ANSWERS of PEDIATRIC RHEUMATOLOGY MCQS Pulished on 10/9/2019

Answer 1. D

Any child with fever and an inflamed, swollen joint should be considered to have septic arthritis until proven otherwise. It is imperative to obtain synovial fluid for gram stain and culture. In general, for this situation, a synovial fluid culture is most likely to achieve the highest rate of identification of the organism, although this rate is still not 100%. Obtaining blood cultures may increase the yield of identifying the organism, but in the absence of osteomyelitis, bone culture will not be useful. While MRI or ultrasound can document effusion and inflammation and help to determine if there is concomitant osteomyelitis, neither test will yield identification of the actual organism.

Answer 2. C

Patients with Kawasaki disease can develop arthritis as part of their disease. The arthritis, which affects approximately 1/3 of patients with KD, usually occurs in the acute phase of the

illness and resolves within 3 weeks to 3 months. The presence of arthritis is not considered a treatment failure and therefore repeat dosing of IVIg is not required. Intermittent NSAID therapy may help joint pain, but chronic treatment is not necessary, with either NSAIDs or aspirin. Intra-articular corticosteroid injections can be helpful in patients with chronic arthritis, but are not indicated in this context.

Answer 3. B

This patient has a history of recurrent oral ulceration and at least 1 episode of genital ulceration. She has a rash and arthritis on exam. All of these findings are consistent with a diagnosis of Behcet Disease (BD). The diagnosis requires recurrent oral ulceration (see Figure 203-2 ) and at least 2 of the following:

recurrent genital ulceration, eye disease, skin lesions, and a positive pathergy test. This patient does not fulfill criteria, as she has had only one episode of genital ulceration. A positive pathergy test would provide sufficient evidence to make a diagnosis of BD. The pustular rash is nonspecific and biopsy would not be definitive. Patients with BD can have CNS involvement, including encephalitis or aseptic meningitis, but the MRI/MRA findings would be nonspecific. A C-reactive protein can be elevated in any systemic inflammation and is not helpful for making a specific diagnosis. This patient, although she has arthritis, is unlikely to have rheumatoid arthritis given her presentation. A positive RF would not be helpful in this case, given the low pretest probability for RA.

Answer 4. A

Treatment of SLE is a balance of benefits of medications against the known toxicities of the drugs used. While prednisone is the mainstay of treatment for significant organ involvement, the side effects of prolonged use, including risk of avascular necrosis, osteoporosis, and growth delay, are significant. Use of prednisone should be minimized, particularly in patients

with mild disease, and weaned as fast as is safe for the patient. Steroid-sparing medications, such as cyclophosphamide and azathioprine, have their own toxicities, including bone marrow suppression and risk of malignancy, and are reserved for serious organ involvement. Low-dose aspirin has been used in patients with anti-phospholipid antibodies to decrease clotting risk, but its actual benefit is uncertain.

Hydroxychloroquine, on the other hand, has been shown to decrease the number of lupus flares and increase the time between flares. It also lowers serum lipid levels, a benefit in patients with renal disease and in chronic corticosteroid use.

Answer 5. E

Systemic sclerosis is very rare in children, with less than 5% of patients developing their disease before the age of 16 years. In children, the most common presenting feature is Raynaud phenomenon, followed by proximal skin induration that develops later. The figure below shows classic Raynaud phenomenon in a 4-year-old girl. Note the ischemic changes (blanching phase) of the second and fourth fingers and the cyanosis (bluish phase) of the fifth finger. Internal organ involvement can be significant, but is not typically an early finding. Dysfunction of the esophagus is the most common gastrointestinal manifestation, seen symptomatically as dysphagia and reflux. Pulmonary involvement can include interstitial fibrosis, pleuritis, or pulmonary hypertension, which can lead to right-sided heart failure.