Etiological, clinical and laboratory evaluation of childhood arthritis

Introduction: Inflammatory changes in the joints are defined as arthritis. To clinically define a condition as arthritis, at least one joint must exhibit swelling, or in the absence of swelling, at least two of the following symptoms must be present: pain, limited range of motion, increased warmth, or redness. Joint pain is one of the most common symptoms in childhood and is observed in various diseases. This study aims to identify and categorize the etiological causes of arthritis symptoms, evaluate patients' demographic characteristics, primary complaints at admission, physical examination findings, the number and location of joint involvement, and analyze laboratory data. Material-Methods: This retrospective study evaluated 234 pediatric patients diagnosed with arthritis and followed up at the Department of Pediatrics, Afyonkarahisar Health Sciences University Medical Faculty Hospital, between 2018 and 2023. Data such as age, gender, presenting complaints, physical examination findings, joint involvement site, number and duration of joint involvement, complete blood count, acute phase reactants, and radiological imaging results were analyzed. Statistical analyses were performed using SPSS 26.0, with p < 0.05 considered statistically significant. Findings: Among the patients presenting with arthritis, 53.8% were male and 46.2% were female, with a mean age of 10 ± 4.2 years. Arthritis was most commonly observed during adolescence. The etiological distribution showed that 57.7% were infectious, 20.5% inflammatory, 10.7% orthopedic, 2.1% hematological and oncological, and 9% other diseases. Brucellosis (36.3%) was the most common cause of arthritis, followed by reactive arthritis (10.7%), undifferentiated arthritis (9%), acute rheumatic fever (7.7%), Henoch-Schönlein purpura (4.3%), familial Mediterranean fever (3.8%), juvenile idiopathic arthritis (3.8%), bursitis (3.4%), transient synovitis (3%), septic arthritis (3%), osteomyelitis (2.6%), and malignancy (2.1%). Regarding joint involvement, 65% of the cases had monoarthritis, 30.8% had oligoarthritis, and 4.3% had polyarthritis. Monoarthritis was primarily seen in brucellosis, septic arthritis, osteomyelitis, acute rheumatic fever, reactive arthritis, trauma, and malignancy. Oligoarthritis was observed in juvenile idiopathic arthritis and Henoch-Schönlein purpura. The most frequently affected joint was the knee (39.7%), followed by the hip (23.9%) and ankle (23.5%). Common presenting complaints included joint pain (94%), swelling (44%), restricted movement (61.5%), and increased warmth in the joint (18.4%). Accompanying symptoms included fever (27.8%), abdominal pain (12%), and rash (6%). A history of prior infection was noted in 30.3% of cases, more common in acute rheumatic fever and reactive arthritis (p < 0.001). Family history was present in 27.7% of the cases. Among patients with prolonged PR intervals on ECG (14.7%), all were diagnosed with acute rheumatic fever. There were no significant differences in qualitative CRP, ASO, ESR, or leukocyte values among diagnostic groups. Acute arthritis was seen in 76.9% and chronic arthritis in 23.1% of cases. Acute arthritis was associated with brucellosis, Henoch-Schönlein purpura, septic arthritis, reactive arthritis, acute rheumatic fever, malignancy, and trauma, while 77.8% of juvenile idiopathic arthritis cases were chronic. Plain radiography was the initial imaging modality for monoarthritis cases, revealing pathological findings in 9.9%. Ultrasound findings were positive in 63.6% and MRI in 76% of cases. Conclusion: The broad differential diagnosis of arthritis poses challenges in diagnosis and can sometimes lead to delays. Diseases like malignancy, acute rheumatic fever, and brucellosis, which can increase morbidity if not diagnosed and treated promptly, highlight the importance of a structured approach in managing arthritis in children. The lack of significant differences in acute phase reactants and imaging findings among diagnostic groups underscores the importance of a thorough history and physical examination. Sociodemographic features such as age, gender, living area, and family history are critical in diagnosing conditions like familial Mediterranean fever, acute rheumatic fever, and brucella arthritis. In monoarthritis cases, malignancy and urgently treatable septic arthritis should be ruled out, while brucellosis should be considered in endemic regions. Although polyarthritis is more common in acute rheumatic fever, monoarthritis should also prompt consideration of acute rheumatic fever in high-risk areas. In patients presenting with oligoarthritis, inflammatory arthritis should be investigated. Keywords: Arthritis, Brucella, Acute Rheumatic Fever, Monoarthritis, Oligoarthritis