Polymyalgia Rheumatica

70 y/o white F with h/o carpal tunnel syndrome presents with gradual onset b/l pain in shoulders, neck, and hips. Reports fatigue, weakness, low-grade fever, morning stiffness lasting >45 minutes, and myalgias/arthralgias that are worse at night. Denies abrupt onset headache, tongue/jaw claudication. Weight loss, proximal joint pain, proximal muscle weakness, asymmetric arthritis in wrist/knees, pitting edema of wrists/ankles on exam.

• Labs

  • ESR > 40 mm/hr

  • CBC shows mild anemia, thrombocytosis

  • Obtain CMP, TSH, CRP, creatinine kinase, rheumatoid factor, urinalysis, and protein electrophoresis to rule out mimics, including paraneoplastic syndrome

• Obtain DEXA scan prior to starting corticosteroid therapy

• Treatment

  • Start prednisone taper: 15 mg qd x3 weeks, then 12.5 mg qd x3 weeks, then 10 mg qd x5 weeks, then decrease by 1 mg every 5 weeks as tolerated

  • Pt on long-term corticosteroid therapy: Prophylax with alendronate 35 mg q weekly to preserve bone mineral density and reduce fracture risk

• Pt counseled that the average length of treatment with steroids is 2 years and that relapses requiring repeat courses may occur

• Pt counseled about long-term risks of corticosteroid use including peptic ulcers and loss of bone mineral density

Notes

• Most common chronic inflammatory condition in older adults

• Affects ~1 in 140 people of European descent >50 y/o

• Giant cell (temporal) arteritis

  • Occurs in up to 25% of polymyalgia rheumatica cases

  • Red flags: Sudden onset headache, jaw/tongue claudication, ESR >100 mm/hr

  • Treatment: Prednisone 60 mg qd, ophthalmology consult +/- temporal artery biopsy

• Associated tenosynovitis may produce carpal tunnel syndrome

Polymyositis and Dermatomyositis

45 y/o F pt with h/o atopy presents with gradual onset muscle weakness. Weakness particularly noticeable when climbing stairs, rising from seated position, and/or picking up heavy objects, e.g. groceries. ROS positive for dysphagia, SOB. Physical exam reveals faint pulmonary crackles, proximal muscle atrophy/weakness affecting deltoids/hip flexors, hyperkeratotic/fissured skin on palmar surfaces (mechanic’s hands). [Gottron’s papules, heliotrope eruption present.]

• Labs

  • Obtain CBC, CMP, creatine kinase (CK) and lactate dehydrogenase (LDH) levels

  • Obtain antinuclear antibodies; if positive

    • Obtain anti-Jo-1 antibodies

    • Consider obtaining anti-Ro, anti-La, anti-Sm, anti-RNP antibodies

  • Concern for heart disease: Obtain CK-MB

• Imaging

  • EKG shows non-specific conduction abnormalities

  • CXR shows interstitial opacities suspicious for interstitial lung disease

  • MRI shows widespread muscle inflammation, fibrosis, calcification

• Muscle biopsy shows lymphocytic infiltrate

• Treatment: Refer/consult rheumatology

  • Unstable: Admit to hospital, start methylprednisolone IV 1000 mg/day

  • Stable

    • Start 1 mg/kg prednisone daily (max dose 80 mg/day)

    • Consider transitioning to azathioprine 50 mg/day for long-term therapy

• Pt counseled about risks of immunosuppressive therapy

Notes

• Prevalence = 2 in 100,000

• Skin changes

  • Nonspecific findings, e.g. mechanic’s hands occur in both disorders

  • Shawl sign: Poikiloderma in sun exposed areas (e.g. upper back, chest) sometimes found in dermatomyositis patients

  • Gottron’s papules/heliotrope eruptions are pathognomonic for dermatomyositis

    • Gottron’s papules: Symmetrical violaceous lesions on extensor surfaces

    • Heliotrope eruption: Symmetrical violaceous eruption on the upper eyelids

• Additional clinical manifestations

  • Interstitial lung disease affects 10% of patients

  • Damaged cardiac muscle may produce conduction abnormalities on EKG

  • Dysphagia may occur due to oropharyngeal muscle weakness

• Diagnostic testing

  • Presence of anti-Ro, anti-La, anti-Sm, or anti-RNP antibodies may indicate presence of other autoimmune conditions

  • MRI is sensitive, but not specific

  • Muscle biopsy showing perifascicular atrophy is pathognomonic for dermatomyositis