Septic arthritis and transient synovitis (pediatrics): Clinical sciences

Chapters:

Watch video only

Introduction0:00–0:27

Septic arthritis is a bacterial infection of the synovium and joint space. While transient synovitis also called toxic synovitis refers to a noninfectious synovial inflammation.
While transient synovitis is a benign and self-limited illness. It's crucial to identify and treat septic arthritis promptly to prevent permanent bone and joint damage.
When a pediatric patient presents with a chief concern, suggesting septic arthritis or transient synovitis first perform an ABCD E assessment to determine if the patient is unstable or stable if unstable, stabilize their airway breathing and circulation.

Unstable patient0:27–1:04

Next, obtain IV access, consider starting IV fluids and put your patient on continuous vital sign monitoring including respiratory rate, pulse oximetry and cardiac monitoring.
Finally, if needed, don't forget to provide supplemental oxygen and administer broad spectrum intravenous antibiotics. Now, let's go back to the ABCD E assessment and take a look at stable patients in this case.

Stable patient1:04–1:25

Obtain a focused history and physical exam and order labs including CBCC RP and E SR first, let's focus on septic arthritis.
Affected Children typically experience a rapid onset of monoarticular joint pain and swelling that most commonly involves a large joint in the lower extremity such as the knee or hip caregivers also often report systemic symptoms like fever, malaise or decreased appetite.

Septic Arthritis1:25–2:34

Some ambulatory Children may develop a limp but most will refuse to bear weight on the affected limb. Finally, infants and nonambulatory Children may display pseudoparalysis which is an inability to move the affected joint due to pain on physical exam.
Patients are usually ill appearing with signs of inflammation including erythema, warmth of the skin, overlying the affected joint and joint effusion.
Patients classically display limited range of motion in the affected joint. And those with hip involvement typically prefer to keep their hips flexed, abducted and externally rotated.
Finally, labs will reveal an elevated white blood cell count with neutrophilia crp greater than 1 mg per deciliter and esr greater than 40 mL per hour.
The presence of these findings should make you suspect septic arthritis. So your next step is to perform an arthrocentesis.

Suspect Septic Arthritis2:34–3:05

This procedure can be both diagnostic and therapeutic. Since removing infected synovial fluid can relieve pressure within the joint space.
Next, syn synovial fluid for analysis, which includes a gram staining culture as well as a cell count and differential. Additionally, consider ordering a blood culture if your patient is ill appearing or if they are an infant.
Once you've performed arthrocentesis, don't wait for results. Instead start empiric IV antibiotics immediately.

Septic Arthritis - antibiotics3:05–4:02

Now, here's a high old fact to keep in mind when selecting an empiric antibiotic, be sure to consider your patient's age and any risk factors to cover the most likely causative pathogens.
Septic arthritis in Children is most commonly caused by staphylococcus aureus, followed by streptococcus pyogenes for unimmunized Children or those younger than five.
Also consider kingella kingae streptococcus pneumoniae and haemophilus influenzae type B. Neonates with suspected septic arthritis should receive antibiotics that cover group B.
Strep staphylococcus aureus and gram negative bacilli. Finally, patients with sickle cell disease should receive coverage for salmonella.
While sexually active adolescents may require coverage for Neisseria, gonorrhea. Now, let's review the lab results.

Septic Arthritis - diagnosis4:02–4:38

The synovial fluid analysis will reveal a positive gram stain in culture with synovial fluid that appears cloudy and purulent.
Additionally, the cell count will be greater than 50,000 white blood cells per cubic millimeter. In some cases, a blood culture might be positive.
These findings confirm the diagnosis of septic arthritis. Here's a clinical pearl to keep in mind.
Although you could use imaging studies to support the diagnosis of septic arthritis, you should not delay arthrocentesis.
Since synovial fluid analysis is the gold standard for diagnosis. Now, let's move on and discuss treatment.

Septic Arthritis - Treatment4:38–5:31

Medical management of septic arthritis starts with intravenous antibiotics that are tailored to the synovial fluid gram stain and culture results as well as your patient's age.
Additionally, you can provide nsaids to reduce inflammation and pain and to relieve fever. Finally obtain a surgical consultation for possible arthroscopic drainage or even arthrotomy.
Here's another clinical pearl for you. If your patient presents with arthritis that has a low grade fever and variable pain as well as possible.
Waxing and waning joint symptoms. You should consider lyme arthritis and test for lyme disease caused by Borrelia.
Burgdorferi, lyme arthritis is a late manifestation of Lyme disease and treating the infection should help resolve the joint symptoms.
All right. Now that we're done with septic arthritis, let's move on to transient synovitis.

Transient Synovitis5:31–6:27

These patients typically present with monoarticular joint pain and swelling that usually affects the hip. However, unlike septic arthritis, the joint pain may wax and wane and most patients will be afebrile or have only a low grade fever.
Some Children may develop a limp but most will be able to bear weight on the affected extremity. Frequently history will reveal a recent upper respiratory infection or episode of acute gastroenteritis.
Additionally, the physical exam reveals a well appearing patient with possible joint effusion in combination with a limited range of motion in the affected joint due to pain.
Moreover, if the hip is involved, you may notice decreased internal rotation. Finally, in transient synovitis, all labs will be normal.
These findings are suggestive of transient synovitis. But if you're still not sure, you can always perform arthrocentesis and syn synovial fluid for analysis.

Transient Synovitis - Arthrocentesis6:27–6:57

In contrast to septic arthritis in transient synovitis, the synovial fluid analysis reveals a negative gram staining culture clear and yellow synovial fluid and between 5000 to 15,000 white blood cells per cubic millimeter.
At this point, you can be sure that your patient is presenting with transient synovitis. Now, the management of transient synovitis primarily relies on supportive care which consists of rest and the use of nsaids for pain.

Transient Synovitis - Treatment6:57–8:31

Transient synovitis is self limited and resolves on its own within two weeks. Now, here's a clinical pearl transient synovitis is one example of post infectious arthritis, which is arthritis occurring after an acute infection that has resolved.
But there's more some pathogens that lead to post infectious arthritis include many viruses like adenovirus, rubella or hepatitis B.
Another common example is post streptococcal reactive arthritis which develops after an acute streptococcal infection that has resolved.
Another similar diagnosis is reactive arthritis, which is arthritis that occurs specifically after either a gastrointestinal or genitourinary infection.
Common gastrointestinal causes include campylobacter species, salmonella species, shigella species, Yersinia species or mycoplasma pneumoniae.
Meanwhile, genitourinary causes are most often due to chlamydia trachomatis. Reactive arthritis is associated with a classic triad of eye findings like conjunctivitis or uveitis, genitourinary findings like urethritis or cervicitis and musculoskeletal findings like arthritis.
A great mnemonic to help you remember this is that patients can't see, can't pee and can't climb a tree. All right.
As a quick recap septic arthritis is a bacterial infection of the synovium and joint space. While transient synovitis also called toxic synovitis refers to a noninfectious synovial inflammation.

Review8:31–9:37

The main difference between the two includes lab and synovial fluid findings in septic arthritis. Labs will reveal an elevated white blood cell count with neutrophilia CRP greater than 1 mg per deciliter and esr greater than 40 millimeters per hour.
Additionally, synovial fluid analysis will reveal a positive gram staining culture, synovial fluid that appears cloudy and purulent and more than 50,000 white blood cells per cubic millimeter.
The management of septic arthritis primarily relies on tailored antibiotics, nsaids and surgical consultations on the flip side in transient synovitis lab and synovial fluid analysis findings are normal.
Finally, the management of transient synovitis is based on supportive care which includes rest and nsaids.
Septic arthritis and transient synovitis (pediatrics): Video | Osmosis