Multicenter comparison of magnetic resonance imaging and transcranial Doppler ultrasonography in the evaluation of the central nervous system in children with sickle cell disease

PURPOSE: To compare the results of standardized magnetic resonance imaging (MRI) of the brain and transcranial Doppler (TCD) ultrasonography of cerebral arteries in school-aged children with sickle cell disease to determine the correlation between these two different neurodiagnostic tests. PATIENTS AND METHODS: Data were analyzed from 78 children with sickle cell disease (mean age 11 yrs) who participated in both the Cooperative Study of Sickle Cell Disease (CSSCD) and the Stroke Prevention Trial in Sickle Cell Anemia (STOP). Patients who had experienced an overt stroke were excluded. MRI findings were classified as normal or "silent infarct." Results of TCD were classified as normal, conditional, or abnormal, based on the time-averaged maximum mean flow velocity in the proximal middle cerebral and distal internal carotid arteries. RESULTS: Of 61 patients who had a normal MRI examination, 11 (18%) had either conditional (5 patients) or abnormal (6 patients) TCD results. Among 17 patients in whom silent infarction was seen on MRI, only 5 (29%) had a conditional (1 patient) or abnormal (4 patients) TCD velocity. Thus, discordant results were seen in 23 patients: 12 in which the TCD result was normal and the MRI abnormal; 11 in which the TCD velocity was elevated and the MRI normal. CONCLUSIONS: Abnormal TCD and MRI examinations reveal different aspects of the pathophysiology of central nervous system (CNS) injury in sickle cell disease and are often discordant. Although TCD abnormality is predictive of overt stroke, the lack of concordance between TCD and MRI findings suggests a need to develop more sensitive and specific indicators of early CNS pathology, such as neuropsychometric testing and positron-emission tomography (PET) scans, and to obtain more information about microvascular pathologic processes that may affect CNS function.     

Alpha Thalassemia is associated with decreased risk of abnormal transcranial Doppler ultrasonography in children with sickle cell anemia

PURPOSE: Cerebrovascular complications of sickle cell disease (SCD) are common, but the risk factors remain unclear. The multicenter Stroke Prevention Trial in Sickle Cell Anemia (STOP) provided an opportunity to examine alpha thalassemia-2 as a modifying risk factor, using abnormal transcranial Doppler ultrasonography (TCD) as a surrogate marker for cerebrovascular disease. The authors hypothesized that children with abnormal TCD are less likely to have alpha thalassemia-2, and an increased hemoglobin level accounts for this protective effect. METHODS: A retrospective study was conducted of children with SCD who had both alpha gene and TCD data from STOP: 128 with TCD of at least 200 cm/s (abnormal TCD) and 172 with TCD less than 170 cm/s (normal TCD). RESULTS: Alpha thalassemia-2 was more frequent in the normal TCD group compared with the abnormal TCD group. The odds ratio for normal TCD and alpha thalassemia-2 was 4.1. Adjusting for either hemoglobin level or red cell size (mean corpuscular volume) reduced the odds ratio only slightly. Age, normal TCD, and alpha thalassemia-2 had significant statistical interaction, so that alpha thalassemia-2 was not related to TCD for age 10 years or older. CONCLUSIONS: The frequency of alpha thalassemia-2 was significantly higher in children with normal TCD. Speculation on mechanisms of effect includes improved erythrocyte deformability, reduced red cell adhesion, and reduced nitric oxide scavenging in alpha thalassemia-2. The association of alpha thalassemia-2 and normal TCD adds to the evidence on the protective effects of alpha thalassemia-2 in SCD and highlights the contribution of epistatic factors.     

Problems with implementing a standardised transcranial Doppler screening programme: impact of instrumentation variation on STOP classification

Background  

The Stroke Prevention Trial in Sickle Cell Anaemia (STOP) demonstrated the value of selective transfusion based on transcranial Doppler (TCD) US screening. This facilitated widespread surveillance, but due to reported differences with non-imaging TCD, imaging velocity thresholds have been reduced in some centres.     

GROWTH STATUS IN CHILDREN AND ADOLESCENTS WITH SICKLE CELL DISEASE

Objectives: To assess the BMI status of children and adolescents with sickle cell disease (SCD) and determine if zBMI status during adolescence is predicted by gender, childhood zBMI status, disease genotype, and healthcare utilization (emergency department visits or hospitalizations). Study Design: Medical chart reviews were conducted on 133 patients followed through a regional Comprehensive Sickle Cell Center to obtain anthropometric measures and healthcare utilization data. Gender-specific BMI z-scores were calculated based on Centers for Disease Control (CDC) norms using Epi Info NutStat Software and SPSS generated syntax. Data were summarized categorically across two time periods for each participant: childhood (age 6–12 years) and adolescence (age 13–18 years). Results: Males were three times more likely to be underweight in adolescence compared to CDC norms, whereas females were three times more likely to be obese in adolescence. In addition, regression analyses indicated that BMI in adolescence was predicted by gender, average weight in childhood, and the average number of emergency department visits. Conclusions: Children with SCD generally exhibit normal growth during childhood and adolescence, although 5–10% are at risk for poor growth or obesity. Prevention and intervention efforts should consider gender, average weight in childhood, and healthcare utilization factors.     

Clinical profile of sickle cell disease in Orissa

Children comprised 52% of patients with Sickle Cell Disease (SCD). Types of Sickle Cell Disease encountered were SS (92.7%). SB thalassaemia (6.7%) and SD disease (0.7%). The disease was widespread in almost all castes and communities in the society; largest number of patients (20%) belonging to scheduled castes and only 1.4% were from scheduled tribes. Maximum number of cases were in the age group 2–4 and 4–6 years, many of whom died around this age. Besides attacks of pain, jaundice and anemia, frequent attacks of fever with anemia or only anemia in childhood were a predominant presenting feature. Splenic sequestration was frequent (10.1%). The patients usually had a steady state hemoglobin level of 6–10 g/dl, with which they thrived well. Fetal hemoglobin was 5–30%. Blood transfusion was not a frequent requirement, but prophylactic long acting penicillin was helpful in preventing frequency of crisis.     

Transcranial Doppler (TCD) screening for stroke prevention in sickle cell anemia: pitfalls in technique variation

Background. The Stroke Prevention Trial in Sickle Cell Anemia (STOP) identified children as being at high stroke risk if the time-averaged maximum mean velocity (TAMMV) of the middle cerebral or intracranial internal carotid arteries measured ≥ 200 cm/s. These values were obtained utilizing a 2-mHz dedicated nonimaging pulsed Doppler technique (TCD) and manual measurements. Questions have been raised as to the comparability of results obtained with different ultrasound machines and measurement techniques.¶Objective. The purpose of this study was to compare nonimaging (TCD) and transcranial duplex imaging (TCDI) findings in children potentially at risk for stroke with sickle cell disease.¶Materials and methods. Twenty-two children with sickle cell disease and no history of stroke were evaluated by both TCD and TCDI. Examinations were performed on the same day without knowledge of the other modality results and read independently using manually obtained measurements. Mean velocities, peak systolic velocities, and end diastolic velocities obtained by the two techniques were compared. In a subgroup, manual measurements were compared to electronically obtained measurements. ¶Results. TCDI values were lower than TCD measurements for all vessels. TCDI TAMMV values were most similar to the TCD values in the middle cerebral artery (–9.0 %) and distal internal cerebral artery (–10.8 %), with greater variability in the anterior cerebral artery (–19.3 %), bifurcation (–16.3 %), and basilar arteries (–23.1 %). Risk group placement based on middle cerebral artery TAMMV values did not change when comparing the two techniques. Measurements obtained electronically were lower than those obtained manually. ¶Conclusion. Velocities obtained by TCDI may be lower than TCD measurements, and these differences should be taken into consideration when performing screening for stroke risk and selection for prophylactic transfusion based on the STOP protocol.     

Transfusion in Sickle Cell Disease: Experience from a Gujarat Centre

Objectives

Following impressions that the use of blood transfusion in sickle cell disease may be inappropriately high, transfusion practice at a major blood bank in an area of high prevalence of sickle cell disease was assessed.

Methods

Retrospective review of blood usage in sickle cell disease at a major blood bank in south Gujarat in 2010 was conducted with prospective more detailed data collection over 18 wk period (April 7 through August 15) in 2011. The results were compared with transfusion usage in the Jamaican Sickle Cell Clinic.

Results

In 2010, this blood bank processed a total of 19,037 units of which 384 (5.2 %) units were for patients with sickle cell disease. Median transfusion use was 1 unit but 16 patients (4.2 %) of those transfused received 10 units or more and five patients received over 20 units. More detailed prospective analysis revealed that most transfusions occurred between ages 5–15 y, 40 % of subjects had pretransfusion hemoglobin levels below 6 g/dL, symptoms were generally vague such as fever, bone pain, weakness and that 26 % denied any specific symptoms.

Conclusions

Transfusion usage greatly exceeds that in the Jamaican Sickle Cell Clinic. Transfusion therapy carries risks and cost and more detailed investigation and diagnosis of anemic episodes is necessary to define the role of transfusion among other potential therapies. Eventually, guidelines evolved by Indian specialists should determine the indications for transfusion in sickle cell disease.     

Impact on weight and height with the use of HAART in HIV-infected children

BACKGROUND: There are few data on long-term effects of highly active antiretroviral therapy (HAART) on weight and height in HIV-infected children. OBJECTIVES: Our objective was to assess the effect of HAART on the weight and height of HIV-infected children over time in the Madrid cohort, and analyze possible factors associated with the effect. PATIENTS AND METHODS: This was a retrospective study of HIV-infected children starting HAART in 1997 or later. Serial measurements of weight, height and body mass index (BMI) were performed and converted to z-scores using the Spanish revised reference data. Changes from baseline in weight, height and BMI at 12, 24, 36, 48 and 60 months were determined. Associations of z-scores at the last visit with immunologic (CD4% above 25%) and virologic responses (more than 50% of samples below 400 copies/mL), CDC (Centers for Disease Control) clinical category, and the presence and type of lipodystrophy (lipoatrophy or lipohypertrophy) were evaluated. RESULTS: Twelve hundred and twelve children, 97% of them vertically-infected, received HAART starting in 1997 for a median of 71 months (4-102 months). Median age at initiation of HAART was 6 years (1 month-18 years). Thirty-nine percentage were antiretroviral naive and 61% had received NRTI therapy previously. Thirty-two percentage and 53% had CDC class C and immunologic class 3, respectively. At the final evaluation, 24% of children remained on their first combination therapy, 39% on the second and 37% had received at least 3 different HAART regimens. Fifty-one percentage were classified as virologic responders. Thirty-nine percentage of children in this study were diagnosed with lipodystrophy. At baseline, median z-score for weight, height and BMI were -0.45, -0.60 and -0.33, respectively. HAART was associated with significant increases in z-scores of weight and height but not BMI at the different time-points analyzed. Virologic nonresponders had significantly lower z-scores for weight and height but not for BMI. CDC class C was associated with lower z-scores for height. No differences in final measurements were observed for baseline CD4, immunologic response or lipoatrophy. Children with lipohypertophy had a significantly higher BMI at the last visit. CONCLUSIONS: HIV-infected children experienced a continued catch-up in weight and height 5 years after starting HAART. Virologic control is related to sustained growth.     

Obesity—Does It Occur in Nigerian Children with Sickle Cell Anemia

Children with sickle cell anemia are vulnerable to growth deficits; thus, it would be thought that obesity would be rare among them. The objective of the study is to examine the prevalence of obesity in a sickle cell anemia population in Lagos. A random sample of children with sickle cell anemia aged 2–15 years was interviewed and anthropometric measurements including weight and height were taken. Their body mass index (BMI) was calculated. Participants were classified as obese or not obese by their BMI or weight-for-height-for-age using World Health Organization standard definitions. The overall prevalence of obesity was 2.5% and 3.8% among hemoglobin genotype SS subjects and hemoglobin genotype AA controls, respectively. The age-specific prevalence for obesity was highest among the adolescent age category in hemoglobin genotype AA controls and the childhood age category in subjects with sickle cell anemia. All the obese subjects with sickle cell anemia were from upper socioeconomic strata, while two and one of the three subjects with hemoglobin genotype AA were from upper and middle socioeconomic strata, respectively. Obesity does exist among children with sickle cell anemia in Lagos, Nigeria. Public health programs aimed at prevention and control of obesity must include children with sickle cell anemia.     

Impact of chronic transfusion on incidence of pain and acute chest syndrome during the Stroke Prevention Trial (STOP) in sickle-cell anemia.

OBJECTIVE: The Stroke Prevention Trial (STOP) demonstrated that chronic transfusion is highly effective in reducing the risk of stroke in children with sickle-cell disease and an abnormal transcranial Doppler ultrasonography examination result. Our objective was to determine whether chronic transfusion therapy reduces the incidence of pain and acute chest syndrome. METHODS: During STOP, 130 children with sickle-cell anemia or sickle beta(0)-thalassemia and abnormal transcranial Doppler ultrasonography examination result were randomly assigned to chronic transfusion (n = 63) or observation (n = 67). In addition to monitoring for stroke, nonneurologic sickle-cell complications were identified and recorded. RESULTS: Mean age at STOP study entry was 8.3 +/- 3.3 years, and mean follow-up was 19.6 +/- 6.5 months. Hospitalization rates (based on intent-to-treat analysis) for acute chest syndrome were 4.8 and 15.3 per 100 patient-years (P =.0027) and for pain were 16.2 and 27.6 per 100 patient-years (P =.13) in the chronic transfusion and observed groups, respectively. If analyzed according to treatment actually received, the difference in pain rate becomes significant (9.7 vs 27.1 events per 100 patient-years, P =.014), and transfusion remains protective from acute chest syndrome (2.2 vs 15.7 events per 100 patient-years, P =.0001). CONCLUSIONS: Compliance with aggressive chronic transfusion reduces the frequency of acute chest syndrome and pain episodes.     

Reversibility of splenic function by transfusion in two young adults with sickle cell anemia

A level of circulating "pitted" or vesiculated red blood cells higher than 3.5% was recently reported in studies in the Cooperative Study of Sickle Cell Disease to correlate with splenic dysfunction as shown by spleen scans. Reversal of splenic dysfunction by transfusion in children with sickle cell anemia (SS disease) is known to occur in the young child. We report two older patients with homozygous sickle cell disease, aged 17 and 21 years, whose spleen function, as measured by pit count, was restored to normal range after transfusion.     

Obesity--does it occur in Nigerian children with sickle cell anemia

Children with sickle cell anemia are vulnerable to growth deficits; thus, it would be thought that obesity would be rare among them. The objective of the study is to examine the prevalence of obesity in a sickle cell anemia population in Lagos. A random sample of children with sickle cell anemia aged 2-15 years was interviewed and anthropometric measurements including weight and height were taken. Their body mass index (BMI) was calculated. Participants were classified as obese or not obese by their BMI or weight-for-height-for-age using World Health Organization standard definitions. The overall prevalence of obesity was 2.5% and 3.8% among hemoglobin genotype SS subjects and hemoglobin genotype AA controls, respectively. The age-specific prevalence for obesity was highest among the adolescent age category in hemoglobin genotype AA controls and the childhood age category in subjects with sickle cell anemia. All the obese subjects with sickle cell anemia were from upper socioeconomic strata, while two and one of the three subjects with hemoglobin genotype AA were from upper and middle socioeconomic strata, respectively. Obesity does exist among children with sickle cell anemia in Lagos, Nigeria. Public health programs aimed at prevention and control of obesity must include children with sickle cell anemia.     

Neuropsychologic performance in school-aged children with sickle cell disease: a report from the Cooperative Study of Sickle Cell Disease

OBJECTIVES: To compare the results of serial neuropsychologic testing in children with sickle cell disease with the results of serial magnetic resonance imaging (MRI) examinations, particularly to evaluate neuropsychologic function in the absence of overt stroke. STUDY DESIGN: In the Cooperative Study of Sickle Cell Disease, serial neuropsychologic and MRI tests were performed in 373 patients (255 with hemoglobin SS and 118 with hemoglobin SC), 6 to 18 years of age. MRI of the brain and a neuropsychologic battery that included the Wechsler Intelligence Scale for Children (WISC-R or WISC-III) and the Woodcock-Johnson Math and Reading Achievement Tests were performed concurrently and repeated every 2 to 3 years. A silent infarct was defined as an MRI finding of increased signal intensity on T(2) imaging in a patient without a history of stroke. RESULTS: Twenty-seven patients, all with hemoglobin SS, had overt strokes and 62 had silent infarcts (52 with hemoglobin SS). Patients with hemoglobin SS and silent infarcts had significantly lower scores for math and reading achievement, Full-Scale IQ, Verbal IQ, and Performance IQ, when compared with those with normal MRI findings. In children with hemoglobin SS and normal MRI findings, the scores for Verbal IQ, math achievement, and coding (a subscale of Performance IQ) declined with increasing age. CONCLUSIONS: School-aged children with sickle cell disease had compromised neuropsychologic function in the presence of silent infarcts. In addition, they had declines in performance in certain areas of function over time. Therapeutic interventions that prevent or lessen cognitive impairment are needed before school entry for children with sickle cell disease.     

A comparison of two transfusion regimens in the perioperative management of children with sickle cell disease undergoing adenotonsillectomy

Adenotonsillar hypertrophy and chronic tonsillitis are common findings in patients with sickle cell disease (SCD). Various preoperative transfusion regimens have been suggested to reduce the population of sickle erythrocytes and correct the anemia, ranging from conservative (correcting the anemia) to aggressive (lowering the level of HbS to less than 30%). A total of 39 patients with SCD were included in the study. They were divided into 2 groups. Fourteen patients in group 1 were assigned aggressive exchange transfusion and 25 patients in group 2 were assigned a conservative (simple) transfusion. The 2 groups were compared for possible operative and postoperative complications. Thirty percent of patients in both groups had postoperative complications. They ranged from mild local infection to acute chest syndrome. Simple transfusion was not associated with higher incidence of complications and resulted in only one-third as many transfusion requirements.     

Growth hormone and insulin-like growth factor I axis and growth of children with different sickle cell anemia haplotypes

BACKGROUND: The purpose of this study was to examine the relationships between growth in children with sickle cell anemia and the different beta-globin haplotypes, as well as components of the insulin-like growth factor (IGF)/insulin-like growth factor binding protein (IGFBP) axis. PATIENTS AND METHODS: Growth parameters and plasma concentrations of growth hormone (GH), IGF-I, and IGFBP-3 were studied in 41 children with sickle cell anemia whose haplotypes were defined. RESULTS: Plasma concentrations of IGF-I (total, free, and free/total fraction) and IGFBP-3 were significantly reduced in all patients with sickle cell anemia compared with the healthy children. Patients with the CAR/CAR haplotype had significantly lower mean growth velocity compared with those with Ben/Ben. When the GH/IGF axis elements were compared in relation with the different haplotypes, total IGF-I levels in CAR/CAR patients were significantly lower compared with levels in patients with Ben/Ben. A positive correlation was found between hematocrit and total IGF-I and between fetal hemoglobin percentages and the z-scores for total IGF-I and IGFBP-3. There was a positive correlation between age, weight, height, bone age, and the various elements of the GH/IGF-I axis when all groups were considered, although the correlation was lost when the auxologic data were expressed as standard deviation score for age. Growth velocity and the z-score for growth velocity were not correlated with any element of the axis. CONCLUSIONS: The positive relationship between hematocrit and fetal hemoglobin percentages with total IGF-I, free/total IGF-I, and IGFBP-3 in patients with sickle cell anemia could show that the delayed growth of these patients may be linked to intrinsic factors of the disease, which also determine the low circulating concentrations of the various elements of the GH/IGF-I axis. It is reasonable to assume that decrease of total IGF-I concentrations in patients with CAR/CAR haplotype is secondary to the severity of the disease.     

Population-Level Obesity Surveillance: Monitoring Childhood Body Mass Index z-Score in a Safety-Net System

ObjectiveTo determine the utility of repeated patient-level body mass index (BMI) measurements among higher-risk patients seen at safety-net clinics as a community-level monitoring tool for overweight and obesity population trends.MethodsData from a network of urban, federally qualified community health centers with computerized tracking of BMI at sequential outpatient visits were analyzed. We performed a longitudinal observational study over 8 years (2005–2012) with children stratified by weight status groups on the basis of BMI. Changes in BMI z-scores were used to estimate population trends among children 2 to 11 years old, with at least 2 visits (at least 1 year apart), for whom weight and height were measured.ResultsAmong children (n = 33,542), the rate of overweight was 16% and rate of obesity was 18% at their last visit. Children were followed for an average of 3.24 ± 1.76 years to measure trends and change in weight status from earlier to later childhood. Children who were obese at first visit had increased odds (adjusted odds ratio 27.8, 95% confidence interval 25.6–30.2) of being obese by last visit. Mean change in BMI z-score per person-year of observation was 0.10 ± 0.38, with a differing rate of change based on weight status category at last visit (not overweight = 0.06 ± 0.39; overweight = 0.17 ± 0.34; obese = 0.19 ± 0.36). Change in BMI z-score per person-year decreased for 40% of obese children; however, their weight status group remained unchanged.ConclusionsChildhood obesity prevalence was high, with substantial progression to overweight and obesity from first to last visit. Clinically derived BMI z-score per person-year measures can effectively show population trends not observed using standard weight status categories.     

Blood transfusion rate in congolese patients with sickle cell anemia

Objective The main objective of this study was to evaluate the rate of blood transfusion in African Sickle Cell Patients and the risks related to the use of total blood. Methods 186 sickle cell patients (95 males and 91 females) aged 0–21 years were regularly followed over a 3 years period in Katanga province, DR Congo. Indications for blood transfusion were mainly based on clinical criteria and Hb level (less than 5g% ml or a drop of 2g% under the steady state value). All the subjects, who were transfused, wer screened for hepatitis B surface antigen (HBs Ag) and Human Immune deficit Virus (HIV). Results Of 186 patients, 150 (80.6%) were transfused, and the average blood transfusion requirement was 0.4 units per patient-year. According to the age of first transfusion, 75.3% (113/150) of them were transfused before the 6^th year of life; but the frequency of transfusions seemed to decline in children aged more than 13 years. The risk of HIV infection from blood transfusion was estimated at 1 per 37.1 units or 26 per 1000 blood units. The hepatitis B surface antigen was detected in 15 cases (10%) and HIV serology was positive in 17 patients (11.3%). Conclusion Because of the complications related to blood transfusions in Africa, efforts are needed in order to reduce the frequency of transfusions, by preventive measures (early diagnosis, malarial and penicillin-prophylaxis) and to use more rational indications.     

How to Reach Rapid Diagnosis in Sickle Cell Disease?

Objective

Sickle cell disease (SCD) is a common hereditary disease in Iran. In developed countries, newborn screening programs have been established to ensure early diagnosis, but in most developing countries, screening is not performed and the diagnosis is often delayed. The aim of the present work was to investigate the clinical presentation of SCD in Iran and comparison of its hematologic indices with normal children.

Methods

The study included 44 pediatric patients (26 boys and 18 girls) with sickle cell anemia (SS), 27 sickle /β°-thalassemia (Sβ°), and 21 sickle /β⁺-thalassemia (Sβ⁺). Fifty seven healthy individuals matched with the patients were randomly selected as controls.

Findings

Mean age at diagnosis in SS group was 4.3 years. At the time of diagnosis all patients were anemic, 89% complained of painful crises. Hemoglobin(Hb) concentration, red blood cell (RBC) count and Hb×RBC product in SS group was significantly lower than in control group (P<0.001), mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) showed no significant differences. Hb×RBC product below 45 and MCH/RBC above 7 have the best sensitivity and specificity for differenting SS group and the control normal group (91 and 98% for Hb×RBC and 89 and 100% for MCH/RBC respectively). Mean age at diagnosis in Sβ⁺ group was higher than in SS and Sβ° groups (7.45 year vs 4.26 and 4.25 year) (P<0.001). In addition, Sβ° and Sβ⁺ groups had significantly lower MCV, MCH, and Hb×RBC indices compared with control group.

Conclusion

We suggest that in an anemic patient with history of pain crises, normochrome normocytic anemia, Hb×RBC <45 and MCH/RBC ≥7, SCD should be considered and the patient evaluated accordingly to confirm the diagnosis.     

Vitamin A status, hospitalizations, and other outcomes in young children with sickle cell disease

OBJECTIVE: To determine the relation of serum vitamin A status to growth, nutritional and hematologic status, and to the number of hospitalizations in children with sickle cell disease-SS (homozygous for the S allele, SCD-SS). STUDY DESIGN: Children (2-9.9 years of age) with SCD-SS were assessed for serum retinol, hemoglobin, hematocrit, reticulocyte count, height, weight, body mass index, and recalled dietary intake. Vitamin A status was defined on the basis of serum retinol concentration as suboptimal (<30 microg/dL) and normal (> or =30 microg/dL). Hospitalizations were determined for 1 year after vitamin A assessment. RESULTS: Mean serum retinol was 26.7 +/- 6.8 microg/dL in 66 subjects (39 girls) and was suboptimal in 66% of children. Compared with those with normal status, children with suboptimal vitamin A had significantly lower body mass index z score (-0.7 +/- 1.0 vs -0.1 +/- 0.6) and hemoglobin (7.9 +/- 1.1 vs 8.5 +/- 1.1), and hematocrit (23.3 +/- 3.0 vs 25.1 +/- 3.8) and significantly more hospitalizations (2.8 +/- 2.0 vs 0.7 +/- 0.8). After adjusting for age and sex, suboptimal vitamin A status was associated with a 10-fold increased risk for hospitalization (OR, 10.5; 95% CI, 2.3, 48.6) and with increased pain (OR,5.3; 95% CI, 1.3, 21.6) and fever episodes (OR, 6.4; 95% CI, 1.7, 24.9) requiring hospitalization. CONCLUSIONS: Suboptimal vitamin A status was prevalent in US children with SCD-SS and was associated with increased hospitalizations and poor growth and hematologic status.     

SPLENIC FUNCTION IN OMANI CHILDREN WITH SICKLE CELL DISEASE: Correlation with Severity Index,Hemoglobin Phenotype,Iron Status,and α -Thalassemia Trait

The prevalence of functional asplenia in Omani children with sickle cell disease (SCD) has not been previously defined. In this study, the authors aim to compare the natural history of splenic dysfunction in their patients to other reports. The splenic function was studied in 72 Omani patients with sickle cell disease (50 homozygous for hemoglobin S (HbS-S), 11 double heterozygotes for HbS and &#103 0 -thalassemia (HbS- &#103 0 -thal), 5 HbS- &#103 + -thal, 5 patients with hemoglobin S-D disease, and 1 child with hemoglobin S oman trait) aged 4.8-16 years, using 99m Tc-labeled tin colloid scintigraphy. The study revealed 4 groups according to their colloid uptake: group I included 20 patients (28%) with normal splenic function; group II, 6 patients (8%) with mild hyposplenism; group III, 20 (28%) with severe hyposplenism; and group IV, 26 (36%) patients with functional asplenia. Overall, more than 60% of them had preserved splenic function. Except for HbS- &#103 + patients, the developmental pattern of hyposplenism was not different among the different Hb phenotypes. Factors associated with preservation of spleen function in these patients were larger splenic size ( p < .01), less clinical severity ( p < .05), lower MCH ( p < .01), higher HbF ( p < .001), and presence of &#102 -thalassemia trait ( p < .05).