Transient synovitis

Infobox_Disease
Name = PAGENAME


Caption = The hip joint is formed between the femur and acetabulum of the pelvis.
DiseasesDB =
ICD10 = ICD10|M|67|3|m|67
ICD9 =
ICDO =
OMIM =
MedlinePlus = 000981
eMedicineSubj = ped
eMedicineTopic = 1676
MeshID =

Transient synovitis of the hip (also called toxic synovitis; see below for more synonyms) is a self-limiting condition in which there is a inflammation of the inner lining (the synovium) of the 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).Fischer SU, Beattie TF. The limping child: epidemiology, assessment and outcome. J Bone Joint Surg [Br] . 1999;81-B:1029-1034.] In every day 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 adultsQuintos-Macasa AM, Serebro L, Menon Y. "Transient synovitis of the hip in an adult." "South Med J" 2006; 99(2): 184-5. PMID 16509560] ). It is the most common cause of sudden hip pain and limp in young children.Hart JJ. "Transient synovitis of the hip in children." "Am Fam Physician" 1996; 54(5): 1587–91, 1595–6. PMID 8857781] Scott Moses, MD. " [http://www.fpnotebook.com/ORT293.htm Transient hip tenosynovitis] ". Family practice notebook. Revision of August 9, 2007. Retrieved December 22, 2007.] Boys are affected two to four times as often as girls.Vijlbrief AS, Bruijnzeels MA, van der Wouden JC, van Suijlekom-Smit LW. "Incidence and management of transient synovitis of the hip: a study in Dutch general practice." Br J Gen Pract 1992; 42(363): 426-8. PMID 1466922 PMC|1466922] [http://www.gpnotebook.co.uk/simplepage.cfm?ID=2047213577 Irritable hip] . General Practice Notebook. Retrieved December 22, 2007.] The exact cause is 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.

Transient synovitis is a diagnosis of exclusion. 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 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, 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.eMedicine|ped|1676]

ynonyms

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.Do TT. Transient synovitis as a cause of painful limps in children. "Curr Opin Pediatr". 2000;12(1):48-51. PMID: 10676774]

ymptoms and signs

Transient synovitis causes pain in the hip, thigh, groin or knee on the affected side. 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 diaper). The condition is nearly always limited to one side. 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). 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.

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. Fever, raised inflammatory markers on blood tests and severe symptoms (inability to bear weight, pronounced muscle guarding) all point to septic arthritis,Caird MS, Flynn JM, Leung YL, Millman JE, D'Italia JG, Dormans JP. "Factors distinguishing septic arthritis from transient synovitis of the hip in children. A prospective study." "J Bone Joint Surg Am" 2006; 88(6): 1251–7. PMID 16757758] Kocher MS, Mandiga R, Zurakowski D, Barnewolt C, Kasser JR. "Validation of a clinical prediction rule for the differentiation between septic arthritis and transient synovitis of the hip in children." "J Bone Joint Surg Am" 2004; 86-A(8): 1629-35. PMID 15292409] but a high index of suspicious remains necessary even if these are not present. Osteomyelitis (infection of the bone tissue) can also cause pain and limp.

Bone fractures, such as a toddler's fracture (spiral fracture of the shin bone), can also cause pain and limp, but are uncommon around the hip joint. Soft tissue 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 when there has been a fall. 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.eMedicine|radio|387]

Neurological conditions can also present with a limp. If 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 testicular disease. Rarely, there is an underlying rheumatic conditions (juvenile idiopathic arthritis, 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.Caird MS, Flynn JM, Leung YL, Millman JE, D'Italia JG, Dormans JP. "Factors distinguishing septic arthritis from transient synovitis of the hip in children. A prospective study." "J Bone Joint Surg Am" 2006; 88(6): 1251–7. PMID 16757758] Kocher MS, Mandiga R, Zurakowski D, Barnewolt C, Kasser JR. "Validation of a clinical prediction rule for the differentiation between septic arthritis and transient synovitis of the hip in children." "J Bone Joint Surg Am" 2004; 86-A(8): 1629–35. PMID 15292409]

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 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.Gough-Palmer A, McHugh K. "Investigating hip pain in a well child." "BMJ" 2007; 334: 1216–1217. PMID 17556478]

An ultrasound scan of the hip can easily demonstrate fluid inside the joint capsule, although this is not always present in transient synovitis.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] However, it cannot reliably distinguish between septic arthritis and transient synovitis.Zamzam MM. "The role of ultrasound in differentiating septic arthritis from transient synovitis of the hip in children." "J Pediatr Orthop B" 2006; 15(6): 418-22. PMID 17001248] Bienvenu-Perrard M, de Suremain N, Wicart P, Moulin F, Benosman A, Kalifa G, Coste J, Adamsbaum C. "Benefit of hip ultrasound in management of the limping child." (French) "J Radiol" 2007; 88(3 Pt 1): 377-83. PMID 17457269] If septic arthritis needs to be ruled out, needle aspiration of the fluid can be performed under ultrasound guidance.Skinner J, Glancy S, Beattie TF, Hendry GM. "Transient synovitis: is there a need to aspirate hip joint effusions?" "Eur J Emerg Med" 2002; 9(1): 15-8. PMID 11989490] In transient synovitis, the joint fluid will be clear. 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).Kwack KS, Cho JH, Lee JH, Cho JH, Oh KK, Kim SY. "Septic arthritis versus transient synovitis of the hip: gadolinium-enhanced MRI finding of decreased perfusion at the femoral epiphysis." "AJR Am J Roentgenol" 2007; 189(2): 437-45. PMID 17646472] Yang WJ, Im SA, Lim GY, Chun HJ, Jung NY, Sung MS, Choi BG. "MR imaging of transient synovitis: differentiation from septic arthritis." "Pediatr Radiol" 2006; 36(11): 1154–8. PMID 17019590] Lee SK, Suh KJ, Kim YW, Ryeom HK, Kim YS, Lee JM, Chang Y, Kim YJ, Kang DS. "Septic arthritis versus transient synovitis at MR imaging: preliminary assessment with signal intensity alterations in bone marrow." "Radiology" 1999; 211(2): 459-65. PMID 10228529] Skeletal scintigraphy can be entirely normal in transient synovitis, and scintigraphic findings do not distinguish transient synovitis from other joint conditions in children.Connolly LP, Treves ST. "Assessing the limping child with skeletal scintigraphy." "J Nucl Med" 1998; 39(6): 1056–61. PMID 9627343] 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).Kermond S, Fink M, Graham K, Carlin JB, Barnett P. "A randomized clinical trial: should the child with transient synovitis of the hip be treated with nonsteroidal anti-inflammatory drugs?" "Ann Emerg Med" 2002; 40(3): 294-9. PMID 12192353] If fever occurs or the symptoms persist, other diagnoses need to be considered.

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.Mattick A, Turner A, Ferguson J, Beattie T, Sharp J. "Seven year follow up of children presenting to the accident and emergency department with irritable hip." "J Accid Emerg Med" 1999; 16(5): 345-7. PMID 10505915]

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.Sharwood PF. "The irritable hip syndrome in children. A long-term follow-up." Acta Orthop Scand 1981; 52(6): 633-8. PMID 7331801] 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.Kallio P, Ryöppy S, Kunnamo I. "Transient synovitis and Perthes' disease. Is there an aetiological connection?" J Bone Joint Surg Br 1986; 68(5): 808-11. PMID 3782251]

Further reading

* Leet AI, Skaggs DL. [http://www.aafp.org/afp/20000215/1011.html Evaluation of the Acutely Limping Child] . Am Fam Physician 2000; 61(4): 1011–8. PMID 10706154:"An illustrated, free full-text review with emphasis on clinical examination of the acutely limping child."

References

* [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
*eMedicine|ped|1676
*eMedicine|emerg|387

Footnotes