1. Poly myositis and dermatomyositis
Are acquired . chronic , inflammatory muscle condition of unknown cause
-Age : most cases are in 5th and 6th decades of life.
-Incidence:0.5 per 100,000 population
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2. Polymyositis (PM) and dermatomyositis (DM)
-adult polymyositis
-adult dermatomyositis
-adult polymyositis, dermatomyositis with malignancies
-PM/DM in association with other connective tissue diseases
-childhood DM.
-inclusion body myositis
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3. -Mascular weakness is the dominant feature of myositis syndromes
-Symmetryical
-Proximal muscle of extremities,trunk and neck
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4. -Lower extremities characterized by .An inability to climb stairs
.To arise from low seat
.Walking may be limited and gait may become poorly coordinated and waddling
-Upper extremities
.Limits lifting
.Handing up clothes and combing the hair
-Weakness of the anterior neck flexor muscles interferes with lifting the head from the supine position and arising from bed become difficult
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5. Adult polymysitis (PM)
- Women: men :1
The onset can be insidious, over month’s, but can be acute
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6. -Malaise- weight loss and fever can develop during the acute phase
-The major feature of PM is proximal muscle weakness which is progressive
-There is wasting of the shoulder and pelvic girdle muscles with weakness
-Pain and tenderness are uncommon
-Patients have difficulty squatting going upstairs, raising from a chair raising their hands above the head and holding their head up.
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7. -Interstitial lung fibrosis -Arthrlgia 50% -Raynaud’s phenomenon
-Involvement of pharyngeal, laryngeal and respiratory muscles can lead to dysphagia , dysphonia and respiratory failure.
-Interstitial lung fibrosis
-Arthrlgia 50%
-Raynaud’s phenomenon
-cardiac abnormalities (heart block ,myocarditis,congestive heart failure)
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8. Adult dermatomyositis
-more in women
-heliotrope rash and perorbital oedema
-gottron rash
-ulcerative vascuilitis
-subcutaneous calcinosis 25%
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9. Dermatomyositis: heliotrope rash
The face of this patient demonstrates bilateral heliotrope lids, mainly involving the upper lids with mild involvement of the left lower lid. Erythema is also present over both malar areas and cheeks. #
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10. Dermatomyositis: diffuse facial erythema
Diffuse, patchy erythema over the forehead, bridge of the nose, malar areas, and chin is present in this patient. This type of rash, which is frequently photosensitive, is commonly seen in patients with dermatomyositis. #
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11. Dermatomyositis: rash, chest
This woman has acute-onset dermatomyositis. An erythematous eruption is prominent in a mantle distribution over light-exposed areas. Telangiectasias are present. Marked inflammatory changes have caused a breakdown in the skin in several areas. Not shown are similar involvement of the face and a typical heliotrope discoloration around the eyes. #
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12. Dermatomyositis: edema and rash, hand
This child's hand shows the skin changes of dermatomyositis. Erythematous flat papules may appear over metacarpophalangeal and proximal interphalangeal joints. The lesions are symmetric and overlie the small joints of the hand. A diffuse puffiness of the hand is present. #
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13. Dermatomyositis: erythematous lesions, hands
Erythematous and slightly scaly lesions are present over the metacarpophalangeal joints of both hands. #
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14. Dermatomyosistis: rash, hands
Dermatomyositis: rash, hands
Typical late cutaneous involvement is seen on the extensor aspect of the joints. The lesions are reddish-white, shiny, slightly scaly, and atrophic. #
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15. Dermatomyositis: “mechanic’s hands”
Cracking of the finger pad skin, commonly involving the first, second, and third fingers, is demonstrated in this patient with dermatomyositis.
Miller FW. Myositis-specific autoantibodies: touchstones for understanding the inflammatory myopathies. JAMA 1993;270: #
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16. Dermatomyosistis: periungual involvement
Dermatomyositis: periungual involvement
Abnormally prominent nailfold capillaries and hemorrhage are present in a patient with dermatomyositis. These vascular changes are essentially indistinguishable from those of systemic lupus erythematosus and scleroderma. #
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17. Dermatomyositis: rash, knees
A typical scaly erythematous rash involves the extensor surfaces of both knees in this child with dermatomyositis. A violaceous discoloration can also be observed in these lesions. The skin of the lower legs is dark, slightly reddened, and thickened, which indicates more widespread involvement. #
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18. Dermatomyositis: subcutaneous calcification, knees
This child with dermatomyositis has moderately severe calcinosis of the soft tissues around the knees. These calcific nodules are discrete, in contrast to the "plate-like" sheets occasionally seen. The nodule of calcium on the left knee is about to erupt and may become infected. The reflecting points of light on the medial aspects of both knees represent calcium deposits that have already extruded. #
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19. Dermatomyositis: calcinosis, thigh (radiograph)
There is extensive calcification in several planes including subcutaneous tissue, fascia, and muscle. In some instances, the skin may show calcification. In scleroderma the calcification usually would not be within the muscle proper. These calcifications are amorphous, contrasting with the trabecular calcification of myositis ossificans. #
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20. Associated with malignancies
-The associated cancer may not become apparent for 2-3 years.
-Recurrent or refractory dermatomyositis should prompt a search for occult malignancy
-Lung, ovary, breast, stomach cancer can predate the onset of myositis particularly in males with dematomyositis
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21. Childhood dermatomyositis
-Age : 4-10 years
-Subcutaneous calcification maybe widespread and severe
-Recurrent abdominal pain due to vascuilitis
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22. Inclusion Body Myositis
General Features
Most common acquired muscle disease over the age of 50
Prevalence of 5-10/million
Affects men > women at 2-3:1
Average time from symptom onset to diagnosis is ~ 6 years
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23. Clinical Features of IBM
• Consider IBM when confronted with refractory
polymyositis patient
• Insidious onset of painless muscle weakness with slow progression
• Tendency to distal (away from the trunk muscles) and asymmetric muscle involvement (“foot drop”)
• Difficulty swallowing
• Characteristic pattern of muscle atrophy (forearm
flexors, muscles of hands, thigh)
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24. Inclusion body myositis
Males affected more than females
Age of onset usually greater than 50
Slowly progressive
Distal and asymmetric muscle weakness
Myopathic and neuropathic changes on EMG
Mononuclear cell infiltrates and vacuoles containing amyloid on
muscle biopsy
Responds poorly to corticosteroids
Inclusion body myositis #
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25. Polymyositis: differential diagnosis
Polymyositis and dermatomyositis
Hypothyroidism
Drug-induced myopathies
Corticosteroids, colchicine, HMG-CoA reductase inhibitors, zidovudine, hydroxychloroquine, alcohol
Infections
Viral, toxoplasmosis, trichinosis, bacterial pyomyositis
Connective tissue disorders
Lupus, scleroderma, MCTD
Systemic vasculitis
PAN, Wegener’s granulomatosis
Polymyositis: differential diagnosis #
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26. Polymyositis: differential diagnosis, cont’d
Metabolic myopathies
Disorders of carbohydrate and lipid metabolism
Electrolyte disturbances
Hypernatremia, hyponatremia, hypokalemia, hypophosphatemia,
hypocalcemia
Inclusion body myositis
Sarcoid myopathy
Amyloid myopathy
Neurologic disorders
Myasthenia gravis, motor neuron disease, muscular dystrophy
Polymyositis: differential diagnosis, cont’d #
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29. Neurological disease -Asymmetrical weakness
-distal extremety inovlvement
-altered sesorium or abnormal cranialnerve function
-myopathies cause proximal and symmetrical weakness except
(IBM, Mitochondrial myopathies, antiSRP antibody)
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30. -Limb-girdle dystrophy positive family history
upper and lower extremity proximal muscle weakness may begin in the first through third decades of life.
muscle wasting
-Duchenn`es musclar dystrophy
The age of 5 years
Muscle weakness and wasting
Hyperlordotic gait
Psuedo hypertrophy of the calf muscle
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31. -Becker`s muscular dystrophy Similar but milder
Patient able to walk beyond the age 16
-Facioscapulo humeral
Autosomal dominant
Weakness begin in the facial muscle
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35. Don’t Forget
Patients with hypothyroidism can present with diffuse and nonspecific arthralgias and myalgias. CKs may be elevated
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37. Think About Toxic Drug Reactions That Can Cause Musculoskeletal Pain
Hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor
Zidovudine (AZT)
Ethanol
Clofibrate
Cyclosporin A
Penicillamine
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38. Soft-Tissue Pain Syndromes: Fibromyalgia
Widespread musculoskeletal pain
Decreased pain threshold and tolerance
May have tenderness in specific regions (tender points)
Associated fatigue, sleep, somatic complaints
No objective inflammation seen on physical examination
Normal laboratory findings
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40. Common Causes of Proximal Muscle Weakness With Elevated CK
Inflammatory myositis
Noninflammatory myopathies Hypothyroidism
Hypokalemia
Alcoholism
Drugs
AZT
HMG-CoA reductase inhibitors (the “statins”)
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41. Myositis-specific antibodies
ANTIBODY
DISEASE ASSOCIATION
PREVALENCE
Anti-tRNA synthetases (Jo-1)
Dermatomyositis, interstitial lung disease, “mechanic’s hands”
20%
Anti-SRP (signal recognition protein)
African-American women, poor prognosis
Rare
Anti-Mi-2
Older women, “shawl sign,” good prognosis 5%
PM/SCL
Polymyositis/scleroderma overlap
Myositis-specific antibodies
Love LA, Leff RL, Fraser DD, et al. A new approach to the classification of idiopathic inflammatory myopathy: Myositis specific antibodies define useful homogeneous patient groups. Medicine 1991; 70:360. #
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42. -screening for malignancy
-EMG
-Needle muscle biopsy
-MRI
-screening for malignancy
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44. Proposed diagnostic criteria for polymyositis and dermatomyositis
PM diagnosed as definite with 4 out of 5 of the below criteria or probable with 3 out of 5
DM diagnosed as definite with rash plus 3 out of 4 of the below criteria or probable with rash plus 2 out of 4 criteria
Symmetric proximal muscle weakness
Elevated muscle enzymes (CPK, aldolase, transaminases, LDH)
Myopathic EMG abnormalities
Typical changes on muscle biopsy
Typical rash of dermatomyositis
Proposed diagnostic criteria for polymyositis and dermatomyositis
Bohan A, Peter JB. Polymyositis and dermatomyositis (first of two parts). N Engl J Med 1975;292: #
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45. Polymyositis/Dermatomyositis
-Therapy
Prednisone 1–2 mg/kg, as initial therapy
Methotrexate or azathioprine is often added
Intravenous immunoglobulin in rapidly progressive or refractory cases
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46. Treatment Options in Myositis
Corticosteroids (prednisone)
Immunosuppressive agents
Methotrexate cyclosporine
Azathioprine cyclophosphamide
leflunomide chlorambucil
mycophenolate mofetil
IVIg
Anti-TNF agents (etanercept, infliximab)
“Biologic” response modifiers
rituximab
Oxandrolone (IBM)
Other (stem cell transplant)
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