ABIM Rheumatology cheat sheet

ACR/EULAR 2010 RA criteria: score ≥6/10 with at least 1 joint with definite clinical synovitis; weights: 1 large joint=0, 2-10 large=1, 1-3 small=2, 4-10 small=3, >10 with ≥1 small=5; serology: RF/anti-CCP low+ =2, high+ =3; acute phase: abnormal CRP/ESR=1; duration ≥6 weeks=1.

SLE classification (2019 EULAR/ACR): entry criterion ANA ≥1:80; additive weighted criteria ≥10 points with ≥1 clinical criterion; domains include constitutional, hematologic, neuropsychiatric, mucocutaneous, serosal, musculoskeletal, renal; specific autoantibodies (anti-dsDNA, anti-Sm, antiphospholipid) add points.

Gout: monosodium urate crystals are needle-shaped and negatively birefringent under polarized light; CPPD crystals are rhomboid and positively birefringent. Acute flare treatment: NSAIDs, colchicine, or glucocorticoids; do not start urate-lowering therapy during a flare unless already indicated.

Systemic sclerosis: limited cutaneous (lcSSc) involves skin distal to elbows/knees and face, associated with anticentromere antibodies and CREST; diffuse cutaneous (dcSSc) involves proximal skin, associated with anti-topoisomerase I (Scl-70) and anti-RNA polymerase III, higher risk of interstitial lung disease and renal crisis.

ANCA-associated vasculitis: c-ANCA/anti-PR3 associated with granulomatosis with polyangiitis (GPA); p-ANCA/anti-MPO associated with microscopic polyangiitis (MPA) and eosinophilic GPA (EGPA). Induction for severe disease: cyclophosphamide or rituximab plus glucocorticoids.

Polymyalgia rheumatica (PMR): age ≥50, bilateral shoulder/hip girdle pain with elevated ESR/CRP; treat with low-dose prednisone (12.5-25 mg/day). Giant cell arteritis (GCA): age ≥50, new headache, jaw claudication, visual symptoms, elevated ESR; treat immediately with high-dose glucocorticoids (prednisone 40-60 mg/day) and consider temporal artery biopsy.

Antiphospholipid syndrome (APS): clinical criteria (vascular thrombosis or pregnancy morbidity) plus laboratory criteria (lupus anticoagulant, anticardiolipin, or anti-β2-glycoprotein I antibodies on two occasions ≥12 weeks apart). Treatment: anticoagulation for thrombosis; aspirin ± heparin for pregnancy.

Spondyloarthritis (axSpA): inflammatory back pain (improves with exercise, worse at rest, night pain), sacroiliitis on imaging, HLA-B27 association, extra-articular manifestations (uveitis, psoriasis, IBD). First-line: NSAIDs; TNF inhibitors or IL-17 inhibitors for inadequate response.

Osteoarthritis: diagnosis is clinical (pain, stiffness <30 min, bony enlargement, crepitus); weight loss and exercise are core treatments; intra-articular glucocorticoids for flares; avoid chronic opioids.

Rheumatic disease in pregnancy: SLE flares are more common; anti-Ro/SSA and anti-La/SSB cross the placenta and can cause congenital heart block (monitor with fetal echocardiography). Avoid methotrexate, leflunomide, and cyclophosphamide; hydroxychloroquine and azathioprine are generally continued.

Infection screening before immunosuppression: screen for latent TB (IGRA or tuberculin skin test) and hepatitis B (HBsAg, anti-HBc, anti-HBs) before starting TNF inhibitors or other biologics; vaccinate against pneumococcus, influenza, and hepatitis B as indicated.

Drug monitoring: methotrexate requires folic acid supplementation and monitoring of CBC, creatinine, and liver enzymes; hydroxychloroquine requires annual dilated eye exam after 5 years of use (or earlier if risk factors); azathioprine: check TPMT activity before starting.

Glucocorticoid complications: osteoporosis (calcium/vitamin D, bisphosphonate if indicated), hyperglycemia, hypertension, infection, avascular necrosis, and adrenal suppression with abrupt withdrawal after long-term use.

Renal involvement in rheumatic disease: SLE nephritis classified by ISN/RPS (class III/IV proliferative) often requires mycophenolate or cyclophosphamide plus glucocorticoids; scleroderma renal crisis presents with hypertension and acute kidney injury and is treated with ACE inhibitors.

Vasculitis mimics: infective endocarditis, cholesterol emboli, and malignancy can mimic vasculitis; obtain blood cultures and evaluate for malignancy when presentation is atypical.

Perioperative management: continue hydroxychloroquine and sulfasalazine; hold methotrexate and biologics around surgery based on infection risk and half-life; stress-dose glucocorticoids for patients on chronic steroids.

Vaccination in immunosuppressed patients: avoid live vaccines (e.g., live attenuated influenza, yellow fever, MMR, varicella) in patients on high-dose immunosuppression; inactivated vaccines are safe but response may be reduced.

Cardiovascular risk: chronic inflammatory diseases (RA, SLE, psoriasis) increase cardiovascular risk; screen and manage traditional risk factors; NSAIDs may increase cardiovascular risk and should be used at the lowest effective dose.