62: Dermatomyositis Flashcards
What are the major criteria for diagnosing clinically amyopathic dermatomyositis (CADM)?
The major criteria for diagnosing CADM include: 1. Heliotrope sign - violaceous erythema on the upper eyelids 2. Gottron papules - papules overlying MCP and IP joints 3. Gottron sign - erythema overlying knees, elbows, and IP joints.
What is the classification of clinically amyopathic dermatomyositis (CADM) based on muscle test results?
Clinically amyopathic dermatomyositis (CADM) can be subclassified into two groups based on muscle test results: 1. Hypomyopathic DM - at least one of the muscle test results is abnormal. 2. Amyopathic DM - all test results are normal.
What are the minor criteria for diagnosing cutaneous dermatomyositis?
The minor criteria for diagnosing cutaneous dermatomyositis include: - Macular violaceous erythema involving various areas (each area counts as one minor criterion) - Nailfold capillary telangiectasia, hemorrhage-infarct - Poikiloderma - Mechanic’s hands - Cutaneous calcinosis - Cutaneous ulcers - Pruritus
What are the epidemiological characteristics of dermatomyositis?
Dermatomyositis has a bimodal distribution occurring at two peaks: - 5 to 14 years old - 45 to 64 years old Additionally, it affects women two to three times more than men.
What triggers significant pruritus in patients with cutaneous dermatomyositis?
Significant pruritus in patients with cutaneous dermatomyositis is often triggered by: - Substantial UV exposure - Strenuous activity (especially for patients with concurrent myositis) - Recent malignancy This pruritus is caused by structural damage to epidermal small fiber nerves.
What is the likely diagnosis for a patient with a heliotrope sign and Gottron papules but no muscle weakness?
The likely diagnosis is Clinically Amyopathic Dermatomyositis (CADM). Further tests include imaging (MRI, electromyography), muscle biopsy, and lab studies of muscle enzymes to classify as hypomyopathic or amyopathic DM.
What are the major and minor criteria for diagnosing Clinically Amyopathic Dermatomyositis (CADM) according to Sontheimer’s proposed criteria?
Major Criteria: 1. Heliotrope sign - violaceous erythema on the upper eyelids 2. Gottron papules - papules overlying MCP and IP joints 3. Gottron sign - erythema overlying knees, elbows, IP joints
Minor Criteria: - Macular violaceous erythema involving various areas (each counts as one minor criterion) - Nailfold capillary telangiectasia, hemorrhage-infarct - Poikiloderma - Mechanic’s hands - Cutaneous calcinosis - Cutaneous ulcers - Pruritus
How does the classification of Clinically Amyopathic Dermatomyositis (CADM) differ between hypomyopathic and amyopathic forms?
Hypomyopathic Dermatomyositis: - At least one abnormal test result (laboratory studies, EMG, or MRI) - No evidence of weakness
Amyopathic Dermatomyositis: - All test results are normal - No evidence of myositis on laboratory studies, EMG, or MRI
What are the clinical features and triggers associated with cutaneous findings in Clinically Amyopathic Dermatomyositis (CADM)?
Clinical Features: - Significant pruritus on affected skin, particularly on the scalp - Characteristic cutaneous feature: Violaceous patches and plaques varying from bright pink to deep violet color
Triggers: - Substantial UV exposure - Strenuous activity (for patients with concurrent myositis) - Recent malignancy
What is the epidemiological distribution of Clinically Amyopathic Dermatomyositis (CADM) in terms of age and gender?
Epidemiological Distribution: - Bimodal distribution with two peaks: 1. Ages 5 to 14 years 2. Ages 45 to 64 years - Affects women two to three times more than men
What is the significance of the Heliotrope sign in dermatomyositis?
The Heliotrope sign is characterized by a pink to purple violet hue on the eyelids, as well as lateral canthi, medial canthi, and adjacent nasal sidewalls. It is one of the cutaneous manifestations of dermatomyositis and indicates the presence of the disease.
What does the Shawl sign indicate in patients with dermatomyositis?
The Shawl sign refers to trunk involvement seen on the posterior neck, upper back, and shoulders, which may extend to the posterior upper arms. It is a characteristic cutaneous finding in dermatomyositis.
How does the Gottron sign present in dermatomyositis?
The Gottron sign is characterized by symmetric macular violaceous erythema over the interphalangeal (IP) joints, olecranon processes, patellae, and medial malleoli. It is a key cutaneous manifestation of dermatomyositis.
What are the clinical implications of cutaneous ulceration in dermatomyositis?
Cutaneous ulceration may be present in 30% of patients with dermatomyositis, often affecting extensor joint surfaces. It is associated with the presence of anti-MDA5 antibodies or malignancy and correlates with interstitial lung disease.
What does the term ‘Mechanic’s hands’ refer to in the context of dermatomyositis?
Mechanic’s hands refer to hyperkeratosis and fissuring along the medial thumb and lateral 2nd and 3rd digits. This finding may be subtle and often requires palpation to appreciate the rough texture, indicating dermatomyositis.
What is the significance of the Ovoid palatal patch in dermatomyositis?
The Ovoid palatal patch is a symmetric violaceous patch across the midline of the hard palate, seen in patients with anti-transcriptional intermediary factor 1γ (TIF1-γ) antibodies. These changes may fade with control of disease activity, indicating a response to treatment.
What does the term ‘Calcinosis’ indicate in patients with dermatomyositis?
Calcinosis is a late manifestation in the skin, subcutaneous tissue, fascia, and muscle, affecting the trunk and proximal extremities. It is associated with areas of previous disease activity, with a prevalence of 20% in adult dermatomyositis and 40% in juvenile dermatomyositis.
What is the underlying cause of severe pruritus in a patient with DM, and how should it be managed?
The pruritus is caused by structural damage to epidermal small fiber nerves. Management includes topical corticosteroids or calcineurin inhibitors for symptomatic relief.
What is the Holster sign in dermatomyositis, and what does it indicate?
This is called the Holster sign, indicating violaceous erythema and poikiloderma in DM. It is a characteristic cutaneous feature of the disease.
What are the common cutaneous signs associated with dermatomyositis and their clinical implications?
Sign | Description | Clinical Implications |
|——|————-|———————|
| Heliotrope sign | Pink to purple violet hue on eyelids and adjacent areas | Indicative of dermatomyositis, often associated with systemic involvement |
| Shawl sign | Trunk involvement on posterior neck and upper back | Suggests dermatomyositis, may indicate more extensive disease |
| Gottron papules | Violaceous to pink papules over IP and MCP joints | Classic sign of dermatomyositis, may correlate with disease activity |
| V-neck sign | Confluent violaceous erythema on sun-exposed areas | Indicates dermatomyositis, often seen in conjunction with other signs |
| Mechanic’s hands | Hyperkeratosis and fissuring on fingers | Suggestive of dermatomyositis, may indicate underlying muscle involvement |
| Cutaneous ulceration | May affect extensor surfaces, present in 30% of patients | Associated with anti-MDA5 antibodies and increased risk of malignancy |
| Ovoid palatal patch | Symmetric violaceous patch on hard palate | Seen in patients with TIF1-γ antibodies, may fade with disease control |
How does the presence of anti-MDA5 antibodies correlate with cutaneous ulceration in dermatomyositis patients?
- Cutaneous ulceration occurs in approximately 30% of dermatomyositis patients.
- It typically affects extensor joint surfaces.
- The presence of anti-MDA5 antibodies is associated with a higher incidence of cutaneous ulceration.
- In patients with anti-MDA5 antibodies, ulceration commonly occurs over Gottron papules.
- There is a noted correlation between cutaneous ulceration and interstitial lung disease in these patients, indicating a more severe disease course.
What are the implications of skin damage patterns observed in dermatomyositis?
- Skin damage in dermatomyositis often presents as brown, reticulated, post-inflammatory hyperpigmented patches.
- Poikiloderma is characterized by: - Atrophy - Hypopigmentation - Hyperpigmentation - Telangiectasias
- These changes are typically found in sun-exposed areas and indicate areas of previous disease activity.
- Understanding these patterns is crucial for monitoring disease progression and potential complications.
What is the association between anti-nuclear matrix protein (NXP-2) antibodies and dermatomyositis (DM)?
Anti-nuclear matrix protein (NXP-2) antibodies are associated with dermatomyositis and may indicate a more severe muscle disease, particularly in patients with subcutaneous edema in the distal extremities.
What are the common pulmonary manifestations of dermatomyositis (DM)?
The most common pulmonary manifestation of dermatomyositis is interstitial lung disease (ILD), which can present in three clinically described patterns: asymptomatic with only radiologic evidence, insidious onset with gradual decrease in exercise capacity, and acute onset with hypoxia and respiratory failure.
What is the significance of anti-MDA5 antibodies in patients with dermatomyositis?
Patients with dermatomyositis who have anti-MDA5 antibodies are at a higher risk of developing interstitial lung disease (ILD), with estimates of risk ranging from 50% to 100%.
How does muscle involvement present in patients with dermatomyositis?
Muscle involvement in dermatomyositis typically presents as symmetrical, proximal muscle weakness, affecting the extensor muscles around the shoulder and pelvic girdles, as well as the proximal limbs. Patients may experience difficulty with activities such as rising from a chair, climbing stairs, and raising their head while lying supine.
What are the common symptoms of myositis in dermatomyositis patients?
Common symptoms of myositis in dermatomyositis patients include symmetrical proximal muscle weakness, myalgia (muscle pain), and dysphonia (hoarse voice) due to cricoarytenoid muscle involvement, which occurs in about 40% of patients.
What is the likely antibody present in a patient with DM and cutaneous ulceration over Gottron papules?
The patient likely has anti-MDA5 antibodies, which are associated with an increased risk of interstitial lung disease (ILD).
What muscles are likely affected in a patient with DM who has difficulty rising from a chair and climbing stairs?
The quadriceps and gluteal muscles are likely affected, indicating proximal muscle weakness due to myositis.
What is the significance of anti-NXP2 antibodies in dermatomyositis (DM) patients regarding muscle disease severity?
Anti-NXP2 antibodies are associated with subcutaneous edema in distal extremities, which may predict more severe muscle disease in patients with dermatomyositis.
How does the presence of anti-MDA5 antibodies affect the risk of alopecia in dermatomyositis patients?
Patients with anti-MDA5 antibodies have a higher risk of developing alopecia, which is commonly nonscarring and diffuse in dermatomyositis.
What are the three clinically described patterns of lung involvement in patients with interstitial lung disease (ILD) associated with dermatomyositis?
The three patterns of lung involvement in ILD associated with dermatomyositis are: 1. Asymptomatic with only radiologic evidence of ILD 2. Insidious onset with gradual decrease in exercise capacity, dyspnea on exertion, or dry cough 3. Acute onset with hypoxia and possibly respiratory failure.
What is the gold standard for diagnosing pulmonary arterial hypertension in dermatomyositis patients?
The gold standard for diagnosing pulmonary arterial hypertension in dermatomyositis patients is right heart catheterization, which shows a mean pulmonary artery pressure of 25 mmHg or greater at rest and an end-expiratory pulmonary artery wedge pressure of 15 mmHg or less.
What are common symptoms of muscle involvement in dermatomyositis, and how do they manifest in daily activities?
Common symptoms of muscle involvement in dermatomyositis include: - Symmetrical proximal muscle weakness, particularly in extensor muscles around the shoulder and pelvic girdles. - Difficulty rising from a chair or toilet, climbing stairs, or stepping onto curbs due to quadriceps and gluteal muscle weakness. - Difficulty washing hair or reaching for items on overhead cupboards due to shoulder and upper extremity weakness. - Difficulty raising the head off the bed while laying supine due to neck flexor muscle involvement.
What are common symptoms of muscle involvement in dermatomyositis?
Common symptoms include symmetrical proximal muscle weakness, difficulty rising from a chair, climbing stairs, washing hair, raising the head off the bed, and myalgia in approximately 30% of patients.
What percentage of patients with dermatomyositis (DM) may experience dysphagia?
Dysphagia may occur in 20 to 50% of patients with DM due to weak pharyngeal musculature.
What are the common joint involvements reported in patients with dermatomyositis (DM)?
Arthralgias are reported in 30 to 40% of patients with DM, typically involving small joints of the hands, wrists, MCP and PIP joints, shoulders, elbows, and ankles.
What is the significance of cardiac troponin I in patients with dermatomyositis (DM)?
Cardiac troponin I is a useful biomarker in detecting subclinical cardiac muscle involvement in patients with DM.
What types of malignancies are associated with dermatomyositis (DM)?
DM is associated with malignancy in 10 to 20% of cases, including breast, lung, ovarian, and colorectal cancers.
What symptoms are associated with gastrointestinal involvement in juvenile dermatomyositis (DM)?
Symptoms include persistent abdominal pain, diarrhea, vomiting, constipation, frank hematemesis, or hematochezia.
What is the ‘anti-synthetase syndrome’ and what symptoms does it include?
The ‘anti-synthetase syndrome’ consists of fever, arthritis, myositis, interstitial lung disease (ILD), mechanic’s hands, or Raynaud phenomenon.
What are the common ECG abnormalities found in patients with dermatomyositis (DM)?
Common ECG abnormalities include ST-T segment changes and conduction abnormalities.
Which antibody is most commonly associated with malignancy in dermatomyositis (DM)?
The major antibody associated with malignancy in DM is anti-TIF1-γ antibodies.
What is the relationship between anti-MDA5 antibodies and cardiac involvement in dermatomyositis (DM)?
Patients with anti-MDA5 antibodies may be at higher risk for cardiac involvement in DM.
What is the clinical significance of dysphagia in patients with dermatomyositis?
Dysphagia occurs in 20 to 50% of patients with dermatomyositis due to weak pharyngeal musculature, and is highly correlated with anterior neck muscle weakness.
How do joint involvements in dermatomyositis differ between patients with anti-MDA5 and anti-synthetase antibodies?
Patients with anti-MDA5 and anti-synthetase antibodies experience more frequent arthralgias and arthritis, with anti-synthetase antibodies presenting nonerosive arthritis in up to 93% of cases.
What are the gastrointestinal manifestations associated with juvenile dermatomyositis?
Gastrointestinal involvement can lead to ulceration and perforation of the bowel wall, with symptoms like persistent abdominal pain and nonspecific symptoms.
What cardiovascular findings are commonly associated with dermatomyositis?
Common findings include ST-T segment changes on ECG and left ventricular hypertrophy or diastolic dysfunction on echocardiography.
What is the relationship between dermatomyositis and internal malignancy?
Dermatomyositis is associated with malignancy in 10 to 20% of cases, typically occurring within the first 1 to 2 years of disease onset.
What role does the innate immune system play in the pathogenesis of Dermatomyositis (DM)?
The innate immune system is involved through high levels of interferon (IFN)-induced genes and proteins, activation of pattern recognition receptors, and induction of DM autoantigens.
How do polymorphisms in the HLA region relate to Dermatomyositis (DM)?
Polymorphisms in the human leukocyte antigen (HLA) region are associated with an increased risk of DM, implicating T cell activation.
What are the key histological findings in the vasculopathy associated with Dermatomyositis (DM)?
Key findings include endothelial degeneration, capillary dropout, and deposition of the membrane attack complex of complement on capillaries.
What genetic factors are associated with Dermatomyositis (DM)?
Genetic factors include the HLA-B8 allele, MHC class I and II genes, including the BLK gene and the TYK2 gene.
What environmental triggers are associated with Dermatomyositis (DM)?
Environmental triggers include UV exposure, infection, and malignancy.
What is the practical approach to diagnosing Dermatomyositis (DM)?
Diagnosis requires organ-specific criteria to be met and relies on the clinician’s impression based on history and physical examination.
What are some helpful skin findings in Dermatomyositis (DM)?
Helpful findings include microscopic periungual telangiectasias, lateral digit hyperkeratosis, scalp erythema, and grossly visible periungual telangiectasias.
What is the significance of muscle enzyme elevation in diagnosing myositis?
Elevation of muscle enzymes indicates muscle inflammation and helps in confirming clinical suspicions.
What are the classic symptoms associated with Anti-MDA5 DM?
Classic symptoms include alopecia, cutaneous or mucosal ulceration, palmar erythematous papules, severe arthralgia or arthritis, and shortness of breath.
What autoantibodies are associated with myositis and should be tested?
Autoantibodies to test include TIF1-γ, NXP2, MDA5, small ubiquitin-like modifier activating enzyme, Mi-2, and Jo-1.
What is the classic triad observed in electromyographic studies for myositis?
The classic triad includes small amplitude, short duration, and polyphasic motor unit potentials.
How does the sensitivity of muscle enzymes change over the course of myositis?
The sensitivity of muscle enzymes decreases mid to late in the course of myositis due to perifascicular muscle atrophy and fibrosis.
What are the classic electromyographic findings associated with myositis?
The classic findings include small amplitude, short duration, polyphasic motor unit potentials, fibrillations, and positive short waves.
How can the sensitivity of detecting myositis be increased during laboratory evaluation?
Sensitivity can be increased by evaluating creatine kinase, aldolase, and LDH as a group when testing muscle enzymes.
What laboratory test is often highly elevated in anti-MDA5 patients?
Serum ferritin (>500mg/dL) is often highly elevated and may be useful for assessing severity of interstitial lung disease (ILD).
What imaging technique is used to differentiate between steroid-myopathy and active myositis?
MRI is used to differentiate weakness caused by damage or steroid-myopathy vs. active myositis.
What are the typical histopathological findings in muscle biopsies of patients with dermatomyositis?
Typical findings include perifascicular atrophy, degenerating and regenerating myofibers, and capillary necrosis.
What is the significance of the lupus band test in diagnosing dermatomyositis (DM)?
The lupus band test has a sensitivity of 78% and specificity of 93% for diagnosing DM over cutaneous lupus.
What are the typical histopathological findings in muscle biopsies of patients with dermatomyositis?
Typical findings include:
1. Perifascicular atrophy
2. Degenerating and regenerating myofibers
3. Membrane attack complex deposition in the endomysial capillary walls
4. Endothelial cell swelling
5. Capillary necrosis
What is the significance of the lupus band test in diagnosing dermatomyositis (DM) over cutaneous lupus?
The lupus band test has a sensitivity of 78% and specificity of 93% for making a diagnosis of DM over cutaneous lupus.
What are the major causes of death in adults with dermatomyositis?
Major causes of death include:
1. Malignancy
2. Pulmonary disease
3. Cardiac disease
4. Infection
What are the major risk factors for chronic disease in children with dermatomyositis?
Major risk factors for chronicity in children include:
1. Delay in therapy
2. Early persistent skin disease (e.g., 3 months)
3. Decline in nailfold capillary density
What is the first step in the management of dermatomyositis?
The first step in management requires assessing the potentially affected organs, namely the skin, muscle, and lungs.
A patient with DM has elevated serum ferritin levels (>500 mg/dL). What antibody is likely present, and what condition should be monitored?
Anti-MDA5 antibodies are likely present. Monitor for interstitial lung disease (ILD).
A patient with DM has perifascicular atrophy and capillary necrosis on muscle biopsy. What does this indicate?
These findings are typical of DM and indicate muscle involvement with perifascicular atrophy and capillary necrosis.
What laboratory test is highly elevated in anti-MDA5 patients and may indicate the severity of interstitial lung disease (ILD)?
Serum ferritin (>500mg/dL) is often highly elevated in anti-MDA5 patients and may be a useful marker to assess severity and follow the clinical response of ILD.
What imaging technique is used to differentiate between steroid myopathy and active myositis when muscle enzymes and electromyography are inconclusive?
MRI is used to differentiate weakness caused by damage or steroid myopathy vs. active myositis when muscle enzymes and electromyography are inconclusive.
What is the significance of the presence of anti-MDA5 antibodies in patients with dermatomyositis?
The presence of anti-MDA5 antibodies is a risk factor for death in patients with dermatomyositis.
What are the principles of management for patients with dermatomyositis?
Management principles include:
1. Assessing potentially affected organs, namely the skin, muscle, and lungs.
2. Prioritizing interstitial lung disease (ILD) and associated cancers as leading causes of disease-related death during treatment selection.
What percentage of patients with dermatomyositis (DM) may have an associated malignancy?
10% to 20% of patients with DM may have an associated malignancy.
What is the role of routine age-appropriate cancer screening in patients with DM?
Routine age-appropriate cancer screening studies (colonoscopy, mammogram, prostate exam) and relevant blood work (CBC, renal and liver function tests) are indicated for patients with DM.
What is the validated muscle test used to assess muscle disease in dermatomyositis?
The validated muscle test used is called MMT8, which tests 8 major muscle groups including neck flexors, deltoids, biceps, wrist extensors, gluteus maximus and medius, quadriceps, and ankle dorsiflexors.
What are the first-line treatments for skin disease in dermatomyositis?
First-line treatments include photoprotection, topical steroids, hydroxychloroquine or chloroquine, and quinacrine.
What is the significance of cardiac troponin I in patients with dermatomyositis?
Cardiac troponin I is specific for myocardial damage and is used to evaluate cardiovascular involvement in patients with dermatomyositis.
What is the recommended monitoring for pulmonary disease in patients with dermatomyositis?
Baseline pulmonary function tests (PFTs) with diffusion capacity should be obtained, followed by annual screening as long as other symptoms of DM continue.
What is the recommended approach for cancer screening in patients with dermatomyositis (DM)?
Routine age-appropriate cancer screening studies such as colonoscopy, mammogram, and prostate exam, along with relevant blood work (CBC, renal and liver function tests) and urinalysis, are indicated. More aggressive screening (e.g., CT scan, PET scan) may be considered if there are concerns, especially within 2-3 years of diagnosis.
What are the key components of monitoring extramuscular disease in patients with dermatomyositis?
Monitoring includes:
1. Muscle Disease: Manual muscle testing (MMT8) to assess 8 major muscle groups, and electromyography or MRI for increased sensitivity in cases of weakness.
2. Pulmonary Disease: Baseline pulmonary function tests (PFTs) with diffusion capacity, annual screening, and high-resolution CT if concerning changes occur.
3. Cardiovascular Involvement: Cardiac troponin I testing for myocardial damage, with echocardiography or ECG if troponin I is positive.
What is the first-line treatment for skin disease in dermatomyositis?
The first-line treatment includes:
- Photoprotection: Key first step in management.
- Topical Steroids: Hydroxychloroquine or Chloroquine, and Quinacrine for skin disease.
- Systemic Corticosteroids: To manage more severe cases.
How do topical corticosteroids help in managing dermatomyositis skin disease?
Topical corticosteroids reduce erythema, scale, and pruritus. Class I or II steroid creams or ointments are used on thick skin areas (elbows, knees, hands) and can help with nailfold sensitivity. Occlusion with plastic wrap at night can enhance potency.
What are the second-line treatment options for dermatomyositis?
Second-line treatments include:
1. Methotrexate
2. Mycophenolate mofetil
3. Intravenous immune globulin
4. Azathioprine
These options are considered when first-line treatments are insufficient or not tolerated.
What is the first line therapy for myositis and why are systemic corticosteroids considered undesirable as monotherapy for cutaneous dermatomyositis?
Systemic corticosteroids are the first line therapy for myositis. They are considered undesirable as monotherapy for cutaneous dermatomyositis because they usually only elicit partial responses and are associated with long-term side effects.
What is the recommended dose of intravenous immunoglobulin (IVIG) for cutaneous dermatomyositis and what percentage of patients achieve a complete response?
The recommended dose of intravenous immunoglobulin (IVIG) for cutaneous dermatomyositis is 2 g/kg/month divided over 3 to 5 days. Approximately 70% to 80% of patients achieve an almost complete or complete response.
What are the potential adverse events associated with intravenous immunoglobulin (IVIG) therapy?
Potential adverse events associated with intravenous immunoglobulin (IVIG) therapy include:
- Headaches (affected by rate of infusion, total dose, formulation of IVIG, volume status of patient)
- Aseptic meningitis
- Anaphylaxis (may occur in primary IgA deficiency)
- Venous thrombosis
- Renal injury
What is the role of azathioprine in the treatment of myositis and how effective is it?
Azathioprine is shown to improve myositis in up to 75% of cases. It is commonly used as maintenance therapy in the treatment of interstitial lung disease (ILD) associated with idiopathic inflammatory myopathies, typically after induction of cyclophosphamide.
What is the first line treatment for myositis in combination with prednisone and what is its dosing?
The first line treatment for myositis in combination with prednisone is methotrexate. The recommended dose is 20 to 25 mg/week. It is effective when concomitant arthritis is present.
What are the critical considerations when using systemic corticosteroids as first-line therapy for myositis?
- Systemic corticosteroids are undesirable as monotherapy for cutaneous dermatomyositis (DM) due to partial responses and long-term side effects.
- Prednisone should be greater than 0.5 mg/kg/day.
- Addition of a corticosteroid-sparing agent may improve control of myositis and extracutaneous manifestations, while minimizing the toxicities of oral steroids.
What is the role of intravenous immunoglobulin (IVIG) in the treatment of cutaneous dermatomyositis?
- IVIG is the single most effective agent for cutaneous DM.
- 70% to 80% of patients achieve an almost complete or complete response.
- The recommended dose is 2 g/kg/month divided over 3 to 5 days.
- Therapeutic effects may be perceived as early as 1 week, but may not be apparent until the 2nd or 3rd month.
- Adverse events include headaches, aseptic meningitis, and anaphylaxis, especially in primary IgA deficiency.
How does the use of azathioprine in combination with methotrexate benefit patients with persistent myositis?
- Azathioprine has shown efficacy in improving myositis in up to 75% of cases.
- It is commonly used in a low dose combination with methotrexate for persistent myositis.
- Azathioprine is also used as maintenance therapy in the treatment of interstitial lung disease (ILD) associated with idiopathic inflammatory myopathies, typically after induction of cyclophosphamide.
What are the potential adverse effects of mycophenolate mofetil when used as a first-line agent for ILD in myositis patients?
- Mycophenolate mofetil is dosed at 2 to 3 g/day and is the first-line agent when ILD is present.
- About 20% of patients may experience nausea and diarrhea at a dose of 2 g/day.
- If side effects occur, switching to enteric-coated mycophenolate sodium may be considered to minimize gastrointestinal issues.
What is the primary use of calcineurin inhibitors in the context of dermatomyositis?
Calcineurin inhibitors are primarily used in the setting of interstitial lung disease (ILD), especially severe ILD associated with anti-MDA5 or antisynthetase antibodies.
What are the recommended physical medicine and rehabilitation strategies for patients with dermatomyositis?
The recommended strategies include:
1. Strength training
2. Aerobic exercise
What surgical intervention is considered most effective for calcinosis in dermatomyositis?
Surgical excision for localized lesions is considered the most effective and definite therapy for calcinosis in dermatomyositis.
What are some conditions that have skin findings similar to dermatomyositis?
Conditions with similar skin findings include:
- Acute cutaneous lupus: Characterized by malar pink patches and plaques; may generalize to the rest of the face and body.
- Photoallergic dermatitis: Rash occurs on sun-exposed skin; often has itching or burning.
- Acne rosacea: Limited to the face; may have itching and burning quality.
- Polymorphous light eruption: Affects sun-exposed sites; rash resolves with sun avoidance.
- Seborrheic dermatitis: Greasy scale and orange-red quality; may affect central chest and neck.
- Psoriasis: Tends to spare the face; lacks characteristic damage of DM.
- Lichenoid drug eruption: Associated with medications; eruption is widespread and papular.
- Mixed connective tissue disease: May have facial rash, calcinosis, and myositis; lacks Gottron papules.
What are the primary uses and nephrotoxicity risks associated with calcineurin inhibitors in the treatment of interstitial lung disease (ILD)?
Calcineurin inhibitors are primarily used in the setting of severe ILD, particularly in patients with anti-MDA5 or antisynthetase antibodies. The nephrotoxicity risk is highest when the dosage exceeds 3 mg/kg/day, necessitating careful monitoring of renal function and blood pressure.
What are the recommended physical rehabilitation strategies for patients with dermatomyositis?
The recommended physical rehabilitation strategies for patients with dermatomyositis include:
1. Strength training
2. Aerobic exercise
These strategies aim to improve overall physical function and quality of life.
What surgical and medical interventions are effective for managing calcinosis in dermatomyositis?
Effective interventions for managing calcinosis in dermatomyositis include:
- Surgical excision for localized lesions, which is the most effective and definitive therapy.
- IVIG (Intravenous Immunoglobulin) has been reported to work well in some cases.
- Bisphosphonates have been cited as effective for calcinosis in juvenile dermatomyositis.
How can acute cutaneous lupus be differentiated from dermatomyositis based on skin findings?
Acute cutaneous lupus can be differentiated from dermatomyositis by the following characteristics:
- Skin Findings: Acute cutaneous lupus is characterized by malar pink patches and plaques that may generalize to the rest of the face and body, while dermatomyositis typically presents with Gottron papules and heliotrope rash.
- Joint Involvement: Acute cutaneous lupus generally spares the PIP and DIP joints and nasolabial folds, whereas dermatomyositis may involve these areas.
- Pruritus: Acute cutaneous lupus usually does not have significant pruritus, while dermatomyositis may present with itching in some cases.
What are the key distinguishing features of polymorphous light eruption compared to dermatomyositis?
Key distinguishing features of polymorphous light eruption compared to dermatomyositis include:
- Timing of Eruption: Polymorphous light eruption typically occurs immediately after sun exposure (delayed 1-2 days in dermatomyositis).
- Distribution: The rash in polymorphous light eruption is not in the classic extensor distribution seen in dermatomyositis.
- Resolution: The eruption in polymorphous light eruption may resolve completely in 1-2 weeks with sun avoidance, while dermatomyositis lesions may persist longer.
- Systemic Symptoms: Polymorphous light eruption does not present with systemic symptoms, whereas dermatomyositis may have associated systemic findings.
