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Polymyositis Treatment & Management

  • Author: Ramesh Pappu, MD, DPH, MBBS; Chief Editor: Herbert S Diamond, MD  more...
 
Updated: Nov 06, 2015
 

Approach Considerations

Treatment of polymyositis (PM) is empirical because of the rarity of the disease and the paucity of randomized, controlled trials.

Corticosteroids

Prednisone is the first-line treatment of choice for polymyositis. Typically, the dose is 1 mg/kg/day, either as a single or divided dose. This high dose is usually continued for 4-8 weeks, until the creatine kinase (CK) level returns to reference ranges. Taper prednisone by 5-10 mg on a monthly basis until the lowest dose that controls the disease is reached.

Monitor response to therapy based on improvement in muscle strength and muscle endurance and decrease in CK levels. Closely monitor patients with polymyositis for disease activity and adverse effects of corticosteroids, such as weight gain, hypertension, osteopenia, and steroid myopathy.

Corticosteroid myopathy can occur during the course of treatment and must be distinguished from reactivation of muscle disease. CK level is usually within reference ranges in patients with steroid myopathy. No improvement is observed with raised doses of steroids, and the condition worsens if the dose is increased.

Immunosuppressants

Immunosuppressive agents are indicated in patients who do not improve with steroids within a reasonable period (ie, 4 wk) or in whom adverse effects from corticosteroids develop. Patients with poor prognostic indicators, such as dysphagia or dysphonia, are likely to require immunosuppressive agents. Under these circumstances, methotrexate is the second-line agent. Patients with inclusion body myositis usually respond poorly to corticosteroids and immunosuppressive agents.

Obtain baseline liver function tests and pulmonary functions before initiating immunosuppressive therapy. Azathioprine, cyclophosphamide, chlorambucil, and cyclosporine have been used with varying success as second-line agents for polymyositis.

Other agents

Intravenous immunoglobulin (IVIG) has been used for the short-term treatment of steroid-resistant cases of polymyositis.[13, 14]

The role of newer agents, such as tumor necrosis factor (TNF) inhibitors, remains unclear. Case reports describe successful use of the TNF inhibitor infliximab in refractory cases, but small clinical trials have yielded mixed results, with clinical flares occurring in some patients.[15, 16, 17, 18] A small trial of the TNF inhibitor etanercept provided encouraging results.[17]

The anti-CD20 monoclonal antibody rituximab may be a new approach to therapy for refractory cases. The benefit of rituximab was demonstrated in the Rituximab in Myositis (RIM) study, the largest randomized trial ever completed in myositis. RIM included 200 patients with polymyositis, dermatomyositis, or juvenile dermatomyositis not controlled by corticosteroids and other immunosuppressive agents.[19]

The study had a placebo phase design in which half the patients received two rituximab infusions at baseline, whereas the other half received rituximab 8 weeks later. At a median of approximately 20 weeks, 83% of study subjects receiving rituximab met the International Myositis Assessment and Clinical Studies Group preliminary definition of improvement. Whether rituximab was received early or late made no significant difference in the time to achieve the definition of improvement.[19]

The calcineurin inhibitor tacrolimus appears to be effective, safe, and well tolerated in patients with polymyositis that is refractory to other treatments. In a systematic review, CK levels patients decreased in all patients treated with tacrolimus, the average glucocorticoid dosage was reduced from 33.8 to 11.5 mg/day, and the majoriy of patients showed improvement in muscle strength and physical function status. However, randomized, controlled trials of tacrolimus in poymyositis have yet to be conducted.[4]

Diet

Patients with polymyositis may benefit from a high-protein diet. Monitor patients to avoid excessive weight gain due to corticosteroid use.

Activity

Encourage patients with polymyositis to start a supervised exercise program early in the disease course.[20] During the acute stage of polymyositis, patients may benefit from heat therapy, passive range-of-motion exercises, and splints to avoid contractures.

Once acute inflammation is under control, the rehabilitation program should include active range-of-motion exercises and isometric contractions of the muscle groups. With improvement in muscle strength, patients should perform isotonic exercises with light resistance. Encourage patients to do 15-30 minute sessions of aerobic exercise when the disease is inactive.

Consultations

A neurologist or rheumatologist is the primary consultant. Consultation may also be required with the following specialists:

  • Pulmonary specialists
  • Cardiologists
  • Physical therapists
  • Speech therapists (for swallow evaluation)
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Extramuscular Manifestations of Polymyositis

Treatment of extramuscular manifestations of polymyositis includes the following:

  • Constitutional symptoms, such as fever and fatigue - Usually respond to corticosteroids
  • Articular symptoms of polymyositis - Usually resolve with treatment of the myositis; some patients develop a rheumatoidlike arthropathy, which may require immunosuppressive treatment such as methotrexate
  • Severe interstitial lung disease - May benefit from high-dose steroids and immunosuppressive treatment, especially cyclophosphamide; in a study of 14 patients with dermatomyositis and acute interstitial pneumonia treated with infliximab, Chen et al reported satisfactory relief in the 10 patients given early treatment but treatment failure and death in those treated late [21]
  • Cardiac abnormalities - May respond to corticosteroids; symptomatic arrhythmias require antiarrhythmic therapy, and symptomatic heart block is treated with placement of a pacemaker

Dysphagia secondary to cricopharyngeal involvement in polymyositis/dermatomyositis is a rare manifestation and usually reflects poor prognosis. Dysphagia responds either slowly or poorly to immunosuppressive therapies or high-dose corticosteroids. A large case series indicated that treatment with IVIG can be effective in patients with steroid-resistant esophageal manifestations of polymyositis/dermatomyositis.[22]

Dysphagia may be severe enough to require enteral feeding through a gastrostomy tube or parenteral nutrition.

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Inpatient and Outpatient Care

Inpatient care

Patients with polymyositis should be closely monitored in the hospital while they are taking high-dose corticosteroids. Ideally, skin testing for tuberculosis should be performed before initiation of corticosteroid treatment.

Serial creatine kinase (CK) levels should be monitored to assess improvement. Severe pulmonary or cardiac involvement may require management in an intensive care setting. In patients treated with immunosuppressive agents, regularly monitor CBC, liver function test findings, and renal function. Patients with polymyositis usually need aggressive inpatient physical therapy.

Outpatient care

Patients with polymyositis should be seen every 2-3 weeks initially; if they are stable, they should be seen at monthly intervals thereafter.

Frequently check laboratory tests, including CK, and document muscle strength evaluation results. Check patients' weight during each visit. Routine age-appropriate cancer screening is recommended. Arrange outpatient physical therapy.

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Deterrence and Prevention

The following precautions can aid against complications associated with polymyositis or its treatment:

  • Raynaud phenomenon - Patients with polymyositis should avoid cold exposure if Raynaud phenomenon is a significant problem
  • Esophageal involvement - Patients with esophageal involvement can elevate the head of the bed and avoid eating before bedtime to minimize reflux and risk of aspiration; histamine 2 receptor antagonists, proton pump inhibitors, and/or prokinetic agents may be useful in patients with esophageal reflux and dysmotility.
  • Osteoporosis - Prescribe calcium with vitamin D supplementation and oral bisphosphonates for osteoporosis prophylaxis
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Contributor Information and Disclosures
Author

Ramesh Pappu, MD, DPH, MBBS Adjunct Associate Professor of Medicine, Drexel University College of Medicine

Ramesh Pappu, MD, DPH, MBBS is a member of the following medical societies: American College of Rheumatology, American Association of Physicians of Indian Origin

Disclosure: Nothing to disclose.

Coauthor(s)

Mythili Seetharaman, MD Consultant Rheumatologist, OAA; Clinical Assistant Professor, Thomas Jefferson University Hospital, St Christopher's Hospital for Children

Mythili Seetharaman, MD is a member of the following medical societies: American College of Rheumatology, American Medical Association

Disclosure: Nothing to disclose.

Chief Editor

Herbert S Diamond, MD Visiting Professor of Medicine, Division of Rheumatology, State University of New York Downstate Medical Center; Chairman Emeritus, Department of Internal Medicine, Western Pennsylvania Hospital

Herbert S Diamond, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American College of Rheumatology, American Medical Association, Phi Beta Kappa

Disclosure: Nothing to disclose.

Acknowledgements

Michael S Beeson, MD, MBA, FACEP, Professor of Emergency Medicine, Northeastern Ohio Universities College of Medicine and Pharmacy; Attending Faculty, Akron General Medical Center

Michael S Beeson, MD, MBA, FACEP is a member of the following medical societies: American College of Emergency Physicians, Council of Emergency Medicine Residency Directors, National Association of EMS Physicians, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Thomas H Brannagan III, MD, Associate Professor of Clinical Neurology and Director, Peripheral Neuropathy Center, Columbia University, College of Physicians and Surgeons; Co-Director, EMG Laboratory, New York-Presbyterian Hospital, Columbia Campus, New York

Thomas H Brannagan III, MD is a member of the following medical societies: American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and Peripheral Nerve Society

Disclosure: Nothing to disclose.

Lawrence H Brent, MD, Associate Professor of Medicine, Jefferson Medical College of Thomas Jefferson University; Chair, Program Director, Department of Medicine, Division of Rheumatology, Albert Einstein Medical Center

Lawrence H Brent, MD is a member of the following medical societies: American Association for the Advancement of Science, American Association of Immunologists, American College of Physicians, and American College of Rheumatology

Disclosure: Genentech Honoraria Speaking and teaching; Genentech Grant/research funds Other; Amgen Honoraria Speaking and teaching; Pfizer Honoraria Speaking and teaching; Abbott Immunology Honoraria Speaking and teaching; Takeda Honoraria Speaking and teaching; UCB Speaking and teaching; Omnicare Consulting fee Consulting; Centocor Consulting fee Consulting

Zaineb Daud, MD, Consulting Staff, Department of Neurology, Medical College of Pennsylvania Hahnemann University

Disclosure: None

Gino A Farina, MD, FACEP, FAAEM, Associate Professor of Clinical Emergency Medicine, Albert Einstein College of Medicine; Program Director, Department of Emergency Medicine, Long Island Jewish Medical Center

Gino A Farina, MD, FACEP, FAAEM is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Francisco de Assis Aquino Gondim, MD, MSc, PhD, Associate Professor of Neurology, Department of Neurology and Psychiatry, St Louis University School of Medicine

Francisco de Assis Aquino Gondim, MD, MSc, PhD is a member of the following medical societies: American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and Movement Disorders Society

Disclosure: Nothing to disclose.

Aamir Hashmat, MD, Consulting Staff, Neurology and Neurodiagnostics Lab, Department of Neurology, Jeff Anderson Regional Medical Center

Aamir Hashmat, MD is a member of the following medical societies: American Academy of Neurology, American Epilepsy Society; American Medical Association, AO Foundation

Disclosure: None

Milind J Kothari, DO, Professor and Vice-Chair, Department of Neurology, Pennsylvania State University College of Medicine; Consulting Staff, Department of Neurology, Penn State Milton S Hershey Medical Center

Milind J Kothari, DO is a member of the following medical societies: American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and American Neurological Association

Disclosure: Nothing to disclose.

Kristine M Lohr, MD, MS, Professor, Department of Internal Medicine, Center for the Advancement of Women's Health and Division of Rheumatology, Director, Rheumatology Training Program, University of Kentucky College of Medicine

Kristine M Lohr, MD, MS is a member of the following medical societies: American College of Physicians, American College of Rheumatology, and American Medical Women's Association

Disclosure: Nothing to disclose.

Glenn Lopate, MD, Associate Professor, Department of Neurology, Division of Neuromuscular Diseases, Washington University School of Medicine; Director of Neurology Clinic, St Louis ConnectCare; Consulting Staff, Department of Neurology, Barnes-Jewish Hospital

Glenn Lopate, MD is a member of the following medical societies: American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and Phi Beta Kappa

Disclosure: Nothing to disclose.

Nicholas Lorenzo, MD, Consulting Staff, Neurology Specialists and Consultants

Nicholas Lorenzo, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Neurology

Disclosure: Nothing to disclose.

Henry Rosenkranz, MD, FAAEM, FACEP, Department of Emergency Medicine, Norwood Hospital

Henry Rosenkranz, MD, FAAEM, FACEP is a member of the following medical societies: American Academy of Emergency Medicine and American College of Emergency Physicians

Disclosure: Nothing to disclose.

Erik D Schraga, MD, Staff Physician, Department of Emergency Medicine, Mills-Peninsula Emergency Medical Associates

Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Reference Salary Employment

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MRI of thighs showing increased signal in the quadriceps muscles bilaterally consistent with inflammatory myositis.
Histopathology of polymyositis showing endomysial mononuclear inflammatory infiltrate and muscle fiber necrosis.
Close view of muscle biopsy, showing chronic inflammatory infiltrate consisting of T lymphocytes, especially CD8+ T lymphocytes.
Hematoxylin and eosin frozen section shows polymyositis. Endomysial chronic inflammation is present among intact myofibers, which are remarkable only for increased variability of fiber size. Image courtesy of Roberta J. Seidman, MD.
Hematoxylin and eosin paraffin section shows polymyositis. Patient had dense endomysial inflammation that contains an abundance of plasma cells, which can be observed in patients with chronic polymyositis. Two necrotic myofibers, characterized by dense eosinophilic staining, are observed. Focal fatty infiltration of the muscle is present in the lower left quadrant of the photomicrograph. Image courtesy of Roberta J. Seidman, MD.
Hematoxylin and eosin paraffin section shows polymyositis. Photomicrograph illustrates attack on a nonnecrotic myofiber by autoaggressive T lymphocytes. On the left, the central myofiber is intact. On the right, it is obliterated by a segmental inflammatory attack. If immunohistochemistry were performed, expected findings would include an admixture of CD8 T lymphocytes and macrophages in the inflammatory process. Image courtesy of Roberta J. Seidman, MD.
Hematoxylin and eosin paraffin shows dermatomyositis. In dermatomyositis, inflammation is characteristically perivascular and perimysial. Vessel oriented approximately vertically in the center has a mild perivascular chronic inflammatory infiltrate. The endothelium is plump. The wall is not necrotic. A few lymphocytes in the wall of the vessel are probably in transit from the lumen to the external aspect of the vessel. Some observers may interpret this finding as vasculitis, but it is certainly neither necrotizing vasculitis nor arteritis. Image courtesy of Roberta J. Seidman, MD.
Hematoxylin and eosin paraffin section shows polymyositis. Longitudinal section shows a dense, chronic, endomysial inflammatory infiltrate. Image courtesy of Roberta J. Seidman, MD.
 
 
 
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