Rheumatology
9 high-yield topics. Open a topic to review its pearls.
Joint Aspirate and Arthritis
Synovial fluid analysis
Joint Fluid Interpretation
- DJD/traumatic: WBC 1000-2000, monos
- RA: WBC 5000-50000, PMNs
- Gout: needle-shaped, negative birefringence
- Pseudogout: rhomboid CPPD, weakly positive birefringence
- Septic: WBC over 50000-100000, positive gram stain
Osteoarthritis
Diagnosis and treatment
Clinical Features
- Joint pain greater in PM, AM stiffness under 30 min
- Heberden nodes (DIP), Bouchard nodes (PIP)
- No inflammatory signs or serology
- X-ray: joint space narrowing, subchondral sclerosis, osteophytes
Treatment
- Weight loss (most important modifiable factor for knee)
- Physical therapy, acetaminophen, COX2 inhibitors
- Intra-articular steroids, surgery
Rheumatoid Arthritis
Diagnosis, extra-articular, DMARDs
Diagnostic Criteria
- 4 of 7 over 6 weeks: AM stiffness over 1h, symmetric arthritis, 3 or more joints, hand arthritis (DIP spared), nodules, positive RF, X-ray changes
- Anti-CCP: high specificity
Extra-articular
- Nodules (type 3 immune complex)
- Rheumatoid vasculitis, mononeuritis multiplex
- Pleural effusions with low glucose (under 30)
- Felty syndrome: splenomegaly + granulocytopenia
- C1-C2 subluxation (check neck before surgery)
Treatment
- Methotrexate: first-line DMARD
- MTX side effects: liver toxicity, pneumonitis, macrocytic anemia (give folate)
- TNF inhibitors: check PPD/Quantiferon before starting
- Hydroxychloroquine: annual retinal exam
- D/C MTX 3 months before pregnancy
SLE
Diagnosis, antibodies, treatment
Serology
- ANA: 95-98 percent sensitive (best screen)
- Anti-Sm: most specific
- Anti-dsDNA + low complement: disease activity
- Anti-Ro/SSA: subacute lupus, neonatal heart block
- Anti-histone: drug-induced
Antiphospholipid Syndrome
- Venous/arterial thrombosis
- Pregnancy loss 2nd/3rd trimester
- Prolonged PTT not corrected by mixing, false positive VDRL
- Libman-Sacks endocarditis
Flares and Treatment
- Flare: high anti-dsDNA, low C3/C4, high ESR
- NSAIDs, hydroxychloroquine (annual eye exam)
- Steroids for severe organ involvement
- Immunosuppressants for lupus nephritis
- Leading cause of death (over 10 years): cardiovascular disease
Drug-Induced Lupus
- Normal complement, anti-histone positive, no CNS/renal
- Drugs: hydralazine, procainamide, INH, minocycline, PTU
- Resolves with discontinuation
Vasculitides
Large, medium, small vessel
Large Vessel
- Temporal arteritis: age over 50, ESR over 50, jaw claudication, visual symptoms, start steroids on suspicion, biopsy within 1 week
- Takayasu: young women, pulse deficits, asymmetric BP
- Associated with PMR (50 percent)
Medium Vessel
- Polyarteritis nodosa: mononeuritis multiplex, mesenteric arteritis, Hep B, abdominal angiogram, steroids + cyclophosphamide
Small Vessel
- Wegener: sinusitis + lung nodules + c-ANCA, cyclophosphamide/rituximab + steroids
- Churg-Strauss: asthma + eosinophilia + neuropathy
- HSP: palpable purpura buttocks/legs, IgA, post-URI
- Cryoglobulinemia: palpable purpura, Hep C, low C4
Spondyloarthropathies
AS, reactive, psoriatic, IBD
Common Features
- HLA-B27 association
- RF negative, sacroiliitis, anterior uveitis, carditis
Ankylosing Spondylitis
- Young male, symmetric sacroiliitis, better with exercise
- Bamboo spine, apical lung fibrosis, aortitis
- Treatment: NSAIDs, PT, TNF inhibitors
Reactive (Reiter)
- Cant see, cant pee, cant climb a tree
- 1-3 weeks after GI/GU infection (Chlamydia, Shigella, Salmonella)
- E. coli does NOT cause it
- Keratoderma blennorrhagicum, circinate balanitis
Psoriatic
- DIP involvement, dactylitis (sausage digits)
- Nail pitting, pencil-in-cup deformity
- Worsened by hydroxychloroquine, beta blockers
Crystal Arthropathies
Gout and pseudogout
Gout
- Sudden asymmetric oligoarthritis, podagra (great toe)
- Negative birefringence, needle-shaped urate crystals
- Do NOT treat asymptomatic hyperuricemia
- Acute: NSAIDs, colchicine, steroids (renal failure)
- Chronic overproducers: allopurinol; underexcretors: probenecid
Pseudogout
- Calcium pyrophosphate, rhomboid crystals, weakly positive birefringence
- Chondrocalcinosis on x-ray
- Associated: hyperparathyroidism, hemochromatosis, hypothyroidism
- Prefers knee joint
Systemic Sclerosis
Scleroderma and CREST
Scleroderma
- Anti-Scl-70 positive
- Skin thickening, sclerodactyly, Raynaud
- Renal crisis: ACE-I regardless of creatinine
- Pulmonary fibrosis and HTN
CREST
- Anti-centromere antibody
- Calcinosis, Raynaud, Esophageal dysmotility, Sclerodactyly, Telangiectasia
- Pulmonary HTN more common than scleroderma
Sjogren and Others
Sjogren, PMR, fibromyalgia
Sjogren
- Dry eyes/mouth, arthralgias, parotid swelling
- Anti-Ro/La (SSA/SSB), increased lymphoma risk
- Salivary gland biopsy, Schirmer test
Polymyalgia Rheumatica
- Bilateral shoulder/hip girdle stiffness
- Elevated ESR, associated temporal arteritis
- Low-dose steroids
Fibromyalgia
- Diffuse pain, fatigue, insomnia, over 11 tender points
- Normal labs and imaging
- Exercise, amitriptyline, duloxetine, pregabalin