Rheumatic symptoms in childhood leukaemia and lymphoma-a ten-year retrospective study

Background: The initial symptoms of childhood leukaemia and lymphoma are often similar to those of juvenile idiopathic arthritis (JIA). In our study, we analyzed the frequency and characteristics of musculoskeletal complaints as the initial presenting symptoms of newly diagnosed leukaemia and lymphoma patients in the past 10 years in our clinic. Methods: Using the Hungarian Tumour Register, we performed a retrospective analysis of the medical records of 166 new leukaemia and 95 new lymphoma pediatric patients treated from 1999 to 2009 at the 2nd. Dept. of Paediatrics of the Semmelweis University in Budapest. Results: Twenty percent of the leukaemic (33 children) and 2% of the lymphoma patients (2 children) had musculoskeletal symptoms at first presentation. Two-thirds of both groups of patients had other general symptoms like fever and/or fatigue. The hip was the most frequently affected joint (7/33) in the leukaemic patients. Twenty-four percent of all the children had been previously evaluated by an orthopaedist; 12% had visited another rheumatologist prior to diagnosis. Imaging had been done in an unexpectedly low number of patients prior to referral to our unit (radiographs: 16 or 48%, ultrasound: 5 patients or 15%). Radiographs of the affected joints were abnormal in only one case (1/16, 6%). The joint ultrasound was abnormal in only three children of 5 studied (3/5, 60%). Anaemia (26/32, 6%), thrombocytopenia (78%) and LDH elevation (3-4 times the normal count) were frequent in the leukaemic patients. Half of the cases had a normal leukocyte count. The lymphoma group had similar results. Two patients of the leukaemia group received steroid treatment before the final diagnosis. Severe pain out of proportion to physical findings is another clue. Conclusions: Haematologic malignancies must be excluded before initiation of therapy for childhood arthritis among children presenting with musculoskeletal signs and symptoms, particularly in atypical cases. Malignancies are to be suspected when pain is disproportionately severe compared to the physical examination findings, and when anaemia, thrombocytopenia, and an elevated LDH level are present. Diagnosing leukaemia early is important because the use of steroids and immunosuppressive medications may mask and delay its diagnosis. Additionally, pre-treatment of presumed JIA patients with these drugs who eventually are diagnosed to have a malignancy may lead to the malignancy being steroid-resistant and more difficult to treat.