O.P. Sharma, M.D.
Professor of Medicine, LAC & USC Medical Center
Dr. Sharma and Sarcoidosis
Sarcoidosis: A Multisystem Disease
As Om P. Sharma, M.D., studies the lung X-ray on his wall, a face from another time and place stares intently at him. The face belongs to Jonathan Hutchinson, M.D., captured forever in a 1890 drawing by Leslie Ward, a.k.a. "Spy," who, more than a century ago, created caricatures of famous physicians for the English society magazine, Vanity Fair.
Dr. Sharma, professor of Medicine at the University of Southern California School of Medicine and sarcoidosis specialist, has an extensive collection of "Spy" portraits on display in his office. The caricature of Hutchinson holds a prominent position on his wall. In 1877, this English physician was the first to describe sarcoidosis.
Sarcoidosis, as defined in 1976 by the Seventh International Conference on Sarcoidosis, is a "multisystem granulomatous disorder of unknown etiology, most commonly affecting young adults and presenting most frequently with bilateral hilar Lymphadenopathy, pulmonary infiltration and skin or eye lesions." Three to 5 percent of sarcoidosis cases result in morbidity due to pulmonary fibrosis, cardiac arrhythmias, renal failure, neurological involvement and blindness.
Although most physicians, radiologists, pathologists and immunologists encounter sarcoidosis at some point in their practice, this commonplace disease remains primarily in the pulmonary physician's domain, as 90 percent of sarcoidosis patients have lung involvement. Because sarcoidosis mimics tuberculosis, lymphoma and other diseases, Dr. Sharma often receives requests for second opinions from pulmonary physicians, as well as ophthalmologists and dermatologists, to clarify the diagnosis.
Dr. Sharma became interested in sarcoidosis during his chest medicine residency and cardio-pulmonary fellowship at Albert Einstein Medical College Hospital in New York, where he treated patients with the disease. He continued his work as a Prophit Research Scholar at the Royal College of Physicians in London, and joined USC in 1969, where he began a sarcoidosis clinic at the Los Angeles County/USC Medical Center.
In the United States, the incidence of sarcoidosis is less than 60 per 100,000 population, with African Americans more likely to suffer the ravages of the disease than whites. Since its opening, the USC clinic has treated many patients within this population, becoming one of the largest centers of its kind in the country.
"At the moment, our faculty, Fellows and researchers follow about 400 patients with sarcoidosis," Dr. Sharma says. He has published original studies dealing with clinical, radiologic, immunologic, physiologic and biochemical aspects of the disease based on his experience with these patients. The disease occurs all over the world. In fact, sarcoidosis appears most prominently in Scandinavian countries, with an incidence rate of 600 per 100,000 population. Japan also has a high incidence rate, yet these patients, for unknown reasons, contract a milder form of the disease.
The exact incidence rate in the United States is difficult to measure because half of the sarcoidosis patient population never experiences symptoms, with the abnormality only appearing in chest X-rays. "Subsequently, we have overlooked many sarcoidosis patients in the United States. The Japanese, on the other hand, begin taking chest X-rays as young children and continue to do so for many years, thus with that population we obtain a more accurate incidence rate of the disease."
In eight out of 10 patients, sarcoidosis symptoms will subside by themselves in approximately 12 to 18 months. With other patients, corticosteroids have proven beneficial in treating pulmonary sarcoidosis, as have chloroquine, immunosuppressive drugs, oxyphenbutazone and levamisole. However, if the disease progresses without treatment, the patient's lungs may be destroyed, resulting in cor pulmonale or failure of the right side of the heart. Dr. Sharma notes that patients whose lungs have been destroyed are excellent candidates for lung transplantation because 60 to 70 percent of sarcoidosis victims are between 20 and 40 years old.
He adds that many of his patients with sarcoidosis also suffer calcium metabolism abnormalities due to elevated levels of blood calcium. "In 10 to 13 percent of sarcoidosis patients, this blood calcium is increased, which, if not treated, gets deposited in various organs, including the kidneys. Kidney failure can develop, and the patients may die if the calcium level is not brought down." Dr. Sharma has linked this disorder to a vitamin D metabolite produced by macrophages, which causes increased absorption of calcium from the intestine, and raised serum calcium.
In addition, Dr. Sharma is conducting HL-A testing in sarcoidosis to study genetic susceptibility. The disease tends not to run in families; but, in families where sarcoidosis has occurred, the disease appears among siblings rather than siblings and parents. This indicates that sarcoidosis may be caused by environmental factors.
In a related project, Dr. Sharma and physicians from universities in Kyoto and London have begun an international study into the epidemiology of sarcoidosis to determine if, on the assumption sarcoidosis is viral, there exist environmental or cultural factors that may induce the transference of the disease.
Dr. Sharma conducts weekly sarcoidosis clinics in the USC Healthcare Consultation Center and at LAC-USC Medical Center, both in Los Angeles, that attract patients from all over the world, including Japan, India, and Middle Eastern, European and South American countries.
A prolific author, Dr. Sharma has published over 450 papers, two books on sarcoidosis and one book on general pulmonary disorders. "Our large numbers of patients provide us with a tremendous opportunity to study the course of sarcoidosis and the effects of various treatments." He has just finished writing a book on Hypersensitivity Pneumonitis, a group of lung diseases caused by inhalation of organic dust particles.
He also has presented numerous papers on his other professional interest, the history of medicine, to the Osler Club of London, the London Harveian Society, the American Osler Society, the Cedars-Sinai Medical History Society, and the Friends of the Norris Medical Library.
In addition, Dr. Sharma serves as associate editor of Lung India and Sarcoidosis: International Review of Sarcoidosis and Other Granulomatous Disorders. He has sat on the editorial board of Chest and on the editorial board of Asian Pacific Journal of Allergy and Immunology.
