A 20-month-old girl was admitted with a 5-month history of prolonged fever, intermittent in the first months and constant in the following two months, with a maximum temperature below 39o and intermittent in the last two months.
It presents maculopapuloeritematous exanthema, evanescent in trunk and proximal part of extremities, lymphadenopathies since 13 months of age, affecting cervical, axillary and inguinal ganglia.
Analytical data showed anemia (9.3 g/dl), leukocytosis (27.340/mm3) and increased ESR.
The clinical and analytical manifestations suggest AlJs, starting treatment with oral prednisone at 2 mg/kg/day (10 mg every 12 hours).
One month later, the dose was reduced by adding an interleukin-1 receptor (Anakinra) to 1 mg/kg/day subcutaneously.
After 2 weeks of treatment she presented with hypertransaminemia of probable viral etiology, removing the anakinra, which causes a worsening of the patient informed of reappearance of cutaneous lesions, arthralgias and high-dose corticoids
Canakinumab is a fully human monoclonal antibody that binds with high affinity to human interleukin-1 beta, thus neutralizing its biological activity4.
At the time of the request canakinumab was indicated for the treatment of Periodic Arrest Syndromes for 4 weeks with Criopyrin (CAPS) in adults, adolescents and children published after 2 years.
The CPF agrees to approve it and treatment is initiated at 2 mg/kg every 4 weeks to check tolerance.
Due to the patient's weight, the Emergency Room was created in order to use several doses and be more efficient.
Adequate tolerance and good response to the biological agent are observed at doses of 2 mg/kg/4 weeks, with symptoms disappearing, which allows reducing the dose of corticoid to 8 mg/day, continuing the good evolution.
The dose of canakinumab was increased to 3 mg/kg/4 weeks and the corticosteroid was discontinued.
After 6 months of treatment she suffered a new relapse with sustained febricula, irritation and some skin lesions, so the dose of canakinumab was increased to the expected optimum of 4 mg/kg corticoids every 4 weeks.
The disease remained stable despite an infectious process that remits without secondary complications, during which the biological administration is suspended.
After 7 months of treatment, methotrexate 7.5 mg/week was added together with calcium folinate, 7 mg/week, due to the development of joint pain in elbows and subcutaneous inflammatory manifestations.
Eight weeks later, the patient developed coagulation disorders and hypertransaminasemia, probably secondary to treatment with methotrexate, and monocytosis that required admission and discontinuation of canakinumatrebate.
During admission, the patient progressed favorably and was diagnosed with active polyarticular JAs, so it was decided to start etanercept 0.4 mg/kg/week subcutaneously for the treatment of joint manifestations.
Although the clinical response to the new biological agent is satisfactory, its administration is suspended for 15 days due to a new rise in transaminase levels until resolution.
2 months later the patient was admitted for arthrocentesis in both knees.
Thereafter, the patient continued treatment with etanercept 0.4mg/week, continuing improvement without skin lesions or fever and allowing the decrease of corticoids up to 4mg/day.
