VAIL, COLO. — Fever and limp that do not resolve within 2-3 days deserve further work-up.
Rather than transient synovitis of the hip, an acute self-limited condition that is the single most common cause of fever accompanied by limp in a child, the cause of the symptoms might be septic arthritis due to Kingella kingae, especially in a 1- to 3-year-old child.
However, many of the other disorders in the differential diagnosis of fever plus limp represent medical and surgical emergencies.
These include septic arthritis, osteomyelitis, pyomyositis, and Kawasaki disease, Dr. Samuel R. Dominguez said at the conference, which was sponsored by the Children's Hospital, Denver.
Another possible diagnosis is pyomyositis, noted Dr. Dominguez, a pediatric infectious diseases specialist at the hospital and the University of Colorado at Denver.
Transient Synovitis
The typical age of onset is 3-8 years, boys are affected twice as often as girls, and the etiology is unknown. Because transient synovitis — sometimes called reactive arthritis — is a diagnosis of exclusion and there is considerable symptomatic overlap with septic arthritis, management algorithms call for watchful waitingain a child who has only a low-grade fever, can walk, and doesn't seem too systemically ill.
If there is no improvement in the first 2-3 days, however, it's worthwhile to order measurement of inflammatory markers. A C-reactive protein (CRP) level of 1.2 mg/dL or greater and/or an erythrocyte sedimentation rate (ESR) of at least 30 mm/hr warrants further work-up, including hip ultrasound and aspiration, in order to exclude joint or bone infection, Dr. Dominguez said.
K. kingae in Septic Arthritis
The causative organisms in septic arthritis vary with age. Although Staphylococcus aureus is the most common organism a French study of 131 childrenwhdmitted with a joint or bone infection showed that K. kingae was by far the most common etiologic agent in the 1- to 2-year-old age group. Many of these youngsters were culture negative but polymerase chain reaction positive for Kingella (Pediatr. Infect. Dis. J. 2007;26:377-81).
The take-home message is to consider the possibility of Kingella as a cause of joint or bone infection in 1- to 2-year-olds, and to cover for that with penicillins or cephalosporins, Dr. Dominguez said.
Israeli physicians conducted a retrospective national survey of all clinical microbiologic laboratories in their country, and turned up 322 pediatric K. kingae infections, more than half of which were skeletal.
Overall, 96% of affected children were younger than age 3 years. Most appeared to be only mildly ill. Nearly a quarter had no fever, a third had a nonelevated ESR, and 22% had a normal CRP (Pediatr. Infect. Dis. J. 2010;29:639-43).
Pyomyositis
The annual case count more than doubled during 2000-2006 at Texas Children's Hospital in Houston. The Texpital's reportconsthe largestcase series of bacterial myositis in previously healthy children ever reported from a nontropical region (Clin. Infect. Dis. 2006;43:953-60). The mean ESR was 62 mm/hr, the mean CRP was 16.3 mg/dL, and creatinine kinase levels were normal in all patients.
Pyomyositis is associated with a remarkable degree of pain, and hospital stays for these patients are often longer than with other musculoskeletal infections. Antibiotic therapy typically lasts for 3-4 weeks, including close to 2 weeks ofiIV therapy. Surgical drainage is often required. MRI is the diagnostic imaging of choice. Theexurging incidence of pyomyositis since 2000 is thought tolie due to the rise of methicillin-resistant S. aureus.
Kawasaki Disease
In a series of 198 children with Kawasaki disease reported by the Pediatric Heart Network investigators, 15% had joint pain during the 10 days prior to diagnosis (J. Pediatr. 2009;154:592-5).
Disclosures: Dr. Dominguez said he has no relevant disclosures.