Idiopathic Inflammatory Myopathies

Question · easy

A 54-year-old woman reports 3 months of progressive difficulty climbing stairs and lifting her arms to wash her hair. Exam shows a violaceous discoloration of the eyelids with mild periorbital edema and scaly violaceous papules over the metacarpophalangeal joints. Serum CK is 18 times the upper limit of normal. In addition to starting treatment, which of the following is most indicated?

Initiation of a statin to treat presumed dyslipidemia Age- and sex-appropriate malignancy screening, with a low threshold for CT chest/abdomen/pelvis Reassurance and repeat CK measurement in 6 months Immediate discontinuation of all glucocorticoids

Question · medium

A 68-year-old man describes 4 years of slowly progressive difficulty rising from a chair and gripping tools. Exam shows asymmetric weakness and atrophy of the finger flexors and quadriceps. Serum CK is 3 times the upper limit of normal. Which of the following is most accurate regarding his condition?

Anti-HMGCR antibodies are the expected serologic finding It is most consistent with inclusion body myositis, which typically does not respond to immunosuppression High-dose glucocorticoids will produce complete and sustained remission A heliotrope rash is the defining diagnostic feature

Question · hard

A 61-year-old woman taking atorvastatin develops severe proximal weakness with a serum CK 40 times the upper limit of normal. The statin is stopped, but her weakness continues to progress over the next 2 months. Testing is positive for anti-HMGCR antibodies. Which of the following is the best interpretation and management?

No treatment is needed because the CK will normalize spontaneously This is immune-mediated necrotizing myopathy requiring immunosuppression (e.g., IVIG, often with glucocorticoids/rituximab); statins must be avoided This is direct statin toxicity that will resolve gradually with continued observation alone The statin should be restarted at a lower dose to confirm causality

Question · medium

A 45-year-old woman has mechanic's hands, symmetric nonerosive arthritis, Raynaud phenomenon, and exertional dyspnea. High-resolution CT shows nonspecific interstitial pneumonitis, and anti-Jo-1 antibodies are positive. Which of the following most determines her prognosis?

Progression to wheelchair dependence within 5 years Development of calcinosis cutis The risk of an occult malignancy The severity and course of her interstitial lung disease

Question · medium

A patient with dermatomyositis on high-dose prednisone reports worsening proximal weakness. Serum CK is normal, she has moon facies and easy bruising, and electromyography shows no spontaneous (membrane irritability) activity. Which of the following is the most likely explanation?

Glucocorticoid-induced (steroid) myopathy New-onset inclusion body myositis Anti-MDA5 rapidly progressive interstitial lung disease Relapse of active dermatomyositis