10 - 62 - DERMATOMYOSITIS - HIGH YIELD

Question 1

affects 20% of patients and is a major source of morbidity and mortality in dermatomyositis

Answer 1

Interstitial lung disease (ILD)

Question 2

In adults, DM heralds the diagnosis of a coexisting internal malignancy in how many percent of patients

Answer 2

10 - 20%

Question 3

how many % of patients does not manifest clinically significant muscle weakness

Answer 3

20%

These patients make up a population now defined as clinically amyopathic dermatomyositis (CADM),

Question 4

antibidoies associated with increased risk of ILD

Answer 4

anti-MDA5 and antisynthetase (tRNA synthetase) autoantibodies

Question 5

antibodies associated with increased risk of having an associated cancer

Answer 5

antiTIF1-γ and anti-NXP2 autoantibodies

Question 6

The CADM umbrella can further be subclassified into exactly two groups depending on the results of further imaging (eg, magnetic resonance imaging [MRI]), electromyographic, muscle biopsy, or (now) laboratory studies of muscle enzymes.

This pertains to the subtype of CADM in which at least one of these test results is abnormal.

Answer 6

Hypomyopathic dermatomyositis

Question 6

This pertains to the subtype of CADM in which all the test results are normal.

Answer 6

Amyopathic DM

Question 7

2 peaks of DM

Answer 7

• 5 to 14 years
• 45 to 64 years of life

The disease affects women two to three times more than often than men

Question 8

Triggers of DM

Answer 8

> UVR
Strenous activity
Recent Malignancy

Question 9

In DM, there is often significant pruritus associated with the affected skin . This is usually seen on what area?

Answer 9

SCALP

which may also be described as a “tightness” or burning or with other dysesthetic qualities such as crawling or tingling. This severe pruritus on the scalp may be caused by structural damage to epidermal small-fiber nerves

Question 10

most common location affected on the scalp

Answer 10

just above and below the frontal hairline

The scalp can be affected in any location but often involves a linear band just above and below the frontal hairline.

Question 11

The skin changes in DM are often distributed to prototypical regions on the body. Enumerate these areas.

Answer 11

Question 12

Diagnostic Criteria for Dermatomyositis

Answer 12

Question 13

Cutaneous Clue to possible presence of Interstitial Lung Disease

Answer 13

*

Question 14

Common locations of mechanic’s hands

Answer 14

This finding was initially described as hyperkeratosis and fissuring along the medial thumb and lateral second and third digits

• This finding may be subtle and often requires palpating the fingers to appreciate the rough texture
• This lateral second digit hyperkeratosis seems to differ in quality and severity with the findings in patients with **antisynthetase antibodies, the latter associated with fissuring and scaling that tends to also involve the distal fingertips**

Question 15

Nail capillaroscopy findings in DM

Answer 15

red, edematous, often tender proximal nailfolds with ramified and dilated capillary loops with intervening pale to white avascular areas with capillary drop-out, cuticular hemorrhages, and elongated, ragged cuticles

Question 16

Cutaneous ulceration in DM warrants concern for the presence of ________

Answer 16

> antiMDA5 antibodies or malignancy (especially if necrosis is seen)
commonly occurs over gottron papules
correlated with the presence of interstitial lung disease (ILD)

Question 17

Visualization of the oral mucosa, particularly the hard palate, may provide a valuable sign to aid in the diagnosis of DM. One can observe a symmetric violaceous patch across the midline of the hard palate, termed the _______

Answer 17

Question 18

Consistent location of ovoid palatal patch

Answer 18

center of the hard palate

Question 19

antibodies associated with ovoid palatal patch

Answer 19

anti–transcriptional intermediary factor 1γ (TIF1-γ) antibodies

Question 20

pathognomonic pattern seen composed of reticulated, sometimes atrophic white macules adjacent to erythema or telangiectasias

Answer 20

“red on white”

Question 21

Calcinosis is most frequent on which areas in DM?

Answer 21

Extremities

vs systemic sclerosis where digital calcinosis is most frequent

Question 22

In both juvenile and adult DM, the presence of which antibody is associated with an increased risk of calcinosis?

Answer 22

anti–nuclear matrix protein 2 (NXP-2) antibodies

Calcinosis is also commonly seen in the anti-MDA5 subset (especially in patients with longstanding disease), 36 which is associated with known vasculopathy.

Question 23

Triad of poikiloderma

Answer 23

hyperpigmentation, hypopigmentation, and telangiectasias

Question 24

most common pulmonary manifestation in DM and is a leading cause of morbidity and mortality in these patients

Answer 24

Interstitial Lung Disease (ILD) - affects 15 - 50% of patients

Question 25

necessary step in establishing the diagnosis of ILD

Answer 25

high-resolution computed tomography (CT) of the chest ## Footnote * may show **subclinical fibrosis** before symptom onset * The most common radiographic and histologic pattern in DM is **nonspecific interstitial pneumonia**

Question 26

Pulmonary function test finding of DM

Answer 26

show a restrictive disease pattern with a decreased forced vital capacity (FVC) 57 or a decreased diffusion capacity of carbon monoxide.

Question 27

most common radiographic and histologic pattern in DM

Answer 27

Nonspecific interstitial pneumonia Radiographically, basilar and peripheral ground-glass opacities and subpleural sparing characterize nonspecific interstitial pneumonia.

Question 28

The gold standard for the diagnosis of pulmonary arterial hypertension

Answer 28

Right heart catheterization

Question 29

Right heart catheterization findings of PAH

Answer 29

mean pulmonary artery pressure of 25 mm Hg or greater at rest and an end-expiratory pulmonary artery wedge pressure of 15 mm Hg or less

Question 29

Question 30

in DM, Patients often report weakness in the extensor muscles surrounding ________________

Answer 30

shoulder and pelvic girdles and proximal limbs

Question 31

Quadriceps and gluteal muscle weakness may manifest as

Answer 31

difficulty rising from a chair or toilet, climbing stairs, or stepping onto curbs.

Question 32

shoulder and upper extremity weakness may manifest as

Answer 32

difficulty washing their hair or reaching for items in overhead cupboards

Question 33

Approximately how many percent of patients complain of muscle pain with or without muscle weakness

Answer 33

30%

Question 34

risk factors for malignancy

Answer 34

increasing age, male gender, cutaneous necrosis, dysphagia, and rapid onset of myositis

Question 35

protective factors for malignancy

Answer 35

ILD, arthritis, and Raynaud phenomenon

Question 36

The major antibody associated with malignancy

Answer 36

**TIF1-γ** More recent data suggest that **anti-NXP2 antibodies** may also be associated with cancer, although this association is not as strong

Question 37

Features of the skin examination that are particularly sensitive for dermatomyositis

Answer 37

> microscopic periungual telangiectasias > lateral digit hyperkeratosis > scalp erythema and dysesthesia

Question 38

classic c triad electromyographic findings of myositis

Answer 38

1. small amplitude, short duration, polyphasic motor unit potentials 2. fibrillations and positive sharp waves 3. complex repetitive discharges

Question 39

If a muscle biopsy is necessary to confirm the diagnosis of DM, it has the highest yield if performed within how many weeks of beginning any immunomodulatory therapy.

Answer 39

2 weeks ## Footnote * In patients referred to a dermatology clinic with a rash and weakness, muscle biopsy is seldom necessary to establish the diagnosis of DM. Evidence of myositis on laboratory testing, electromyography, or MRI is often sufficient in the setting of a cutaneous eruption supporting DM. * Muscle biopsy can yield false-negative results, both because of immunosuppressive medications and the patchy nature of the inflammation.

Question 40

ong-term survival rate for adults with DM

Answer 40

approximately 65% to 75%

Question 41

presence of this antibody is a risk factor for death

Answer 41

anti-MDA 5 antibodies

Question 42

Three major criteria of dermatomyositis

Answer 42

* Heliotrope sign (violaceous erythema on the upper eyelids), * Gottron papules (papules overlying the metacarpophalangeal [MCP] and interphalangeal [IP] joints), * Gottron sign (erythema overlying the knees, elbows, or IP joints)

Question 43

Question 44

a diagnosis of clinically amyopathic DM could be made if the patient has how many major and minor criteria

Answer 44

t**wo major criteria were present or one major criterion and two minor criteria** were present in addition to biopsy of at least one region showing **histopathologic changes consistent with DM**

Question 45

T/F Clinically amyopathic DM appear to harbor the same risks for systemic disease (eg, interstitial lung disease [ILD]) and malignancy as their classic counterparts

Answer 45

TRUE

Question 46

can be an exemplary sign of **vasculopathy**, although it can also be the result of robust, liquefactive interface dermatitis, or excoriation

Answer 46

Cutaneous ulceration

Question 47

frequent place to visualize the “red-on-white” pattern

Answer 47

thin skin along the **bitemporal hairline**

Question 48

edema in the distal extremities has recently been found to be associated with what antibodies and may predict more severe muscle disease?

Answer 48

anti-NXP2 antibodies

Question 49

If patients with DM do develop weakness, then about how many % of patients develop weakness within the first year of symptom onset.

Answer 49

80%

Question 50

Arthritis and arthralgias are more common among patients with DM with what antibodies?

Answer 50

anti-MDA5 and antisynthetase antibodies

Question 51

Muscle and skin biopsies show infiltration of what cells?

Answer 51

**CD3+ T cells**, plasmacytoid dendritic cells, and macrophages as well as **B cells** (especially in muscle)

Question 52

often highly elevated (>500 mg/dL) in anti-MDA5 patients with DM

Answer 52

serum ferritin

Question 53

may be a useful biomarker to **assess the severity and follow the clinical response of ILD in anti-MDA5 patients with DM**

Answer 53

serum ferritin

Question 54

sensitive indicator of myositis and correlates with creatine kinase levels.

Answer 54

Muscle edema ## Footnote On short tau inversion recovery, in which normal muscle is dark and** inflamed muscle is bright,** an **increased signal intensity **within muscle tissue suggests **muscle inflammation, necrosis, or degeneration**

Question 55

key first step in management in DM

Answer 55

photoprotection

Question 55

classic histopath findings of DM

Answer 55

cell-poor interface dermatitis, increased dermal mucin, a perivascular lymphocytic infiltrate, and vascular ectasia ## Footnote * Other inconstant findings include epidermal atrophy and basement membrane thickening * when interface dermatitis was absent (20% of cases), increased dermal mucin was always present.

Question 56

first-line therapy in the treatment of myositis

Answer 56

Systemic corticosteroids ## Footnote * Complete clinical responses in muscle inflammation with prednisone monotherapy at doses greater than 0.5 mg/kg/day * They can also be used for joint disease and ILD, although often a corticosteroid-sparing agent is required.

Question 57

typically regarded as first-line agents for skin disease

Answer 57

Antimalarials ## Footnote * The addition of quinacrine to hydroxychloroquine or chloroquine may be more effective than a single agent

Question 57

In patients with DM with suspected or diagnosed ILD, this medication should not be used because of its potential to **induce acute pneumonitis and pulmonary fibrosis,** thereby complicating the evaluation and management of ILD.

Answer 57

methotrexate

Question 57

first-line treatment for myositis in combination with prednisone

Answer 57

**methotrexate 20 to 25 mg/wk** are typically necessary to control muscle inflammation ## Footnote * Methotrexate is effective in significantly reducing cutaneous disease severity in 50% to 100% of patients with DM * Methotrexate is also an effective treatment choice when concomitant arthritis is present

Question 58

first-line oral agent when ILD is present

Answer 58

**Mycophenolate mofetil **has been shown to be effective at dosages of 2 to 3 g/day in reducing cutaneous disease severity and myositis ## Footnote * About 20% of patients experience nausea or diarrhea t 2 g/day. * If GI side effects are dose limiting, then switching to enteric-coated mycophenolate sodium is an option for maintaining a patient on therapy

Question 59

single most effective agent for cutaneous DM

Answer 59

Intravenous immunoglobulin (IVIG) ## Footnote * IVIG is also effective for myositis. * The standard dosing regimen is **2 g/kg/mo divided over 3 to 5 days.**

Question 60

it can be used in patients who are rapidly declining or are acutely ill with dysphagia or respiratory muscle involvement.

Answer 60

IVIG ## Footnote * coz it works relatively quickly * Headaches may occur in up to 56% of patients and may be severe and debilitating. * The rate of infusion, the total dose, 176 the formulation of IVIG, and the volume status of the patient may influence the occurrence of headache * Aseptic meningitis is a rare adverse event manifesting as fever, headache, photophobia, meningismus, neutrophilic pleocytosis, or eosinophilia in the cerebrospinal fluid. * Anaphylaxis is also rare but may occur in primary IgA deficiency; therefore, checking serum IgA levels before infusion is recommended. * However, there is no evidence that having low but detectable immunoglobulin levels confers any increased risk for anaphylaxis

Question 60