Answer Key

  1. The correct is C. The patient’s back symptoms are classic for inflammatory back pain (IBP).  These characteristic features include:  1) insidious onset over 3 months; 2) pain improving with activity but not with rest; 3) nocturnal pain, particularly in the second half of the night; and 4) alternating buttock pain suggesting SI joint involvement.  Usually mechanical pain is worse with activity and improves with rest.  Spinal stenosis and sciatica have pain radiating from the low back down the legs and extend past the knee but again, the pain is more problematic with activity.  Spinal stenosis and facet arthropathy would be highly unusual given his age.    Nocturnal pain is often a worrisome sign of infection or malignant disease within or near the spine.  In this patient, given his age, duration of symptoms and lack of systemic complaints, these two considerations are less likely but should remain in the differential. 

  2. The correct answer is A. This patient has acute post-enteric reactive arthritis.  By the time she presented, usually 2-6 weeks after the gastrointestinal infection, there is low likelihood that stool culture will be positive.  Antibiotics have not been proven to be effective for post-enteric reactive arthritis while there is still some suggestion that prolonged antibiotics for post-chlamydial reactive arthritis might benefit from prolonged antibiotics such as lymecycline, ciprofloxacin, or azithromycin.  The prevalence of HLA B27 is estimated to be anywhere from 30-50% in reactive arthritis and not likely to predict susceptibility but perhaps predictor of more severe disease.  Since this patient is in the acute phase of reactive arthritis, a trial of different NSAIDs is most appropriate as initial therapy and use of corticosteroids if NSAIDs are ineffective may provide short term relief.  If the patient evolves into more chronic reactive arthritis, then sulfasalazine, methotrexate may be necessary.

  3. The correct answer is C. The term undifferentiated spondyloarthritis is sometimes very useful in a patient who presents with feature of spondyloarthritis but without associated features of psoriasis, inflammatory bowel disease, or features of true ankylosing spondylitis. Sometimes, the joint manifestations present prior to the onset of skin disease (psoriasis) or bowel symptoms (inflammatory bowel disease).  The unifying features of this group of diseases include uveitis, enthesitis, asymmetrical arthritis, tendonitis, and/or inflammatory back pain.  This patient’s symptoms would also fit into the proposed ASAS classification of peripheral spondyloarthritis since most of his clinical features are peripheral but there are patients who have component of both.  Rheumatoid arthritis can present in asymmetrical fashion but is not usually associated with uveitis or enthesopathy.  Sarcoid is associated with uveitis and arthritis /periarthritis but the enthesopathic features of the chest wall is uncommon.  

  4. The correct answer is B. Arthritis mutilans is a rare but destructive form of psoriatic arthritis that is associated with progressive loss of bone in the affected joint.  This results in progressive changes and on radiograph, the findings of “pencil cup “deformities.  This subset of arthritis is very suggestive of psoriatic arthritis even if the patient has no skin manifestations.   All the other listed clinical features above are also seen in reactive arthritis, ankylosing spondylitis, and arthropathy associated with inflammatory bowel disease.

  5. The correct answer is C. TNF alpha inhibitors have multiple potential side effects and before initiation of these drugs, risk assessment should be carefully weighed.  The most important exclusion would be the presence of active infection or presence of latent tuberculosis.  Reactivation of tuberculosis has been observed in initial clinical trials and other fungal infections including histoplasmosis and coccidiomycosis have also been reported.  All patients should have PPD or interferon-gamma release assay for latent TB and treatment should be initiated before start of TNFi.  Other infections include untreated hepatitis B or C.  Patients with heart failure, NYHA functioparnal class III/IV should avoid these drugs due to potential worsening of congestive heart failure.  Other relative contraindications to these drugs include prior or current history of demyelinating disease, history of melanoma, or pregnancy.

Last modified: Thursday, February 17, 2022, 6:38 PM