Polymyositis Dermatomyositis

MYOSITISZia ul HaqJawad Munir

Definition

Sabacute or slowly progressive, symmetrical weakness primarily affecting the proximal limb and trunk muscles.

Classification of Myositis

Polymyositis DermatomyositisPoly/Dermato-myositis associated with

MalignancyPoly/Dermato-myositis associated with

Connective Tissue DiseaseInclusion Body myositisAmyopathic Dermatomyositis

EPIDEMIOLOGY

Annual Incidence: 2-10 case /millionPeak age : 10-15 and 45-55 years old

Female: Male ratio: 3:1 total Black: White : 4:1

CLINICAL MANIFESTATIONS

Weakness of muscles -shoulder girdle - pelvic girdle - neck flexorsMyalgia is minimal

Constitutional symptoms-fatigue, fever, weight loss

CLINICAL MANIFESTATIONS

Rheumatic: Arthralgia/Arthritis 20-70%

Pulmonary: Interstitial Lung Disease 10%

GIT: Esophageal Dysmotility 10-30%Cardiac: Conduction Blocks and

ArrhythmiaVascular: Raynaud’s Phenomenon 20-

40%Skin : Rash, Livedo Reticularis

Myositis-PROGNOSIS

5-YEAR SURVIVAL IS AROUND 85% IN PM, DM, PM/DM ASSOC. CTD.

MUCH LOWER IN PM/DM ASSOC. MALIGNANCY.

Polymyositis

A persistent inflammatory muscle disease that causes weakness of the skeletal muscles, which control movement.

Medically, polymyositis is classified as a chronic inflammatory myopathy — one of only three such diseases.

Polymyositis

Can occur at any age, Adults -30s, 40s or 50s. BlacksWomen

Polymyositis

signs and symptoms usually develop gradually,over weeks or months.

Remissions - rare

Remissions: periods during which symptoms spontaneously disappear

Signs and symptoms

appear gradually,Progressive muscle weakness Difficulty swallowing (dysphagia) Difficulty speakingMild joint or muscle tenderness FatigueShortness of breath

Signs and symptoms

affects the muscles closest to the trunk, particularly hips, thighs, shoulders, upper arms and neck.

weakness is symmetricalworsens over time.As muscle weakness progresses,

difficult to climb stairs, rise from a seated position, liftobjects or reach overhead.

Complications

DysphagiaWhich in turn may cause weight loss and malnutrition.

Aspiration pneumoniaShortness of breath or respiratory failure.

CalcinosisCalcium deposits in muscles, skin and connective tissues

Associated conditions

Polymyositis is often associated with other conditions that may cause further complications of their own, or in combination with polymyositis symptoms. Associated conditions include:Raynaud's phenomenon.

Other connective tissue diseases. Cardiovascular disease.Lung disease.

DIAGNOSTIC CRITERIA

1 .PROXIMAL MOTOR WEAKNESS: symmetric, proximal muscles

2 .HIGH SERUM MUSCLE ENZYMES: CPK, aldolase, myoglobin, AST,

ALT, LDH

DIAGNOSTIC CRITERIA

3 .EDT= electro-diagnostic tests

NEUROPATHIC DISORDER PM/DM

-Poly-phasic action potentials

-long duration-large amplitude

-Poly-phasic action potentials

-short duration-low amplitude

EMG

abnormal normal NCV

DIAGNOSTIC CRITERIA

4 .MUSCLE BIOPSY: biopsy a clinically weak muscle, contralateral to an

abnormal muscle ( by EDT), MRI directed.

a. Perivascular and endomysial inflammationCD8+ T cells in PM,

CD8+, CD4+ T and B cells in DM

.bb. Muscle fiber necrosis and regeneration

LABORATORY TESTS

HIGH MUSCLE ENZYMES:- CPKELEVATED ESR , CRP:- 50%POSITIVE ANA:- 50-80%

AUTOANTIBODIES-: anti- RNP (MCTD)

anti-PM/Scl (OVERLAP)

Myositis-specific AUTOANTIBODIES

ANTI Jo-1 part of ANTI SYNTHETASE Ab’s Antibodies to the antigen- Aminoacyl-tRNA synthetase, in 20-50% of PM>>DM ANTI SRP = anti signal recognition particleIn 5% of PM

ANTI Mi-2 in 10% of DM .

Treatment

1 .STEROIDS 2 .IMMUNOSUPPRESSIVE AGENTS:

methotrexate, azathioprine, cytoxan, cellcept3 .IMMUNOMODULATORY AGENTS:

IVIG, Plasmapheresis4 .REHABILITATION

Cytokines in Inflammation

Pro-inflammatory Anti-inflammatory

TNFaIL-1b

sTNFRIL-10

IL-1Ra

Macrophage or Activated T Cell

Soluble TNFa

Target Cell

TNFa Receptor

Signal Induction

Synthesis and Function of TNFa

Transmembrane TNFa

Receptor-Bound TNFa

Adapted with permission from Choy EHS, Panayi GS. N Engl J Med. 2001;344:907-916.Copyright © 2001 Massachusetts Medical Society. All rights reserved.

Inhibition of Cytokines

Inflammatory cytokine

Normal interaction Neutralization of cytokines

Receptor blockadeActivation of

anti-inflammatory pathways

Cytokine receptor

Soluble receptor

Monoclonal antibody

Monoclonal antibody

Receptor antagonist

Anti-inflammatorycytokine

Suppression ofinflammatorycytokines

No signal

No signal

Inflammatory signal

Humira- The first fully human antiTNFa

Chimeric Antibody

70% Human

Humanized Antibody

95% Human

Fully Human Antibody

100% HumanMouse

Human

Chimeric Humanized Fully Human

24

Treatment

corticosteroidWhen muscle strength improves, usually in 4 to 6weeks, the medication is slowly tapered off.Maintenance therapy with prednisone may becontinued indefinitely.

DMARDs - If unresponsive to corticosteroids

methotrexate and azathioprine,

Treatment

Intravenous gamma globulinIVIGis a purified blood product that contains healthy antibodies from thousands of blood donors.

The healthy antibodies in IVIG can block the damaging antibodies that attack muscle in polymyositis.

Repeat infusions q 6-8 weeks

Other immunosuppressivemedicine

Tacrolimus (Prograf)is a transplant-rejection drug that may work to inhibitthe immune system.

Immunosuppressants,cyclophosphamide (Cytoxan) and cyclosporine

)Gengraf, Neoral, Sandimmune,(

Biological therapies

Rituximab (Rituxan)Tumor necrosis factor (TNF) inhibitorsetanercept (Enbrel) and infliximab (Remicade),

Nursing management

Coping and support Educate about the illness Balance Rest and exercise

Myositis associated with skin diseases

Dermatomyositis

Dermatomyositis

a muscle disease characterized by inflammation and a skin rash. It is a type of inflammatory myopathy.

5 - 15 and adults age 40 - 60.Women

Polymyositis is a similar condition, but the symptoms occur without a skin rash.

Maria Carmela L. Domocmat, RN, MSN

Symptoms

DysphagiaMuscle weakness, stiffness, or soreness Purple or violet colored upper eyelids Purple-red skin (violaceous) rashSOB


Symptoms

The muscle weakness may appear suddenly or develop slowly over weeks or months. may have difficulty raising arms over head, rising from a sitting position, and climbing stairs.The rash may appear over the face, knuckles, neck,shoulders, upper chest, and back.


reddish-purple (violaceous) rash

reddish-purple(violaceous) rash.The rash is named after the tendency of plants to grow toward the sun (heliotropic) and is characteristic of dermatomyositis.


purple (violaceous) plaques

The appearance of purple (violaceous) plaques on the knees may be associated with dermatomyositis.


Gottron's sign

Red, thickened, scaly skin over the knuckles


Heliotrope eyelids

eyelids develop a brown (violaceous - rather than red) color.Heliotrope eyelids and Gottron's papules on the knuckles are characteristic findings in dermatomyositis.


violet-colored inflammation (erythema) over theknuckles


periungual erythema

Candida paronychia produced periungualerythema, edema and nail fold maceration.


Dx Exams

CPK & aldolaseECGElectromyographyMagnetic resonance imaging (MRI) Muscle biopsy


Treatment

CorticosteroidsImmunosuppressantsWhen muscle strength gets better – taper off corticosHowever, most people take prednisoneindefinitely.If the condition is associated with a tumor, the muscle weakness and rash may improve when the tumor is removed.


Outlook (Prognosis)

Some recover and have symptoms completelydisappear - especially in children.

In adults, death may result from severe and prolonged muscle weakness,

malnutrition, pneumonia, or lung failure. The major causes of death are cancer (malignancy) and lung disease.


Possible Complications

Acute renal failure Cancer (malignancy) Inflammation of the heart Joint painLung disease


DIFFERENTIAL DIAGNOSIS

-MYOPATHY- DRUG/TOXIN-NEURO-MUSCULAR-ENDOCRINE DISEASE-INFECTIOUS MYOSITIS-METABOLIC STORAGE MYOPATHIES -MITOCHONDRIAL MYOPATHY-OTHERS

ANTI-SYNTHETASE SYNDROME

associated with anti-Jo1 antibodies with acute onset of PM>> DM disease.

Associated with ILD -40-60%, deforming and non-erosive arthritis, Mechanic’s hands and Raynaud’s phenomenon

Steroid response

prognosis HLA Clinical association

prevalence Ab’s

moderate moderate DR3 Anti-synthetase syndrome

20-50%)PM(

Anti-Jo-1

poor bad)cardiac(

DR5 Severe PM 5%)PM(

Anti-SRP

good good DR7 Classical DM

5-10%)DM(

Anti-Mi-2

Myositis-specific AUTOANTIBODIES

Poly/Dermato-myositis associated with malignancy

Associated neoplasms present within the first 2 years of PM/DM followup

In PM- 10 %In DM- 15 %Reports of: carcinoma-lung, stomach,

ovary lymphomaRoutine screening in DM

Health & Medicine

Polymyositis Dermatomyositis