title: Overflow proteinuria as a manifestation of unrecognized polymyositis.
abstract: Polymyositis is a rare and gradually progressive autoimmune disease of skeletal muscle. Two main types of renal involvement have been described: acute tubular necrosis related to rhabdomyolysis and glomerulonephritis. However, cases of overflow proteinuria related to polymyositis have rarely been reported. Herein, we report a case of a 41-year-old male who presented with edema of both lower extremities. Laboratory studies revealed elevated creatine phosphokinase level, hypoalbuminemia, and a moderate amount of proteinuria, although albuminuria was not dominant. Urine electrophoresis showed an abnormally restricted zone in the β-fraction, which suggested overflow proteinuria of non-glomerular origin. Despite intravenous hydration, his serum creatine phosphokinase level did not decrease and his symptoms did not improve. Electromyography showed myopathy, and muscle biopsy revealed findings consistent with polymyositis. After corticosteroid therapy, his creatine phosphokinase level and proteinuria decreased and his clinical symptoms improved. This case demonstrates an atypical presentation of polymyositis manifested by overflow proteinuria.
authors.affiliation: Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Republic of Korea.
authors.forename: Hyun Ho
authors.initials: HH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Republic of Korea.
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Republic of Korea ; Division of Nephrology, Department of Internal Medicine, Incheon St Mary's Hospital, Republic of Korea.
authors.forename: Sung Jun
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Pathology, Incheon St Mary's Hospital, Republic of Korea.
authors.forename: Eun Su
authors.initials: ES
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Republic of Korea ; Division of Nephrology, Department of Internal Medicine, Incheon St Mary's Hospital, Republic of Korea.
authors.forename: Seok Joon
authors.initials: SJ
authors.lastname: Shin
authors.affiliation: Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Republic of Korea ; Division of Rheumatology, Department of Internal Medicine, Incheon St Mary's Hospital, Incheon, Republic of Korea.
authors.forename: Kwi Young
authors.initials: KY
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Republic of Korea ; Division of Rheumatology, Department of Internal Medicine, Incheon St Mary's Hospital, Incheon, Republic of Korea.
authors.forename: Yeon Sik
authors.initials: YS
authors.lastname: Hong
authors.affiliation: Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Republic of Korea ; Division of Nephrology, Department of Internal Medicine, Incheon St Mary's Hospital, Republic of Korea.
authors.forename: Hye Eun
authors.initials: HE
authors.lastname: Yoon
keywords: polymyositis; proteinuria; rhabdomyolysis
references.citation: J Am Soc Nephrol. 2000 Aug;11(8):1553-1561
references.pmid: 10906171
references.citation: Nephrol Dial Transplant. 2005 Oct;20(10):2255-8
references.pmid: 15985512
references.citation: Mod Rheumatol. 2004;14(5):422-3
references.pmid: 17143706
references.citation: Kidney Int. 1996 Feb;49(2):314-26
references.pmid: 8821813
references.citation: Adv Chronic Kidney Dis. 2011 Jul;18(4):243-8
references.pmid: 21782130
references.citation: Medicine (Baltimore). 2014 Jan;93(1):33-41
references.pmid: 24378741
references.citation: Ann N Y Acad Sci. 2010 Jan;1184:134-53
references.pmid: 20146695
references.citation: Intern Emerg Med. 2007 Oct;2(3):210-8
references.pmid: 17909702
references.citation: Clin Dermatol. 1988 Apr-Jun;6(2):76-92
references.pmid: 3293746
references.citation: Arch Intern Med. 1977 Jul;137(7):939-41
references.pmid: 301732
references.citation: Int J Clin Pract. 2005 Feb;59(2):188-93
references.pmid: 15854195
references.citation: N Engl J Med. 1975 Feb 13;292(7):344-7
references.pmid: 1090839
references.citation: Clin Chem. 1989 Aug;35(8):1713-20
references.pmid: 2758641
references.citation: Clin Rheumatol. 2007 May;26(5):792-6
references.pmid: 16541204
references.citation: J Rheumatol. 1996 Apr;23(4):782-3
references.pmid: 8730148
references.citation: Br J Sports Med. 2005 Jan;39(1):e3
references.pmid: 15618327
references.citation: Clin Nephrol. 2008 Sep;70(3):245-50
references.pmid: 18793567