Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 23-year-old woman is evaluated for a 1-year history of morning stiffness and achiness of the hands as well as Raynaud phenomenon. Two months ago, she experienced a sun-induced rash on the chest and back and patches of discoloration on the hands.

On physical examination, temperature is 36.4 °C (97.5 °F), blood pressure is 106/66 mm Hg, pulse rate is 60/min, and respiration rate is 16/min. The lungs are clear. Erythematous, violaceous, clumped papules over the extensor surfaces of the elbows, metacarpophalangeal joints, and proximal interphalangeal joints are present; there are nailfold capillary abnormalities with cuticular hypertrophy. Bilateral proximal upper and lower extremity weakness is noted; there is tenderness of the metacarpophalangeal and proximal interphalangeal joints bilaterally without synovitis.

Laboratory studies reveal an erythrocyte sedimentation rate of 82 mm/h, a serum creatine kinase level of 650 units/L, and an antinuclear antibody titer of 1:160 (speckled pattern).

Chest radiograph is normal. Electromyography shows muscle irritability without evidence of neuropathy.

Which of the following is the most appropriate initial treatment?

A: Intravenous immune globulin
B: Prednisone
C: Prednisone and azathioprine
D: Prednisone and methotrexate

MKSAP Answer and Critique

The correct answer is B: Prednisone.

Initial treatment with prednisone is indicated for this patient with dermatomyositis without evidence of severe myositis or extramuscular manifestations. She has Gottron papules, which are pathognomonic for this disorder. This patient also has fatigue, arthralgia, Raynaud phenomenon, nailfold capillary abnormalities with cuticular hypertrophy, proximal muscle weakness, and a photosensitive rash, findings that are consistent with dermatomyositis. She does not have evidence of other extramuscular manifestations such as systemic symptoms of fever and weight loss or pulmonary, cardiac, or gastrointestinal symptoms. High-dose corticosteroids are standard first-line treatment for uncomplicated dermatomyositis and are indicated for this patient. This initial therapy is generally continued for 4 weeks or until serum creatine kinase levels are normalized; treatment is then slowly tapered. For severe cases, intravenous pulse corticosteroids may be administered. Baseline bone mineral density testing is indicated in patients who undergo long-term high-dose corticosteroid therapy. These patients also should begin prophylactic therapy for osteoporosis with calcium and vitamin D supplementation and bisphosphonates. Physical and occupational therapy are crucial adjuncts to pharmacologic therapy in patients with an inflammatory myopathy. Exercise improves aerobic capacity and strength and provides cardiopulmonary benefits. Exercise also is not typically associated with increases in muscle enzyme levels, which are indicative of muscle dysfunction.

Intravenous immune globulin is reserved for patients who require additional therapy in conjunction with corticosteroids or for those who have a contraindication to the use of corticosteroids or other immunosuppressive therapies.

Immunosuppressive therapy such as azathioprine or methotrexate in conjunction with corticosteroids is an important and frequently utilized treatment option for steroid-resistant disease or as steroid-sparing therapy and is often started concurrently with prednisone for severe disease or for those in poor prognosis groups, including patients with extramuscular manifestations of cardiovascular or pulmonary involvement.

Key Point

• High-dose corticosteroids are standard first-line treatment for patients with uncomplicated dermatomyositis.

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