The significance of inadequate transcranial Doppler studies in children with sickle cell disease.

Sickle cell disease (SCD) is a common cause of cerebrovascular disease in childhood. Primary stroke prevention is effective using transcranial Doppler (TCD) scans to measure intracranial blood velocities, and regular blood transfusions or hydroxycarbamide when these are abnormal. Inadequate TCD scans occur when it is not possible to measure velocities in all the main arteries. We have investigated the prevalence and significance of this in a retrospective audit of 3915 TCD scans in 1191 children, performed between 2008 and 2015. 79% scans were normal, 6.4% conditional, 2.8% abnormal and 12% inadequate. 21.6% of 1191 patients had an inadequate scan at least once. The median age of first inadequate scan was 3.3 years (0.7-19.4), with a U-shaped frequency distribution with age: 28% aged 2-3 years, 3.5% age 10 years, 25% age 16 years. In young children reduced compliance was the main reason for inadequate TCDs, whereas in older children it was due to a poor temporal ultrasound window. The prevalence of inadequate TCD was 8% in the main Vascular Laboratory at King's College Hospital and significantly higher at 16% in the outreach clinics (P<0.0001), probably due to the use of a portable ultrasound machine. Inadequate TCD scans were not associated with underlying cerebrovascular disease.

Autoimmune Liver Disease in Children with Sickle Cell Disease.

OBJECTIVE: To assess the incidence, clinical features, and outcome of autoimmune liver disease (AILD) in patients with sickle cell disease (SCD). STUDY DESIGN: Single center retrospective review of patients with SCD with AILD referred between 1999 and 2015. RESULTS: Thirteen of 77 (17%) patients with SCD with hepatic dysfunction were diagnosed with AILD (median age 11, range, 3.4-16 years) with a female preponderance (77%). Acute hepatitis and insidious onset were the commonest presentations. Two patients (15%) presented with acute liver failure. In 2 patients (15%), parvovirus B19-induced transient red cell aplasia preceded the diagnosis of AILD. All patients were positive for antinuclear and/or smooth muscle autoantibodies. Six of 12 patients (50%) had cholangiopathy on cholangiogram suggesting autoimmune sclerosing cholangitis (ASC). Liver biopsy, performed in 11 patients without complications, showed interface hepatitis in 90%. Patients with AILD were treated with standard immunosuppression. After a median follow-up of 3.8 years (range, 0.2-14.3), 10 patients are alive (1 was transplanted 6.4 years after diagnosis); 2 are lost to follow-up; 1 died of subdural hemorrhage before starting treatment for AILD. Five (42%) achieved full and 4 (33%) partial biochemical remission. Ulcerative colitis, present in 4 patients (2 male patients, 3 with ASC) was diagnosed in 2 patients before and in 2 patients after the diagnosis of AILD. CONCLUSIONS: AILD is not uncommon in patients with SCD, affecting mainly female patients and responding satisfactorily to immunosuppressive treatment. Liver biopsy is helpful in confirming the diagnosis and can be safely performed in the absence of acute vaso-occlusive sickling episodes. Ulcerative colitis is common in the presence of ASC.

Extracranial internal carotid artery stenosis in children with sickle cell disease - Which transducer, what measurement?

BACKGROUND: Transcranial Doppler ultrasound is used to screen and assess the intracranial arteries of children with sickle cell disease. Recent findings suggest that extracranial internal carotid artery (eICA) stenosis is also a contributing factor to silent cerebral infarction. Stenosis has been measured using phased array transducers with no beam/flow angle correction and linear arrays with angle correction. METHODS: A total of 124 children undergoing TCD assessment were investigated for eICA velocities. Manual measurements of peak systolic velocity and TCD mean velocity were made with phased and linear array transducers. RESULTS: Peak systolic velocities ranged from 60 to 534 cm/s (median 126 cm/s) using the linear array and 53 to 394 cm/s (median 115 cm/s) using the phased array transducers. TCD mean ranged from 39 to 419 cm/s (median 81 cm/s) using the linear array and 34 to 295 cm/s (median 72 cm/s) using the phased array transducers. CONCLUSIONS: There are advantages and disadvantages of each method, but stenoses were readily identified as focal velocity increases. We suggest thresholds for each transducer and recommend that imaging of the eICA forms part of screening for this group of children.

Lung function, transfusion, pulmonary capillary blood volume and sickle cell disease.

Lung function abnormalities occur in children with sickle cell disease (SCD) and may be associated with elevated pulmonary blood volume. To investigate that association, we determined whether blood transfusion in SCD children acutely increased pulmonary capillary blood volume (PCBV) and increased respiratory system resistance (Rrs5). Measurements of Rrs5 and spirometry were made before and after blood transfusion in 18 children, median age 14.2 (6.6-18.5) years. Diffusing capacity for carbon monoxide and nitric oxide were assessed to calculate the PCBV. Post transfusion, the median Rrs5 had increased from 127.4 to 141.3% predicted (p<0.0001) and pulmonary capillary blood volume from 39.7 to 64.1 ml/m2 (p<0.0001); forced expiratory volume in one second (p=0.0056) and vital capacity (p=0.0008) decreased. The increase in Rrs5 correlated with the increase in PCBV (r=0.50, p=0.0493). Increased pulmonary capillary blood volume may at least partially explain the lung function abnormalities in SCD children.

Longitudinal assessment of lung function in children with sickle cell disease.

OBJECTIVES: To prospectively assess longitudinal lung function in children with sickle cell disease (SCD). WORKING HYPOTHESIS: Lung function in SCD children deteriorates with increasing age and the decline is more marked in younger children who have recently suffered ACS episodes. STUDY DESIGN: Two prospective longitudinal studies. PATIENT-SUBJECT SELECTION: Two cohorts of SCD children and age and ethnic matched controls were recruited. Cohort One (47 SCD and 26 controls) had a median age of 8.8 years and follow up of 2 years and Cohort Two (45 SCD and 26 controls) a median age of 10.2 years and follow up of 10 years. METHODOLOGY: Forced expiratory volume in one second (FEV1 ), vital capacity (VC), forced expiratory flow between 25% and 75% of VC (FEF 25-75 ), total lung capacity (TLC) and residual volume (RV) were measured on two occasions. RESULTS: In both groups of SCD children, lung function declined significantly, but in neither control group. ACS episodes were more frequent during the follow up period in Cohort One than Cohort Two (P < 0.0001). The rate of decline was greater in Cohort One than Cohort Two for FEV1 (P = 0.008), VC (P = 0.001), FEF25-75 (P = 0.030), TLC (P = 0.004), and RV (P = 0.043). In Cohort Two restrictive abnormalities were more common at follow up (P = 0.006). CONCLUSIONS: Lung function deteriorated with increasing age in SCD children and the rate of decline was greater in younger children in whom ACS episodes were more common. Pediatr Pulmonol. 2016;51:717-723. © 2015 Wiley Periodicals, Inc.

Airways obstruction and pulmonary capillary blood volume in children with sickle cell disease.

OBJECTIVES AND WORKING HYPOTHESIS: Airways obstruction occurs in young children with sickle cell disease (SCD). Our aim was to test the hypothesis that increased pulmonary capillary blood volume at least in part explained the increased airways obstruction as this would inform which therapy might be most appropriate to treat the airway obstruction. STUDY DESIGN: Observational study. PATIENT-SUBJECT SELECTION: Twenty-five SCD children and 25 ethnic origin matched controls were recruited. METHODOLOGY: Respiratory system resistance, using impulse oscillometry at 5 Hz (R5 %pred), pulmonary capillary blood volume (Vc), alveolar volume (VA), and spirometry were assessed before and after bronchodilator (ipratropium bromide). Lung volume measurements were also made. RESULTS: The SCD children compared to the controls had a higher R5 %pred before (median 133 (range 88-181)% vs. 102 (83-184)%, P = 0.0046) and after (105 (79-150)% vs. 91 (64-147)%, P = 0.0489) bronchodilator and their median Vc/VA (ml/L) was higher before (26 (18-38) vs. 18 (14-28) P < 0.0001) and after (26 (19-41) vs. 18 (13-27) P < 0.0001) bronchodilator. There were similar decreases in R5 %pred post-bronchodilator in the two groups, but no significant changes in Vc/VA in either group. Vc/VA correlated significantly with R5 %pred in the SCD children only. CONCLUSIONS: Increased pulmonary capillary blood volume contributes to the increased airways obstruction in children with SCD, hence, bronchodilators may be of limited benefit in reducing their airways obstruction.

Long-term outcome for immune suppression and immune related lymphoproliferative disorder: prospective data from the United Kingdom Children's Leukaemia and Cancer Group registry 1994-2004.

Prospective national registry data on 98 patients were studied to determine the long-term outcome of immune related lymphoproliferative disease (LPD) and define prognostic factors. Seventy-three developed LPD following organ transplant (26 liver, 21 heart, 15 kidney, nine bone marrow [BM], two bowel). Twenty-five had non-transplant related immunosuppression. Age was 1.1-17 years (median 8.6). Fifty-eight patients had lymphomatous, 21 systemic and 17 lymphadenopathic disease. Sixty (73%) were disseminated and 22 (27%) localized. Thirty-three (54%) were monoclonal. Seventy-three (83%) were Epstein-Barr virus (EBV) positive. Median follow-up was 7.6 years. LPD developed earlier after liver and BM as compared to heart or kidney transplant. Five-year overall survival (OS) was 58%. Prognosis was best after liver and kidney transplant (OS >77%). Mortality was higher following heart (2.5 times) and BM transplant (5 times). Adverse prognostic factors were disseminated or lymphomatous disease and lack of reduction of immunosuppression. With appropriate reduction of immunosuppression, rituximab and low-dose chemotherapy, long-term survival is high.

Changing pattern of hospital admissions of children with sickle cell disease over the last 50 years.

A study published in 1981 examined the causes of hospital admission for a cohort of children with sickle cell disease (SCD). Since that time, the incidence and prevalence of SCD has increased markedly in the UK, and there have been many changes in the management of this disease. We undertook a study examining the causes of hospital admission of children with SCD to the same hospital as the previous study, over the 2-year period from 2008 to 2009. We found that the numbers of children being cared for by our hospital had dramatically increased over the last 50 years, but rates of hospital admission had significantly fallen (41 hospital admissions per 100 patient-years, compared with 111.3 admissions per 100 patient-years in the original study). This fall in admission rates is accounted for by 2 major components: acute painful episodes (15.7 admissions per 100 patient-years compared with 39.3 in the previous study) and admission for elective blood transfusion (0.2 admissions per 100 patient-years compared with 26.7 in the previous study). It is interesting to note that, 541 elective transfusions were carried out during the study period, but in a day-care setting rather than requiring overnight admission. This study illustrates the changes in management of SCD over the past 30 years, and reflects the overall trend common to most hospital specialties of increasing community and ambulatory care.

Soluble CD163 levels in children with sickle cell disease.

Sickle cell disease (SCD) is characterized by vasculopathy, which has been causally linked to intravascular haemolysis and high levels of free plasma haemoglobin. Soluble CD163 (sCD163) is implicated in the clearance of free plasma haemoglobin and high plasma concentrations have been linked to arterial disease. We therefore investigated the value of sCD163 as a biomarker in children with SCD, and also measured haptoglobin levels in this population. We measured sCD163 in 25 control children with no haemoglobinopathy, 41 with sickle cell anaemia (HbSS) in the steady state, 27 with HbSS taking hydroxycarbamide, and 7 with HbSC disease. There was no significant difference between sCD163 levels in steady-state HbSS (1·78 mg/l) and controls (1·81 mg/l) (P = 0·86). However, sCD163 levels were significantly lower in those HbSS children taking hydroxycarbamide (1·35 mg/l) compared to both steady state HbSS (P = 0·004) and controls (P = 0·036). In children on hydroxycarbamide, sCD163 correlated negatively and highly significantly with percentage HbF (R = -0·76, P < 0·001), and this relationship was absent in those not taking hydroxycarbamide (R = 0·07, P = 0·65). sCD163 is a potentially useful biomarker in children with SCD, and may have a role in monitoring responses to hydroxycarbamide.

Portacaths are safe for long-term regular blood transfusion in children with sickle cell anaemia.

Peripheral venous access in children with sickle cell anaemia (SCA) requiring regular blood transfusions can become difficult over time. Previous reports have suggested the use of totally implantable venous access devices, Portacaths (PAC) in this patient group are associated with unacceptable high rates of complications. We present our experience in seven children with SCA over a 9-year period. Seven devices were placed for a total of 9754 PAC days during the study period. The median age at insertion was 6.3 years (range 3-15 years). The rate of PAC associated infection was 0.2 per 1000 PAC days. There were no episodes of thrombosis. The median length of time in situ during the study period was 3.7 years (range 1.3-7.5 years). Our experience highlights the safe and reliable use of PAC in children with SCA requiring regular blood transfusions when venous access has become a major problem.

Outcome of children with sickle cell disease admitted to intensive care - a single institution experience.

We retrospectively audited children with sickle cell disease (SCD) admitted to paediatric intensive care (PICU) at King's College Hospital between January 2000 and December 2008. Forty-six children with SCD were admitted, on 49 separate occasions. Ages ranged from 4 months to 15 years (median 7.6 years). Three children died in PICU, however two presented to hospital in cardiorespiratory arrest; overall mortality was 6%. The most common reason for admission was acute chest syndrome (43%). 88% of admissions required blood transfusion, of which 74% had exchange blood transfusions. The mortality among children with SCD admitted to PICU is low.

Successful desensitization to immunoglobulin A in a case of transfusion-related anaphylaxis.

BACKGROUND: A history of anaphylaxis after transfusion of immunoglobulin A (IgA)-containing blood products in selective IgA-deficient (sIgAD) patients can be a major problem, particularly in emergencies, when large quantities of blood products are required. CASE REPORT: A 19-year-old woman with end-stage Type 2 autoimmune hepatitis required liver transplantation as her only remaining treatment option. However, she also had sIgAD, anti-IgA antibodies, and episodes of anaphylaxis after receiving IgA-containing blood products. Liver transplantation would have been extremely challenging due to the difficulty of obtaining sufficient blood products from suitable IgA-deficient donors. Hence, it became imperative to devise a protocol to desensitize her to IgA-containing blood products. RESULTS: Using a continuous infusion of an IgA-enriched (6 mg/mL IgA) immunoglobulin preparation with gradual increases in concentration, she was successfully desensitized to IgA. Consequently, she was able to receive standard platelets, fresh-frozen plasma, and red blood cells with no complications. CONCLUSION: This approach could prove very useful in similar cases that may require administration of large quantities of blood products particularly in emergency lifesaving circumstances.

Extracranial internal carotid arterial disease in children with sickle cell anemia.

BACKGROUND: Sickle cell anemia is one of the commonest causes of stroke in children. It is usually, but not always, associated with intracranial vasculopathy. We have assessed the value of ultrasound screening for extracranial internal carotid artery disease. DESIGN AND METHODS: Using Doppler ultrasound scanning, we assessed peak systolic blood velocity, tortuosity and stenosis in the extracranial internal carotid arteries of 236 children with sickle cell anemia. Seventeen of the children had previously had a stroke. All measurements were performed as part of routine clinical care. RESULTS: The median extracranial internal carotid artery velocity was 148cm/s (5(th) centile 84, 95(th) centile 236). Higher velocities were significantly correlated with younger age, higher white blood cell counts and higher rates of hemolysis. Fourteen (5.9%) had tortuous extracranial internal carotid arteries and 13 (5.4%) had stenosis or occlusion. None of the children with tortuous vessels but 8 of those with stenosis had previously had a stroke; the presence of stenosis was strongly associated with overt clinical stroke (OR 35.9, 95% C.I. 9.77-132, P<0.001). In 6 children, extracranial stenosis was part of extensive intracranial vasculopathy, but in 2 there was no evidence of intracranial disease. Stenosis seemed to be more common in older children. CONCLUSIONS: Extracranial internal carotid artery stenosis is strongly associated with stroke in children with sickle cell anemia, and may explain some cases of stroke without overt intracranial vasculopathy. Doppler ultrasound scanning of extracranial internal carotid arteries is non-invasive and fairly quick to perform and may identify children at increased risk of stroke who would otherwise be missed. The value of extracranial internal carotid artery scanning should be studied prospectively.

Auto-adjusting positive airway pressure in children with sickle cell anemia: results of a phase I randomized controlled trial.

Low nocturnal oxygen saturation (SpO(2)) is implicated in complications of Sickle Cell Anemia (SCA). Twenty-four children with SCA were randomized to receive overnight auto-adjusting continuous positive airway pressure (auto-CPAP) with supplemental oxygen, if required, to maintain SpO(2) >or=94% or as controls. We assessed adherence, safety, sleep parameters, cognition and pain. Twelve participants randomized to auto-CPAP (3 with oxygen) showed improvement in Apnea/Hypopnea Index (p<0.001), average desaturation events >3%/hour (p=0.02), mean nocturnal SpO(2) (p=0.02) and cognition. Primary efficacy endpoint (Processing Speed Index) showed no group differences (p=0.67), but a second measure of processing speed and attention (Cancellation) improved in those receiving treatment (p=0.01). No bone marrow suppression, rebound pain or serious adverse event resulting from auto-CPAP use was observed. Six weeks of auto-CPAP therapy is feasible and safe in children with SCA, significantly improving sleep-related breathing disorders and at least one aspect of cognition.

Efficacy and tolerability of high-dose methotrexate in central nervous system positive or relapsed lymphoproliferative disease following liver transplant in children.

Childhood post-transplant lymphoproliferative disease (PTLD) is a heterogeneous condition in which treatment varies, from the reduction of immunosuppression to moderately intensive chemotherapy. While low-dose chemotherapy/rituximab has been found to be effective, moderately intensive chemotherapy is required for patients who relapse, have classic non-Hodgkin lymphoma or have fulminant PTLD. Methotrexate (Mtx) is highly effective in lymphomas and crosses the blood-brain barrier. However, there are no data in the literature regarding its safety in post-liver transplant patients. We describe four cases of high-grade lymphomas (three diffuse large B cell and one T-cell lymphoblastic), post-liver transplant, for which chemotherapy including high-dose Mtx (HDMTX) was the treatment of choice. In total, 20 doses of HDMTX (1-5 g/m(2)) were given. The treatment was well tolerated and all four patients had a good response. One case of central nervous system (CNS) diffuse large B-cell lymphoma was treated with HDMTX alone. We conclude that, in the absence of significant organ damage, HDMTX can safely be given to liver transplant patients, but should only be administered in specialist oncology units. Proof of effectiveness as a single agent in CNS lymphoma needs further studies.

Serum lactate dehydrogenase activity as a biomarker in children with sickle cell disease.

Serum lactate dehydrogenase (LDH) levels were studied in children with HbSS and HbSC in a single institution, and their relationship to cerebral vasculopathy as assessed by transcranial Doppler scanning (TCD). All children with HbSS (n = 97) and HbSC (n = 18) who underwent a TCD scan in 2006 were studied. LDH levels were higher in HbSS patients than HbSC (581 IU/l vs. 305 IU/l, P < 0.001). In children with HbSS, LDH correlated significantly with haemoglobin, reticulocytes, aspartate transaminase and creatinine. LDH also correlated positively and significantly with TCD measurements in the middle and anterior cerebral artery circulations in the children with HbSS.

Evolution in the management of acute liver failure-associated aplastic anaemia in children: a single centre experience.

BACKGROUND/AIMS: Bone marrow failure (BMF) is a potentially life-threatening complication of acute liver failure (ALF). METHODS: To investigate prevalence and evolving management of BMF associated with ALF, we reviewed all cases seen in our centre over 17 years. BMF was classified as: (a) bone marrow hypoplasia, (b) severe aplastic anaemia (SAA) and (c) very severe aplastic anaemia (VSAA), using standard criteria. We compared outcomes in children receiving: (1) medical treatment only with or without immunomodulation (anti-lymphocyte globulin, calcineurin inhibitors, G-CSF); (2) medical treatment with or without immunomodulation plus liver transplantation (LT); (3) haematopoietic stem cell transplantation (HSCT). RESULTS: Of 213 patients with ALF, 20 [(9.4%); 14 (70%) boys] developed BMF after a median of 1 month (range, 0.5 to 7). Seven had VSAA, 7 SAA and 6 bone marrow hypoplasia. Five children were treated medically, including 3 by immunomodulation; 10 (50%) received LT, with immunomodulation in 6; 5 (25%) received HSCT, in one after LT. Four (20%) children died, only one as consequence of AA. There was no difference in recovery, complication rates or outcome among the three groups. CONCLUSIONS: Aggressive management of ALF-associated AA, including immunomodulation, HSCT and LT, is successful in most cases. HSCT has the advantage of removing the risk of late clonal disorders.

The associations between air quality and the number of hospital admissions for acute pain and sickle-cell disease in an urban environment.

The clinical severity of sickle-cell disease (SCD) is dependent on genetic and environmental variables. Environmental factors have been poorly studied. We have investigated possible links between air pollution and acute pain in SCD. We retrospectively studied the numbers of daily admissions with acute sickle-cell pain to King's College Hospital, London, in relation to local daily air quality measurements. We analysed 1047 admissions over 1400 d (1st January 1998-31st October 2001). Time series analysis was performed using the cross-correlation function (CCF). CCF showed a significant association between increased numbers of admissions and low levels of nitric oxide (NO), low levels of carbon monoxide (CO) and high levels of ozone (O(3)). There was no association with sulphur dioxide (SO(2)), nitrogen dioxide or PM(10) (dust). The significant results were further examined using quartile analysis. This confirmed that high levels of O(3) and low levels of CO were associated with increased numbers of hospital admissions. Low NO levels were also associated with increased admissions but did not reach statistical significance on quartile analysis. Our study suggests air quality has a significant effect on acute pain in SCD and that patients should be counselled accordingly. The potential beneficial effect of CO and NO is intriguing and requires further investigation.

Windy weather and low humidity are associated with an increased number of hospital admissions for acute pain and sickle cell disease in an urban environment with a maritime temperate climate.

Sickle cell disease (SCD) is characterised by intermittent episodes of acute severe pain, related to vaso-occlusion. Environmental factors are thought to play an important role, and studies in tropical countries have suggested that cold and rainy seasons are associated with increased episodes of acute pain. We have studied retrospectively the number of admissions with acute pain and SCD to King's College Hospital, London, together with daily meteorological records collected locally. Data from 1400 d and 1047 separate admissions were analysed. Increased admissions were significantly associated with increased wind speed and low humidity, but showed no relationship to temperature, rainfall or barometric pressure. The strongest effect was for (maximum wind speed)/humidity, with 464 admissions on days in the lowest two quartiles of this parameter and 582 in the highest quartiles. The effect of high wind and low humidity is likely to be related to skin cooling.