What is Parkinsonian syndrome?
{{mergeto|Parkinson's disease}} '''Parkinsonian syndrome''' (also known as '''Parkinsonism''', '''atypical Parkinson's''' or '''secondary Parkinson's''') is a [[neurology|neurological]] [[syndrome]] characterized by [[tremor]], [[hypokinesia]], [[Rigidity (neurology)|rigidity]], and [[balance disorder|postural instability]].<ref name=Aminoff_2005>{{cite book | author = Aminoff MJ, Greenberg DA, Simon RP | title = Clinical Neurology | url = https://archive.org/details/clinicalneurolog00amin | publisher = Lange: McGraw-Hill Medical | edition = 6th | pages = [https://archive.org/details/clinicalneurolog00amin/page/241 241]–5 |year = 2005 | isbn = 0-07-142360-5 }}</ref> There are many conditions that lead to Parkinsonism, and diagnosis can be difficult.<ref>{{cite journal | author = Tuite PJ, Krawczewski K | title = Parkinsonism: a review-of-systems approach to diagnosis | journal = Seminars in Neurology | volume = 27 | issue = 2 | pages = 113–22 | year = 2007 | pmid = 17390256 | doi = 10.1055/s-2007-971174}}</ref> While the [[neurodegenerative]] condition [[Parkinson's disease]] (PD) is the most common cause of parkinsonism, a wide range of other causes may lead to a similar set of symptoms, including some [[toxin]]s, a few [[metabolic disease]]s, and a handful of neurological conditions unrelated to Parkinson's disease.<ref>{{cite journal | author = Christine CW, Aminoff MJ | title = Clinical differentiation of parkinsonian syndromes: prognostic and therapeutic relevance | journal = Am. J. Med. | volume = 117 | issue = 6 | pages = 412–9 | year = 2004 | pmid = 15380498 | doi = 10.1016/j.amjmed.2004.03.032 }}</ref> Its most common cause is as a side effect of [[drug|medications]], mainly [[neuroleptic]] [[antipsychotics]] especially the [[phenothiazine]]s (such as perphenazine and [[chlorpromazine]]), [[thioxanthene]]s (such as flupenthixol and zuclopenthixol) and [[butyrophenone]]s (such as haloperidol (Haldol)), [[piperazine]]s (such as ziprasidone), and, rarely, antidepressants.{{Citation needed|date=Apri