Musculoskeletal

Missed Concepts

• Hemochromatosis diagnosis and association with HCC
• Paget disease diagnosis: bony pain, thickened cortex with sclerotic lesions on xray, elevated ALK, normal Ca.
• Treat Paget disease with alendronate (bisphosphanate) if patient has intolerable pain or involvement of weight-bearing bone.
• Complications of untreated scaphoid fracture (e.g. non-union, avascular necrosis)
• Chronic exertional compartment syndrome (worse with exertion) vs. tibial stress fracture (pain with standing) vs. shin splints
• Septic arthritis of the hip in an infant can lack fever, but presents with pseudo paralysis (due to pain), elevated WBCs, elevated CRP, and effusion. *Legg-Calvé-Perthes disease (idiopathic avascular necrosis of the hip) occurs in children aged 3-8, is insidious in onset, and does not have elevated inflammatory markers.
• Myotonic dystrophy (most common form of adult onset muscular dystrophy) is autosomal dominant, caused by CTG repeats with genetic anticipation. Classic form presents in adulthood with muscle weakness and myotonia (impaired muscular relaxation). Infantile presentation includes respiratory failure, hypotonia, inverted V upper lip, cataracts, poor feeding, and clubbed foot. Diagnosis is via genetic testing.
• FOOSH with "sail sign" (fat pad visible on xray), should be immobilized in a splint.
• Osteoporosis can lead to vertebral compression fractures after minimal trauma in elderly patients, manage with Tylenol/NSAIDs and PT.
• Indications for bariatric surgery include BMI > 40, BMI > 35 with T2DM/OSA/HTN, BMI > 30 w/ T2DM resistant to treatment or metabolic syndrome.
• Raynaud is treated with dhp-CCBs like nifedipine.
• Lateral shoulder pain is the most common symptom in torn rotator cuff.
• Scoliosis that causes back pain, is rapidly progressive, or associated with neurological symptoms may be pathologic (e.g. spinal tumor). Most cases are idiopathic.
• Fracture of Pars interarticularis causes spondylolisthesis

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), anti-dsDNA is relatively sensitive and specific, and anti-Sm is the most specific, but not sensitive. 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; DMARDS (Sulfasalazine, Hydroxychloroquine, Azathioprine) ± Glucocorticoids for mild disease; Methotrexate (1st line), anti-TNF biologics (2nd line) ± 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. Patients taking methotrexate should also get folate supplementation.

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. More common in patients with HLA-B27 serotype.
• Dx: Urine PCR for Chlamydia. Joint aspiration shows inflammatory profile with negative culture.
• 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 criteria for Kawasaki—Conjunctivitis, Rash, Adenopathy, Strawberry tongue, Hand/feet swelling, AND fever ≥ 5 days; 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: Age > 50, F>M. Proximal muscle pain and decreased active ROM but no weakness in neck/hips/shoulders, prolonged morning stiffness, subjective difficulty getting out a chair. Symptoms last at least 2 weeks. Fever, malaise, weight loss. Associated with giant cell arteritis.
• Dx: Elevated ESR, normocytic anemia, or normal studies
• Tx: Low dose glucocorticoids. Follow with a long steroid taper. Symptoms usually resolve rapidly.

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. Order CBC, TSH, ESR to rule out anemia, hypothyroidism, or inflammatory arthropathy, which can look like fibromyalgia. Ddx includes polymyositis and PMR.
• Tx: TCAs, SSRIs, Gabapentin, Pregabalin, exercise, PT, hydrotherapy, heat, pain psych

Polymyositis

• H&P: Proximal muscle weakness
• Dx: Elevated CK; Differential includes fibromyalgia and PMR.
• Tx: Can be complicated by ILD.

Dermatomyositis

• H&P: Symmetric proximal muscle weakness. Gottron papules, heliotrope rash
• Dx: Elevated CPK; positive ANA, anti-Jo-1 antibodies
• Tx: High-dose corticosteroids. Screen for malignancy. Screen for ILD with CXR.

Scleroderma

• H&P: Women ages 30-65. Skin thickening on the face and extremities.
• Dx: CREST syndrome—Calcinosis, Raynaud's phenomenon, Esophageal dysmotility (GERD), Sclerodactly, and Telangiectasias. It involves the distal extremities and face only, is slowly progressive, has positive anti-centromere antibodies, a fair prognosis, and is associated with pulmonary hypertension. Diffuse scleroderma has generalized skin involvement, is rapidly progressive, has anti Scl-70 (topoisomerase I) antibodies, a poor prognosis, weaker association with calcinosis and telangiectasias, is associated with pulmonary interstitial fibrosis, and is more likely to trigger renal failure. Both can cause scleroderma renal crisis, which presents as acute malignant hypertension
• Tx: ACEI (captopril is preferred) is 1st line for scleroderma renal crisis, even though ACEI are generally avoided in acute renal failure. Also give IV nitroprusside if there is concomitant malignant HTN