Distinguishing Lyme Arthritis From Septic Arthritis in Children: Presented at AAOS
By Sophie BainbridgeNEW ORLEANS — March 17, 2010 — Physicians should have a high suspicion of Lyme arthritis when a child with a swollen knee joint comes to the emergency department, researchers said here at the 2010 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS).
Almost half of children with fluid in the knee in the northeastern part of the United States are likely to have Lyme arthritis, the researchers said.
"Distinguishing children who have Lyme arthritis from those who have septic arthritis can be a challenge in the emergency department but doing so is essential because their treatment is so different," said Matthew Milewski, MD, Yale University and Yale-New Haven Children’s Hospital, New Haven, Connecticut. "In a paediatric population, Lyme arthritis is probably the first diagnosis to consider if you are in an endemic area," he said here in a podium presentation on March 10.
Distinguishing the 2 is important because the treatments are different. Septic arthritis requires surgical intervention; Lyme arthritis requires antibiotics.
Distinguishing Lyme Arthritis From Septic Arthritis in Children
By Sophie Bainbridge
NEW ORLEANS -- March 17, 2010 -- Physicians should have a high suspicion of
Lyme arthritis when a child with a swollen knee joint comes to the emergency
department, researchers said here at the 2010 Annual Meeting of the American
Academy of Orthopaedic Surgeons (AAOS).
Almost half of children with fluid in the knee in the northeastern part of the
United States are likely to have Lyme arthritis, the researchers said.
“Distinguishing children who have Lyme arthritis from those who have septic
arthritis can be a challenge in the emergency department but doing so is
essential because their treatment is so different,” said Matthew Milewski, MD,
Yale University and Yale-New Haven Children’s Hospital, New Haven, Connecticut.
“In a paediatric population, Lyme arthritis is probably the first diagnosis to
consider if you are in an endemic area,” he said here in a podium presentation
on March 10.
Distinguishing the 2 is important because the treatments are different. Septic
arthritis requires surgical intervention; Lyme arthritis requires antibiotics.
The investigators reviewed all joint aspirations that were done at their centre
from January 1992 through April 2009 in children aged younger than 18 years.
They collected data on cell count, fluid differential, culture, haematologic
inflammatory markers including peripheral white blood cell count, peripheral
blood differential, erythrocyte sedimentation rate, C-reactive protein, and
Lyme disease serological testing.
They also reviewed charts for the presence of fever and weight bearing status
at the time the children presented, as well as for radiographic or ultrasound
evidence of effusion.
Of the 391 patients who were analysed, 123, (31%) tested positive for Lyme, and
51 (13%) had septic arthritis.
They also found that children with septic arthritis had a higher nucleated cell
count (123,000 cells/mm versus 60,200 cells/mm in the Lyme arthritis cohort;
P = .007).
They were also more likely to have fever. Twenty-seven of 49 septic arthritis
patients (55%) had temperatures of at least 38.6 degrees Celsius compared with
26 of 120 Lyme patients (22%). Of the 49 septic arthritis patients, 33 (67%)
had a low-grade fever, defined as a temperature of at least 38 degrees Celsius
compared with 46 of 120 Lyme patients (38%).
Almost all of the children with septic arthritis refused to bear weight,
compared with only 39% of the children with Lyme arthritis (P <
.001).
The erythrocyte sedimentation rate and C-reactive protein values were similar
in the 2 groups. “We can’t use these measures to differentiate between Lyme and
septic arthritis,” Dr. Milewski noted.
Presentation title: Distinguishing Lyme Arthritis From Septic Arthritis
in Children Presenting With a Joint Effusion. Podium Number 141
