Dermatomyositis

Question 1

Types of adult onset dermatomyositis

Answer 1

Classic
Classic with malignancy
Classic with overlapping connective tissue disorder
Amyopathic  DM 
Hypomyopathic DM

Question 2

Types of juvenile onset DM

Answer 2

Classic
Amyopathic DM
Hypomyopathic

Question 3

Types of polymyositis

Answer 3

Isolated polymyositis
Polymyositis as part of an overlapping connective tissue disorder
Polymyoisitis associated with internal malignancy

Question 4

Drugs associated with DM

Answer 4

PHD TO BOOST (the) CV
Penicillamine, Hydroxyurea
Diclofenac, Tamoxifen
Benzalkonium Chloride
Carbamazepine
Vaccination (BCG)

Question 5

Characteristics of amyopathic

Answer 5

1% amyopathic, 76% female

29% ILD (17% classic)

Question 6

Anti-aminoacyl-tRNA synthetases: eg anti-Jo-1, antiPL-7
Anti-SRP
Anti-Mi-2

Answer 6

More common in adult onset classic

Question 7

Abs in adult onset amyopathic

Answer 7

Anti-p155/140: 80%
Anti-SAE
Anti-CADM-140 (MDA5)- associated with ILD

Question 8

Abs in juvenile disease

Answer 8

Anti-aminoacyl-tRNA synthetases: 
eg anti-Jo-1, antiPL-7
Anti-SRP
Anti-Mi-2
Anti-p155/140
Anti-p140

Question 9

Anti-SRP

Answer 9

Acute onset, necrotising myopathy (severe weakness, high CK), may be refractory to tx

Question 10

AntiMi2

Answer 10

Milder disease, hallmark is cutaneous disease, milder muscle disease with good response to treatment

Question 11

Antip155/140

Answer 11

More associated with cancer associated myositis, severe cutaneous disease and amyopathic disease

Question 12

antip140

Answer 12

Associated with juvenile + calcinosis

Question 13

anti-SAE

Answer 13

Adults, may present with amyopathic

Question 14

Anti CADM140 (MDA5)

Answer 14

Clinically amyopathic

Question 15

Types of malignancies

Answer 15

Mainly Carcinomas
Genitourinary malignancies esp ovarian, colon cancer
South east Asian populations: nasopharyngeal CA
Breast, lung, gastric, pancreatitic, lymphomas, female genital
Risk may return to normal after 2-5 years

Question 16

What is antisynthetase syndrome

Answer 16

Antiaminoacyl-tRNA synthetases (eg antiJo1, threonyl): antisynthetase syndrome: myositis, mechanics hands, fever, raynauds, gottrons, arthritis, ILD.

Question 17

Investigations for DM (not myositis)

Answer 17

ANA, ENA, dsDNA, TSH, fbc, elfts- look for overlapping disease
Lung 15-30%: RFTs with diffusion capacity – screen yearly, Chest Xray, HRCT . Associated with antisynthetase syndrome, MDA5
Cardiac - arrythmias: ECG, if symptomatic Echo, holter
GIT: if symptoms: barium swallow
If planning CS: DEXA bone

Question 18

Investigations for myositis

Answer 18

Serum muscle enzyme levels – CK (95% at some point), aldolase, urine creatine, urine or serum myoglobulin
AST, ALT and LDH may be elevated in myositis

Electromyography (90% abnormal), less helpful in polymyositis as overlap with other dx

T2 weighted MRI of proximal limbs
Muscle bx - triceps

If amyopathic: examine for muscle weakness and enzymes 2-3/12 for 2 years

Question 19

Evaluation for malignancy

Answer 19

Baseline and regularly for at least 2-5 years 
Both
Urinalysis, CT chest/abdo/elvis
FOBT or if Sx/anaemia 
Colonscopy 
Upper endoscopy 
Serum protein and immunofixation electrophoresis 
CA19.9
Males:PSA
Females: Mammogram, TV pelvic USS, CA125

Question 20

Common skin signs (9)

Answer 20

Heliotrope sign
Eyelid oedema
Gottron’s papules – flat topped lichenoid papules on PIP and MCP joints
Gottron’s sign – violaceous discoloration of knuckles, elbows or knees
Photodistributed poikiloderma (includes facial erythema, shawl sign)
Scalp poikiloderma
Non scarring alopecia
Calcinosis cutis (especially in juvenile dermatomyositis)- associated with delay in CS, or severe disease. May drain a chalky material via fistulae. Usually elbows, knees, fingers, may be painful (sites of trauma)
Nail fold changes (ragged cutis, nail fold telangiectasis – dilated capillary loops alternating with vessel dropout)

Question 21

Uncommon signs

Answer 21

Cutaneous erosions or ulceration
Holster sign (poikiloderma of the lateral thighs)
Flagellate erythema
Vesicobullous lesions
Efoliative erythroderma
Panniculitis
Gingival telangiectasis
Pustular eruption of the elbows and knees
Lipoatrophy (esp in juvenile)
Small vessel vasculitis (esp in juvenile)

Question 22

Poor prognostic features

Answer 22

Malignancy, Cardiac involvement, older age, progressive disease, initiation of therapy after 24 months of muscle weakness, longer duration of symptoms prior to Dx, pulmonary disease, dysphagia, extensive cutaneous involvement of the trunk.

Question 23

Good prognostic features

Answer 23

With no muscle involvement – better

Calcinosis is a good prognostic feature

Question 24

Mortality

Answer 24

1/4

Question 25

Death from?

Answer 25

Death usually from : CA, respiratory infection, cardiac failure, malnutrition, weakness due to difficulty in swallowing

Question 26

Cutaneous tx

Answer 26

Photoprotection (sunscreen including protection against UVA) Topical CSA – particularly for pruritis Topical Tacrolimus- particularly for pruritis HCQ 200mg bd (increased frequency of drug eruptions in DM) – 1/3 have rash usually morbilliform, may tolerate switch to chloroquine Low dose weekly MTX (5-15mg/week) MMF High dose IVIg (2g/kg/month) – then spread to 7 week 2g/kg over 2 days Retinoids Dapsone Thalidomide Leflunomide Anti-oestrogens TNF alpha – can cause DM Rituximab Tacrolimus

Question 27

Systemic treatment

Answer 27

``` Oral pred 1mg/kg/day tapered to 50% over 6 months, then to zero over 2-3 years MTX 5-20mg weekly AZA 2-3mg/kg/day High dose IVIg 2g/kg/month Pulse cyclophosmaide 0.5-1g/m2 Chlorambucil Cyclosporine 3-5mg/kg/day Tacrolimus MMF 1g bd Sirolimus Infliximab Etanercept Rituximab Fludarabine Haematopoietic stem cell transplant Plasmaphoresis ```

Question 28

Ongoing monitoring

Answer 28

Regular muscle enzyme monitoring every 2-3 months for 2-3 years if amyopathic at baseline Regular RFTS including diffusion capacity Baseline: DEXA, lipids and fasting glucose if on oral pred (children esp: check developmental milestones, lipodystrophy, hypertrigs, insulin resistance) Regular malignancy screening 4-6 months for 2-3 years Physical therapy Calcinosis cutis may respond to diltiazem and /or surgical excision Not all derm disease will be treated with muscle disease remittance Rare panniculitis may respond to HCQ