A 6 year old child presents with pain and tenderness in hip

A 6 year old child presents with pain and tenderness in hip in femoral triangle region. limitation of movements, X-ray does not reveal any abnormality. What is the next step?
A. USG
B. MRI
C. traction
D. Wait and watch

Ans:A/B(PROBABLY B>A)

What are the symptoms?

Symptoms of septic arthritis occur suddenly and are characterized by severe pain, swelling in the affected joint along with acute pain. Chills and fever are also common symptoms. Septic arthritis in the hip may be experienced as pain in the groin area that becomes much worse if the patient tries to walk. In the majority of cases, there is some leakage of tissue fluid into the affected joint. The joint is sore to the touch, and may or may not be warm to the touch, depending on how deep the infection lies within the joint. Children sometimes develop nausea and vomiting.
How is it diagnosed?

Your doctor will diagnose septic arthritis based upon your symptoms, your medical history, a complete physical exam, and synovial fluid and blood tests. After numbing the area, he or she will withdraw a sample of synovial fluid from the affected joint. This fluid will be tested for white blood cells, which are usually high, and for bacteria and other organisms. Some of the joint fluid will be placed in a special container in which many types of bacteria can grow and be identified.

The doctor may perform an arthrocentesis, which is a procedure that involves withdrawing a sample of synovial fluid from the joint with a needle and syringe for testing. The doctor may also perform a culture of blood and urine to rule out other causes such as gout, acute rheumatic fever, rheumatoid arthritis, Lyme disease and other disorders that can cause a combination of joint pain and fever. In some cases, the doctor may consult a specialist in orthopedics or rheumatology to avoid misdiagnosis. Because septic arthritis can quickly destroy a joint unless treated, your doctor may also order x-rays to assess any joint damage.
What is the treatment?

Septic arthritis must be diagnosed quickly and treated with antibiotics. Your doctor may first give these antibiotics intravenously (through a vein) to make sure the infected joint receives medication to kill the bacteria as quickly as possible. Then, the remaining course of antibiotics is taken orally.

The doctor may also need to drain the fluid from the infected joints if it rapidly reaccumulates and causes symptoms. Immediate surgical drainage is reserved for septic arthritis of the hip, because that site is inaccessible for repeated fluid removal. For most other joints, surgical drainage is used only if medical therapy fails over two to four days to alleviate symptoms. Hot compresses and splinting the joint to provide it with rest and support can help relieve pain. After a period of rest, your doctor will recommend gentle exercise to prevent stiffness. If septic arthritis occurs in an artificial joint, antibiotic treatment may need to be followed by surgery to replace the joint. Most patients with no other serious underlying disease recover fully from septic arthritis with antibiotic therapy.

Recovery from septic arthritis is usually good with most patients undergoing treatment, although many patients will develop osteoarthritis or deformed joints. Children with infected hip joints sometimes suffer damage to the growth plate. Patients with severe damage to bone or cartilage may need reconstructive surgery, but it cannot be performed until the infection is completely gone.

Septic Arthritis Versus Transient Synovitis of the Hip: Gadolinium-Enhanced MRI Finding of Decreased Perfusion at the Femoral Epiphysis
Kyu-Sung Kwack1, Jae Hyun Cho1, Jei Hee Lee1, Jae Ho Cho2, Ki Keun Oh3 and Sun Yong Kim1

1 Department of Radiology, Ajou University Medical Center, Wonchun Dong, Yongtong Gu, Suwon 442-721, Republic of Korea.
2 Department of Orthopaedic Surgery, Ajou University Medical Center, Suwon, South Korea.
3 Department of Radiology, Yonsei University College of Medicine, Seoul, Korea.

OBJECTIVE. The purpose of this study was to identify differences in the MRI findings of septic arthritis and transient synovitis in patients with nontraumatic acute hip pain and hip effusion.

MATERIALS AND METHODS. The MRI findings in nine patients with septic arthritis and 11 with transient synovitis were reviewed retrospectively. This study was approved by our institutional review board. The diagnoses were based on findings at physical examination, laboratory studies, and joint aspiration and bacteriologic study. The MRI findings were analyzed with emphasis on the grade of joint effusion, alterations in signal intensity in the soft tissues and bone marrow, and the presence of decreased perfusion at the femoral head.

RESULTS. Low signal intensity on fat-suppressed gadolinium-enhanced T1-weighted coronal MRI suggesting decreased perfusion at the femoral head of the affected hip joint was seen in eight of nine patients with septic arthritis and in two of 11 patients with transient synovitis. Statistically reliable differences (p = 0.005) were found between the two groups. Alterations in signal intensity in the bone marrow were seen in three patients with septic arthritis but in none of the patients with transient synovitis. Decreased perfusion on fat-suppressed gadolinium-enhanced coronal T1-weighted MRI was seen in the six patients with septic arthritis who did not have alterations in signal intensity involving the bone marrow.

CONCLUSION. Decreased perfusion at the femoral epiphysis on fat-suppressed gadolinium-enhanced coronal T1-weighted MRI is useful for differentiating septic arthritis from transient synovitis.

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.

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.

An ultrasound scan of the hip can easily demonstrate fluid inside the joint capsule, although this is not always present in transient synovitis. However, it cannot reliably distinguish between septic arthritis and transient synovitis. If septic arthritis needs to be ruled out, needle aspiration of the fluid can be performed under ultrasound guidance. 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)

Diagnosis

Septic arthritis should be considered whenever one is assessing a patient with joint pain. Usually only one joint is affected (monoarthritis) however in seeding arthritis, several joints can be affected simultaneously; this is especially the case when the infection is caused by staphylococcus or gonococcus bacteria.

The diagnosis of septic arthritic can be difficult as no test is able to completely rule out the possibility.

A number of factors should increase one's suspicion of the presence of an infection. In children these are: fever > 38.5 C, non-weight-bearing, serum WBCs > 12 x 10^9, ESR > 40 mm/hr, CRP > 20 mg/dL, a previous visit for the same.

Diagnosis is by aspiration (giving a turbid, non-viscous fluid), Gram stain and culture of fluid from the joint, as well as tell-tale signs in laboratory testing (such as a highly elevated neutrophils (approx. 90%), ESR or CRP). The ESR and CRP are almost always raised on admission, CRP being faster in diagnostics.

The Gram stain can rule in the diagnosis of septic arthritis however cannot exclude it.
Treatment

Therapy is usually with intravenous antibiotics, analgesia and washout/aspiration of the joint to dryness. Among pediatric patients with an acute hematogenous septic arthritis a short total course of 10 days of antimicrobials is sufficient in uncomplicated cases.

In infection of a prosthetic joint, a biofilm is often created on the surface of the prosthesis which is resistant to antibiotics. Surgical debridement or arthrotomy is usually indicated in these cases. A replacement prosthesis is usually not inserted at the time of removal to allow antibiotics to clear infection of the region.

Patients in whom surgery is contraindicated may trial long-term antibiotic therapy.
Radiologic findings

The diagnosis of septic arthritis is based on clinical assessment and prompt arthrocentesis. Imaging can sometimes be used to aid in the diagnosis of septic arthritis.

Native X-ray of the joint is neither sensitive nor specific. Ultrasound can detect joint-swelling. MRI findings include: synovial enhancement, perisynovial edema and joint effusion. Signal abnormalities in the bone marrow can indicate a concomitant osteomyelitis. The sensitivity and specificity of MRI for the detection of septic arthritis has been reported to be 67% and 98% respectively.

Ans: MRI/WAIT AND WATCH?

Surgery

Surgery is not usually necessary. In severe cases of transient synovitis children may be hospitalized for observation and leg traction. Applying pull on the hip through the leg can reduce the pressure inside the joint capsule. If the child is cooperative, home traction may be possible.

Transient synovitis of the hip in childhood. "observation hip" (author's transl)].


Abstract

Thirty-eight children suffering of a transient synovitis of the hip joint have been reviewed with a follow up of 2 to 20 years (mean 7 years). It appears that this affection is not as benign as it seems, for in 1/3 of the cases it remains clinical and roentgenographic sequelae some of them looking like a minor degree of Legg Perthes' disease. The authors insist on the treatment, with traction in bed, and on the necessity of a new roentgenogram 45 days after the onset of the illness, to exclude the risk of an osteochondritis of the hip joint. Nuclide bone scan cannot affirm the diagnosis of transient synovitis, but can only eliminate an osteochondritis of the hip when it shows hyperfixation of the hip.

Diagnosis

How do doctors diagnose this condition?

The history and physical examination are probably the most important tools the physician uses to diagnose transient synovitis of the hip. Motion is usually limited and painful. The hip is tender to palpation.

X-rays are usually taken. Though radiographs don't show synovitis, they do help the physician rule out a fracture, tumor, or slipped capital femoral epiphysis (slippage of the growth plate). More advanced imaging such as MRI or bone scan may be needed if there is a need to rule out other more serious problems.

A blood test will show mild inflammation. If needed, the physician may order an ultrasound of the hip. This test will show any effusion (fluid collection) in the hip joint. Drawing the fluid out with a needle called needle aspiration will show if there is pus in the joint from septic (bacterial) arthritis. The fluid is clear in transient synovitis.

Transient Synovitis

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- Discussion:
- relatively short lived acute inflammatory process;
- usually seen in boys aged 2 to 10 years;
- frequently follows an upper respiratory tract infection;
- most common cause of painful hips in childhood;
- is a diagnosis of exclusion;
- diff dx: (see diff dx of childhood arthritis)
- septic arthritis;
- in the report by MS Kocher et al., the authors sought to distinguish transient synovitis vs sepsis on the basis of lab data and patient history;
- independent clinical predictors between septic arthritis and transient synovitis included history of fever, non-wt-bearing,
ESR of at least forty mm/hr, and serum WBC of more than 12,000;
- the predicted probability for septic arthritis were 93% if three of these variables were present and were over 99% if all 4 predictors were present;
- the authors recommend careful observation without aspiration if none of the four independent predictors are present;
- reference:
- Differentiating Between Septic Arthritis and Transient Synovitis of the Hip in Children: An Evidence-Based Clinical Prediction Algorithm. MS Kocher MD. JBJS. Vol 81-A. Dec 1999. p 1662.


- JRA
- Perthes disease;
- if initial radiographs are normal and there is strong suspicion of Perthes disease, bone
scanning and MRI may be helpful;
- likelihood of transient synovitis leading to Perthes disease is small, certainly less than 3%;




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- Clinical Findings:
- findings include hip pain, muscle spasm, restriction of motion, refusal to walk, and low grade fever;
- onset can be acute or insidious;


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- Management:
- aspiration of the hip joint is usually needed to rule out septic arthritis;
- consider this to be a dx of exclusion;
- symptoms of toxic synovitis should show improvement after 24 hrs of traction;


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Coxa magna following transient synovitis of the hip.