Evaluation of platelet cross-matching in the management of patients refractory to platelet transfusions.

BACKGROUND: Cross-match-compatible platelets are used to support thrombocytopenic patients who are refractory to randomly selected platelets. However, few studies have addressed the efficacy of using this strategy for patients requiring intensive platelet transfusion therapy. The aim of this study was to determine the effectiveness of cross-match-compatible platelets in an unselected group of patients refractory to platelets from random donors. MATERIALS AND METHODS: A total of 406 cross-match-compatible platelet components were administered to 40 evaluable patients who were refractory to random-donor platelets. A solid-phase red cell adherence method was used for platelet cross-matching. The corrected count increment was used to monitor the effectiveness of each platelet transfusion. Multivariate analysis was performed to detect whether any variables could predict the response to transfusion. RESULTS: Statistically significant improvements were found in the mean corrected count increment when comparing cross-match-compatible platelets with randomly selected and incompatible platelets (p<0.001 for each). Compatible platelet transfusions were associated with a good response in 72.9% of cases while incompatible platelets were associated with a poor response in 66.7% of transfusion events (p<0.001). In the presence of clinical factors or alloimmunisation, compatible platelets were associated with good responses in 67.9% and 28.0% respectively vs 100% and 93.3% in their absence (p=0.009, p<0.001). Multivariate analysis revealed that cross-matching and alloimmunisation were the strongest predictors of transfusion response at 1 hour, while ABO compatibility, type of units received, followed by alloimmunisation then clinical factors were predictors at 24 hours. DISCUSSION: Platelet cross-matching using the solid-phase red cell adherence technique is an effective and rapid first-line approach for the management of patients refractory to platelet transfusions.

Nosocomial infections and fever of unknown origin in pediatric hematology/oncology unit: a retrospective annual study.

BACKGROUND: pediatric hematology/oncology patients are faced with an increased risk of nosocomial infections (NIs) that vary in different populations and different institutions with considerable morbidity and mortality. This study was undertaken to assess the frequency and patterns of NIs in 1564 pediatric patients and to determine the prevalence of causative organisms and their antimicrobial sensitivity. METHODS: a retrospective analysis was made in the patients admitted between January 2007 and January 2008 to the pediatric hematoloy/oncology unit of Mansoura University, Egypt. The 1564 patients showed 2084 admissions and 27 092 inpatient days. The Centers for Disease Control and Prevention criteria were used as a standard definition for NI. RESULTS: the overall rate of NIs in all patients and neutropenic patients was 8.6 and 25.3 per 1000 patient-days respectively. The frequent sites of NIs were blood stream (42.7%), the respiratory system (25.3%), the urinary system (22.2%) and the central nervous system (9.8%), whereas nosocomial fever of unknown origin constituted 52.9% of cases. The incidence of NIs was significantly higher during neutropenic days (P<0.001). Gram-positive organisms represented 64.5% of pathogens (Staphylococci 71.5%, Streptococci 16%, and pneumococci 7%), and Gram-negative organisms represented 30% (E. coli 48.6%, Klebsiella 15.7%, Pseudomonas 35.7%, and C. albicans 5.5%). Positive cultures were more frequent in summer (July to September). Susceptibility of isolated organisms was relatively low (cefoperazone/sulbactam 49.9%, amikacin 35.9%, imipenem/cilastin 34.4%, cefoperazone 33.6%, and vancomycin 36.5%). Methicillin-resistant S. aureus, extended spectrum beta lactamase and vancomycin resistant enterococci represented 30%, 45% and 75% of isolated S. aureus, Gram-negative organisms and Enterococci, respectively. CONCLUSIONS: blood stream infection and fever of unknown origin are the most common nosocomial infections in pediatric hematology/oncology patients with a higher risk during neutropenic days. Isolated organisms are multi-drug resistant, predominantly Gram-positive pathogens with a high incidence of methicillin-resistant S. aureus, extended spectrum beta lactamase and vancomycin resistant enterococci organisms.

Low bone mass in children with malignant lymphoma.

The aim of this work was to study the effect of disease process on bone mass and calcium homeo-stasis in children with malignant lymphoma at diagnosis, 3 months after starting chemotherapy, and after 1 year. Evaluation of lumber vertebrae (L2-L4) bone mineral density using dual-energy X-ray absorptiometry and calcium homeostasis parameters and bone turnover biochemical markers (serum osteocalcin and urinary deoxypyridinoline) had been assayed in twenty lymphoma patients at presentation and after treatment. Low bone mass for chronological age was observed in 4 patients (20%) at diagnosis and persisted after 3 months and 1 year. Parathyroid hormone level demonstrated no differences between children with lymphoma at different stages of therapy and controls, while 25(OH) D(3) was significantly lower in lymphoma patients at different stages of therapy as compared to controls (p < .001). Osteocalcin was significantly lower in lymphoma patients at different stages of therapy. Deoxypyridinoline showed only significant higher values after 3 months of therapy compared to controls (p = .01). In conclusion, low bone mass was observed in children with lymphoma and is related to decreased osteoblastic activity and decreased mineralization of bone.

Unbalanced bone turnover in children with beta-thalassemia.

The life expectancy of patients with thalassemia has greatly improved over the last decade as a result of regular transfusions and increased compliance with iron chelation therapy, however, this improvement is often accompanied by a series of serious complications including osteopenia and osteoporosis. The pathogenesis of these skeletal disorders is multifactorial which may be due to hormonal deficiency, compromised nutritional status, bone marrow expansion due to erythroid hyperplasia, increased iron stores or desferrioxamine toxicity. The non invasive assessment of bone turnover has markedly improved with the development of specific and sensitive markers of bone formation. The aim of this work is to assess the value of bone formation markers in patients with beta-thalassemia. To achieve this goal, 36 patients with thalassemia were recruited in this study. There were 20 males (56.6%) and 16 females (44.4%) and their ages ranged from 3 to 18 years. A control group of 20 apparently healthy subjects of matched age and sex was used. The patients were selected from the outpatient clinic and inpatients of the Hematology/Oncology Unit of Mansoura University Children's Hospital (MUCH). The selected subjects were subjected to thorough history taking, clinical examination, radiological evaluation and laboratory investigations in the form of: complete blood count, serum iron, serum ferritin, total iron binding capacity, serum calcium, serum phosphorus and estimation of bone formation markers as alkaline phosphatase and osteocalcin. The results were as follows: serum calcium level was within normal range and showed no statistical significance (p = 0.176) when compared to the control group, while serum phosphorus level was significantly higher in thalassemic patients than the controls (p = 0.002); this may reflect hypoparathyroidism. Analysis of the level of bone formation markers showed serum alkaline phosphatase levels slightly higher in patients than controls but not significant (p = 0.055), and this elevation can be referred to associated liver disease in these patients. On the other hand, osteocalcin level was significantly lower in patients than controls (p = 0.011), and this may be due to osteoblast poisoning by iron overload. In conclusion, thalassemic patients have unbalanced bone turnover between the bone formation and resorption markers and this is evidenced by non significant changes or decreased levels of bone formation markers, while bone resorption is an active process.

Low turnover bone disease in Egyptian children with acute leukemia.

The aim of this work was to study bone turnover markers, calcium homeostasis and bone mineral density (BMD) in children with acute leukemia at diagnosis, after induction chemotherapy, and during maintenance therapy to delineate abnormalities present. After evaluation of L2-L4 BMD using dual-energy X-ray absorptiometry in patients with acute myeloid and lymphoid leukemia at presentation and after treatment, the results were compared to 352 healthy age- and sex-matched Egyptian controls. Calcium homeostasis parameters and bone turnover biochemical markers (serum osteocalcin and urinary deoxypyridinoline) were also assayed and the results were compared to 12 healthy age- and sex-matched controls. Osteopenia was observed at diagnosis and during treatment in patients with acute leukemia. At diagnosis osteopenia was observed in 27 patients (62.8%): 10 (23.3%) had non severe osteopenia and 17 (39.5%) had severe osteopenia. This low BMD persisted in those who were followed up. Parathyroid hormone (PTH) (pg/ml) levels demonstrated non significant differences between children with acute leukemia at different stages of therapy and controls, while, 25 (OH) D3 (ng/ml) was significantly lower in acute leukemia patients at different stages of therapy compared to controls (p<0.001). Osteocalcin (ng/ml) is significantly lower in patients at different stages of the disease compared to controls (p<0.001) but there was no significant difference between patients at different stages of therapy. Deoxy-pyridoline cross links showed non-significant difference between the different types of acute leukemia and with controls. Osteopenia is a significant problem in children with acute leukemia at presentation and after chemotherapy. Osteopenia in acute leukemia appears to be of the low turnover type (decreased osteoblastic activity and decreased bone mineralization).