MSK-21 · SLE, Inflammatory Myopathies, and Scleroderma

SLE, Inflammatory Myopathies, and Scleroderma. Part of the Musculoskeletal series of the Reflex PM&R Board Review podcast. Audio corrections: (1) In the audio: If you apply the massive mechanical shear force of an eccentric contraction to an actively inflamed fragile muscle, you will cause massive necrosis. — Correct: The program is right, the mechanism is not. Eccentric loading is deferred while CK is elevated because it generates the greatest mechanical force of any contraction type, not because it has been shown to cause necrosis in inflamed human muscle. (2) In the audio: Low-dose prednisone, around 10 to 20 milligrams a day, produces dramatic, near-miraculous improvement in their symptoms within 24 to 72 hours. — Correct: 12.5 to 25 mg a day is the recommended initial prednisone-equivalent range for polymyalgia rheumatica. Improvement is dramatic within days and near complete by 2 to 4 weeks. (3) In the audio: Adult dermatomyositis carries a 20 to 25 percent risk of an underlying cancer. — Correct: The commonly cited absolute range is 15 to 25 percent, concentrated about 3 years either side of diagnosis. The cohort figure quoted beside it is a standardised incidence ratio near 3, a relative risk rather than a percentage. (4) In the audio: Diffuse scleroderma with the anti-Scl-70 antibody ends in interstitial lung disease and renal crisis — Correct: Interstitial lung disease leads, then pulmonary arterial hypertension and cardiac causes. Scleroderma renal crisis has fallen well down the list of causes of death since ACE inhibitors became standard. The written chapter is correct. Full correction register: https://www.reflexpmr.com/errata. The full companion chapter and a linked board-style Q-bank set for this topic are at https://www.reflexpmr.com/read/MSK-21.