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Septic Arthritis in an Afebrile Young Infant With a Urinary Tract Infection
Andzelika Dechnik1, Thomas M Kennedy1
1Division of Pediatric Emergency Medicine, Department of Emergency Medicine, NewYork-Presbyterian Morgan Stanley Children's Hospital, Columbia University Irving Medical Center, New York, New York.
Pediatrics
|July 8, 2025
Summary
Serious bacterial infections, like Escherichia coli septic arthritis, can occur in afebrile infants. Early diagnostic testing, including urinalysis, is crucial for prompt identification and treatment in young children.
Area of Science:
- Pediatrics
- Infectious Diseases
- Neonatology
Background:
- Guidelines for febrile infants exist, but afebrile infants are often overlooked for serious bacterial infections.
- Young infants, especially those under two months, can present with subtle signs of severe illness.
Purpose of the Study:
- To highlight the importance of considering serious bacterial infections in afebrile infants.
- To present a case of Escherichia coli septic arthritis originating from a urinary tract infection in an afebrile infant.
- To emphasize the need for diagnostic urine testing in young infants with septic arthritis.
Main Methods:
- Case report of a 5-week-old afebrile infant presenting with knee swelling.
- Diagnostic workup including identification of Escherichia coli in urine and joint fluid.
- Review of existing guidelines for evaluating febrile infants.
Main Results:
- The infant was diagnosed with an Escherichia coli urinary tract infection complicated by septic arthritis.
- The causative pathogen, E. coli, was identified in both urine and synovial fluid.
- The infant, despite being afebrile and well-appearing, had a serious bacterial infection.
Conclusions:
- Serious bacterial infections should be considered in afebrile infants under two months old.
- A low threshold for diagnostic testing, including urinalysis, is essential for early detection.
- Septic arthritis in young infants can have a urinary source, necessitating urine culture.
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