View source for Myositis

__NOTOC__
{{Myositis}}
{{CMG}};{{AE}}{{MIR}}

{{SK}}

==Overview==

'''Myositis''' is a general term for [[inflammation]] of the [[muscle]]s.  Many such conditions are considered likely to be caused by [[autoimmune]] conditions, rather than directly due to [[infection]] (although [[autoimmune]] conditions can be activated or exacerbated by infections.)

Elevation of [[creatine kinase]] ([[CK]]) in blood is indicative of myositis. The MM and not the MB or BB fraction of the CK will be elevated.

==Differential diagnosis of myositis==
Myositis must be differentiated from the following conditions causing [[muscle weakness]], [[hypotonia]], or [[flaccid paralysis]]:<ref name="pmid29433111">{{cite journal |vauthors=Kira R |title=[Acute Flaccid Myelitis] |language=Japanese |journal=Brain Nerve |volume=70 |issue=2 |pages=99–112 |date=February 2018 |pmid=29433111 |doi=10.11477/mf.1416200962 |url=}}</ref><ref name="pmid29433111">{{cite journal |vauthors=Kira R |title=[Acute Flaccid Myelitis] |language=Japanese |journal=Brain Nerve |volume=70 |issue=2 |pages=99–112 |date=February 2018 |pmid=29433111 |doi=10.11477/mf.1416200962 |url=}}</ref><ref name="pmid29181601">{{cite journal |vauthors=Hopkins SE |title=Acute Flaccid Myelitis: Etiologic Challenges, Diagnostic and Management Considerations |journal=Curr Treat Options Neurol |volume=19 |issue=12 |pages=48 |date=November 2017 |pmid=29181601 |doi=10.1007/s11940-017-0480-3 |url=}}</ref><ref name="pmid27422805">{{cite journal |vauthors=Messacar K, Schreiner TL, Van Haren K, Yang M, Glaser CA, Tyler KL, Dominguez SR |title=Acute flaccid myelitis: A clinical review of US cases 2012-2015 |journal=Ann. Neurol. |volume=80 |issue=3 |pages=326–38 |date=September 2016 |pmid=27422805 |pmc=5098271 |doi=10.1002/ana.24730 |url=}}</ref><ref name="pmid29028962">{{cite journal |vauthors=Chong PF, Kira R, Mori H, Okumura A, Torisu H, Yasumoto S, Shimizu H, Fujimoto T, Hanaoka N, Kusunoki S, Takahashi T, Oishi K, Tanaka-Taya K |title=Clinical Features of Acute Flaccid Myelitis Temporally Associated With an Enterovirus D68 Outbreak: Results of a Nationwide Survey of Acute Flaccid Paralysis in Japan, August-December 2015 |journal=Clin. Infect. Dis. |volume=66 |issue=5 |pages=653–664 |date=February 2018 |pmid=29028962 |pmc=5850449 |doi=10.1093/cid/cix860 |url=}}</ref><ref name="pmid29482893">{{cite journal |vauthors=Messacar K, Asturias EJ, Hixon AM, Van Leer-Buter C, Niesters HGM, Tyler KL, Abzug MJ, Dominguez SR |title=Enterovirus D68 and acute flaccid myelitis-evaluating the evidence for causality |journal=Lancet Infect Dis |volume=18 |issue=8 |pages=e239–e247 |date=August 2018 |pmid=29482893 |doi=10.1016/S1473-3099(18)30094-X |url=}}</ref><ref name="pmid30200066">{{cite journal |vauthors=Chen IJ, Hu SC, Hung KL, Lo CW |title=Acute flaccid myelitis associated with enterovirus D68 infection: A case report |journal=Medicine (Baltimore) |volume=97 |issue=36 |pages=e11831 |date=September 2018 |pmid=30200066 |pmc=6133480 |doi=10.1097/MD.0000000000011831 |url=}}</ref><ref name="urlBotulism | Botulism | CDC">{{cite web |url=https://www.cdc.gov/botulism/index.html |title=Botulism &#124; Botulism &#124; CDC |format= |work= |accessdate=}}</ref><ref name="pmid3290234">{{cite journal |vauthors=McCroskey LM, Hatheway CL |title=Laboratory findings in four cases of adult botulism suggest colonization of the intestinal tract |journal=J. Clin. Microbiol. |volume=26 |issue=5 |pages=1052–4 |date=May 1988 |pmid=3290234 |pmc=266519 |doi= |url=}}</ref><ref name="pmid16614251">{{cite journal |vauthors=Lindström M, Korkeala H |title=Laboratory diagnostics of botulism |journal=Clin. Microbiol. Rev. |volume=19 |issue=2 |pages=298–314 |date=April 2006 |pmid=16614251 |pmc=1471988 |doi=10.1128/CMR.19.2.298-314.2006 |url=}}</ref><ref name="pmid17224901">{{cite journal |vauthors=Brook I |title=Botulism: the challenge of diagnosis and treatment |journal=Rev Neurol Dis |volume=3 |issue=4 |pages=182–9 |date=2006 |pmid=17224901 |doi= |url=}}</ref><ref name="pmid23642721">{{cite journal |vauthors=Dimachkie MM, Barohn RJ |title=Guillain-Barré syndrome and variants |journal=Neurol Clin |volume=31 |issue=2 |pages=491–510 |date=May 2013 |pmid=23642721 |pmc=3939842 |doi=10.1016/j.ncl.2013.01.005 |url=}}</ref><ref name="pmid23418763">{{cite journal |vauthors=Walling AD, Dickson G |title=Guillain-Barré syndrome |journal=Am Fam Physician |volume=87 |issue=3 |pages=191–7 |date=February 2013 |pmid=23418763 |doi= |url=}}</ref><ref name="pmid21969911">{{cite journal |vauthors=Gilhus NE |title=Lambert-eaton myasthenic syndrome; pathogenesis, diagnosis, and therapy |journal=Autoimmune Dis |volume=2011 |issue= |pages=973808 |date=2011 |pmid=21969911 |pmc=3182560 |doi=10.4061/2011/973808 |url=}}</ref><ref name="pmid14977560">{{cite journal |vauthors=Krishnan C, Kaplin AI, Deshpande DM, Pardo CA, Kerr DA |title=Transverse Myelitis: pathogenesis, diagnosis and treatment |journal=Front. Biosci. |volume=9 |issue= |pages=1483–99 |date=May 2004 |pmid=14977560 |doi= |url=}}</ref><ref name="pmid24305450">{{cite journal |vauthors=Amato AA, Greenberg SA |title=Inflammatory myopathies |journal=Continuum (Minneap Minn) |volume=19 |issue=6 Muscle Disease |pages=1615–33 |date=December 2013 |pmid=24305450 |doi=10.1212/01.CON.0000440662.26427.bd |url=}}</ref><ref name="pmid24365430">{{cite journal |vauthors=Berger JR, Dean D |title=Neurosyphilis |journal=Handb Clin Neurol |volume=121 |issue= |pages=1461–72 |date=2014 |pmid=24365430 |doi=10.1016/B978-0-7020-4088-7.00098-5 |url=}}</ref>
{|
|- style="background: #4479BA; color: #FFFFFF; text-align: center;"
! rowspan="2" |<small>Diseases</small>
! colspan="8" |<small>History and Physical
! colspan="2" |<small>Diagnostic tests</small>
! rowspan="2" |<small>Other Findings</small>
|- style="background: #4479BA; color: #FFFFFF; text-align: center;"
!<small>Motor Deficit</small>
!<small>Sensory deficit</small>
!<small>Cranial nerve Involvement</small>
!<small>Autonomic dysfunction</small>
!<small>Proximal/Distal/Generalized</small>
!<small>Ascending/Descending/Systemic</small>
!<small>Unilateral (UL) 
or Bilateral (BL) 

or 

No Lateralization (NL)</small>
!<small>Onset</small> 
!<small>Lab or Imaging Findings</small>
!<small>Specific  test</small>
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" | Adult Botulism
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>+</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Descending
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Sudden
| style="background: #F5F5F5; padding: 5px; text-align:center" |Toxin test
| style="background: #F5F5F5; padding: 5px; text-align:center" |Blood, Wound, or Stool culture 
| style="background: #F5F5F5; padding: 5px; text-align:center" |[[Diplopia]], [[Hyporeflexia|Hyporeflexia,]] [[Hypotonia]], possible respiratory paralysis
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |Infant Botulism
| style="background: #F5F5F5; padding: 5px; text-align:center" |+
| style="background: #F5F5F5; padding: 5px; text-align:center" |-
| style="background: #F5F5F5; padding: 5px; text-align:center" |+
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>+</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Descending
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Sudden
| style="background: #F5F5F5; padding: 5px; text-align:center" |Toxin test
| style="background: #F5F5F5; padding: 5px; text-align:center" |Blood, Wound, or Stool culture
| style="background: #F5F5F5; padding: 5px; text-align:center" |[[Flaccid paralysis]] ([[Floppy baby syndrome]]), possible respiratory paralysis
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" | [[Guillian-Barre syndrome]]<ref name="pmid22081202">{{cite journal| author=Talukder RK, Sutradhar SR, Rahman KM, Uddin MJ, Akhter H| title=Guillian-Barre syndrome. | journal=Mymensingh Med J | year= 2011 | volume= 20 | issue= 4 | pages= 748-56 | pmid=22081202 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22081202  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>-</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Ascending
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Insidious
| style="background: #F5F5F5; padding: 5px; text-align:center" |CSF: ↑Protein

↓Cells

| style="background: #F5F5F5; padding: 5px; text-align:center" |Clinical & Lumbar Puncture
| style="background: #F5F5F5; padding: 5px; text-align:center" |Progressive [[ascending paralysis]] following infection, possible respiratory paralysis
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" | [[Eaton lambert syndrome|Eaton Lambert syndrome]]<ref name="pmid27412406">{{cite journal| author=Merino-Ramírez MÁ, Bolton CF| title=Review of the Diagnostic Challenges of Lambert-Eaton Syndrome Revealed Through Three Case Reports. | journal=Can J Neurol Sci | year= 2016 | volume= 43 | issue= 5 | pages= 635-47 | pmid=27412406 | doi=10.1017/cjn.2016.268 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=27412406  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>+</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Intermittent
| style="background: #F5F5F5; padding: 5px; text-align:center" | [[EMG]], repetitive nerve stimulation test (RNS)
| style="background: #F5F5F5; padding: 5px; text-align:center" |[[Voltage gated calcium channel|Voltage gated calcium channe]]<nowiki/>l<nowiki/> (VGCC) antibody
| style="background: #F5F5F5; padding: 5px; text-align:center" |[[Diplopia]], [[ptosis]], improves with movement (as the day progresses)
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |[[Myasthenia gravis]]<ref name="pmid28029925">{{cite journal| author=Gilhus NE| title=Myasthenia Gravis. | journal=N Engl J Med | year= 2016 | volume= 375 | issue= 26 | pages= 2570-2581 | pmid=28029925 | doi=10.1056/NEJMra1602678 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28029925  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>+</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Intermittent
| style="background: #F5F5F5; padding: 5px; text-align:center" | [[Electromyography|EMG]], [[Edrophonium|Edrophonium test]]
| style="background: #F5F5F5; padding: 5px; text-align:center" |[[Acetylcholine receptor|Ach receptor]] antibody
| style="background: #F5F5F5; padding: 5px; text-align:center" |[[Diplopia]], [[ptosis]], worsening with movement (as the day progresses)
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |[[Electrolyte disturbance]]<ref name="pmid26813501">{{cite journal| author=Ozono K| title=[Diagnostic criteria for vitamin D-deficient rickets and hypocalcemia-]. | journal=Clin Calcium | year= 2016 | volume= 26 | issue= 2 | pages= 215-22 | pmid=26813501 | doi=CliCa1602215222 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26813501  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>-</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Insidious
| style="background: #F5F5F5; padding: 5px; text-align:center" | Electrolyte panel
| style="background: #F5F5F5; padding: 5px; text-align:center" |↓Ca++, ↓Mg++, ↓K+
| style="background: #F5F5F5; padding: 5px; text-align:center" |Possible [[arrhythmia]]
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |[[Organophosphate poisoning|Organophosphate toxicity]]<ref name="pmid15020723">{{cite journal| author=Kamanyire R, Karalliedde L| title=Organophosphate toxicity and occupational exposure. | journal=Occup Med (Lond) | year= 2004 | volume= 54 | issue= 2 | pages= 69-75 | pmid=15020723 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15020723  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>+</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Ascending
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Sudden
| style="background: #F5F5F5; padding: 5px; text-align:center" | Clinical diagnosis: physical exam & history
| style="background: #F5F5F5; padding: 5px; text-align:center" |Clinical suspicion confirmed with RBC AchE activity
| style="background: #F5F5F5; padding: 5px; text-align:center" |History of exposure to i[[Insecticide|nsecticide]] or living in farming environment. with : [[Diarrhea]], [[Urination]], [[Miosis]], [[Bradycardia]], [[Lacrimation]], [[Emesis]], [[Salivation]], [[Sweating]]
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |[[Tick paralysis]] ([[Dermacentor andersoni|Dermacentor tick]])<ref name="pmid23677663">{{cite journal| author=Pecina CA| title=Tick paralysis. | journal=Semin Neurol | year= 2012 | volume= 32 | issue= 5 | pages= 531-2 | pmid=23677663 | doi=10.1055/s-0033-1334474 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23677663  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>-</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Ascending
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Insidious
| style="background: #F5F5F5; padding: 5px; text-align:center" | Clinical diagnosis: physical exam & history
| style="background: #F5F5F5; padding: 5px; text-align:center" |-
| style="background: #F5F5F5; padding: 5px; text-align:center" |History of outdoor activity in Northeastern United States. The tick is often still latched to the patient at presentation (often in head and neck area)
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |[[Tetrodotoxin]] poisoning<ref name="pmid24566728">{{cite journal| author=Bane V, Lehane M, Dikshit M, O'Riordan A, Furey A| title=Tetrodotoxin: chemistry, toxicity, source, distribution and detection. | journal=Toxins (Basel) | year= 2014 | volume= 6 | issue= 2 | pages= 693-755 | pmid=24566728 | doi=10.3390/toxins6020693 | pmc=3942760 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24566728  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>+</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Sudden
| style="background: #F5F5F5; padding: 5px; text-align:center" | Clinical diagnosis: physical exam & dietary history
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" | History of consumption of puffer fish species.
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |[[Stroke]]<ref name="pmid8848683">{{cite journal| author=Kuntzer T, Hirt L, Bogousslavsky J| title=[Neuromuscular involvement and cerebrovascular accidents]. | journal=Rev Med Suisse Romande | year= 1996 | volume= 116 | issue= 8 | pages= 605-9 | pmid=8848683 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8848683  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +/-
| style="background: #F5F5F5; padding: 5px; text-align:center" | +/-
| style="background: #F5F5F5; padding: 5px; text-align:center" | +/-
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>+/-</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |UL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Sudden
| style="background: #F5F5F5; padding: 5px; text-align:center" | MRI +ve for ischemia or hemorrhage
| style="background: #F5F5F5; padding: 5px; text-align:center" |MRI
| style="background: #F5F5F5; padding: 5px; text-align:center" |Sudden unilateral motor and sensory deficit in a patient with a history of [[Atherosclerosis|atherosclero]]<nowiki/>tic risk factors (diabetes, hypertension, smoking) or [[Atrial fibrillation|atrial fibrillation.]]
|-
| style="background: #DCDCDC; padding: 5px; text-align:center;" | [[Poliomyelitis]]<ref name="pmid19944665">{{cite journal| author=Laffont I, Julia M, Tiffreau V, Yelnik A, Herisson C, Pelissier J| title=Aging and sequelae of poliomyelitis. | journal=Ann Phys Rehabil Med | year= 2010 | volume= 53 | issue= 1 | pages= 24-33 | pmid=19944665 | doi=10.1016/j.rehab.2009.10.002 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19944665  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" |+
| style="background: #F5F5F5; padding: 5px; text-align:center" |+
| style="background: #F5F5F5; padding: 5px; text-align:center" |+
| style="background: #F5F5F5; padding: 5px; text-align:center" |+/-
| style="background: #F5F5F5; padding: 5px; text-align:center" |Proximal > Distal
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL or UL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Sudden
| style="background: #F5F5F5; padding: 5px; text-align:center" |
| style="background: #F5F5F5; padding: 5px; text-align:center" |PCR of CSF
| style="background: #F5F5F5; padding: 5px; text-align:center" |Asymmetric paralysis following a flu-like syndrome.
|-
| style="background: #DCDCDC; padding: 5px; text-align:center;" | [[Transverse myelitis]]<ref name="pmid24099672">{{cite journal| author=West TW| title=Transverse myelitis--a review of the presentation, diagnosis, and initial management. | journal=Discov Med | year= 2013 | volume= 16 | issue= 88 | pages= 167-77 | pmid=24099672 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24099672  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" |+
| style="background: #F5F5F5; padding: 5px; text-align:center" |+
| style="background: #F5F5F5; padding: 5px; text-align:center" |+
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>+</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Proximal > Distal
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL or UL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Sudden
| style="background: #F5F5F5; padding: 5px; text-align:center" |MRI & [[Lumbar puncture]]
| style="background: #F5F5F5; padding: 5px; text-align:center" |MRI
| style="background: #F5F5F5; padding: 5px; text-align:center" |History of chronic viral or autoimmune disease (e.g. [[HIV]])
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |[[Neurosyphilis]]<ref name="pmid22482824">{{cite journal| author=Liu LL, Zheng WH, Tong ML, Liu GL, Zhang HL, Fu ZG et al.| title=Ischemic stroke as a primary symptom of neurosyphilis among HIV-negative emergency patients. | journal=J Neurol Sci | year= 2012 | volume= 317 | issue= 1-2 | pages= 35-9 | pmid=22482824 | doi=10.1016/j.jns.2012.03.003 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22482824  }} </ref><ref name="pmid24365430">{{cite journal |vauthors=Berger JR, Dean D |title=Neurosyphilis |journal=Handb Clin Neurol |volume=121 |issue= |pages=1461–72 |year=2014 |pmid=24365430 |doi=10.1016/B978-0-7020-4088-7.00098-5 |url=}}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" |+/-
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Insidious<nowiki/>
| style="background: #F5F5F5; padding: 5px; text-align:center" |MRI & [[Lumbar puncture]]
| style="background: #F5F5F5; padding: 5px; text-align:center" |CSF [[VDRL]]-specifc
CSF [[FTA-ABS|FTA-Ab]] -sensitive<ref name="pmid22421697">{{cite journal| author=Ho EL, Marra CM| title=Treponemal tests for neurosyphilis--less accurate than what we thought? | journal=Sex Transm Dis | year= 2012 | volume= 39 | issue= 4 | pages= 298-9 | pmid=22421697 | doi=10.1097/OLQ.0b013e31824ee574 | pmc=3746559 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22421697  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" |History of unprotected sex or multiple sexual partners.

History of [[genital ulcer]] ([[chancre]]), diffuse [[Maculopapular rash|maculopapular ras]]<nowiki/>h. 
|-
| style="background: #DCDCDC; padding: 5px; text-align:center;" |[[Muscular dystrophy]]<ref name="pmid26457695">{{cite journal| author=Falzarano MS, Scotton C, Passarelli C, Ferlini A| title=Duchenne Muscular Dystrophy: From Diagnosis to Therapy. | journal=Molecules | year= 2015 | volume= 20 | issue= 10 | pages= 18168-84 | pmid=26457695 | doi=10.3390/molecules201018168 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26457695  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>-</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Proximal > Distal
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Insidious
| style="background: #F5F5F5; padding: 5px; text-align:center" | Genetic testing
| style="background: #F5F5F5; padding: 5px; text-align:center" |[[Muscle biopsy]]
| style="background: #F5F5F5; padding: 5px; text-align:center" |Progressive proximal lower limb weakness with calf pseudohypertrophy in early childhood. [[Gowers' sign|Gower sign]] positive.
|-
| style="background: #DCDCDC; padding: 5px; text-align: center;" |[[Multiple sclerosis]] exacerbation<ref name="pmid27432676">{{cite journal| author=Filippi M, Preziosa P, Rocca MA| title=Multiple sclerosis. | journal=Handb Clin Neurol | year= 2016 | volume= 135 | issue=  | pages= 399-423 | pmid=27432676 | doi=10.1016/B978-0-444-53485-9.00020-9 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=27432676  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>+</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |NL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Sudden
| style="background: #F5F5F5; padding: 5px; text-align:center" |'''[[CSF|↑]]'''[[CSF]] [[IgG]] levels
(monoclonal)
| style="background: #F5F5F5; padding: 5px; text-align:center" |Clinical assessment and [[MRI]] <ref name="pmid8274111">{{cite journal| author=Giang DW, Grow VM, Mooney C, Mushlin AI, Goodman AD, Mattson DH et al.| title=Clinical diagnosis of multiple sclerosis. The impact of magnetic resonance imaging and ancillary testing. Rochester-Toronto Magnetic Resonance Study Group. | journal=Arch Neurol | year= 1994 | volume= 51 | issue= 1 | pages= 61-6 | pmid=8274111 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8274111  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" |[[Blurred vision|Blurry vision]], [[urinary incontinence]], [[fatigue]]
|-
| style="background: #DCDCDC; padding: 5px; text-align:center" |[[Amyotrophic lateral sclerosis]]<ref name="pmid27025851">{{cite journal| author=Riva N, Agosta F, Lunetta C, Filippi M, Quattrini A| title=Recent advances in amyotrophic lateral sclerosis. | journal=J Neurol | year= 2016 | volume= 263 | issue= 6 | pages= 1241-54 | pmid=27025851 | doi=10.1007/s00415-016-8091-6 | pmc=4893385 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=27025851  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" | +
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>-</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Generalized
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Insidious
| style="background: #F5F5F5; padding: 5px; text-align:center" | Normal [[Lumbar puncture|LP]] (to rule out DDx)
| style="background: #F5F5F5; padding: 5px; text-align:center" |MRI & [[Lumbar puncture|LP]]
| style="background: #F5F5F5; padding: 5px; text-align:center" |Patient initially presents with [[upper motor neuron]] deficit ([[spasticity]]) followed by [[lower motor neuron]] deficit ([[flaccidity]]).
|-
| style="background: #DCDCDC; padding: 5px; text-align:center;" | [[Myositis|Inflammatory myopathy]]<ref name="pmid26290112">{{cite journal| author=Michelle EH, Mammen AL| title=Myositis Mimics. | journal=Curr Rheumatol Rep | year= 2015 | volume= 17 | issue= 10 | pages= 63 | pmid=26290112 | doi=10.1007/s11926-015-0541-0 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26290112  }}</ref>
| style="background: #F5F5F5; padding: 5px; text-align:center" |+
| style="background: #F5F5F5; padding: 5px; text-align:center" |-
| style="background: #F5F5F5; padding: 5px; text-align:center" | -
| style="background: #F5F5F5; padding: 5px; text-align:center" |<nowiki>-</nowiki>
| style="background: #F5F5F5; padding: 5px; text-align:center" |Proximal > Distal
| style="background: #F5F5F5; padding: 5px; text-align:center" |Systemic
| style="background: #F5F5F5; padding: 5px; text-align:center" |UL or BL
| style="background: #F5F5F5; padding: 5px; text-align:center" |Insidious
| style="background: #F5F5F5; padding: 5px; text-align:center" |Elevated [[Creatine kinase|CK]] & [[Aldolase]]
| style="background: #F5F5F5; padding: 5px; text-align:center" |[[Muscle biopsy]]
| style="background: #F5F5F5; padding: 5px; text-align:center" |Progressive proximal muscle weakness in 3rd to 5th decade of life. With or without skin manifestations.
|-
|}


The following drugs or conditions may additionally need to be differentiated from myositis:

[[Atorvastatin]]

[[Cellulitis]]

[[Deep vein thrombosis]]

[[Dermatomyositis]]

[[Dolutegravir]] 

[[Hematoma]]

[[Idiopathic]] [[inflammatory]] myopathies

[[Inclusion body myositis]]

[[Influenza]] myositis

[[Juvenile dermatomyositis]]

[[Lovastatin]]

[[Lyme]] myositis

[[Myositis ossificans]]

Neuromuscular complications accompanying [[AIDS]]

[[Osteoarthritis]]

[[Osteomyelitis]]

[[Paraneoplastic]] neuropathy

[[Peripheral vascular disease]]

[[Polymyositis]]

[[Pravastatin]] (less likely than other statins)

[[Pyomyositis]]

[[Rheumatoid arthritis]]

[[Simvastatin]]

[[Statin]] therapy

[[Systemic lupus erythematosus]]

[[Toxoplasma]] myositis

[[Trichinosis]]

[[Trypanosomiasis]]

[[Tuberculous pyomyositis]]

Viral myositis (including following an episode of influenza)

[[Wasting syndrome]]

===Causes===

===Drug Side Effect===
*[[Pembrolizumab]]
*[[Pergolide]] 
*[[Zidovudine]]

==Diagnostic Findings==

===MRI===

([http://www.radswiki.net Images courtesy of RadsWiki])

<gallery>
Image:Myositis_MRI_001.jpg|Myositis 
Image:Myositis_MRI_002.jpg|Myositis 
Image:Myositis_MRI_003.jpg|Myositis 
Image:Myositis_MRI_004.jpg|Myositis 
Image:Myositis_MRI_005.jpg|Myositis 
</gallery>

==See also==
* [[myopathy]] (muscle '''disease''')
* [[myalgia]] (muscle '''pain''')

==External links==
* [http://www.myositis.org The Myositis Association]
* [http://www.nlm.nih.gov/medlineplus/myositis.html NIH]
* [http://www.myositis.org/about_myositis/faq_general.cfm FAQ]
* [http://www.arthritis.org/conditions/DiseaseCenter/myositis.asp Arthritis.org]
* [http://www.hopkinsmedicine.org/myositis The Johns Hopkins Myositis Center]

[[Category:Inflammations]]
{{SIB}}
{{Diseases of the musculoskeletal system and connective tissue}}
[[de:Myositis]]
[[pt:Miosite]]
[[ru:Миозит]]
[[sq:Myositis]]

{{WH}}
{{WS}}