Inflammatory Myopathies

Question 1

what are inflammatory myopathies characterised by

Answer 1

muscle weakness

Question 2

describe what myopathy is

Answer 2

literally means “muscle disease”, it is a disease of the muscle in which the fibres do not function properly

Question 3

what are the main inflammatory myopathies

Answer 3

polymyositis and dermatomyositis

Question 4

describe what type of disease polymyositis and dermamyositis are

Answer 4

they are idiopathic autoimmune diseases

Question 5

what group of people are inflammatory myopathies most common in

Answer 5

female 2:1 male, and between 40-50 y/o

Question 6

what do inflammatory myopathies increase the risk of

Answer 6

increased incidence of malignancy

risk greatest in men> 45

Question 7

describe the clinical features of myositis

Answer 7

predominantly muscle weakness, myalgia(usually mild), often specific problems eg difficulty walking up stairs

Question 8

describe the onset of myositis

Answer 8

insidious onset, worsening over months

Question 9

what muscles are usually affected by myositis

Answer 9

often proximal muscles(eg shoulder, hip, thigh, chest), usually symmetrical

Question 10

what is seen in dermatomyositis alongside the muscle issues

Answer 10

skin involvement

Question 11

describe Gottron’s sign/papules seen in dermatomyositis

Answer 11

purple/red discolouration over backs of hands, over MCP and PIP joints

Question 12

describe Heliotrope rash seen in dermatomyositis

Answer 12

purple/red discolouration around the eyes, sometimes along with eye oedema/swelling

Question 13

describe what Shawl’s sign is in dermatomyositis

Answer 13

purple/red rash seen over back of shoulders and on the chest

Question 14

what other organs can be involved in polymyositis and dermatomyositis

Answer 14

lungs(most common), oesophagus, heart

Question 15

what systemic signs can be seen in dermatomyositis and polymyositis

Answer 15

fever, weight loss, Raynaud’s phenomenon, inflammatory arthritis

Question 16

what lung involvement can be seen in poly- or dermato- myositis

Answer 16

interstitial lung disease(10% patients), less commonly respiratory muscle weakness

Question 17

what oesophageal involvement may be seen in poly- or dermato- myositis

Answer 17

dysphagia

Question 18

what cardiac involvement may be seen in poly- or dermato- myositis

Answer 18

myocarditis

Question 19

describe what is confrontational testing in examination of inflammatory myopathies and what its used for

Answer 19

it is a direct test of power, checking the patients muscle power compared to your own by pushing against each other

Question 20

what is isotonic testing in examination of inflammatory myopathies and what is it used for

Answer 20

30 second sit to stand test, to see if muscles fatigue over time

Question 21

what is looked for in blood tests of inflammatory myopathies

Answer 21

creatine kinase(CK), inflammatory markers, autoantibodies, and then electrolytes, Ca etc to rule out other causes

Question 22

what muscle enzyme is almost always raised in inflammatory myositis

Answer 22

creatine kinase(CK)
(CRP often high also)

Question 23

what are some specific autoantibodies associated with inflammatory myositis

Answer 23

ANA(anti nuclear antibody)(non-specific), anti-Jo-1(specific)

Question 24

what other tests may be used in inflammatory myopathy investigation

Answer 24

electromyography(EMG), muscle biopsy, MRI

Question 25

what would be seen on the electromyography(EMG) of a myositis patient

Answer 25

increased fibrillations, abnormal motor potentials, complex repetitive discharges

Question 26

what is the definitive test used in diagnosis of myositis

Answer 26

muscle biopsy

Question 27

what may be seen on an MRI of myositis

Answer 27

muscle inflammation, oedema, fibrosis and calcification

Question 28

how is myositis treated

Answer 28

corticosteroids and immunosuppressants

Question 29

describe the use of corticosteroids in myositis

Answer 29

orally given at start of treatment and gradually reduced, limit use if possible

Question 30

what immunosuppressants may be used in myositis treatment

Answer 30

azathioprine, methotrexate, ciclosporin

Question 31

what may be given if immunosuppressant drugs are not working in myositis

Answer 31

IV immunoglobin or

Rituximab(biologic therapy)