How to use a coagulation screen.

A coagulation screen is an important screening test when investigating a child who presents with easy bruising or bleeding. Interpretation of a coagulation screen can be challenging for clinicians. Evolution of the haemostasis system during childhood means normal ranges vary with age and needs to be interpreted alongside the clinical information. It is essential to consider preanalytical variables when interpreting a coagulation screen, and the reason for the investigation must always be considered. It is important that the sample is taken under optimal conditions, including sample technique, use of the correct bottle and prompt transport to the laboratory. An abnormal coagulation screen may indicate an underlying congenital bleeding disorder or an acquired bleeding disorder, or may be due to sampling error. Limitations of the coagulation screen are essential to be aware of, as some children with normal coagulation screen results may have bleeding disorders. Conversely, an abnormal coagulation screen does not always indicate a bleeding disorder.

How to use iron studies.

Iron studies are frequently requested in paediatric practice. They are useful both as a diagnostic tool and as a way of monitoring certain conditions, particularly those causing iron overload. This article outlines the physiology of iron metabolism and discusses laboratory aspects of performing iron studies, including factors influencing interpretation. Clinical scenarios are used to highlight how the tests can be used in different clinical situations.

How to use a blood film.

The diagnostic relevance of the blood film cannot be underestimated in the assessment of children with suspected primary or secondary haematological conditions. The blood film not only serves as a diagnostic tool but also allows for screening, monitoring of disease progression and therapeutic response in children with a variety of haematological conditions. This article outlines the appearance of normal paediatric and neonatal blood films. The technical aspects involved in preparing a blood film are discussed. Consideration is given to the indications for preparing a blood film and some of the limitations of blood films. Finally, attempts are made to highlight the role of the blood film in the diagnosis of some common paediatric and neonatal conditions.

Molecular characterization of six new cases of red blood cell hexokinase deficiency yields four novel mutations in HK1.

Hexokinase (HK) is a key enzyme of glycolysis, the only metabolic pathway able to provide the red blood cell with ATP. HK deficiency is a very rare hereditary disorder with severe chronic nonspherocytic hemolytic anemia (HNSHA) as a major clinical feature. To date, only 24 patients with HK deficiency have been identified. Here, we report the molecular analysis of six new cases of HK deficiency. A total of six different mutations were detected in HK1, four of them described here for the first time: c.2599C>T p.(His867Tyr), c.1799C>T p.(Thr600Met), c.873-2A>G and c.493-1G>A. The pathogenic nature of the identified missense mutations was confirmed by biochemical and 3-dimensional structural analysis. The effects of the novel splice site mutation c.873-2A>G were studied at the level of pre-mRNA processing, and confirmed at the protein level. All together, these results provide a better insight into the pathogenesis of this rare red cell disorder, and contribute to a better understanding of the genotype-phenotype correlation in HK deficiency.

Strategies to Prevent and Manage Thrombotic Complications of Acute Lymphoblastic Leukemia in Children and Young People Vary Between Centers in the United Kingdom.

There is a lack of evidence-based guidance for the prevention and management of thrombosis in children and young people treated for acute lymphoblastic leukemia. To determine current UK practice, a survey was sent to 28 centers participating in the Medical Research Council UKALL 2011 trial. Marked variation in practice was noted. In total, 43% of centers defer central venous access device insertion until end of induction for treatment of low-risk disease. Central venous access devices are removed at the end of intensive blocks in 38% and end of treatment in 42%. Duration of anticoagulation for line-associated thrombosis is 6 weeks in 43% and 3 months in 33% and for cerebral sinovenous thrombosis is 3 months in 71% and 6 months in 24%. Platelet transfusion to maintain platelet count >50×10/L, in preference to interrupting therapeutic anticoagulation, is used by 50% for line-associated thrombosis and 73% for cerebral sinovenous thrombosis. Conformity of practice was seen in some areas. In total, 70% treat thrombosis with twice-daily low-molecular weight heparin and 86% monitor antifactor Xa activity levels. In total, 91% reexpose individuals to asparaginase following a thrombotic event. Given this variation in practice, in the absence of high-quality evidence, consensus guidelines may be helpful.

Assessment of the outcomes associated with periprocedural anticoagulation management in children with acute lymphoblastic leukemia.

OBJECTIVE: To report the outcomes of an institutional protocol for periprocedural anticoagulant (AC) management in children with acute lymphoblastic leukemia (ALL). STUDY DESIGN: Children being treated for ALL who received full-dose (therapeutic) anticoagulation before undergoing at least 1 lumbar puncture (LP) were included in this retrospective cohort study. The main outcome was the risk of traumatic LP; exploratory analysis included the risks of symptomatic spinal hematoma and progression/recurrence of the thrombotic event. Analyses were conducted using logistic regression analysis with a generalized estimating equation approach. RESULTS: Twenty-two children with ALL receiving an AC underwent a total of 396 LPs. Although traumatic LP was associated with full-dose AC therapy in univariable analysis, a multiple logistic regression model controlling for other risk factors for traumatic LP showed that AC therapy was not significantly associated with the risk of traumatic LP when the ACs were held as per the institutional protocol. No patient developed symptomatic spinal hematoma. Exploratory analysis revealed that AC dose, a likely marker of thrombus burden, was significantly associated with progression/recurrence of the thrombotic event in univariable analysis. CONCLUSION: In our cohort, recent AC therapy was not statistically associated with an increased risk of bleeding after LP when following a specific protocol for periprocedural AC management. The risk associated with the progression/recurrence of thromboembolic events requires further evaluation.

A severe bleeding diathesis in a 6-year-old girl secondary to a composite diagnosis of splenic hemangiomatosis and small bowel lymphangiomatosis.

A 6-year-old girl presented with presumed relapse of childhood immune thrombocytopenia. Investigations revealed deranged coagulation parameters, abnormal small bowel thickening, and splenomegaly. A clinically significant bleeding diathesis emerged which was refractory to most hemostatic interventions. Laparatomy revealed a composite diagnosis of splenic hemangiomatosis and small bowel lymphangiomatosis. Splenectomy resulted in complete resolution of the coagulopathy. The diagnosis and management of these conditions is inherently complex and without clear guidance. We discuss our perioperative management of the bleeding diathesis. There is a need for long-term follow-up of the underlying pathologies particularly as potentially useful therapeutic agents have emerged.

Thrombosis in children.

Thrombosis in children is becoming more prevalent due to increased awareness of these issues in the pediatric population and advances in medicine. Management of affected children are challenging due to differences in their hemostatic system compared with adults. Prospective, controlled trials for management/treatment of children with thrombosis are lacking. Many of the available guidelines for treatment of thrombosis in children are extrapolated from adult data and do not account for the uniqueness of the pediatric hemostatic system, although more research and data are becoming available. This review will focus on children over 1 year of age, including adolescents, looking at the etiology of thrombosis, diagnosis, management options, and any associated complications in this pediatric population.

Unusual functional manifestations of a novel STX11 frameshift mutation in two infants with familial hemophagocytic lymphohistiocytosis type 4 (FHL4).

Familial hemophagocytic lymphohistiocytosis (FHL) is typically an autosomal recessive, early-onset, life-threatening immune disorder. Loss-of-function mutations in STX11 have been found to impair NK cell degranulation and cytotoxicity. Here, we describe two unrelated infants of Punjabi descent presenting with FHL and carrying a novel, homozygous STX11 frameshift mutation [c.867dupG]. Western blot analysis indicated absence of syntaxin-11. Unexpectedly, degranulation by NK cells from one of the patients was not impaired, although patient NK cells showed mildly and significantly decreased cytotoxicity, respectively. Importantly, these observations imply that STX11 should be sequenced in HLH patients even when impaired NK cell degranulation is not found.

Complete response to tacrolimus in a child with severe aplastic anemia resistant to cyclosporin A.

Aplastic anemia (AA) is a rare disorder in children, usually treated with immunosuppressive therapy (IST) including antithymocyte globulin (ATG) and cyclosporin A. There are no current widely used alternative therapies with comparable efficacy. We describe a child with severe aplastic anemia (SAA), who developed severe gingival hyperplasia secondary to cyclosporin A, unresponsive to intensive dental intervention. When IST was changed to tacrolimus there was a significant improvement in the gingival hyperplasia, but equally important, he achieved complete response of his AA within several months. The use of tacrolimus in children with AA may be a potential modality of treatment.

Novel uses for recombinant erythropoietin therapy in unlicensed indications.

Clinical uses for recombinant human erythropoietin (rHuEPO) therapy continue to expand. Initial use was in anaemia associated with end-stage renal disease, but more recently there have been many reports of the benefits of erythropoietin in other clinical situations such as cancer-related anaemia. Recombinant erythropoietin reduces the need for blood transfusion and hence exposure to donor blood products as well as improving quality of life. We report four patients who were transfusion dependent, none of whom had licensed indications for the use of recombinant erythropoietin. Two patients had microangiopathic haemolytic anaemia secondary to mechanical valve haemolysis and were unsuitable for any further cardiac intervention. One patient had anaemia of chronic disease and anti-Vel red cell antibodies, making compatible blood transfusions difficult to obtain. The fourth patient had primary thrombocythaemia and developed transfusion-dependent anaemia secondary to myelosuppressive agents. All four patients had a relative deficiency in endogenous erythropoietin levels ranging between 7 and 41 IU/l. After commencing recombinant erythropoietin therapy, all had a response in haemoglobin of at least 1 g/dl with an overall improvement in their quality of life. We conclude that rHuEPO is a very convenient and useful form of treatment in transfusion-dependent anaemia and in some cases beyond the licensed indications.