Polymyositis

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Polymyositis Classification and external resources
ICD-10	M33.2
ICD-9	710.4
DiseasesDB	10343
MedlinePlus	000428
eMedicine	med/3441  emerg/474
MeSH	D017285

Polymyositis is a type of inflammatory myopathy, related to dermatomyositis and inclusion body myositis. Polymyositis means 'many muscle inflammation'.

Contents 1 Presentation 2 Causes 3 Diagnosis 4 References

[edit] Presentation

Polymyositis tends to become evident in adulthood, presenting with bilateral proximal muscle weakness, often noted in the upper legs due to early fatigue while walking. Sometimes the weakness presents itself by the person being unable to rise from a seated position without help, or inability to raise their arms above their head. The weakness is generally progressive, accompanied by lymphocytic inflammation (mainly cytotoxic T8 lymphocytes).

Polymyositis, like dermatomyositis, strikes females with greater frequency than males. The skin involvement of dermatomyositis is absent in polymyositis.

[edit] Causes

The cause is unknown, but seems to be related to autoimmune factors,^[1] genetics, and perhaps viruses. In rare cases, the cause is known to be infectious, associated with the pathogens that cause Lyme disease, toxoplasmosis, and others.

[edit] Diagnosis

Diagnosis is fourfold, including elevation of creatine kinase, signs and symptoms, electromyograph (EMG) alteration, and a positive muscle biopsy. Treatment generally involves glucocorticoids, especially prednisone. At present, a number of studies are underway to determine whether patients diagnosed with polymyositis will benefit from newer drugs inhibiting the biologic effects of TNF alpha, such as infliximab.

Sporadic inclusion body myositis (sIBM): IBM is often confused with (misdiagnosed as) polymyositis and polymyositis that does not respond to treatment is likely IBM. sIBM comes on over months to years, polymyositis comes on over weeks to months. It appears that sIBM and polymyositis share some common features, especially the initial sequence of immune system activation, however, polymyositis does not display the subsequent muscle degeneration and protein abnormalities as seen in IBM. As well, polymyositis tends to respond well to treatments, IBM does not. IBM and polymyositis apparently involve different disease mechanisms than are seen in dermatomyositis.

[edit] References

1. ^ Polymyositis and Dermatomyositis: Autoimmune Disorders of Connective Tissue: Merck Manual Home Edition.

• The Myositis Association [1]

• Kasper DL, Braunwald E, Fauci AS, Hauser SL, Longo DL, Jameson JL. Harrison's Principles of Internal Medicine. New York: McGraw-Hill, 2005. ISBN 0-07-139140-1

v • d • e Diseases of the musculoskeletal system and connective tissue (M, 710-739) Arthropathies Arthritis (Septic arthritis, Reactive arthritis, Rheumatoid arthritis, Psoriatic arthritis, Felty's syndrome, Juvenile idiopathic arthritis, Still's disease) - crystal (Gout, Chondrocalcinosis) - Osteoarthritis (Heberden's node, Bouchard's nodes) acquired deformities of fingers and toes (Boutonniere deformity, Bunion, Hallux rigidus, Hallux varus, Hammer toe, Swan neck deformity) - other acquired deformities of limbs (Valgus deformity, Varus deformity, Wrist drop, Foot drop, Flat feet, Club foot, Unequal leg length, Winged scapula) patella (Luxating patella, Chondromalacia patellae) Protrusio acetabuli - Hemarthrosis - Arthralgia - Osteophyte Systemic CT disorders vasculitis: Churg-Strauss syndrome - Kawasaki disease - Hypersensitivity vasculitis - Wegener's granulomatosis - Arteritis (Polyarteritis nodosa, Takayasu's arteritis, Temporal arteritis) immune/autoimmune: Goodpasture's syndrome - Microscopic polyangiitis - Systemic lupus erythematosus (Drug-induced) - Dermatomyositis (Juvenile dermatomyositis) - Polymyositis - Scleroderma - Sjögren's syndrome - Behçet's disease - Polymyalgia rheumatica - Eosinophilic fasciitis Hypermobility Dorsopathies spinal curvature (Kyphosis, Lordosis, Scoliosis) - Scheuermann's disease - Spondylolysis - Torticollis - Spondylolisthesis Spondylopathies (Ankylosing spondylitis, Spondylosis, Spinal stenosis) - Schmorl's nodes - Degenerative disc disease - Coccydynia - Back pain (Radiculopathy, Neck pain, Sciatica, Low back pain) Soft tissue disorders muscle: Myositis (Pyomyositis) - Myositis ossificans (Fibrodysplasia ossificans progressiva) synovium and tendon: Synovitis/Tenosynovitis (Calcific tendinitis, Stenosing tenosynovitis, Trigger finger, DeQuervain's syndrome) - Irritable hip - Ganglion cyst bursa: bursitis (Olecranon, Prepatellar, Trochanteric) - Baker's cyst fibroblastic disorders: Dupuytren's contracture - Fasciitis (Plantar fasciitis, Nodular fasciitis, Necrotizing fasciitis) - Fibromatosis shoulder lesions: Adhesive capsulitis - Rotator cuff tear - Subacromial bursitis enthesis: enthesopathies (Iliotibial band syndrome, Achilles tendinitis, Patellar tendinitis, Golfer's elbow, Tennis elbow, Metatarsalgia, Bone spur, Tendinitis) other, NEC: Muscle weakness - Rheumatism - Myalgia - Neuralgia - Neuritis - Panniculitis - Fibromyalgia Osteopathies disorders of bone density and structure: Osteoporosis - Osteomalacia - continuity of bone (Pseudarthrosis, Stress fracture) - Monostotic fibrous dysplasia - Skeletal fluorosis - Aneurysmal bone cyst - Hyperostosis - Osteosclerosis Osteomyelitis - Avascular necrosis - Paget's disease of bone - Algoneurodystrophy - Osteolysis - Infantile cortical hyperostosis Chondropathies Juvenile osteochondrosis (Legg-Calvé-Perthes syndrome, Osgood-Schlatter disease, Köhler disease, Sever's disease) - Osteochondritis - Tietze's syndrome - Relapsing polychondritis See also congenital conditions (Q65-Q79, 754-756)