Editing Mumps (section)

==Signs and symptoms==
===Common symptoms===
The [[incubation period]], the time between the start of an infection and when symptoms begin to show, is about 7–25 days,<ref name=su >{{cite journal |vauthors=Su SB, Chang HL, Chen AK |date=5 March 2020 |title=Current Status of Mumps Virus Infection: Epidemiology, Pathogenesis, and Vaccine |journal=Int J Environ Res Public Health |volume=17 |issue=5 |pages=1686 |doi=10.3390/ijerph17051686 |pmc=7084951 |pmid=32150969 |doi-access=free }}</ref><ref name=davison >{{cite journal |url=https://www.ncbi.nlm.nih.gov/books/NBK534785/ |title=Mumps |vauthors=Davison P, Morris J |date=13 August 2020 |website=NCBI |publisher=StatPearls |pmid=30521206 |access-date=30 October 2020}}</ref> averaging 16–18 days.<ref name=levine >{{cite journal |vauthors=Levine DA |date=December 2016 |title=Vaccine-Preventable Diseases In Pediatric Patients: A Review Of Measles, Mumps, Rubella, And Varicella |url=https://www.ebmedicine.net/topics/infectious-disease/pediatric-mmr-varicella |journal=Pediatr Emerg Med Pract |volume=13 |issue=12 |pages=1–20 |pmid=27893360 |access-date=30 October 2020}}</ref> 20–40%<ref name=kutty >{{cite journal |vauthors=Kutty PK, Kyaw MH, Dayan GH, Brady MT, Bocchini JA, Reef SE, Bellini WJ, Seward JF |title=Guidance for isolation precautions for mumps in the United States: a review of the scientific basis for policy change |journal=Clinical Infectious Diseases |date=15 June 2010 |volume=50 |issue=12 |pages=1619–1628 |doi=10.1086/652770 |pmid=20455692 |doi-access=|s2cid=15656133 }}</ref> of infections are asymptomatic or are restricted to mild respiratory symptoms, sometimes with a fever.<ref name=rubin >{{cite journal |vauthors=Rubin S, Eckhaus M, Rennick LJ, Bamford CG, Duprex WP |date=January 2015 |title=Molecular biology, pathogenesis and pathology of mumps virus |journal=J Pathol |volume=235 |issue=2 |pages=242–252 |doi=10.1002/path.4445 |pmc=4268314 |pmid=25229387}}</ref><ref name=kessler >{{cite journal |vauthors=Kessler AT, Bhatt AA |date=15 November 2018 |title=Review of the Major and Minor Salivary Glands, Part 1: Anatomy, Infectious, and Inflammatory Processes |journal=J Clin Imaging Sci |volume=8 |pages=47 |doi=10.4103/jcis.JCIS_45_18 |pmc=6251248 |pmid=30546931 |doi-access=free }}</ref> Over the course of the disease, three distinct phases are recognized: prodromal, early acute, and established acute. The prodromal phase typically has non-specific, mild symptoms such as a low-grade fever, headache, malaise, muscle pain, loss of appetite, and sore throat.<ref name=rubin /><ref name=cdc >{{cite web |url=https://www.cdc.gov/vaccines/pubs/pinkbook/mumps.html |title=Mumps |author=<!--Not stated--> |website=Centers for Disease Control and Prevention (CDC) |publisher=CDC |access-date=30 October 2020 }}</ref><ref name=pmh >{{cite web |url=http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002524/ |title=Mumps |author=<!--Not stated--> |website=National Center for Biotechnology Information |publisher=A.D.A.M. Medical Encyclopedia |archive-url=https://web.archive.org/web/20141017215609/http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002524/ |access-date=30 October 2020 |archive-date=17 October 2014 }}</ref> In the early acute phase, as the mumps virus spreads throughout the body, systemic symptoms emerge. Most commonly, parotitis occurs during this time period. During the established acute phase, orchitis, meningitis, and encephalitis may occur, and these conditions are responsible for the bulk of mumps morbidity.<ref name=rubin />

The parotid glands are salivary glands situated on the sides of the mouth in front of the ears. Inflammation of them, called parotitis, is the most common mumps symptom and occurs in about 90%<ref name=who >{{cite journal |vauthors=<!--No authors listed--> |date=1 June 2012 |title=Mumps virus nomenclature update: 2012 |url=https://iris.who.int/bitstream/handle/10665/241923/WER8722.PDF| journal=Wkly Epidemiol Rec|volume=87 |issue=22 |pages=217–224 |pmid=24340404 |format=PDF |access-date=30 October 2020}}</ref> of symptomatic cases and 60–70% of total infections.<ref name=davis >{{cite journal |vauthors=Davis NF, McGuire BB, Mahon JA, Smyth AE, O'Malley KJ, Fitzpatrick JM |date=April 2010 |title=The increasing incidence of mumps orchitis: a comprehensive review |journal=BJU Int |volume=105 |issue=8 |pages=1060–1065 |doi=10.1111/j.1464-410X.2009.09148.x |pmid=20070300 |s2cid=20761646 |doi-access=free }}</ref> During mumps parotitis, usually both the left and right parotid glands experience painful swelling,<ref name=davis /> with unilateral swelling in a small percentage of cases.<ref name=kessler /> Parotitis occurs 2–3 weeks after exposure to the virus, within two days of developing symptoms, and usually lasts 2–3 days, but it may last as long as a week or longer.<ref name=rubin /><ref name=cdc />

In 90% of parotitis cases, swelling on one side is delayed rather than both sides swelling in unison.<ref name=davis /> The [[parotid duct]], which is the opening that provides saliva from the parotid glands to the mouth, may become red, swollen, and filled with fluid. Parotitis is usually preceded by local tenderness and occasionally earache.<ref name=davison /><ref name=gupta >{{cite journal |vauthors=Gupta RK, Best J, MacMahon E |date=14 May 2005 |title=Mumps and the UK epidemic 2005 |journal=BMJ |volume=330 |issue=7500 |pages=1132–1135 |doi=10.1136/bmj.330.7500.1132 |pmc=557899 |pmid=15891229}}</ref> Other salivary glands, namely the [[Submandibular gland|submandibular]], and [[sublingual gland]]s, may also swell. Inflammation of these glands is rarely the only symptom.<ref name=rubin />

===Complications===
Outside of the salivary glands, inflammation of the [[testes]], called [[orchitis]], is the most common symptom of infection. Pain, swelling, and warmness of a testis appear usually 1–2 weeks<ref name=masarani >{{cite journal |vauthors=Masarani M, Wazait H, Dinneen M |date=November 2006 |title=Mumps orchitis |journal=J R Soc Med |volume=99 |issue=11 |pages=573–575 |doi=10.1177/014107680609901116 |pmc=1633545 |pmid=17082302 }}</ref> after the onset of parotitis but can occur up to six weeks later. During mumps orchitis, the scrotum is tender and inflamed. It occurs in 10–40% of pubertal and post-pubertal males who contract mumps. Usually, mumps orchitis affects only one testis but in 10–30%<ref name=masarani /> of cases both are affected. Mumps orchitis is accompanied by inflammation of the [[epididymis]], called [[epididymitis]], about 85% of the time, typically occurring before orchitis. The onset of mumps orchitis is associated with a high-grade fever, vomiting, headache, and malaise.<ref name=rubin /><ref name=davis /> In prepubertal males, orchitis is rare as symptoms are usually restricted to parotitis.<ref name=davis />

A variety of other inflammatory conditions may also occur as a result of mumps virus infection, including:<ref name=rubin />
* [[Mastitis]], inflammation of the breasts, in up to about 30% of post-pubertal women<ref name=shu >{{cite journal |vauthors=Shu M, Zhang YQ, Li Z, Liu GJ, Wan C, Wen Y |date=18 April 2015 |title=Chinese medicinal herbs for mumps |journal=Cochrane Database Syst Rev |volume=2015 |issue=4 |pages=CD008578 |doi=10.1002/14651858.CD008578.pub3 |pmc=7198052 |pmid=25887348 }}</ref>
* [[Oophoritis]], inflammation of an ovary, in 5–10% of post-pubertal women, which usually presents as pelvic pain
* Aseptic [[meningitis]], inflammation of the meninges, in 5–10% of cases<ref name=latner >{{cite journal |vauthors=Latner DR, Hickman CJ |date=7 May 2015 |title=Remembering mumps |journal=PLOS Pathog |volume=11 |issue=5 |pages=e1004791 |doi=10.1371/journal.ppat.1004791 |pmc=4423963 |pmid=25951183 |doi-access=free }}</ref> and 4–6% of those with parotitis, typically occurring 4–10 days after the onset of symptoms. Mumps meningitis can also occur up to one week before parotitis as well as in the absence of parotitis. It is commonly accompanied by fever, headache, vomiting, and neck stiffness.<ref name=junghanss >{{cite book |author=Junghanss T |title=Manson's tropical diseases |date=2013 |publisher=Elsevier/Saunders |location=Oxford |isbn=978-0-7020-5306-1 |page=261 |edition=23rd |url=https://books.google.com/books?id=GTjRAQAAQBAJ&pg=PA261 |url-status=live |access-date=30 October 2020 |archive-url=https://web.archive.org/web/20160513194608/https://books.google.com/books?id=GTjRAQAAQBAJ&pg=PA261 |archive-date=13 May 2016}}</ref>
* [[Pancreatitis]], inflammation of the pancreas, in about 4% of cases, which causes severe pain and tenderness in the upper abdomen below the ribs
* [[Encephalitis]], inflammation of the brain, in less than 0.5% of cases.<ref name=latner /> People who experience mumps encephalitis typically experience a fever, altered consciousness, seizures, and weakness. Like meningitis, mumps encephalitis can occur in the absence of parotitis.<ref name=junghanss />
* [[Meningoencephalitis]], inflammation of the brain and its surrounding membranes. Mumps meningoencephalitis is commonly accompanied by fever 97% of the time, vomiting 94% of the time, and headache 88.8% of the time.<ref name=kanra >{{cite journal |vauthors=Kanra G, Isik P, Kara A, Cengiz AB, Seçmeer G, Ceyhan M |date=December 2004 |title=Complementary findings in clinical and epidemiologic features of mumps and mumps meningoencephalitis in children without mumps vaccination |journal=Pediatr Int |volume=46 |issue=6 |pages=663–668 |doi=10.1111/j.1442-200x.2004.01968.x |pmid=15660864|s2cid=43534364 }}</ref>
* [[Nephritis]], inflammation of the kidneys, which is rare because kidney involvement in mumps is usually benign but leads to [[Viruria|presence of the virus in urine]]
* Inflammation of the joints ([[arthritis]]), which may affect at least five joints ([[polyarthritis]]),<ref name=senanayake >{{cite journal |vauthors=Senanayake SN |date=20 October 2008 |title=Mumps: a resurgent disease with protean manifestations |url=https://www.mja.com.au/journal/2008/189/8/mumps-resurgent-disease-protean-manifestations |journal=Med J Aust |volume=189 |issue=8 |pages=456–459 |doi=10.5694/j.1326-5377.2008.tb02121.x |pmid=18928441 |s2cid=13771290 |access-date=30 October 2020|url-access=subscription }}</ref> multiple nerves in the peripheral nervous system ([[polyneuritis]]), [[pneumonia]],<ref name=davison /> gallbladder without gallstones (acalculous cholecystitis), cornea and uveal tract (keratouveitis), thyroids ([[thyroiditis]]), liver ([[hepatitis]]), retina ([[retinitis]]), and [[corneal endothelium]] (corneal endothelitis), all of which are rare<ref name=rubin /><ref name=shu />
* Recurrent [[sialadenitis]], inflammation of the salivary glands, which is frequent<ref name=davison />

A relatively common complication is [[deafness]], which occurs in about 4% of cases.<ref name=who /> Mumps deafness is often accompanied by vestibular symptoms such as [[vertigo]] and [[Nystagmus|repetitive, uncontrolled eye movements]]. Based on electrocardiographic abnormalities in the infected, MuV also likely infects cardiac tissue, but this is usually asymptomatic. Rarely, [[myocarditis]] and [[pericarditis]] can occur. Fluid buildup in the brain, called [[hydrocephalus]], has also been observed.<ref name=rubin /><ref name=junghanss /> In the first trimester of pregnancy, mumps may increase the risk of miscarriage. Otherwise, mumps is not associated with birth defects.<ref name=gupta /><ref name=shu />

Other rare complications of infection include: paralysis, seizures, cranial nerve palsies, [[cerebellar ataxia]], [[transverse myelitis]], [[ascending polyradiculitis]], a [[polio]]-like disease, [[arthropathy]], [[autoimmune hemolytic anemia]],<ref name=rubin /> [[idiopathic thrombocytopenic purpura]], [[Guillain–Barré syndrome]], post-infectious encephalitis<ref name=shu /> [[encephalomyelitis]],<ref name=senanayake /> and [[hemophagocytic syndrome]].<ref name=davis /> At least one complication occurs in combination with the standard mumps symptoms in up to 42% of cases.<ref name=davis /> Mumps has also been connected to the onset of [[type&nbsp;1 diabetes]], and, relatedly, the mumps virus is able to infect and replicate in [[insulin]]-producing [[beta cell]]s.<ref name=smatti >{{cite journal |vauthors=Smatti MK, Cyprian FS, Nasrallah GK, Al-Thani AA, Almishal RO, Yassine HM |date=19 August 2019 |title=Viruses and Autoimmunity: A Review on the Potential Interaction and Molecular Mechanisms |journal=Viruses |volume=11 |issue=8 |pages=762 |doi=10.3390/v11080762 |pmc=6723519 |pmid=31430946 |doi-access=free }}</ref> Among children, seizures occur in about 20–30% of cases involving the central nervous system.<ref name=gupta />