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- Polymyositis
- Diagnosis
- Antibodies Anti-Jo-1 associated ILD responds more to steroids than other ILD (scleroderma, RA) Anti-Ku
- Dermatomyositis
- Biopsy
- Scleroderma
- Diffuse type
- Genetics : anti-Scl 70 or anti-topoisomerase I CrEST type
- Anti U1-RNP/nRNP Anti-Ku (see PM) Ddx
- Treatment
AntibodiesMany with (-) Ab’s, but if (+) very specific for autoimmune myositis anti-Jo1 (his-tRNA synthetase) – moderate prognosis 30% of PM, 20% of DM arthritis, interstitial lung disease, fever, Raynaud’s, mechanics hands all patients with Jo-1 are DR52, whites may also have DR3 or DR6
anti-SRP (signal recognition particle) – poor prognosis cardiac (with palpitations), myalgias, mostly blacks / DR5 Anti-Mi-2 – good prognosis 8% PM/DM, 20% of DM classic DM picture / 7, DRW53 Polymyositis Onset usually > 50 yrs Genetics: HLA-DR3, DQA1*0501 (whites and blacks), 0401 (blacks) Mechanism: CD8 T-cell mediated destruction Muscle: inflammatory myopathy Lungs: pulmonary inflammation / mostly CD8, some CD4 Heart: can get cardiomyopathy (even heart block) Diagnosis: clinical, EMG, biopsy Presentation: proximal muscle weakness, up to 30% with esophageal dysphagia, Raynaud’s (30%); eyes are spared; unlike myasthenia gravis; up to 50% will have additional connective tissue disease at same time Diagnosis: electromyography, biopsy (not always conclusive) / often confused with other forms of myopathy Labs: elevated plasma CK ESR may be elevated (but a super-high ESR may hint that something else instead or along with myositis is happening) Antibodies Anti-Jo-1 associated ILD responds more to steroids than other ILD (scleroderma, RA) Anti-Ku SCL/PM overlap (mostly in Japanese) / association with Graves, pulmonary HTN, and RNAP-II Course: less prolonged than muscular dystrophies / mortality usually from aspiration (pharyngeal weakness) Malignancy: risk ~2.0 x (no particular types, usually occur after PM diagnosis) Treatment: high-dose steroids (up to ~100 mg/day IV then PO) / improvement should occur with first few weeks with continued improvement over 3 to 6 months / continue initial dose until strength and CK normalizes for 4-8 weeks / CK can remain elevated due to leaky membranes and strength can remain low with normal CK due to steroid myopathy (i.e. steroid myopathy does not cause elevated CK) / reduce steroids by 10 mg/month, then qod dosing / 90% will improve at least partially / 50-75% will enter remission / can try MTX, azathioprine or even both together after 6 weeks of non-response to steroids / Plaquenil can help with skin manifestations of DM / others like cyclosporin and Cytoxan have been used / IVIG is useful for DM, and is being tried for IBM Dermatomyositis bimodal age peaks [15-20] and [45-55] Mechanism: CD4 T-cell and B-cell mediated destruction / humoral response more important Skin changes without muscle involvement occurs in ~10% of cases Skin/Joints: heliotrope rash on face (Shawl sign) [pic], V-sign, mechanic’s hands, cuticle Changes (capillary engorgement, capillary dropout), periungual telangiectasia [pic], calcinosis [pic] [dermis], Gotron’s papules over finger joints, knuckles, elbows, patella Lungs: can have bad lung disease (usu. w/ anti-Jo1) Vasculitis of the gastrointestinal tract, kidneys, lungs, and eyes can complicate dermatomyositis (but not polymyositis), particularly in children Malignancy: relative risk 6.2 (about 20%, no particular type) / DM often diagnosed after or at same time as cancer, then risk decreases to 1.6 after 5 yrs Biopsy: classically different pattern than PM / ?can it look like SLE Treatment: similar to PM (with exception that IVIG can be particularly useful) / newly diagnosed patients should have basic workup for malignancy Juvenile Dermatomyositis (JDM) ANA negative / disease usually lasts about 2 years / diagnosis often suggested by calcinosis on plain films [pic] Scleroderma more in females Presentation: CREST (60-98%), raynaud’s (20%) [pic], diffuse systemic sclerosis (10%) / cardiovascular, skin, kidney, GI, lungs / fibrosis, infarction may develop rapidly progressing renal disease / malignant hypertension in 1-2 weeks Diffuse type: rapid, early visceral involvement, diffuse skin involvement [dermis] (morphea) ~50% mortality rate at 5 years Lungs: pulmonary fibrosis or primary pulmonary HTN Diagnostic criteria: major - proximal skin thickening / minor – sclerodactyly, digital pitting (ischemia), pulmonary fibrosis (CXR) Early signs: look for drop out capillaries in nail folds Genetics: anti-Scl 70 or anti-topoisomerase I CrEST type: calcinosis, Raynaud’s, esophageal dismotility (loss of smooth muscle may occur anywhere in GI tract), sclerodactyly, telangiectasia (mat and periungual) Labs: schistocytes on peripheral blood smear, ANA (20-30%), RF (20%) SCl-70 (DNA topoisomerase I) 70-80% of diffuse scleroderma Anti-centromere 70-80% CrEST, 25% Raynaud’s Nucleolar antigens 4-8% of scleroderma PM-Scl polymyositis, scleroderma overlap Anti U1-RNP/nRNP Anti-Ku (see PM) Ddx: eosinophilic fasciitis, porphyria cutanea tarda, papular mucinosis (i.e., scleromyxedema), lichen sclerosis et atrophicus, melorheostosis, chronic GVHD, eosinophilia-myalgia syndrome Treatment: ACE inhibitors, Ca blockers (Raynaud’s), metoclopramide, sucralfate, omeprazole (GI problems), cisapride (from Mexico) Prognosis: may survive up to 20 years before succumbing to pulmonary hypertension Download 3.95 Mb. Share with your friends:
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