Patient case: Dermatomyositis
A 50-year-old female presents to the rheumatology clinic with a three-month history of progressive muscle weakness affecting her shoulders and thighs. She reports difficulty rising from a chair, climbing stairs, and lifting objects. Additionally, she has noticed a rash on her face, hands, and chest that has not improved with topical treatments. She experiences mild joint pain but denies sensory loss or muscle cramping.
Medical History & Social Background
• Medical history: Hypertension, hypothyroidism.
• Family history: No known autoimmune diseases.
• Occupation: Schoolteacher, struggles with prolonged standing.
• Social history: Non-smoker, no history of alcohol or drug use.
Physical Examination
• Neuromuscular:
√. Symmetric proximal muscle weakness (shoulders, hip flexors).
√. Intact reflexes and sensation.
• Skin:
√. Heliotrope rash (violaceous discoloration around the eyes).
√. Gottron’s papules (raised, scaly plaques over the knuckles).
√. Shawl sign (erythema over upper chest and shoulders).
• Pulmonary: Mild tachypnea but normal breath sounds.
Laboratory & Diagnostic Findings
• Creatine kinase (CK): Elevated (4,200 U/L).
• Aldolase, AST, ALT: Elevated.
• Antinuclear antibody (ANA): Positive.
• Anti-Mi-2 antibody: Positive (specific for dermatomyositis).
• Electromyography (EMG): Myopathic changes with fibrillations.
• Muscle biopsy: Perifascicular atrophy with perivascular inflammation, confirming dermatomyositis.
• High-resolution CT (HRCT): Early signs of interstitial lung disease (ILD).
• Cancer screening: Negative (mammogram, abdominal ultrasound, and tumor markers).
Diagnosis
The combination of proximal muscle weakness, characteristic rashes (heliotrope, Gottron’s papules), elevated muscle enzymes, and anti-Mi-2 positivity confirms a diagnosis of dermatomyositis.
Management Plan
1. First-line treatment
• High-dose corticosteroids (prednisone 1 mg/kg/day).
• Physical therapy to prevent muscle atrophy.
2. Immunosuppressive therapy (for steroid-sparing effect and ILD)
• Methotrexate or azathioprine for long-term disease control.
• Mycophenolate mofetil or rituximab if lung involvement progresses.
3. Monitoring & Long-Term Care
• Regular CK and muscle strength assessments.
• Lung function tests for ILD progression.
• Cancer screening, as dermatomyositis is associated with malignancy.
Challenges & Considerations
• Increased malignancy risk, requiring close monitoring.
• Severe ILD can lead to respiratory failure.
• Steroid complications (diabetes, osteoporosis, infections) need management.
Prognosis
With early treatment, muscle strength can improve, but some patients develop chronic weakness and lung complications. Cancer screening remains a priority due to increased risk.
A) Polymyositis
B) Dermatomyositis
C) Systemic lupus erythematosus (SLE)
D) Rheumatoid arthritis
A) Malar rash
B) Livedo reticularis
C) Gottron’s papules
D) Erythema nodosum
A) Hydroxychloroquine
B) High-dose corticosteroids
C) Colchicine
D) Acetylcholinesterase inhibitors
A) Malignancy
B) Peripheral neuropathy
C) Hepatomegaly
D) Deep vein thromb
osis
