigmine (Exelon). Clozapine was recommended for treating psychosis in these patients, although the subcommittee reminded that absolute neutrophil count must be closely monitored to prevent possible development of agranulocytosis. Quetiapine (Seroquel) was named as another possible option. Routine use of olanzapine (Zyprexa) for psychosis in patients with PD was discouraged.Pdf files of the full reports of the practice parameters, including at-a-glance information sheets for clinicians and also for patients and caregivers, are available at: www.aan.com/ professionals/practice/guideline/index.cfm.