Environmental Factor, February 2011, National Institute of Environmental Health Sciences
NIEHS clinical researchers highlighted in JAMA
Rider, above, delivered the first half of the NIH presentation that parallels her discussion of the various types of myositis and attendant manifestations throughout the body in the JAMA article. (Photo courtesy of Cure JM [Juvenile Myositis] Foundation)
In his part of the NIH presentation, Miller highlighted the role of ultraviolet exposures and photosensitivity in myositis. (Photo courtesy of Steve McCaw)
NIEHS clinical researchers are promoting a new systematic methodology for treatment of and research into a mysterious and debilitating autoimmune disease thought to be triggered by environmental exposures and genetic polymorphisms. Their review(http://www.ncbi.nlm.nih.gov/pubmed/21224460) , "Deciphering the clinical presentations, pathogenesis, and treatment of the idiopathic inflammatory myopathies," appeared in the Clinician's Corner section of the high-impact Journal of the American Medical Association (JAMA) in January.
The Bethesda-based NIEHS Environmental Autoimmunity Group Principal Investigator and Chief Frederick Miller, M.D., Ph.D., and Deputy Chief Lisa Rider, M.D., present a compelling argument for systematically categorizing heterogeneous myositis syndromes into mutually exclusive and stable phenotypes by using clinical and immune response features of the myositis syndromes.
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"Research suggests that categorizing heterogeneous myositis syndromes into mutually exclusive and stable phenotypes... is useful for predicting clinical signs and symptoms, associated genetic and environmental risk factors, and responses to therapy and prognosis," the authors conclude. "Knowledge of myositis phenotypes should enhance clinicians' ability to recognize and manage these rare disorders."
A rare and mysterious condition
As Rider and Miller explain, "Myositis syndromes are the most common causes of acquired muscle disease in adults, but are still rare disorders.... Epidemiological studies of U.S. populations [however] suggest these disorders are increasing in frequency, perhaps due to environmental influences." Patients with advanced cases of myositis can be so impaired that they are confined to bed or wheelchairs. Some forms can elevate cancer risk two to four times.
Although there is evidence that a handful of genetic polymorphisms and several environmental triggers, such as infectious agents, certain drugs, ultraviolet radiation, and other exposures, are involved in myositis, the causes of these rare conditions remain unknown. According to the authors, the estimated overall prevalence of the condition is 50 to 100 cases per million, and myositis, with its unexplained skin rashes, is often misdiagnosed and undertreated in its early stages, as exemplified by the case presentation which begins the review.
According to the researchers, the need for raising physician awareness of myositis syndromes is pressing, due to the need to exclude a number of mimicking conditions in making the diagnosis. The skin rash common in dermatomyositis, for instance, can easily be confused with other skin conditions, including psoriasis and eczema, and other autoimmune diseases. Patients with polymyositis and inclusion body myositis may present with symptoms almost indistinguishable from a range of muscular dystrophies.
The next step for physicians
Practitioners, who are members of the American Medical Association (AMA) or subscribers to the AMA family of journals, can obtain AMA Physician's Recognition Award(http://www.ama-assn.org/ama/pub/education-careers/continuing-medical-education/physicians-recognition-award-credit-system/full-text-booklet.shtml) Category 1 Credit by reading the article by Rider and Miller and completing a brief online quiz with 60 percent or greater accuracy. These credits can count toward the annual Continuing Medical Education requirements for maintaining a valid license to practice medicine. Annual requirements vary from state to state, ranging from as few as 12 in Alabama to as many as 50 in such states as California, Pennsylvania, and Illinois.
Citation: Rider LG, Miller FW(http://www.ncbi.nlm.nih.gov/pubmed/21224460) . 2011. Deciphering the clinical presentations, pathogenesis, and treatment of the idiopathic inflammatory myopathies. JAMA 305 (2):183-190.