DERM: Dermatomyositis

Question 1

what is dermatomyositis?

Answer 1

autoimmune disorder where there is inflammation in the skin (derma) and muscles (myositis)

is an uncommon inflammatory disease marked by muscle weakness and a distinctive skin rash

Question 2

dermatomyositis can be described as a paraneoplastic syndrome, what does this mean?

Answer 2

can be caused by an underlying malignancy

Question 3

what are the symptoms of dermatomyositis?

Answer 3

• distinctive rash: violet-colored or dusky red rash develops, most commonly on your face and eyelids and on knuckles, elbows, knees, chest and back.
• Muscle pain, fatigue and weakness
• Occurs bilaterally and typically affects the proximal muscles
• Mostly affects the shoulder and pelvic girdle
• Develops over weeks

Question 4

what is the cause of dermatomyositis?

Answer 4

The cause of dermatomyositis is unknown, but the disease has much in common with autoimmune disorders

Question 5

what is a complication of dermatomyositis?

Answer 5

Calcium deposits.

These can occur in your muscles, skin and connective tissues (calcinosis) as the disease progresses. These deposits are more common in children with dermatomyositis and develop earlier in the course of the disease.

Question 6

what are some skin features of dermatomyositis?

Answer 6

• Gottron lesions (scary erythematous patches) on the knuckles, elbows and knees
• Photosensitive erythematous rash on the back, shoulders and neck
• Purple rash on the face and eyelids
• Periorbital oedema (swelling around the eyes)
• Subcutaneous calcinosis (calcium deposits in the subcutaneous tissue)

Question 7

what autoantibodies are present in dermatomyositis?

Answer 7

Anti-Jo-1 antibodies

Anti-Mi-2 antibodies

Anti-nuclear antibodies

Question 8

how do you diagnose dermatomyositis?

Answer 8

Clinical presentation

bloods: Elevated creatine kinase + Autoantibodies

Electromyography (EMG): measures electrical activity of the muscle via nodes

Muscle biopsy can be used to establish a definitive diagnosis.

Question 9

why will you find elevated creatine kinase levels in a patient with dermatomyositis?

Answer 9

Creatine kinase is an enzyme found inside muscle cells. Inflammation in the muscle cells (myositis) leads to the release of creatine kinase

Question 10

how is dermatomyositis managed?

Answer 10

• New cases should be assessed for possible underling cancer.
• Corticosteroids are the first line treatment e.g. prednisone
• sunscreens
• physio / occupational therapy