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 colchicine, 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

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 of SI joint (earliest radiographic finding), "bamboo spine", squaring of lumbar vertebrae, kyphosis, ascending fusion of spinal column. 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.

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