ESTER Reumatologia cheat sheet

Autoantibody screening: ANA is sensitive but not specific; positivity in 1:40 dilution occurs in ~20-30% of healthy people, so titer and pattern guide, not diagnose.

Inflammatory markers: CRP rises and falls within days; ESR lags 1-2 weeks and is falsely elevated by anemia, age, pregnancy, and paraproteins.

Synovial fluid: noninflammatory <2000 WBC/µL, inflammatory 2000-50,000, septic typically >50,000 with >90% neutrophils; crystals under polarized light confirm gout (negatively birefringent) vs CPPD (positively birefringent).

Monoarthritis workup: arthrocentesis with cell count, Gram stain, culture, and crystal examination before antibiotics; septic arthritis is a joint emergency.

DAS28 and CDAI are composite disease-activity scores used to guide treat-to-target escalation in rheumatoid arthritis; remission target is DAS28 <2.6.

Antinuclear antibody patterns: homogeneous suggests dsDNA/histone; speckled suggests extractable nuclear antigens (Sm, RNP, Ro/La, Scl-70); nucleolar suggests systemic sclerosis.

Complement: low C3/C4 with high consumption suggests active SLE or cryoglobulinemia; hereditary angioedema shows low C4 with normal C3.

Drug monitoring: methotrexate requires FBC, renal and liver function at baseline and periodically; hydroxychloroquine needs annual ophthalmologic screening after 5 years of use.

Rheumatoid arthritis classification (ACR/EULAR 2010): score joints, serology, acute-phase reactants, and symptom duration; ≥6/10 indicates definite RA.

RA radiographic hallmarks: symmetric marginal erosions, periarticular osteopenia, uniform joint-space narrowing; osteophytes and subchondral sclerosis indicate osteoarthritis instead.

Extra-articular RA: rheumatoid nodules, interstitial lung disease, scleritis, Felty syndrome (splenomegaly, neutropenia), and cervical C1-C2 instability.

Gout: monosodium urate crystals are needle-shaped and negatively birefringent; flares are triggered by urate shifts, so do not start or stop urate-lowering therapy during an acute attack without cover.

Acute gout treatment options: NSAIDs, colchicine (low-dose within 24 h), glucocorticoids (intra-articular or systemic); urate-lowering targets serum urate <360 µmol/L (<6 mg/dL).

Psoriatic arthritis domains: peripheral arthritis, dactylitis, enthesitis, axial disease, and skin/nail involvement; treat with methotrexate or biologics, and avoid systemic steroids due to withdrawal flares.

Spondyloarthritis: inflammatory back pain (morning stiffness, improvement with exercise), sacroiliitis on imaging, HLA-B27 association, and elevated CRP in a subset.

Septic arthritis vs flare: fever, exquisite pain with any movement, and >50,000 WBC/µL favor infection; do not delay aspiration and empiric antibiotics.

SLE classification (2019 EULAR/ACR): positive ANA ≥1:80 as entry criterion plus weighted clinical and immunologic domains totaling ≥10 points.

Lupus nephritis: biopsy for proteinuria >0.5 g/day or active urinary sediment; class III/IV proliferative disease requires immunosuppression (mycophenolate or cyclophosphamide plus steroids).

Systemic sclerosis: limited cutaneous (face, hands, esophagus; anticentromere) vs diffuse (truncal skin; anti-topoisomerase/Scl-70); screen annually for pulmonary arterial hypertension and interstitial lung disease.

Sjögren syndrome: sicca symptoms, anti-Ro/La, positive Schirmer test and labial biopsy; monitor for lymphoma (persistent parotid enlargement) and extraglandular involvement.

ANCA vasculitis: c-ANCA/anti-PR3 associates with granulomatosis with polyangiitis; p-ANCA/anti-MPO with microscopic polyangiitis and eosinophilic GPA; induction with cyclophosphamide or rituximab plus steroids.

Giant cell arteritis: age >50, new headache, jaw claudication, elevated ESR; start high-dose glucocorticoids immediately and confirm with temporal artery biopsy or ultrasound.

Polymyalgia rheumatica: shoulder and hip girdle pain with morning stiffness, ESR >40, rapid response to low-dose prednisone; exclude GCA and mimic conditions.

Antiphospholipid syndrome: thrombosis or pregnancy morbidity plus persistent anticardiolipin, anti-beta2-glycoprotein I, or lupus anticoagulant ≥12 weeks apart; long-term anticoagulation for thrombotic events.

DXA diagnosis: T-score ≤ -2.5 at hip or lumbar spine defines osteoporosis; -1.0 to -2.5 is osteopenia; Z-score is used in premenopausal women and men <50.

FRAX estimates 10-year major osteoporotic and hip fracture probability; treat when hip probability ≥3% or major osteoporotic ≥20% in many guidelines.

Calcium intake target ~1000-1200 mg/day and vitamin D 800-1000 IU/day for bone health; check 25-hydroxyvitamin D in deficiency risk groups.

Bisphosphonates: alendronate and risedronate first-line; take on empty stomach with water and remain upright 30 minutes; consider drug holiday after 3-5 years of oral therapy in moderate-risk patients.

Denosumab: RANKL inhibitor given every 6 months; do not stop abruptly because rebound vertebral fractures occur; transition to bisphosphonate if discontinuing.

Teriparatide and abaloparatide are anabolic agents for severe osteoporosis; avoid use with prior skeletal malignancy or unexplained alkaline phosphatase elevation.

Osteomalacia: low calcium/phosphate with elevated alkaline phosphatase and bone pain; vitamin D deficiency causes proximal myopathy and Looser zones on radiographs.

Hyperparathyroidism: elevated calcium with elevated or inappropriately normal PTH; primary disease causes bone resorption and nephrolithiasis, treated by parathyroidectomy when indicated.

Fibromyalgia: widespread pain ≥3 months with fatigue, sleep disturbance, and cognitive symptoms; diagnosis is clinical without inflammatory markers or erosions.

Carpal tunnel syndrome: nocturnal paresthesia in median nerve distribution, positive Tinel and Phalen signs; confirm with nerve conduction studies and treat with splinting, injection, or surgery.

Rotator cuff tendinopathy: painful arc with overhead abduction, worse at night; imaging with ultrasound or MRI when conservative therapy fails.

Lateral epicondylitis: pain at the common extensor origin with resisted wrist extension; self-limited, treated with activity modification and eccentric exercise.

Plantar fasciitis: first-step heel pain, tenderness at the medial calcaneal tubercle; stretching and orthoses are first-line, with imaging only for atypical cases.

Polymyalgia vs shoulder pathology: bilateral girdle pain with markedly elevated ESR and rapid steroid response suggests PMR rather than rotator cuff disease.

Achilles tendinopathy: insertional vs midportion pain, morning stiffness, and nodular thickening; avoid quinolones as they increase tendon rupture risk.

De Quervain tenosynovitis: pain over the radial styloid with positive Finkelstein test; common postpartum and associated with repetitive thumb use.

Juvenile idiopathic arthritis: arthritis ≥6 weeks in a child <16 years, classified by ILAR subtypes (oligoarticular, polyarticular RF+/-, systemic, psoriatic, enthesitis-related, undifferentiated).

Uveitis screening: children with JIA need periodic slit-lamp examination; highest risk with oligoarticular onset, young age, and positive ANA.

Kawasaki disease: fever ≥5 days plus conjunctivitis, mucositis, rash, extremity changes, and cervical adenopathy; treat with IVIG and aspirin to prevent coronary aneurysms.

Henoch-Schönlein (IgA) vasculitis: palpable purpura on dependent areas, abdominal pain, arthritis, and nephritis; monitor urine for hematuria and proteinuria.

Systemic lupus erythematosus in children: more severe renal and hematologic involvement than adults; positive ANA and anti-dsDNA support diagnosis.

Growing pains: bilateral, evening leg pain in children 3-12 years, no morning stiffness, normal examination and inflammatory markers.

Septic arthritis in children: refusal to bear weight, fever, and elevated ESR/CRP; joint aspiration and urgent drainage plus antibiotics are required.

Periodic fever syndromes: familial Mediterranean fever responds to colchicine; PFAPA shows periodic fever with aphthous stomatitis, pharyngitis, and adenitis.