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MyDermatology-Bolognia > Ch. 42-Dermatomyositis > Flashcards

Ch. 42-Dermatomyositis Flashcards

1
Q

Difference in pathophysiology of polymyositis vs. dermatomyositis?

A

Polymyositis-Autoreactive CD8+ T-cells clonal expansion, attack myocytes with MHC class I antigens

DM-Activation humoral immune response with complement deposition

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2
Q

What % DM patients have malignancy?

A

25%

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3
Q

What are the idiopathic inflammatory myopathies?

A

DM

PM (antisynthetase syndrome included)

Inclusion body

Necrotizing autoimmune myopathy

Overlap

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4
Q

What % DM patients amyopathic?

A

20%

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5
Q

What are the clinical subtypes DM

A

Adult onset classic (classic, with malig, with CTD)
Adult onset amyopathic
Adult onset hypomyopathic /(no sx but lab/image evidence)
Drug induced

Juvenile onset with above classifications

Juvenile Onset:
Classical DM.
Clinically Amyopathic DM:
· Amyopathic.
· Hypomyopathic.
Drug-induced

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6
Q

Most common DM ASSOCIATED antibodies

A

anti-Ro52 (SSA)
anti-PM-Scl
anti-Ku
anti-U1RNP.

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7
Q

Age of onset DM?

A

Bimodal: Age 7-10 and age 50

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8
Q

Name the 6 DM specific antibodies

A

anti-aminoacyl-tRNA synthetases (Jo-1, PL-7, PL-12) –> Anti synthethase syndrome

anti-Mi-2 DM
anti-MDA5 DM
anti-TIF1 DM(P155/p140)
anti-NXP2 DM
anti-SAE DM

Also anti-SRP-necrotizing myopathy in blacks, severe disease, no skin

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9
Q

What is anti-synthetase syndrome?

A

Myositis
Fever
Mechanics hands
ILD
Raynauds
Erosive poly arthritis

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10
Q

Anti-SRP associated DM

A

Acute-onset necrotizing myopathy (severe weakness, high CK)
may be refractory to treatment
Cardiac involvement

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11
Q

Anti-Mi-2 DM

A

Classic adult and juvenile DM
-high creatine kinase levels
- good response to treatment
- good prognosis, although relapses often occur.
-ILD is rare in anti-Mi-2 DM
-No malig

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12
Q

What 2 ab-associated DM’s are amyopathic/hypomyopathic?

A

Tiff-1-gamma
MDA5

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13
Q

Features of Tiff-1-gamma DM?

A

Mild myositis

Highly malignancy associated in adults

Extensive cutaneous rash:
-with blistering and erosions, psoriasiform lesions on palms, ovoid palatal patch, red on white telangiectatic patches, palmar hyperkeratotic papules (inverse gotttrons)

Vasculopathy

Dysphagia can be severe

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14
Q

Features of MDA5 DM

A

Amyopathic/hypo

High risk rapidly progressive ILD (in East Asian especially but also not was asian)

Skin-
-Ulcerations over gottrons papules, elbows,
-mucosal ulcerations
-tender palmar papules
-alopecia

Vasculopathy

Arthritis

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15
Q

Clinical features NXP-2

A

Prominent myositis with mild skin, even absent in some patients (DM sine dermatitis)

2nd high risk malignancy

Calcinosis and peripheral oedema is also characteristic, dysphagia

Common in kids but no malignancy risk

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16
Q

Clinical features SAE

A

may present with clinically amyopathic DM

Extensive rash

Dysphagia

mild ILD

Malignancy associated

Psoriasiform reaction to plaquenil

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17
Q

Name the classic cutaneous signs of DM?

A

Heliotrope rash
Poikolderma in V-neck or shawl sign or Holster sign, facial erythema
Gottrons papules
Gottrons sign
Raynauds
Nailfold changes (dilated and drop out capillaries)
Calcinosis cutis
Psoriasiform lesions
scalp poikiloderma,scalingand non scarring alopecia

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18
Q

Describe heliotrope rash of DM

A

pink–violet color of the eyelids and periorbital skin, +- edema

Can be only mild erythema, may wax and wane in intensity.

May have more widespread facial erythema or midfacial erythema that tends to involve the nasolabial folds (vs. lupus)

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19
Q

What are the nail fold changes in DM?

A

Cuticular dystrohphy: Ragged cuticles and cuticular hypertrophy

Dilated capillaries alternating with capillary drop out

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20
Q

What is Gottron sign vs. papules

A

Gottron’s papules: lichenoid papules on the knuckles

Gottron’s sign: thin plaques, papules and pink-violet erythema over elbows or knees (often in addition to knuckles)

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21
Q

What is the v-sign, shawl sign and holster sign?

A

Poikoldermatous photo distributed eruption of neck (V-sign), shoulders/back (shawl) and lateral thigh (holster)

In lupus more red, DM more violet-pink (unless darker skin then maybe red)

Sometimes there is white silvery scale

22
Q

What is the one symptom of the rash in DM to help distinguish from LE?

A

Pruritus!

23
Q

Is calcinosis more common in adults or juvenile DM

A

Juvenile 25-75%

24
Q

Where does calcinosis occur in DM?

A

Favor sites of trauma (elbows, knees) but can occur anywhere

Often painful, hard, irregular papules or nodules that can sometimes drain chalky material

Can also occur in fascia and intramuscular connective tissues

25
Q

Name some less common findings in DM

A

Cutaneous erosions or ulcerations
Flagellate erythema
Tender palmar papules
Hyperkeratotic palmar papules
Exfoliative erythroderma
Cutaneous eruption that mimics PRP (Wong variant in asians)
Vesiculobullous lesions
Pustular eruption of the elbows and knees
Ovoid palatal patch
Gingival telangiectasias
Panniculitis
Lipoatrophy (especially in juvenile dermatomyositis)
Small vessel vasculitis (especially in juvenile dermatomyositis)
Scalp pruritic plaques and alopecia
psoarisiform palmar papules

26
Q

Which muscles most affected in dM

A

Proximal >Distal
Especially extensors (triceps and quads)

27
Q

Which muscles most affected in dM

A

Proximal >Distal
Especially extensors (triceps and quads)

28
Q

How does the lung disease present in DM

A

Diffuse interstitial fibrosis
Dry cough and dyspnea

29
Q

How to screen for ILD in DM?

A

PFTs with DLCO
If DLCO impaired–> high rest CT

30
Q

What % patients have ILD?

A

15-30%

31
Q

What DM-specific ab most associated with rapidly progressive ILD?

A

MDA-5:
-in Eastern Asian populations with anti-MDA5
-non-Asian population with tender palmar papules and cutaneous ulcerations, primarily on the elbows, dorsal hands, and periungual region

Anti-synthethase syndrome (PL7, Jo-1)

32
Q

% chance pulmonary disease if Jo-1 +

A

70% chance ILD

33
Q

Other than malignancy, what is major contributor to death in DM?

A

Cardiac involvement which is often asymptomatic, often dsyrhytmias or conduction defects

34
Q

Most common overlaps CTD with DM?

A

RA
Scleroderma
Systemic LE

35
Q

Other than skin and muscle, other organs affected in DM?

A

GI-dysphagia
Cardiac-conduction defects
Joints/arthritis
Rayanuds
Malignancy screening

36
Q

Risk of malignancy in DM

A

15-25%
*For classic and amyopathic
Not juvenile or polymyositis

37
Q

At which point after no malignancy found are you at normal baseline risk?

A

3 yrs

38
Q

Most common malignancies in DM?

A

GU-ovarian esp.
Colorectal

Nasopharyngeal in asian

Other common ones:
Breast
Lung
gastric
pancreatic
Lymphoma

39
Q

2 antibodies with highest association with malignancy

A

Tiff-1 gamma
NXP2

40
Q

Workup for suspected DM?

A

Skin: biopsy

Labs: CBC, LEs, Cr,Mitogen panel for Ab’s/ANA

Muscles: CK, AST/ALT, muscle MRI vs. EMG and muscle biopsy (increasingly more MRI’s being done)

Lungs: PFTs +- high res CT

Cardiac: EKG

If dysphagia: manometry

41
Q

Malignancy workup for DM

A

History and physical!

UA

FOBT

Pelvic US

Pap smear

Mammogram

CT CAP

Labs:
CBC, PSA, CA 19-9, CA 125 (women)

Colonoscopy–> if age-appropriate, iron deficiency anemia, occult blood in stool, or symptoms
EGD–> If IDA, symptoms, occult blood

*annually for 3 years
*Can add SPEP

42
Q

Histopath findings in DM

A

Epidermis
-epidermal atrophy
-interface dermatitis with vacuolar alteration of basal keratinocytes
-pigment incontinence
-Gottron papules show an interface dermatitis but have acanthosis and hyperkeratosis rather than epidermal atrophy

dermal changes
- mucin deposition
- sparse lymphocytic infiltrate.

  • may be indistinguishable from those of LE. G
43
Q

muscle biopsy findings

A

type II muscle fiber atrophy, necrosis, regeneration, and hypertrophy with centralized sarcolemmal nuclei, plus lymphocytes in both a perifascicular and a perivascular distribution, is classic

44
Q

What muscle to biopsy in suspected myositis

A

triceps

45
Q

Best therapeutic option for DM with clinically significant myosititis

A

Oral prednisone:
1 mg/kg/day tapered to 50% over 6 months and to zero over 2–3 years

46
Q

True or false: Treatment response of muscles and skin are similarly aligned and follow same trajectory

A

FALSE-very discordant

47
Q

Treatment ladder for myositis aspect

A

Lifestyle: Physical therapy

Prednisone
Often add steroid-sparing:
e.g. MTX. AZA, MMF etc.

Ritux and IVIG also evaluated, not much effect on skin it seems but ritux was helpful

48
Q

Treatment of amyopathic DM

A

Evidence weak, often hard to treat, and sometimes myositis improves but cutaneous doesn’t

-topical corticosteroids
-topical tacrolimus
-antimalarial therapy (either as monotherapy or in combination, which is less dramatic in its effect than when used for cutaneous LE and an increased risk of a cutaneous drug reaction to hydroxychloroquine
-low-dose weekly methotrexate,
-mycophenolate mofetil
-IVIg
-dapsone
-tofacitinib
-thalidomide

49
Q

Common treatment ladder for cutaneous DM/amyopathic

A

Anti-malarials, then MTX, then MMF
then IVIg for cases of refractory cutaneous dermatomyositi

50
Q

Treatment calcinosis

A

Amlodipine
surgical excision

Others:
low-dose warfarin, bisphosphonates, probenecid, colchicine, TNF inhibitors, aluminum hydroxide, sodium thiosulfate, and electric shock wave lithotripsy (ESWL).

MyDermatology-Bolognia (31 decks)

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