Rheumatoid Arthritis
Rheumatology · Rheumatoid Arthritis · study mode — pick an answer, then reveal.
Question · easy
A 48-year-old woman presents with 3 months of symmetric swelling and pain of the metacarpophalangeal and proximal interphalangeal joints of both hands, with 90 minutes of morning stiffness. Which laboratory test is the MOST specific for confirming the most likely diagnosis?
Anti-CCP (ACPA) antibodies have a sensitivity of ~70% — similar to rheumatoid factor — but a specificity of ~95%, making them the most specific serologic test for RA; they also predict erosive disease better than RF. Rheumatoid factor (~70% sensitive, ~85% specific) occurs in other conditions (viral hepatitis, endocarditis, other connective tissue diseases) and increases with age. ANA is positive in ~30% of RA patients but is nonspecific, and ESR merely reflects inflammation.
<ol>
<li>MKSAP 19 Rheumatology — "Rheumatoid Arthritis," Ch. 3, pp. 17–23. ACP, 2022.</li>
<li>Harrison's 22e — Shah A, St. Clair EW. "Rheumatoid Arthritis," Ch. 370, pp. 2839–2854.</li>
<li>Fraenkel L, et al. 2021 ACR Guideline for the Treatment of RA. <em>Arthritis Care Res</em> 2021;73(7):924–939.</li>
<li>Smolen JS, et al. EULAR RA management recommendations: 2022 update. <em>Ann Rheum Dis</em> 2023;82(1):3–18.</li>
<li>Studenic P, et al. ACR/EULAR remission criteria for RA: 2022 revision. <em>Ann Rheum Dis</em> 2022.</li>
<li>U.S. FDA Drug Safety Communication, Dec 2021 — JAK inhibitors (ORAL Surveillance; <em>N Engl J Med</em> 2022;386:316–326).</li>
</ol>
Question · medium
The 2010 ACR/EULAR classification criteria for rheumatoid arthritis assign points across four domains (joint involvement, serology, acute-phase reactants, duration), with a score ≥6/10 classifying definite RA. Which of the following IS part of these criteria?
Duration ≥6 weeks scores 1 point (<6 weeks scores 0). The 2010 criteria were redesigned for EARLY classification, so radiographic erosions and rheumatoid nodules — items of the 1987 criteria — were deliberately removed because they are rare early in disease. DIP joints (along with the first carpometacarpal and first MTP joints) are explicitly excluded from the joint-involvement scoring.
<ol>
<li>MKSAP 19 Rheumatology — "Rheumatoid Arthritis," Ch. 3, pp. 17–23. ACP, 2022.</li>
<li>Harrison's 22e — Shah A, St. Clair EW. "Rheumatoid Arthritis," Ch. 370, pp. 2839–2854.</li>
<li>Fraenkel L, et al. 2021 ACR Guideline for the Treatment of RA. <em>Arthritis Care Res</em> 2021;73(7):924–939.</li>
<li>Smolen JS, et al. EULAR RA management recommendations: 2022 update. <em>Ann Rheum Dis</em> 2023;82(1):3–18.</li>
<li>Studenic P, et al. ACR/EULAR remission criteria for RA: 2022 revision. <em>Ann Rheum Dis</em> 2022.</li>
<li>U.S. FDA Drug Safety Communication, Dec 2021 — JAK inhibitors (ORAL Surveillance; <em>N Engl J Med</em> 2022;386:316–326).</li>
</ol>
Question · medium
A 62-year-old man with longstanding seropositive rheumatoid arthritis develops progressive dyspnea. Imaging shows a moderate left pleural effusion. Thoracentesis: glucose 25 mg/dL, pH 7.10, low complement, elevated protein and LDH, and a mononuclear cell predominance. What is the most likely explanation?
RA pleural effusions are characteristically exudative with strikingly low glucose and pH, low complement levels, elevated total protein and LDH, and mononuclear predominance — this profile can mimic bacterial, tubercular, or malignant effusions. A neutrophil-predominant RA effusion should instead raise suspicion of infection. Heart failure produces a transudate, and chylothorax is triglyceride-rich and unrelated to this biochemical signature.
<ol>
<li>MKSAP 19 Rheumatology — "Rheumatoid Arthritis," Ch. 3, pp. 17–23. ACP, 2022.</li>
<li>Harrison's 22e — Shah A, St. Clair EW. "Rheumatoid Arthritis," Ch. 370, pp. 2839–2854.</li>
<li>Fraenkel L, et al. 2021 ACR Guideline for the Treatment of RA. <em>Arthritis Care Res</em> 2021;73(7):924–939.</li>
<li>Smolen JS, et al. EULAR RA management recommendations: 2022 update. <em>Ann Rheum Dis</em> 2023;82(1):3–18.</li>
<li>Studenic P, et al. ACR/EULAR remission criteria for RA: 2022 revision. <em>Ann Rheum Dis</em> 2022.</li>
<li>U.S. FDA Drug Safety Communication, Dec 2021 — JAK inhibitors (ORAL Surveillance; <em>N Engl J Med</em> 2022;386:316–326).</li>
</ol>
Question · medium
A 52-year-old woman is newly diagnosed with rheumatoid arthritis: 14 swollen joints, CRP 48 mg/L, and no prior therapy. She has moderate-to-high disease activity and no contraindications. What is the most appropriate INITIAL disease-modifying therapy?
Methotrexate is the anchor drug for RA and first-line therapy for moderate-to-high activity: titrate (up to 25 mg/week; switch to subcutaneous above ~15 mg/week or if oral therapy misses target) with folic acid, and reassess at 12-week intervals toward remission or low disease activity. Biologics are added when the target is not met, not as initial monotherapy in a DMARD-naïve patient. NSAIDs are adjunctive and not disease-modifying, and chronic glucocorticoids carry unacceptable long-term toxicity (osteoporosis, diabetes, infection) — they are bridging agents, not sole therapy.
<ol>
<li>MKSAP 19 Rheumatology — "Rheumatoid Arthritis," Ch. 3, pp. 17–23. ACP, 2022.</li>
<li>Harrison's 22e — Shah A, St. Clair EW. "Rheumatoid Arthritis," Ch. 370, pp. 2839–2854.</li>
<li>Fraenkel L, et al. 2021 ACR Guideline for the Treatment of RA. <em>Arthritis Care Res</em> 2021;73(7):924–939.</li>
<li>Smolen JS, et al. EULAR RA management recommendations: 2022 update. <em>Ann Rheum Dis</em> 2023;82(1):3–18.</li>
<li>Studenic P, et al. ACR/EULAR remission criteria for RA: 2022 revision. <em>Ann Rheum Dis</em> 2022.</li>
<li>U.S. FDA Drug Safety Communication, Dec 2021 — JAK inhibitors (ORAL Surveillance; <em>N Engl J Med</em> 2022;386:316–326).</li>
</ol>
Question · hard
A 67-year-old man with rheumatoid arthritis, hypertension, and a 40-pack-year smoking history has persistent moderate disease activity despite maximized subcutaneous methotrexate. He asks about starting tofacitinib. According to current FDA and EMA guidance, what is the most appropriate approach?
The ORAL Surveillance trial (tofacitinib vs TNF inhibitors in RA patients ≥50 with ≥1 cardiovascular risk factor) showed increased major adverse cardiovascular events, malignancies (notably lung cancer and lymphoma), venous thromboembolism, and death with tofacitinib. The FDA applied a class boxed warning to tofacitinib, baricitinib, and upadacitinib and restricted them to patients with inadequate response/intolerance to ≥1 TNF blocker; the EMA recommends using them in patients ≥65, current/past long-term smokers, or those with CV/malignancy risk factors only if no suitable alternative exists. This patient has all three risk features. Combining a JAK inhibitor with a biologic is avoided because of compounded immunosuppression and infection risk.
<ol>
<li>MKSAP 19 Rheumatology — "Rheumatoid Arthritis," Ch. 3, pp. 17–23. ACP, 2022.</li>
<li>Harrison's 22e — Shah A, St. Clair EW. "Rheumatoid Arthritis," Ch. 370, pp. 2839–2854.</li>
<li>Fraenkel L, et al. 2021 ACR Guideline for the Treatment of RA. <em>Arthritis Care Res</em> 2021;73(7):924–939.</li>
<li>Smolen JS, et al. EULAR RA management recommendations: 2022 update. <em>Ann Rheum Dis</em> 2023;82(1):3–18.</li>
<li>Studenic P, et al. ACR/EULAR remission criteria for RA: 2022 revision. <em>Ann Rheum Dis</em> 2022.</li>
<li>U.S. FDA Drug Safety Communication, Dec 2021 — JAK inhibitors (ORAL Surveillance; <em>N Engl J Med</em> 2022;386:316–326).</li>
</ol>