The early onset of seronegative polyarthritis juvenile idiopathic arthritis in female patient — a case report

Background: Juvenile idiopathic arthritis (JIA) is a chronic inflammatory joint disease with a complex etiology. It is characterised by symptoms such as swelling, exudates, soreness, and reduced mobility. Early diagnosis and treatment are crucial to improving long-term prognosis and preventing complications. Case presentation: A 5-year-old girl with polyarticular seronegative, human leukocyte antigen B27 (HLA-B27)-positive JIA previously under the care of another medical centre was admitted for evaluation of disease activity and possible reintroduction of treatment. The patient's history began at the age of 14 months when symptoms of inflammation of the small joints of the hands appeared. On physical examination pain and swelling of the proximal interphalangeal joints of the hands were detected. Laboratory tests revealed low inflammatory indices. Rheumatoid factor, anti-citrullinated protein antibodies, and a genetic test for HLA-Cw6 were negative. An ultrasound of the hands confirmed the presence of arthritis. Furthermore, a magnetic resonance imaging (MRI) scan and a computed tomography (CT) scan were performed, revealing sacroiliitis. The treatment initially included two disease-modifying drugs — methotrexate and sulphasalazine with folic acid shielding. Subsequently, due to the poor response to treatment, the child was qualified for biological treatment with adalimumab, achieving a significant improvement in clinical condition and imaging findings. Follow-up hospital admissions confirmed the stabilisation of the patient's condition and the absence of disease progression. Conclusion: This case emphasises the importance of early diagnosis and an individualised therapeutic approach in the treatment of JIA. Biological therapy with adalimumab, combined with conventional drugs, proved effective in controlling the disease's symptoms and improving the patient's quality of life.