Core Rheumatologic Conditions and Diagnostic Criteria
Understanding diagnostic criteria is fundamental to Step 2 CK success. The American College of Rheumatology (ACR) has established standardized criteria for major conditions you must master.
Rheumatoid Arthritis and Systemic Lupus Erythematosus
For Rheumatoid Arthritis, the 2010 ACR/EULAR criteria focus on joint involvement pattern, serology (RF and anti-CCP), acute phase reactants, and symptom duration. Systemic Lupus Erythematosus diagnosis requires four of eleven criteria including:
- Malar rash
- Discoid rash
- Photosensitivity
- Oral ulcers
- Arthritis
- Serositis
- Renal involvement
- Neurologic involvement
- Hematologic abnormalities
- Immunologic findings
- ANA positivity
Sjögren Syndrome, Scleroderma, and Other Conditions
For Sjögren Syndrome, recognize both primary and secondary forms with specific antibodies (anti-SSA/Ro and anti-SSB/La). Scleroderma presentations vary between limited cutaneous (lcSSc) and diffuse cutaneous (dcSSc) forms with different organ involvement patterns.
Polymyalgia Rheumatica typically affects patients over 50 with proximal muscle pain and constitutional symptoms. Often it associates with temporal arteritis.
Gout and Pseudogout
Gout diagnosis requires needle-shaped, negatively-birefringent monosodium urate crystals in synovial fluid. Pseudogout involves calcium pyrophosphate dihydrate crystals instead.
Mastering these criteria through repetitive flashcard review allows rapid pattern matching during clinical vignettes on the exam.
Laboratory Tests, Imaging, and Interpretation
Step 2 CK rheumatology questions frequently test your ability to interpret lab findings and imaging studies. Understanding what each test reveals helps you synthesize clinical information accurately.
Serologic Markers and Antibody Patterns
Know the distinction between RF (rheumatoid factor) and anti-CCP antibodies: anti-CCP is more specific for RA and predicts erosive disease better. ANA patterns matter significantly for diagnosis:
- Homogeneous pattern suggests SLE
- Centromere pattern indicates limited scleroderma
- Anti-topoisomerase associates with diffuse scleroderma
Complement levels (C3 and C4) are low in active SLE and help assess disease activity. ESR and CRP are non-specific inflammation markers, but CRP rises faster in acute bacterial infections while ESR lags.
Imaging and Synovial Fluid Analysis
For imaging, understand that RA causes periarticular osteopenia and marginal erosions starting in small joints. Osteoarthritis shows joint space narrowing with osteophytes and subchondral sclerosis. MRI is most sensitive for erosions and inflammatory changes. Hand X-rays are essential for RA assessment and monitoring.
Inflammatory markers are typically normal in osteoarthritis but elevated in inflammatory conditions. Synovial fluid analysis is crucial for distinguishing arthritis types:
- Inflammatory arthritis: WBC 2,000-50,000
- Septic arthritis: often exceeds 50,000
- Check for crystals and culture bacteria
Understanding these diagnostic tools helps you arrive at correct diagnoses confidently.
Pharmacotherapy and Drug Management
Drug knowledge comprises a substantial portion of Step 2 CK rheumatology content, and flashcards excel at organizing this information efficiently.
NSAIDs and Corticosteroids
NSAIDs are first-line for pain and inflammation in many conditions but carry risks of GI bleeding, renal dysfunction, and cardiovascular events. Use caution in elderly patients. Corticosteroids provide rapid anti-inflammatory effects but cause significant side effects including infection risk, osteoporosis, and metabolic complications with long-term use.
Disease-Modifying Antirheumatic Drugs (DMARDs)
Conventional DMARDs like methotrexate, sulfasalazine, and hydroxychloroquine require baseline lab work and monitoring. Methotrexate is standard first-line DMARD for RA with mandatory CBC and LFT monitoring due to hepatotoxicity and bone marrow suppression.
Biologic agents including TNF inhibitors, IL-6 inhibitors, and JAK inhibitors require TB testing and live vaccine avoidance. Know common biologic-associated infections and contraindications.
Gout and SLE Management
For gout, acute attacks are treated with NSAIDs, colchicine, or corticosteroids. Uric acid-lowering therapy uses allopurinol or febuxostat. Allopurinol requires dose reduction in renal insufficiency.
Hydroxychloroquine is foundational for SLE management, particularly for cutaneous and joint involvement. Understanding mechanism of action, monitoring requirements, and side effect profiles for each drug class is essential for clinical decision-making on the exam.
Vasculitis Classification and Clinical Presentations
Vasculitis questions appear regularly on Step 2 CK, and classification by vessel size is the organizational framework you need to master.
Large and Medium Vessel Vasculitis
Large vessel vasculitis includes temporal (giant cell) arteritis and Takayasu arteritis. Both present with constitutional symptoms and vessel inflammation on imaging.
Medium vessel vasculitis encompasses polyarteritis nodosa and Kawasaki disease. Kawasaki disease notably causes coronary aneurysms in children.
Small Vessel Vasculitis and ANCA-Associated Diseases
Small vessel vasculitis is subdivided into ANCA-associated and immune complex-mediated forms. GPA (Granulomatosis with Polyangiitis) classically presents with:
- Upper respiratory tract involvement
- Glomerulonephritis
- Pulmonary infiltrates
- Positive c-ANCA and anti-PR3 antibodies
Microscopic polyangiitis spares upper respiratory tract and associates with p-ANCA and anti-MPO antibodies.
EGPA (formerly Churg-Strauss) requires asthma, eosinophilia, and neuropathy. Cardiac involvement is common.
IgA Vasculitis and Temporal Arteritis
IgA vasculitis presents with palpable purpura on lower extremities and buttocks, often with abdominal pain. IgA-dominant patterns appear on kidney biopsy.
Temporal arteritis requires urgent recognition to prevent blindness. Obtain temporal artery biopsy and start immediate corticosteroid treatment. Understanding these distinctions and organ involvement patterns prevents serious complications.
Study Strategies and Flashcard Optimization for Rheumatology
Rheumatology demands a systematic approach to learning, and flashcards are uniquely suited to this subject's organizational requirements.
Organizing Your Flashcard Deck
Create flashcards organized by diagnostic criteria, grouping all ACR criteria for a single disease on one card. Emphasize numerical thresholds in your answers. Develop separate card sets for diagnostic tests, drug mechanisms, and management algorithms.
Use the front of cards for clinical vignettes or images, and backs for differential diagnoses with distinguishing features. For complex concepts like vasculitis classification, create hierarchical cards starting with vessel size, then specific diagnoses, then clinical features and antibodies.
Active Recall and Spaced Repetition
Study in focused sessions of 20-30 minutes using spaced repetition, reviewing cards at increasing intervals. Prioritize high-yield topics:
- RA diagnostic criteria
- Complement patterns in SLE
- Drug monitoring requirements
- Vasculitis classification
Use active recall during your review. Cover the answer and force yourself to retrieve information before checking.
Connecting Concepts and Practice
Connect clinical presentation cards to diagnostic criteria cards to lab findings cards. This creates mental networks that mirror how clinicians think. Consider creating image cards with hand X-rays or rash pictures paired with diagnostic information.
Test yourself with practice questions while reviewing flashcards. This reinforces both recognition and recall abilities needed for the exam. Group study with classmates using flashcards promotes discussion and reinforces learning through explanation.