Childhood Mimicking Arthritis J Am Board Fam Pract: first published as 10.3122/jabfm.9.1.56 on 1 January 1996. Downloaded from

Michael Needleman, MD

Family physicians frequently care for children included a white cell count of 380011lL, including with vague and varying musculoskeletal com­ a normal differential. A count was plaints. Rarely such complaints represent serious 114,0001IlL, and her sedimentation rate was malignant hematologic processes. Certain clinical 54mmlh. and laboratory clues will help the physician avoid The patient was admitted to the hospital with a delays in making the diagnosis, as occurred in the tentative diagnosis of juvenile rheumatoid arthri­ following case. tis. On consultation, the rheumatologist was im­ mediately suspicious that her problem was an Case Report acute leukemia. A confirmed A 12-year-old girl complained of pain in her right that she had acute lymphoblastic leukemia. upper arm shortly after removal of a cast for a radi­ al fracture. At the initial physical examination she Discussion had some limited range of motion at the shoulder. This case contains distinctive features-disabling Radiographic findings were within normal limits. bone pain and leukopenia-that should alert She was prescribed a nonsteroidal anti-inflamma­ physicians to a nonrheumatic malignant condi­ tory medication and had some initial improve­ tion. 1 Bone pain causing nighttime awakening is a ment. She then returned 1 month later complain­ classic feature of a leukemic process. Leukemic ing of dizziness as well as persistent right arm arthritis occurs in 12 to 65 percent of childhood discomfort. Findings on her physical examination leukemia.2 Classic hematologic findings, such as were unchanged. A complete count at lymphadenopathy and hepatosplenomegaly, are that time showed a white cell count of 32001llL surprisingly present equally in juvenile rheuma­ with 63 percent segmented cells and 37 percent toid arthritis and leukemia.3 . The hemoglobin was 15.3g/dL, and Leukopenia is the most discriminating laboratory the platelet count was 94,00011lL. The patient was feature ofleukemia. In one series all cases of juvenile told that she most likely had a viral illness and was rheumatoid arthritis had leukocytosis, whereas 40 sent home with no additional treatment. percent of leukemic arthritis cases showed a

She returned 4 weeks later unable to move her leukopenia.3 Many other laboratory abnormalities, http://www.jabfm.org/ shoulder. At that time she was referred to an including thrombocytosis and elevated sedimenta­ orthopedist, who thought her disability was more tion rates, are similar in both groups of patients. 3 neurologic in origin. An electromyogram was ob­ A is necessary for a ' tained, the results of which were within normal definitive diagnosis and should be repeated if the limits. The patient was then referred to a pediatric first aspiration proves negative. 1

neurologist, who thought the problem was mus­ on 1 October 2021 by guest. Protected copyright. culoskeletal in origin and recommended further Summary nonsteroidal anti-inflammatory medication. Physicians who take care of children must con­ She improved somewhat only to return to her sider the differential diagnosis of acute leukemia family physician 2 months later with increasing ar­ with any unexplained musculoskeletal symptom. thralgias associated with a painful right knee effusion. A mild leukopenia could be the first laboratory At that time her temperature was 100.2°E She abnormality associated with early symptoms. had a questionable palpable tip and a tender, References swollen, warm knee. Repeat laboratory studies 1. Bradlow A, Barton C. Arthritic presentation of child­ hood leukemia. Postgrad Med J 1991 ;67 :562-4. 2. Evans TI, Nercessian BM, Sanders KM. Leukemic Submitted, revised, 31 August 1995. arthritis. Semin Arthritis Rheum 1994;24:48-56. From the Department of Farnily and Community Medicine, Uni­ 3. Ostrov BE, Goldsmith DP, Athreya BH. Differentia­ versity of Louisville, Louisville, Kentucky. Address reprint requests tion of systemic juvenile rheumatoid arthritis from to l\lichael Needleman, MD, Department of Family and Com­ acute leukemia near the onset of disease. J Pediatr munity Medicine, University of Louisville, Louisville, KY 40292. 1993;122:595-8.

56 JABFP Jan.-Feb.1996 Vol. 9 No.1