Rheumatology Flashcards
A three-year-old girl develops otitis media and is treated with an antimicrobial agent. Eight days later she presents with fever, an urticarial rash and painful swelling of her ankles and right knee. Examination shows a resolving otitis media and confirms there is some swelling and painful limitation of movement of the ankles and right knee. An urticarial rash is noted. She has a temperature of 38.5°C.
Which one of the following antimicrobial agents is most likely to have caused this clinical picture?
Description of a child presenting with fever, urticarial rash and joint swelling 8 days after starting an antimicrobial agent is most consistent with a serum sickness- like reaction that is most common in children young who are treated with Cefaclor. Although other antibiotics (eg. amoxycillin), NSAIDs and other medications can cause a serum-sickness like reaction, Cefaclor is the commonest causative agent.
Serum sickness-like reactions occur secondary to medications, and although they clinically resemble serum sickness, they are NOT caused by the formation and deposition of immune complexes. Serum sickness-like reactions are most commonly seen in children <6years old and are most often secondary to Cefaclor. Symptoms may occur as early as 1-2 days following exposure to the medication, but usually develop 1-3 weeks following exposure. Patients may present with fever, malaise, urticarial rash, facial swelling, joint pain and/or swelling, which is usually symmetrical. Other less common features include headache, lymphadenopathy, nausea, vomiting and abdominal pain and myalgia. The rash may also atypical and has been reported as being morbilliform, scarlatiniform and erythema multiforme-like.
Management of serum sickness-like reactions involves stopping the offending medication and providing symptomatic relief. Symptoms ususally settle within 1-2 days of ceasing the triggering medication. It is recommended that causative medications be avoided in the future.
A girl with polyarticular JIA is being treated with an IL6 inhibitor infusion
Tocilizumab is a recombinant humanized anti-human monoclonal antibody directed against the IL 6 receptor which is used in the treatment of systemic onset JIA and polyarticular JIA. It is given by infusion.
A boy diagnosed with Kawasaki disease continues to have a fever in spite of being treated with IV immunoglobulin twice and with steroids
Infliximab is used in the treatment of children with refractory Kawasaki Disease. It is a chimeric monoclonal antibody that binds to TNF alpha.
Etanercept also binds to TNF alpha but is a recombinant protein. It has not been shown to be effective in children with refractory Kawasaki Disease.
A girl with systemic JIA is receiving a daily subcutaneous IL1 inhibitor.
Anakinra is an IL1 inhibitor used in the treatment of systemic JIA.
Canakinumab is also an IL1 inhibitor but is administered monthly. Rilonacept is another Il1 inhibitor used in the treatment of systemic JIA but it is administered weekly. All are subcutaneous injections.
