Musculoskeletal

Systemic Lupus Erythematosus

Autoimmune inflammatory condition caused by antibody-antigen deposition in various tissues.

• H&P: Young women, blacks, hispanics, asians
• Dx: DOPAMINe RASH 4 of 11 criteria, rule out 2° causes (drug-induced lupus SHIPP: sulfonamides, hydralazine, isoniazid, phenytoin, procainamide). Best screening test is ANA (98% sensitivity), most specific are anti ds-DNA, anti-Sm. Complement C3 and C4 levels can also be low, especially during acute flares.
• Tx: NSAIDs for arthritis and mild serositis; hydroxychloroquine for skin and renal disease; for moderate to severe disease, use corticosteroids or anti B cell biologics; for acute flares, use steroid tapers. Test for anti-SSA in patients thinking about getting pregnant, as this antibody can cross the placenta and cause neonatal lupus and complete heart block. If patient has anti-phospholipid antibody syndrome, they need lifelong warfarin.

Rheumatoid Arthritis

• H&P: middle aged women, HLA-DR4 serotype; morning stiffness that lasts > 30 min and improves with activity; Swan Neck deformity (PIP extension, DIP flexion), Boutonniere deformity (PIP flexion, DIP extension), ulnar deviation of MCP.
• Dx: 4 criteria for 6+ weeks. 3 or more joints (PIP, MCP, wrist, elbow, knee, ankle); symmetrical joint synovial hypertrophy with cartilage loss and osteoporosis on xray; elevated CRP, ESR (sensitive, not specific), rheumatoid factor (75% sensitive), or anti-CCP (most specific); inflammatory synovial fluid on joint aspiration; rheumatoid skin nodules (elbow most common).
• Tx: NSAIDs and PT; Sulfasalazine, Hydroxychloroquine, or Glucocorticoids for milds disease; Methotrexate, anti-TNF biologics, or corticosteroids for moderate-severe disease; anti-TNF biologics AND corticosteroids for severe disease. Avoid methotrexate in patients with HIV, liver disease, ILD, renal disease, pregnancy, or bone marrow suppression; avoid anti-TNF in patients with TB.

Osteoarthritis

• H&P: Older patients; polyarticular arthritis in the DIP (Heberden), PIP (Bouchard), 1st CMC, elbow, hip, knee, and back; Morning stiffness lasts < 30 min, but pain worsens with activity as the day progresses; can be secondary to trauma or metabolic disease (Wilson or Hemochromatosis)
• Dx: Xrays and clinical findings asymmetric joint sclerosis, narrowing, periarticular bone spurs; inflammatory lab markers are normal; joint aspiration has WBCs < 2000
• Tx: Exercise, PT, weight loss; NSAIDs, APAP; Glucocorticoid injections; Joint replacement.

Gout

• H&P: Monoarthritis, swollen, red, very painful joint, most commonly the first carpometatarsal joint; can be associated with tophi if chronic; risk factors include obesity, male, Pacific Islanders, cancer, renal disease, Thiazide diuretic use, and high meat/alcohol consumption.
• Dx: Joint aspirate reveals negatively birefringent needle shaped monosodium urate crystals that are yellow with parallel light, with WBCs 3-50k. Differential diagnosis of monoarthritis includes pseudogout (rhomboid shaped, positively birefringent, calcium pyrophosphate crystals), septic arthritis, trauma, reactive arthritis, Hemochromatosis, and Lyme disease.
• Tx: First-line is high-dose NSAIDs (e.g. Indomethacin, but avoid in ESRD or GI bleed) or colchicine (avoid in ESRD), second-line is intra-articular corticocorticoids. Give allopurinol once the acute symptoms resolve to prevent recurrences.

Low Back Pain

• H&P: Look for history of weight loss, morning stiffness, sciatica, trauma, IV drug use, surgery, bowel bladder incontinence, weakness, saddle anesthesia
• Dx: Straight leg raise, abdominal exam, palpate spine and paraspinal area, ± neuro and DRE; get X-rays if indicated. Malignancy, cauda equina, osteomyelitis, epidural abscess, ankylosing spondylitis, degenerative (disc herniation, spinal stenosis, spondylolisthesis), muscular strain, referred pain from abdomen, trauma
• Tx: Treat underlying cause if possible. Multimodal, PT, weight loss, exercise, pain psych. Avoid muscle relaxers and opioids.

Spondyloarthropathies

Spondyloarthropathy	Spondyloarthritis	Enthesitis	Uveitis	Psoriasis	Nail Pitting	Urethritis	Monoarticular
Ankylosing Spondylitis	+	+	+	+	-	-	-
Reactive Arthritis	+	+	+	-	-	+	+
Psoriatic Arthritis	+	+	-	+	+	-	-

Ankylosing Spondylitis

• H&P: Chronic low back pain in young men that is worse in the morning and improves throughout the day, associated with HLA-B27 serotype
• Dx: X-rays show fusion of SI joints (earliest radiographic finding), squaring of lumbar vertebrae, kyphosis, ascending fusion of spinal column ("bamboo spine"). Associated with apical pulmonary fibrosis (ILD), uveitis, aortitis, psoriasis, IBD
• Tx: NSAIDs and exercise are first line. Second line is anti-TNF

Reactive Arthritis

• H&P: Monoarticular arthritis, most commonly in the knee, associated with uveitis, and urethritis, after infection with Chlamydia, Shigella, Salmonella, Campylobacter, Yersinia, or C. diff
• Dx: Urine PCR for Chlamydia
• Tx: NSAIDs first line. Intraarticular glucocorticoids or methotrexate are second line.

Psoriatic Arthritis

• H&P: Arthritis and psoriasis
• Dx: Clinical, PIP and DIP joints (as in OA), SI joint, and spondylitis, nail pitting
• Tx: NSAIDS 1st line. Methotrexate or anti-TNF 2nd line

Vasculitides

Temporal Arteritis

• H&P: Large vessel vasculitis; scalp and temple pain, headache, monocular blindness; associated with rheumatoid arthritis
• Dx: Clinical, temporal artery biopsy
• Tx: High dose prednisone for months before tapering. Start treatment immediately to avoid blindness, don't wait for biopsy results

Polyarteritis Nodosa

• H&P: Medium vessel vasculitis; Strong association with HBC and HCV
• Dx:
• Tx:

Kawasaki Disease

• H&P: Medium vessel vasculitis; ≥ 5 days fever with at least 4 of 5 other criteria in a child; often Asian
• Dx: CRASH and Burn; differential includes acute rheumatic fever from S. pyogenes (no uveitis); CRP is elevated but not required
• Tx: IVIG; Hold off on live vaccines for 12 months after IVIG therapy; get a TTE to eval for coronary artery aneurysm

Polymyalgia Rheumatica

• H&P: proximal muscle pain without weakness, subjective difficulty getting out a chair
• Dx:
• Tx:

Fibromyalgia

• H&P: Older women, history of depression or trauma, or IBS; widespread chronic muscle pain in pre-defined areas, insomnia, weakness, fatigue
• Dx: WPI 3-6 and SSI > 9, or WPI ≥ 7 and SSI ≥ 5, labs are all negative
• Tx: TCAs, SSRIs, Gabapentin, Pregabalin, exercise, PT, hydrotherapy, heat, pain psych

Missed Concepts

• Hemochromatosis diagnosis and association with HCC
• Paget disease diagnosis
• Complications of untreated scaphoid fracture
• Chronic exertional compartment syndrome vs. tibial stress fracture vs. shin splints
• Myotonic dystrophy diagnosis