10 - 62 - DERMATOMYOSITIS Flashcards
affects 20% of patients and is a major source of morbidity and mortality in dermatomyositis
Interstitial lung disease (ILD)
In adults, DM heralds the diagnosis of a coexisting internal malignancy in how many percent of patients
10 - 20%
how many % of patients does not manifest clinically significant muscle weakness
20%
These patients make up a population now defined as clinically amyopathic dermatomyositis (CADM),
antibidoies associated with increased risk of ILD
anti-MDA5 and antisynthetase autoantibodies
antibodies associated with increased risk of having an associated cancer
antiTIF1-γ and anti-NXP2 autoantibodies
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.
Hypomyopathic dermatomyositis
This pertains to the subtype of CADM in which all the test results are normal.
Amyopathic DM
2 peaks of DM
- 5 to 14 years
- 45 to 64 years of life
The disease affects women two to three times more than often than men
Triggers of DM
> UVR
Strenous activity
Recent Malignancy
In DM, there is often significant pruritus associated with the affected skin . This is usually seen on what area?
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
most common location affected on the scalp
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.
The skin changes in DM are often distributed to prototypical regions on the body. Enumerate these areas.
Diagnostic Criteria for Dermatomyositis
Cutaneous Clue to possible presence of Interstitial Lung Disease
*
Common locations of mechanic’s hands
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**
Nail capillaroscopy findings in DM
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
Cutaneous ulceration in DM warrants concern for the presence of ________
> antiMDA5 antibodies or malignancy (especially if necrosis is seen)
commonly occurs over gottron papules
correlated with the presence of interstitial lung disease (ILD)
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 _______
Consistent location of ovoid palatal patch
center of the hard palate
antibodies associated with ovoid palatal patch
anti–transcriptional intermediary factor 1γ (TIF1-γ) antibodies
pathognomonic pattern seen composed of reticulated, sometimes atrophic white macules adjacent to erythema or telangiectasias
“red on white”
Calcinosis is most frequent on which areas in DM?
Extremities
vs systemic sclerosis where digital calcinosis is most frequent
In both juvenile and adult DM, the presence of which antibody is associated with an increased risk of calcinosis?
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.
Triad of poikiloderma
hyperpigmentation, hypopigmentation, and telangiectasias
most common pulmonary manifestation in DM and is a leading cause of morbidity and mortality in these patients
Interstitial Lung Disease (ILD)
- affects 15 - 50% of patients
necessary step in establishing the diagnosis of ILD
high-resolution computed tomography (CT) of the chest
- may show subclinical fibrosis before symptom onset
- The most common radiographic and histologic pattern in DM is nonspecific interstitial pneumonia
Pulmonary function test finding of DM
show a restrictive disease pattern with a decreased forced vital capacity (FVC) 57 or a decreased diffusion capacity of carbon monoxide.
most common radiographic and histologic pattern in DM
Nonspecific interstitial pneumonia
Radiographically, basilar and peripheral ground-glass opacities and subpleural sparing characterize nonspecific interstitial pneumonia.
The gold standard for the diagnosis of pulmonary arterial hypertension
Right heart catheterization
Right heart catheterization findings of PAH
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
in DM, Patients often report weakness in the extensor muscles surrounding ________________
shoulder and pelvic girdles and proximal limbs
Quadriceps and gluteal muscle weakness may manifest as
difficulty rising from a chair or toilet, climbing stairs, or stepping onto curbs.
shoulder and upper extremity weakness may manifest as
difficulty washing their hair or reaching for items in overhead cupboards
Approximately how many percent of patients complain of muscle pain with or without muscle weakness
30%
risk factors for malignancy
increasing age, male gender, cutaneous necrosis, dysphagia, and rapid onset of myositis
protective factors for malignancy
ILD, arthritis, and Raynaud phenomenon
The major antibody associated with malignancy
TIF1-γ
More recent data suggest that anti-NXP2 antibodies may also be associated with cancer, although this association is not as strong
Features of the skin examination that are particularly sensitive for dermatomyositis
> microscopic periungual telangiectasias
lateral digit hyperkeratosis
scalp erythema and dysesthesia
classic c triad electromyographic findings of myositis
- small amplitude, short duration, polyphasic motor unit potentials
- fibrillations and positive sharp waves
- complex repetitive discharges
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.
2 weeks
- 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.
ong-term survival rate for adults with DM
approximately 65% to 75%
presence of this antibody is a risk factor for death
anti-MDA 5 antibodies
Three major criteria of dermatomyositis
- 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)
a diagnosis of clinically amyopathic DM could be made if the patient has how many major and minor criteria
two 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
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
TRUE
can be an exemplary sign of vasculopathy, although it can also be the result of robust, liquefactive interface dermatitis, or excoriation
Cutaneous ulceration
frequent place to visualize the “red-on-white” pattern
thin skin along the bitemporal hairline
edema in the distal extremities has recently been found to be associated with what antibodies and may predict more severe muscle disease?
anti-NXP2 antibodies
If patients with DM do develop weakness, then about how many % of patients develop weakness within the first year of symptom onset.
80%
Arthritis and arthralgias are more common among patients with DM with what antibodies?
anti-MDA5 and antisynthetase antibodies
Muscle and skin biopsies show infiltration of what cells?
CD3+ T cells, plasmacytoid dendritic cells, and macrophages as well as B cells (especially in muscle)
often highly elevated (>500 mg/dL) in anti-MDA5 patients with DM
serum ferritin
may be a useful biomarker to assess the severity and follow the clinical response of ILD in anti-MDA5 patients with DM
serum ferritin
sensitive indicator of myositis and correlates with creatine kinase levels.
Muscle edema
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
key first step in management in DM
photoprotection
classic histopath findings of DM
cell-poor interface dermatitis, increased dermal mucin, a perivascular lymphocytic infiltrate, and vascular ectasia
- Other inconstant findings include epidermal atrophy and basement membrane thickening
- when interface dermatitis was absent (20% of cases), increased dermal mucin was always present.
first-line therapy in the treatment of myositis
Systemic corticosteroids
- 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.
typically regarded as first-line agents for skin disease
Antimalarials
- The addition of quinacrine to hydroxychloroquine or chloroquine may be more effective than a single agent
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.
methotrexate
first-line treatment for myositis in combination with prednisone
methotrexate 20 to 25 mg/wk are typically necessary to control muscle inflammation
- 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
first-line oral agent when ILD is present
**Mycophenolate mofetil **has been shown to be effective at dosages of 2 to 3 g/day in reducing cutaneous disease severity and myositis
- 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
single most effective agent for cutaneous DM
Intravenous immunoglobulin (IVIG)
- IVIG is also effective for myositis.
- The standard dosing regimen is 2 g/kg/mo divided over 3 to 5 days.
it can be used in patients who are rapidly declining or are acutely ill with dysphagia or respiratory muscle involvement.
IVIG
- 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
