Rheumatology Lecture – Comprehensive Study Notes

Polymyalgia Rheumatica (PMR)

• Auto-immune, inflammatory disorder of joints (NOT muscles)
• Epidemiology
  • Age >50 (often 70–80 y.o.)
  • Female > male
• Classic triad of pain & morning stiffness (usually >30 min)
  • Shoulders
  • Neck
  • Hips / pelvic girdle
• Lab pattern
  • Markedly ↑ inflammatory markers: $\text{ESR},\; \text{CRP}$
  • All other rheum serologies negative (diagnosis of exclusion)
• Diagnostic pearl
  • Rapid relief ("within doses–days") after starting a moderate-dose glucocorticoid (e.g. prednisone); therapeutic trial doubles as diagnostic test
• Association: Giant-Cell (Temporal) Arteritis
  • Mnemonic: “Paul Bunyan (giant) carries a giant axe on sore shoulders.” → always screen for GCA symptoms (HA, scalp tenderness, vision changes)

Giant-Cell / Temporal Arteritis (GCA)

• Large-vessel vasculitis of branches of external carotid (temporal a.)
• Red-flag features
  • New, unilateral temporal headache ± scalp tenderness
  • Jaw claudication
  • Visual disturbances → risk of irreversible blindness
• Exam
  • Palpable, tender, thickened temporal artery
  • Fundoscopy: pale, edematous optic disc
• Work-up
  • ↑↑ $\text{ESR}$ (often >100 mm/h) & $\text{CRP}$
  • Definitive test = temporal-artery biopsy (skip lesions possible)
• Treatment
  • Immediate high-dose steroids (IV methyl-pred if visual sx); do not delay for biopsy

Polymyositis & Dermatomyositis (PM/DM)

• Idiopathic autoimmune muscle inflammation (proximal > distal)
• Shared clinical core
  • Symmetric proximal muscle weakness & pain (shoulder, pelvic girdles)
  • Progression → difficulty climbing stairs, rising from chair
  • Possible respiratory muscle involvement
• Dermatomyositis extras
  • Cutaneous signs:
  • Gottron papules – violaceous plaques over MCP/PIP knuckles
  • Heliotrope rash – lilac periorbital discoloration
  • Photodistributed “shawl/ V-sign” (polinkidermal rash)
• Key labs
  • ↑ muscle enzymes: $\text{CK},\; \text{aldolase}$
  • Auto-antibodies
  • Anti-Jo-1 (PM-specific)
  • Anti-Mi-2 (DM-specific) – mnemonic: 80-y.o. lady shows new “tat” → friend says “Me too”
• Diagnosis & staging: EMG, MRI, muscle biopsy (inflammatory infiltrate)
• Treatment
  • 1st-line systemic glucocorticoids ± taper
  • DM skin lesions → add hydroxy-chloroquine
  • Refractory: immunosuppressants (methotrexate, azathioprine) + physiotherapy

Psoriatic Arthritis (PsA)

• Autoimmune arthropathy developing years after cutaneous psoriasis
• Joints/structures
  • Dactylitis (“sausage” fingers/toes)
  • Asymmetric oligo- or poly-arthritis of hands, feet, sacro-iliac, low back
  • Enthesitis / tendon pain (Achilles, plantar fascia)
• Derm & nails
  • Classic red plaques with silvery scale
  • Pitting / onycholysis / crumbling nails
• Other: anterior uveitis
• Labs/Imaging
  • RF & anti-CCP negative
  • No crystals on joint aspirate
  • X-ray: “pencil-in-cup” erosions
• Therapy
  • NSAIDs → corticosteroids (oral / Intra-articular)
  • DMARDs (methotrexate), biologic agents (TNF-α inhibitors) early to prevent damage

Reactive Arthritis (ReA, formerly Reiter)

• Sterile arthritis 1–4 wks after GU or GI infection
  • GU: Chlamydia trachomatis (classic) > Gonorrhea
  • GI: Salmonella, Shigella, Campylobacter, C. difficile
• Triad mnemonic: “Can’t see (uveitis) – Can’t pee (urethritis) – Can’t climb a tree (arthritis)”
• Findings
  • Asymmetric oligo-arthritis, usually lower limb/knee
  • Dactylitis, enthesitis
  • Conjunctivitis/uveitis; mucocutaneous lesions possible
• Work-up
  • Joint aspirate: inflammatory, culture negative
  • HLA-B27 often positive
• Management
  • Treat underlying infection (e.g. doxycycline for Chlamydia)
  • NSAIDs ± steroids for joint sx; severe → DMARDs/biologics

Rheumatoid Arthritis (RA)

• Chronic, systemic autoimmune synovitis → pannus (hyper-vascular, hypertrophied synovium) → cartilage & bone erosion
• Demographics: F > M, peak 30–50 y
• Joint pattern
  • Symmetric, poly-articular small joints (MCP, PIP, wrist, MTP) – spares DIP
  • Morning stiffness >$30$ min (vs OA <$20$ min) improves with use
  • Warm, boggy swelling; ↓ROM, weakness, fatigue
• Deformities
  • Ulnar deviation at MCP
  • Swan-neck & Boutonnière finger deformities
• Serology
  • Anti-CCP antibody (highly specific)
  • Rheumatoid factor (sensitive but nonspecific)
  • ↑ ESR/CRP
• Imaging: juxta-articular osteopenia, joint-space narrowing, marginal erosions
• Extra-articular: rheumatoid nodules, lung, eye, vasculitis, anemia
• Therapy
  • Immediate NSAID or low-dose steroid for symptoms
  • Early, aggressive DMARD (methotrexate = gold standard); hydroxy-chloroquine, sulfasalazine
  • Biologics (TNF-α, IL-6 blockers) if refractory

Sjögren’s Syndrome

• Autoimmune lymphocytic infiltration of exocrine glands
  • Xerophthalmia (dry, gritty eyes)
  • Xerostomia (dry mouth, chapped lips, dental caries)
  • Arthralgias ± parotid enlargement
• Diagnostics
  • Schirmer test (<5 mm wetting in 5 min = positive)
  • Auto-Abs: Anti-Ro (SSA), Anti-La (SSB); ± RF
  • Salivary gland biopsy (lymphoid aggregates) if uncertain
• Management
  • Symptom control: artificial tears, sugar-free candy, saliva substitutes, ↑hydration
  • Systemic: NSAIDs/steroids for joints; pilocarpine, cevimeline to stimulate secretions

Systemic Lupus Erythematosus (SLE)

• Multisystem autoimmune disorder; African-American females (childbearing) >> others
• Constitutional: fatigue, fever, weight loss
• Cutaneous
  • Malar (butterfly) rash sparing nasolabial folds; photosensitive
  • Discoid lesions – round, scarring plaques
  • Photosensitivity, alopecia
• MSK: symmetric non-erosive arthritis (>90 %)
• Renal: nephritis (hematuria, proteinuria, HTN)
• Cardiac: pericarditis, Libman-Sacks endocarditis
• Hematologic: cytopenias; Neuro: seizures, psychosis
• Labs
  • Screening: +ANA (sensitive)
  • Specific: Anti-dsDNA, Anti-Smith (Sm)
  • Others: hypocomplementemia, antiphospholipid Abs
• Treatment
  • Hydroxy-chloroquine (baseline & annual ophthalmic exam)
  • NSAIDs or steroids for flares
  • Immunosuppressants (azathioprine, cyclophosphamide, mycophenolate) for severe organ dz

Scleroderma (Systemic Sclerosis)

• Path: autoimmune → fibroblast activation → excess collagen deposition → fibrosis
• Two phenotypes
  1. Limited cutaneous (aka CREST):
  • Calcinosis cutis
  • Raynaud phenomenon
  • Esophageal dys-motility/GERD
  • Sclerodactyly (tight, shiny skin)
  • Telangiectasias
  • Antibody: Anti-centromere
  1. Diffuse cutaneous
  • Widespread skin + early visceral (lung, heart, kidney)
  • Antibody: Anti-topoisomerase I (Anti-Scl-70)
• Complications
  • Interstitial lung disease, pulmonary HTN, renal crisis
• Management (organ-based)
  • Raynaud: CCBs (nifedipine)
  • GERD: PPIs
  • Renal crisis: ACE-inhibitors
  • Immunosuppressants (methotrexate, mycophenolate); biologics under study

Ankylosing Spondylitis (AS)

• Seronegative spondylo-arthritis; HLA-B27 positive (~90 %)
• Onset in teens–30s, M > F
• Features
  • Chronic inflammatory back pain & stiffness >3 mo, improves with exercise, not rest
  • ↓ Lumbar flexion; +Schober test
  • Enthesitis (Achilles), costochondral pain → ↓ chest expansion
  • Extra-articular: uveitis, aortitis (AR), apical lung fibrosis
• Imaging
  • X-ray/MRI sacro-iliitis early
  • Spinal "bamboo spine" (syndesmophyte fusion)
• Labs: ↑ ESR/CRP, RF & ANA negative, HLA-B27 positive
• Treatment
  • NSAIDs 1st-line (indomethacin)
  • TNF-α inhibitors (etanercept, adalimumab) or IL-17 blockers for refract/axial dz
  • Posture & extension-based physical therapy

High-Yield Mnemonics & Patterns

• Paul Bunyan → PMR ↔ Giant Cell Arteritis (big axe on shoulder)
• Me Too tattoo → Anti-Mi-2 for Dermatomyositis
• Can’t see, can’t pee, can’t climb a tree → Reactive Arthritis
• CREST → Limited scleroderma features
• Bamboo spine + HLA-B27 → Ankylosing spondylitis

Quick Reference: Key Labs & Drugs

Sample Knowledge-Check Pearls

• PMR pt should feel better within days/doses of starting prednisone; if not, rethink dx.
• Temporal arteritis left untreated → blindness in up to $\frac{1}{3}$ pts.
• Anti-CCP > RF for specificity in RA.
• Schirmer test <5 mm wetting → ocular dryness diagnostic for Sjögren.
• Malar rash spares nasolabial folds; worsens after sun exposure.
• CREST patients are prone to Renaud attacks; advise cold avoidance & CCBs.
• Ankylosing pts often lose lumbar lordosis; emphasize daily extension exercises.