View source for Transient synovitis

{{Infobox disease
 | Name           = Transient synovitis
 | Image          = Hip.jpg
 | Caption        = The hip joint is formed between the [[femur]] and [[acetabulum]] of the [[pelvis]].
 | DiseasesDB     = 
 | ICD10          = {{ICD10|M|67|3|m|67}}
 | ICD9           = {{ICD9|727.00}}
 | ICDO           = 
 | OMIM           = 
 | MedlinePlus    = 000981
 | eMedicineSubj  = ped
 | eMedicineTopic = 1676
 | eMedicine_mult = {{eMedicine2|emerg|387}}}
 | MeshID         = 
}}
'''Transient synovitis of the hip''' (also called '''toxic synovitis'''; see below for more synonyms) is a self-limiting condition in which there is an [[inflammation]] of the inner lining (the [[synovium]]) of the [[joint capsule|capsule]] of the [[hip joint]]. The term '''irritable hip''' refers to the [[syndrome]] of acute hip pain, joint stiffness, limp or non-weightbearing, indicative of an underlying condition such as transient synovitis or orthopedic infections (like septic arthritis or osteomyelitis).<ref name="limpchild">{{cite journal |author=Fischer SU, Beattie TF |title=The limping child: epidemiology, assessment and outcome |journal=J Bone Joint Surg Br. |volume=81 |issue=6 |pages=1029–34 |year=1999 |month=Nov |pmid=10615981 |doi= 10.1302/0301-620X.81B6.9607|url=http://www.jbjs.org.uk/cgi/pmidlookup?view=long&pmid=10615981}}</ref> In everyday clinical practice however, irritable hip is commonly used as a synonym for transient synovitis.

Transient synovitis usually affects children between three and ten years old (but it has been reported in a 3-month-old infant and in adults<ref name="adult">{{cite journal |author=Quintos-Macasa AM, Serebro L, Menon Y |title=Transient synovitis of the hip in an adult |journal=South Med J |volume=99 |issue=2 |pages=184–5 |year=2006 |month=Feb |pmid=16509560 |doi= 10.1097/01.smj.0000199746.29009.4c|url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0038-4348&volume=99&issue=2&spage=184}}</ref>). It is the most common cause of sudden hip pain and limp in young children.<ref name=Hart>{{cite journal |author=Hart JJ |title=Transient synovitis of the hip in children |journal=Am Fam Physician |volume=54 |issue=5 |pages=1587–91, 1595–6 |year=1996 |month=Oct |pmid=8857781 |doi= |url=}}</ref><ref name=fpnotebook>Scott Moses, MD. "[http://www.fpnotebook.com/ORT293.htm Transient hip tenosynovitis]". Family practice notebook. Revision of August 9, 2007. Retrieved December 22, 2007.</ref> Boys are affected two to four times as often as girls.<ref name=fpnotebook/><ref name=GP>{{cite journal |author=Vijlbrief AS, Bruijnzeels MA, van der Wouden JC, van Suijlekom-Smit LW |title=Incidence and management of transient synovitis of the hip: a study in Dutch general practice |journal= The British journal of general practice : the journal of the Royal College of General Practitioners|volume=42 |issue=363 |pages=426–8 |year=1992 |month=Oct |pmid=1466922 |pmc=1372234 }}</ref><ref name=GPNotebook>[http://www.gpnotebook.co.uk/simplepage.cfm?ID=2047213577 Irritable hip]. General Practice Notebook. Retrieved December 22, 2007.</ref> The exact cause is [[idiopathic|unknown]]. A recent [[viral infection]] (most commonly an [[upper respiratory tract infection]]) or a trauma have been postulated as precipitating events, although these are reported only in 30% and 5% of cases, respectively.<ref name=GPNotebook/>

Transient synovitis is a [[diagnosis of exclusion]].<ref name="Hart"/> The diagnosis can be made in the typical setting of pain or limp in a young child who is not generally unwell and has no recent [[Physical trauma|trauma]]. There is a limited [[range of motion]] of the hip joint. Blood tests may show mild inflammation. An [[ultrasound scan]] of the hip joint can show a fluid collection ([[effusion]]). Treatment is with [[non-steroidal anti-inflammatory drugs]] and limited weight-bearing. The condition usually clears by itself within seven to ten days,<ref name="fpnotebook"/> but a small group of patients will continue to have symptoms for several weeks. The recurrence rate is 4–17%, most of which is in the first six months.<ref name=eMedicine>{{eMedicine|ped|1676}}</ref>

==Synonyms==
In addition to the terms mentioned above, irritable hip has historically been termed transitory coxitis, coxitis fugax, acute transient epiphysitis, coxitis serosa seu simplex, phantom hip disease and observation hip.<ref name=Do>{{cite journal |author=Do TT |title=Transient synovitis as a cause of painful limps in children |journal=Curr Opin Pediatr |volume=12 |issue=1 |pages=48–51 |year=2000 |month=Feb |pmid=10676774 |doi= 10.1097/00008480-200002000-00010|url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=1040-8703&volume=12&issue=1&spage=48}}</ref>

==Symptoms and signs==
Transient synovitis causes pain in the hip, [[thigh]], [[groin]] or [[knee]] on the affected side.<ref name=fpnotebook/> There may be a [[limp]] (or abnormal [[crawling]] in infants) with or without pain. In small infants, the [[presenting complaint]] can be unexplained crying (for example, when changing a nappy). The condition is nearly always limited to one side.<ref name=fpnotebook/> The pain and limp can range from mild to severe. 

Some children may have a slightly raised temperature; high [[fever]] and general [[malaise]] point to other, more serious conditions. On [[clinical examination]], the child typically holds the hip slightly bent, turned outwards and away from the middle line ([[flexion]], [[external rotation]] and [[Abduction (kinesiology)|abduction]]).<ref name="GPNotebook"/> Active and passive movements may be limited because of pain, especially abduction and [[internal rotation]]. The hip can be tender to [[palpation]]. The log roll test involves gently rotating the entire lower limb inwards and outwards with the patient on his back, to check when muscle guarding occurs. The unaffected hip and the knees, ankles, feet and spine are found to be normal.<ref name=eMedicine/>

==Differential diagnosis==
Pain in or around the hip and/or limp in children can be due to a large number of conditions. [[Septic arthritis]] (a bacterial infection of the joint) is the most important [[differential diagnosis]], because it can quickly cause irreversible damage to the hip joint.<ref name="Hart"/> Fever, raised inflammatory markers on [[blood test]]s and severe symptoms (inability to bear weight, pronounced muscle guarding) all point to septic arthritis,<ref name=Septic2006>{{cite journal |author=Caird MS, Flynn JM, Leung YL, Millman JE, D'Italia JG, Dormans JP |title=Factors distinguishing septic arthritis from transient synovitis of the hip in children. A prospective study |journal=J Bone Joint Surg Am |volume=88 |issue=6 |pages=1251–7 |year=2006 |month=Jun |pmid=16757758 |doi=10.2106/JBJS.E.00216 |url=}}</ref><ref name=Kocher2004/> but a high index of suspicious remains necessary even if these are not present.<ref name=fpnotebook/> [[Osteomyelitis]] (infection of the bone tissue) can also cause pain and limp.

[[Bone fracture]]s, such as a [[toddler's fracture]] (spiral fracture of the [[tibia|shin bone]]), can also cause pain and limp, but are uncommon around the hip joint. [[Soft tissue]] [[injury|injuries]] can be evident when [[bruises]] are present. [[Muscle]] or [[ligament]] injuries can be contracted during heavy physical activity —however, it is important not to miss a [[slipped upper femoral epiphysis]]. Avascular necrosis of the femoral head ([[Legg-Calvé-Perthes disease]]) typically occurs in children aged 4–8, and is also more common in boys. There may be an effusion on ultrasound, similar to transient synovitis.<ref name=LCP>{{eMedicine|radio|387|Legg-Calve-Perthes Disease}}</ref>

[[Neurological]] conditions can also present with a limp. If [[Hip dysplasia (human)|developmental dysplasia of the hip]] is missed early in life, it can come to attention later in this way. Pain in the groin can also be caused by diseases of the organs in the [[abdomen]] (such as a [[psoas abscess]]) or by [[testicle|testicular]] disease. Rarely, there is an underlying [[rheumatology|rheumatic]] conditions ([[juvenile idiopathic arthritis]], [[Lyme disease|Lyme arthritis]], [[gonococcal arthritis]], ...) or [[bone tumour]].

==Diagnosis==
There are no set standards for the diagnosis of suspected transient synovitis, so the amount of investigations will depend on the need to exclude other, more serious diseases.

Inflammatory parameters in the blood may be slightly raised (these include [[erythrocyte sedimentation rate]], [[C-reactive protein]] and [[white blood cell count]]), but raised inflammatory markers are strong predictors of other more serious conditions such as septic arthritis.<ref name="Septic2006"/><ref name=Kocher2004>{{cite journal |author=Kocher MS, Mandiga R, Zurakowski D, Barnewolt C, Kasser JR |title=Validation of a clinical prediction rule for the differentiation between septic arthritis and transient synovitis of the hip in children |journal=J Bone Joint Surg Am |volume=86-A |issue=8 |pages=1629–35 |year=2004 |month=Aug |pmid=15292409 |doi= |url=http://www.ejbjs.org/cgi/pmidlookup?view=long&pmid=15292409}}</ref>

[[X-ray]] imaging of the hip is most often unremarkable. Subtle radiographic signs include an accentuated pericapsular shadow, widening of the joint space, lateral displacement of the femoral epiphyses with surface flattening ([[Waldenström sign]]), prominent [[obturator muscle|obturator]] shadow, diminution of soft tissue planes around the hip joint or slight demineralisation of the proximal femur. The main reason for radiographic examination is to exclude bony lesions such as occult fractures, [[slipped upper femoral epiphysis]] or bone tumours (such as [[osteoid osteoma]]). An anteroposterior and frog lateral (Lauenstein) view of the pelvis and both hips is advisable.<ref name=BMJ2007>{{cite journal |author=Gough-Palmer A, McHugh K |title=Investigating hip pain in a well child |journal=BMJ |volume=334 |issue=7605 |pages=1216–7 |year=2007 |month=Jun |pmid=17556478 |pmc=1892599 |doi=10.1136/bmj.39188.515741.47 |url=}}</ref>

An [[ultrasound scan]] of the hip can easily demonstrate fluid inside the joint capsule, although this is not always present in transient synovitis.<ref name=GPNotebook/><ref name=BestBETs>Nicola Wright, Vince Choudhery. [http://www.bestbets.org/cgi-bin/bets.pl?record=00108 Ultrasound is better than x-ray at detecting hip effusions in the limping child]. BestBETs.org . Retrieved December 22, 2007</ref> However, it cannot reliably distinguish between septic arthritis and transient synovitis.<ref name=Zamzam>{{cite journal |author=Zamzam MM |title=The role of ultrasound in differentiating septic arthritis from transient synovitis of the hip in children |journal=J Pediatr Orthop B |volume=15 |issue=6 |pages=418–22 |year=2006 |month=Nov |pmid=17001248 |doi=10.1097/01.bpb.0000228388.32184.7f |doi_brokendate=2008-10-18 }}</ref><ref name=Radiol>{{cite journal |author=Bienvenu-Perrard M, de Suremain N, Wicart P, ''et al.'' |title=[Benefit of hip ultrasound in management of the limping child] |language=French |journal=J Radiol |volume=88 |issue=3 Pt 1 |pages=377–83 |year=2007 |month=Mar |pmid=17457269 |doi= 10.1016/S0221-0363(07)89834-9|url=http://www.masson.fr/masson/MDOI-JR-03-2007-88-3-C1-0221-0363-101019-200700352 |trans_title=Benefit of hip ultrasound in management of the limping child}}</ref> If septic arthritis needs to be ruled out, [[needle aspiration]] of the fluid can be performed under ultrasound guidance.<ref name=aspiration>{{cite journal |author=Skinner J, Glancy S, Beattie TF, Hendry GM |title=Transient synovitis: is there a need to aspirate hip joint effusions? |journal=Eur J Emerg Med |volume=9 |issue=1 |pages=15–8 |year=2002 |month=Mar |pmid=11989490 |doi= 10.1097/00063110-200203000-00005|url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0969-9546&volume=9&issue=1&spage=15}}</ref> In transient synovitis, the joint fluid will be clear.<ref name=fpnotebook/> In septic arthritis, there will be [[pus]] in the joint, which can be sent for [[bacterial culture]] and [[antibiotic sensitivity]] testing.

More advanced imaging techniques can be used if the clinical picture is unclear; the exact role of different imaging modalities remains uncertain. Some studies have demonstrated findings on [[magnetic resonance imaging]] (MRI scan) that can differentiate between septic arthritis and transient synovitis (for example, signal intensity of adjacent [[bone marrow]]).<ref name=AJR>{{cite journal |author=Kwack KS, Cho JH, Lee JH, Cho JH, Oh KK, Kim SY |title=Septic arthritis versus transient synovitis of the hip: gadolinium-enhanced MRI finding of decreased perfusion at the femoral epiphysis |journal=AJR Am J Roentgenol |volume=189 |issue=2 |pages=437–45 |year=2007 |month=Aug |pmid=17646472 |doi=10.2214/AJR.07.2080 |url=}}</ref><ref name=Yang2006>{{cite journal |author=Yang WJ, Im SA, Lim GY, ''et al.'' |title=MR imaging of transient synovitis: differentiation from septic arthritis |journal=Pediatr Radiol |volume=36 |issue=11 |pages=1154–8 |year=2006 |month=Nov |pmid=17019590 |doi=10.1007/s00247-006-0289-9 |url=}}</ref><ref name=Lee1999>{{cite journal |author=Lee SK, Suh KJ, Kim YW, ''et al.'' |title=Septic arthritis versus transient synovitis at MR imaging: preliminary assessment with signal intensity alterations in bone marrow |journal=Radiology |volume=211 |issue=2 |pages=459–65 |year=1999 |month=May |pmid=10228529 |doi= |url=http://radiology.rsnajnls.org/cgi/pmidlookup?view=long&pmid=10228529}}</ref> [[Skeletal scintigraphy]] can be entirely normal in transient synovitis, and scintigraphic findings do not distinguish transient synovitis from other joint conditions in children.<ref name=scintigraphy>{{cite journal |author=Connolly LP, Treves ST |title=Assessing the limping child with skeletal scintigraphy |journal=J Nucl Med |volume=39 |issue=6 |pages=1056–61 |year=1998 |month=Jun |pmid=9627343 |doi= |url=http://jnm.snmjournals.org/cgi/pmidlookup?view=long&pmid=9627343}}</ref> [[Computer tomography|CT scanning]] does not appear helpful.

==Treatment==
Treatment consists of rest, non-weightbearing and [[painkillers]] when needed. A small study showed that the [[non-steroidal anti-inflammatory drug]] [[ibuprofen]] could shorten the disease course (from 4.5 to 2 days) and provide pain control with minimal side effects (mainly [[gastrointestinal]] disturbances).<ref name=Kermond2002>{{cite journal |author=Kermond S, Fink M, Graham K, Carlin JB, Barnett P |title=A randomized clinical trial: should the child with transient synovitis of the hip be treated with nonsteroidal anti-inflammatory drugs? |journal=Ann Emerg Med |volume=40 |issue=3 |pages=294–9 |year=2002 |month=Sep |pmid=12192353 |doi= 10.1067/mem.2002.126171|url=http://linkinghub.elsevier.com/retrieve/pii/S0196064402000422}}</ref> If fever occurs or the symptoms persist, other diagnoses need to be considered.<ref name=eMedicine/>

==Complications==
In the past, there have been speculations about possible complications after transient synovitis. The current consensus however is that there is no proof of an increased risk of complications after transient synovitis.<ref name="follow-up">{{cite journal |author=Mattick A, Turner A, Ferguson J, Beattie T, Sharp J |title=Seven year follow up of children presenting to the accident and emergency department with irritable hip |journal=J Accid Emerg Med |volume=16 |issue=5 |pages=345–7 |year=1999 |month=Sep |pmid=10505915 |pmc=1347055 |doi= |url=}}</ref>

One such previously suspected complication was [[coxa magna]], which is an overgrowth of the femoral head and broadening of the femoral neck, accompanied by changes in the acetabulum, which may lead to subluxation of the femur.<ref name=eMedicine/><ref name=coxa>{{cite journal |author=Sharwood PF |title=The irritable hip syndrome in children. A long-term follow-up |journal=Acta Orthop Scand |volume=52 |issue=6 |pages=633–8 |year=1981 |month=Dec |pmid=7331801 |doi=10.3109/17453678108992159 }}</ref> There was also some controversy about whether continuous high intra-articular pressure in transient synovitis could cause avascular necrosis of the femoral head ([[Legg-Calvé-Perthes disease]]), but further studies did not confirm any link between the two conditions.<ref name=Perthes>{{cite journal |author=Kallio P, Ryöppy S, Kunnamo I |title=Transient synovitis and Perthes' disease. Is there an aetiological connection? |journal=J Bone Joint Surg Br |volume=68 |issue=5 |pages=808–11 |year=1986 |month=Nov |pmid=3782251 |doi= |url=http://www.jbjs.org.uk/cgi/pmidlookup?view=long&pmid=3782251}}</ref>

==References==
{{Reflist|2}}

==External links==
* {{cite journal |author=Leet AI, Skaggs DL |title=Evaluation of the acutely limping child |journal=Am Fam Physician |volume=61 |issue=4 |pages=1011–8 |year=2000 |month=Feb |pmid=10706154 |doi= |url=http://www.aafp.org/afp/20000215/1011.html}}: ''An illustrated, free full-text review with emphasis on clinical examination of the acutely limping child.''
*[http://www.nhsdirect.nhs.uk/articles/article.aspx?articleId=218&sectionId=11074 Irritable hip] - [[NHS Direct]] - Health encyclopaedia
*[http://familydoctor.org/online/famdocen/home/children/parents/special/bone/181.html Transient Synovitis of the Hip: A Cause of Hip Pain in Children] - by Familydoctor.org, a web site operated by the [[American Academy of Family Physicians]]
*[http://knol.google.com/k/aria-nouri/transient-synovitis-a-complete-review/323l6mxrqspt7/5# Transient Synovitis: A Complete Review] - by knol.google.com
{{Soft tissue disorders}}

[[Category:Pediatrics]]
[[Category:Inflammations]]
[[Category:Disorders of synovium and tendon]]

[[cy:Clun lidus]]
[[de:Coxitis fugax]]
[[fr:Rhume de hanche]]
[[Category:2Fix]]