WBR0752
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology |
| Sub Category | SubCategory::Musculoskeletal/Rheumatology |
| Prompt | [[Prompt::A 27 year old man, previously healthy, presents to the physician's office for recurrent left knee pain. The patient explains that he has recently recovered from a urethral infection 2 weeks ago that required antibiotics without identifying the bacteria. He reports his knee pain does not involve his right knee, and is moderately relieved with naproxen use. Work-up is remarkable elevated C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) and a strong increase in HLA-B27. What is the most likely additional finding during physical examination of this patient?]] |
| Answer A | AnswerA::Conjunctivitis |
| Answer A Explanation | AnswerAExp::Reactive arthritis has a classic triad: conjunctivitis, urethritis, and arthritis. |
| Answer B | AnswerB::Aortic stenosis |
| Answer B Explanation | AnswerBExp::Aortic stenosis is not commonly seen in patients with reactive arthritis. Patients with ankylosing spondylitis, another disease associated with HLA-B27, have high rates of aortic regurgitation. |
| Answer C | AnswerC::Malar rash |
| Answer C Explanation | AnswerCExp::Malar rash is common in systemic lupus erythematosus. |
| Answer D | AnswerD::Heliotrope rash |
| Answer D Explanation | AnswerDExp::Heliotrope rash is commonly seen in patients with dermatomyositis. |
| Answer E | AnswerE::Excoriation of skin |
| Answer E Explanation | AnswerEExp::Skin excoriation is not associate with reactive arthritis. |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::The patient is presenting with reactive arthritis (ReA), formerly known as Reiter's syndrome. ReA is an autoimmune inflammatory arthritis that typically follows a gastrointestinal or a urethral infection. Chlamydia infections are strongly associated with ReA, in addition to other bacterial infections, such as Salmonella, Shigella, and Campylobacter.
The typical presentation of ReA is mono-inflammatory non-migratory arthritic pain that follows a gastrointestinal or a urethral infection by 2-4 weeks. Laboratroy findings are usually unremarkable except for elevation of acute phase reactants, such as CRP and ESR. ReA is associated with HLA-B27, along with other conditions (i.e. psoriatric arthritis, ankylosing spondylitis, and inflammatory bowel disease), all of which are called seronegative spondyloarthropathies because they patients have negative serological levels of rheumatoid factor (RF). The classic triad of ReA is: Conjunctivitis, urethritis, and arthritis. [Mnemonic: Can't see (conjunctivitis), can't pee (urethritis), can't climb a tree (arthritis)] The diagnosis of ReA is mainly clinical. Treatment of the arthritis in ReA includes NSAIDs for symptomatic relief in most of the cases until the pain self-resolves. However, rare refractory cases might require intra-articular or rarely systemic steroids, or even disease-modifying antirheumatic drugs (DMARDs) Educational Objective: Reactive arthritis has a classic triad of conjunctivitis, urethritis, and arthritis. Reference:
Kim PS, Klausmeier TL, Orr DP. Reactive arthritis: a review. J Adolesc Health. 2009; 44(4):309-15. |
| Approved | Approved::No |
| Keyword | WBRKeyword::reactive, WBRKeyword::arthritis, WBRKeyword::knee, WBRKeyword::pain, WBRKeyword::urethritis, WBRKeyword::chlamydia, WBRKeyword::chlamydial, WBRKeyword::infection, WBRKeyword::conjunctivitis, WBRKeyword::spondyloarthropathy, WBRKeyword::spondyloarthropathies, WBRKeyword::arthritis, WBRKeyword::HLA-B27, WBRKeyword::seronegative |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |