Editing Serotonin syndrome (section)

===Differential diagnosis===

Serotonin toxicity has a characteristic picture which is generally hard to confuse with other [[medical conditions]], but in some situations it may go unrecognized because it may be mistaken for a [[viral illness]], [[anxiety disorder]]s, [[neurological disorder]], [[anticholinergic]] poisoning, [[sympathomimetic]] toxicity, or worsening psychiatric condition.<ref name=Boy2005/><ref name="Isbister Buckley"/><ref>{{cite journal|vauthors=Fennell J, Hussain M |title=Serotonin syndrome: case report and current concepts |journal=Ir Med J |volume=98 |issue=5 |pages=143–4 |year=2005 |pmid=16010782}}</ref> The condition most often confused with serotonin syndrome is [[neuroleptic malignant syndrome]] (NMS).<ref>{{cite book|vauthors=Nisijima K, Shioda K, Iwamura T |title=Neurobiology of Hyperthermia |chapter=Neuroleptic malignant syndrome and serotonin syndrome |journal=Prog Brain Res |volume=162 |pages=81–104 |year=2007 |pmid=17645916 |doi=10.1016/S0079-6123(06)62006-2 |series=Progress in Brain Research |isbn=9780444519269}}</ref><ref name="Tormoehlen">{{cite book |last1=Tormoehlen |first1=LM |last2=Rusyniak |first2=DE |title=Thermoregulation: From Basic Neuroscience to Clinical Neurology, Part II |chapter=Neuroleptic malignant syndrome and serotonin syndrome |series=Handbook of Clinical Neurology |date=2018 |volume=157 |pages=663–675 |doi=10.1016/B978-0-444-64074-1.00039-2 |pmid=30459031|isbn=9780444640741 }}</ref> The clinical features of neuroleptic malignant syndrome and SS share some features which can make differentiating them difficult.<ref>{{cite journal|vauthors=Christensen V, Glenthøj B |title=[Malignant neuroleptic syndrome or serotonergic syndrome] |journal=Ugeskrift for Lægerer |volume=163 |issue=3 |pages=301–2 |year=2001 |pmid=11219110}}</ref> In both conditions, [[Autonomic nervous system|autonomic]] dysfunction and altered [[mental status]] develop.<ref name="Whyte"/> However, they are actually very different conditions with different underlying dysfunction (serotonin excess vs dopamine blockade). Both the time course and the clinical features of NMS differ significantly from those of serotonin toxicity.<ref name="Dunkley"/> Serotonin toxicity has a rapid onset after the administration of a serotonergic drug and responds to serotonin blockade such as drugs like [[chlorpromazine]] and [[cyproheptadine]]. [[Dopamine receptor]] blockade (NMS) has a slow onset, typically evolves over several days after administration of a [[neuroleptic]] drug, and responds to dopamine agonists such as [[bromocriptine]].<ref name=Boy2005/><ref name="Whyte"/>

[[Differential diagnosis]] may become difficult in patients recently exposed to both serotonergic and neuroleptic drugs. [[Bradykinesia]] and [[extrapyramidal symptoms|extrapyramidal]] "lead pipe" rigidity are classically present in NMS, whereas SS causes [[hyperkinesia]] and clonus; these distinct symptoms can aid in differentiation.<ref name="Birmes">{{cite journal|vauthors=Birmes P, Coppin D, Schmitt L, Lauque D |title=Serotonin syndrome: a brief review |journal=CMAJ |volume=168 |issue=11 |pages=1439–42 |date=May 2003 |pmid=12771076 |pmc=155963 |url=http://www.cmaj.ca/cgi/pmidlookup?view=long&pmid=12771076}}</ref><ref>{{cite journal|vauthors=Isbister GK, Dawson A, Whyte IM |title=Citalopram overdose, serotonin toxicity, or neuroleptic malignant syndrome? |journal=Can J Psychiatry |volume=46 |issue=7 |pages=657–9 |date=September 2001 |pmid=11582830 |doi= 10.1177/070674370104600718|doi-access=free }}</ref>