Distinguishing Kingella kingae from Pyogenic Acute Septic Arthritis in Young Portuguese Children

Area of Science:

• Pediatric Infectious Diseases
• Microbiology
• Clinical Diagnostics

Background:

• Distinguishing Kingella kingae septic arthritis (SA) from pyogenic SA in young children is clinically important.
• Kingella kingae is an increasingly recognized cause of pediatric SA.

Purpose of the Study:

• To identify clinical and laboratory parameters differentiating Kingella kingae from pyogenic SA in children under 5 years old.
• To develop a predictive model for Kingella kingae SA.

Main Methods:

• A longitudinal, observational, single-center study included 75 children (<5 years) with microbiologically confirmed SA.
• Clinical and laboratory data were collected at admission, 48 hours, and during treatment.
• Multivariate analysis and ROC curves were used to identify predictive factors.

Main Results:

• 44 cases of Kingella kingae SA and 31 of pyogenic SA were identified.
• Kingella kingae SA was associated with younger age, absence of fever, and lower inflammatory markers (CRP, ESR).
• A predictive model (age >6 months ≤2 years, apyrexia, CRP ≤100 mg/L) showed high accuracy (AUC 0.861) in differentiating Kingella kingae SA.

Conclusions:

• Age between 6 months and 2 years, absence of fever, and CRP ≤100 mg/L are key predictors for Kingella kingae SA in children under 5.
• These findings can aid in early diagnosis and management of pediatric SA.
• Further validation in larger studies is recommended.