Nonsurgical Management of Acute Appendicitis in Sickle Cell Disease.

A 9-year-old child with sickle cell disease (sickle beta zero thalassemia) was diagnosed to have acute appendicitis during a hospitalization for pain, acute chest syndrome, and exacerbation of asthma. Because of his high surgical risk, his appendicitis was treated nonsurgically, successfully deferring his appendectomy. He remains well after 1 year. This approach should be considered at least in other sickle cell patients with appendicitis, and perhaps other high-risk populations, if not all children with appendicitis.

Massive Splenic Infarction in a Child With Sickle Cell Disease on Chronic Transfusion Therapy.

Massive splenic infarction (MSI) is a rare complication of sickle cell disease, as the spleen generally atrophies within the first few years of life. We report a case of MSI in a 12-year-old boy with homozygous sickle cell anemia (Hb SS) whose chronic transfusion therapy resulted in hypersplenism. The occurrence of a complicated MSI in our patient should perhaps further encourage elective splenectomy in such patients, despite known potential perioperative complications and postsplenectomy risks of infection and thrombosis.

Unexpected Anemia and Reticulocytopenia in an Adolescent With Sickle Cell Anemia Receiving Chronic Transfusion Therapy.

In a patient with sickle cell disease receiving chronic transfusion, exacerbation of anemia with reticulocytopenia must prompt consideration of a delayed hemolytic transfusion reaction with hyperhemolysis, as further transfusion may worsen this condition; definitive diagnosis is sometimes difficult. Anemia evolving during parvovirus B19-induced erythroid hypoplasia (transient aplastic crisis) should be attenuated in chronic transfusion patients due to superior survival of transfused over endogenous red blood cells. A 16-year-old with sickle cell disease receiving chronic transfusion of modified intensity (goal to maintain hemoglobin S<50%) who developed symptomatic anemia with reticulocytopenia was later shown to have had transient aplastic crisis.

Therapeutic phlebotomy is safe in children with sickle cell anaemia and can be effective treatment for transfusional iron overload.

Serial phlebotomy was performed on sixty children with sickle cell anaemia, stroke and transfusional iron overload randomized to hydroxycarbamide in the Stroke With Transfusions Changing to Hydroxyurea trial. There were 927 phlebotomy procedures with only 33 adverse events, all of which were grade 2. Among 23 children completing 30 months of study treatment, the net iron balance was favourable (-8·7 mg Fe/kg) with significant decrease in ferritin, although liver iron concentration remained unchanged. Therapeutic phlebotomy was safe and well-tolerated, with net iron removal in most children who completed 30 months of protocol-directed treatment.

Impact of hydroxyurea on clinical events in the BABY HUG trial.

The Pediatric Hydroxyurea Phase 3 Clinical Trial (BABY HUG) was a phase 3 multicenter, randomized, double-blind, placebo-controlled clinical trial of hydroxyurea in infants (beginning at 9-18 months of age) with sickle cell anemia. An important secondary objective of this study was to compare clinical events between the hydroxyurea and placebo groups. One hundred and ninety-three subjects were randomized to hydroxyurea (20 mg/kg/d) or placebo; there were 374 patient-years of on-study observation. Hydroxyurea was associated with statistically significantly lower rates of initial and recurrent episodes of pain, dactylitis, acute chest syndrome, and hospitalization; even infants who were asymptomatic at enrollment had less dactylitis as well as fewer hospitalizations and transfusions if treated with hydroxyurea. Despite expected mild myelosuppression, hydroxyurea was not associated with an increased risk of bacteremia or serious infection. These data provide important safety and efficacy information for clinicians considering hydroxyurea therapy for very young children with sickle cell anemia. This clinical trial is registered with the National Institutes of Health (NCT00006400, www.clinicaltrials.gov).

Effect of hydroxyurea treatment on renal function parameters: results from the multi-center placebo-controlled BABY HUG clinical trial for infants with sickle cell anemia.

BACKGROUND: Children with sickle cell anemia (SCA) often develop hyposthenuria and renal hyperfiltration at an early age, possibly contributing to the glomerular injury and renal insufficiency commonly seen later in life. The Phase III randomized double-blinded Clinical Trial of Hydroxyurea in Infants with SCA (BABY HUG) tested the hypothesis that hydroxyurea can prevent kidney dysfunction by reducing hyperfiltration. PROCEDURE: 193 infants with SCA (mean age 13.8 months) received hydroxyurea 20 mg/kg/day or placebo for 24 months. (99m) Tc diethylenetriaminepentaacetic acid (DTPA) clearance, serum creatinine, serum cystatin C, urinalysis, serum and urine osmolality after parent-supervised fluid deprivation, and renal ultrasonography were obtained at baseline and at exit to measure treatment effects on renal function. RESULTS: At exit children treated with hydroxyurea had significantly higher urine osmolality (mean 495 mOsm/kg H(2) O compared to 452 in the placebo group, P = 0.007) and a larger percentage of subjects taking hydroxyurea achieved urine osmolality >500 mOsm/kg H(2) O. Moreover, children treated with hydroxyurea had smaller renal volumes (P = 0.007). DTPA-derived glomerular filtration rate (GFR) was not significantly different between the two treatment groups, but was significantly higher than published norms. GFR estimated by the Chronic Kidney Disease in Children (CKiD) Schwartz formula was the best non-invasive method to estimate GFR in these children, as it was the closest to the DTPA-derived GFR. CONCLUSION: Treatment with hydroxyurea for 24 months did not influence GFR in young children with SCA. However, hydroxyurea was associated with better urine concentrating ability and less renal enlargement, suggesting some benefit to renal function.

Massive accidental overdose of hydroxyurea in a young child with sickle cell anemia.

The Pediatric Hydroxyurea Phase III Clinical Trial (BABY HUG) confirmed safety and efficacy of hydroxyurea therapy for infants with sickle cell anemia. Treatment was associated with reduction in rates of pain, acute chest syndrome, hospitalizations, and blood transfusions; improved hematologic values; and, perhaps, preservation of organ function. During the study, a 2-year-old ingested at one time an entire 35-day supply of hydroxyurea (612 mg/kg body weight). Despite a serum level of 7,756 µM 4 hours post-ingestion, the only toxicity was transient mild myelosuppression. With wider usage of hydroxyurea anticipated, conservative management of future overdoses seems reasonable (ClinicalTrials.gov NCT00006400).

Influence of severity of anemia on clinical findings in infants with sickle cell anemia: analyses from the BABY HUG study.

BACKGROUND: Clinical complications of sickle cell anemia begin in infancy. BABY HUG (ClinicalTrials.gov, NCT00006400) was a NHLBI-NICHD supported randomized phase III placebo-controlled trial of hydroxyurea (HU) in infants (recruited at 9-18 months) unselected for clinical severity with sickle cell anemia. This secondary analysis of data from BABY HUG examines the influence of anemia on the incidence of sickle cell related complications, and the impact of hydroxyurea therapy in altering these events by comparing children with lower (<25th percentile) and higher (>75th percentile) hemoglobin concentrations at study entry. PROCEDURE: Infants were categorized by: (1) age-adjusted hemoglobin quartiles as determined by higher (Hi) and lower (Lo) hemoglobin concentrations at study entry (9-12 months old: <8.0 and >10.0 gm/dL; 12-18 months old: <8.1 and >9.9 gm/dL) and (2) treatment arm (hydroxyurea or placebo). Four subgroups were created: placebo (PL) LoHb (n = 25), PL HiHb (n = 27), hydroxyurea (HU) LoHb (n = 21), and HU HiHb (n = 18). The primary and secondary endpoints of BABY HUG were analyzed by subgroup. RESULTS: Infants with lower hemoglobin at baseline were more likely to have a higher incidence of clinical events (acute chest syndrome, pain crisis, fever) as well as higher TCD velocities and lower neuropsychological scores at study exit. Hydroxyurea reduced the incidence of these findings. CONCLUSION: Infants with more severe anemia are at risk for increased clinical events that may be prevented by early initiation of hydroxyurea.

Sleep-disordered breathing and transcranial Dopplers in sickle cell disease.

OBJECTIVES: To determine the prevalence of sleep-disordered breathing in children with sickle cell disease and whether there is an association of sleep-disordered breathing with high-risk transcranial Doppler ultrasonography (TCD) velocities. Study DESIGN: Cross-sectional. SETTING: Tertiary care academic medical center. PATIENTS: Sixty-four children (aged 2-14 years) selected for eligible genotype (type SS or Sß(0)-thalassemia) and no history of stroke. INTERVENTIONS: Parents completed the Pediatric Sleep Questionnaire. Overnight polysomnography was performed for children with snoring. The TCD was performed or existing results were obtained for all children; for children who underwent transfusion therapy, readings prior to the transfusion were analyzed. Children with abnormal or conditional TCD (flow velocity ≥170 cm/s in any vessel) were considered high risk. MAIN OUTCOME MEASURES: Prevalence of sleep-disordered breathing and TCD velocity and frequency of high-risk TCD in patients with and without sleep-disordered breathing. RESULTS: The prevalence of snoring was 37.5% (95% CI, 26.7%-49.8%), the prevalence of positive polysomnography findings was 23.7% (14.6%-36.1%), and the prevalence of positive Pediatric Sleep Questionnaire scores was 21.9% (13.4%-33.6%). There was no significant difference in TCD velocity or number of patients with high-risk TCD between nonsnorers and children with snoring but negative polysomnography findings and children with snoring and positive polysomnography findings (P = .91 and P = .66, respectively) or between nonsnorers and snorers with a negative Pediatric Sleep Questionnaire score and snorers with a positive Pediatric Sleep Questionnaire score (P = .76 and P = .33, respectively). CONCLUSION: There is a high prevalence of snoring and sleep-disordered breathing among children with sickle cell disease, but our results do not support an association with cerebrovascular risk.

Stroke With Transfusions Changing to Hydroxyurea (SWiTCH): a phase III randomized clinical trial for treatment of children with sickle cell anemia, stroke, and iron overload.

BACKGROUND: Stroke occurs in 5-10% of children with sickle cell anemia (SCA) and has a high (>50%) risk of recurrence without therapy. Chronic monthly erythrocyte transfusions effectively prevent recurrent stroke, but their long-term use is limited by serious side effects, including iron overload. An alternative to transfusion for secondary stroke prevention in SCA is needed, especially one that also improves the management of iron overload. METHODS: Stroke With Transfusions Changing to Hydroxyurea (SWiTCH) is an NHLBI-sponsored Phase III multicenter randomized controlled clinical trial for children with SCA, stroke, and iron overload (NCT00122980). The primary goal of SWiTCH is to compare 30 months of alternative therapy (hydroxyurea and phlebotomy) with standard therapy (transfusions and chelation) for the prevention of secondary stroke and reduction of transfusional iron overload. DISCUSSION: SWiTCH has several distinctive study features including novel methodological and design components: (1) composite primary endpoint including both stroke recurrence rate and iron burden; (2) non-inferiority design with an "acceptable" increased stroke risk; (3) transfusion goals based on current academic community practices; (4) special oversight for the enrollment and randomization process; (5) overlap treatment period within the alternative treatment arm; (6) masking of the overall trial Principal Investigator to treatment results; (7) inclusive independent stroke adjudication process for all suspected new neurological events; and (8) periodic therapeutic phlebotomy program to alleviate iron overload. CONCLUSION: Investigation of alternative treatments in SWiTCH could lead to changes in the management of cerebrovascular disease for selected patients with SCA, stroke, and iron overload.

A short course of prednisone in the management of acute chest syndrome of sickle cell disease.

BACKGROUND: A short course of dexamethasone therapy may attenuate the course of acute chest syndrome (ACS) of sickle cell disease, but it also increases the risk of early readmission after discharge. Over several years at our institution, an "asthma regimen" of prednisone [2 mg/kg/d (max 80 mg) in 2 divided doses for 5 days] has increasingly been used to treat moderate-to-severe ACS. METHODS: Review of medical records identified 63 patients hospitalized 78 times with ACS over a 2-year period. The clinical course of patients who received prednisone was compared with that of those who did not, particularly to assess the frequency of early (within 2 weeks) readmission after discharge. RESULTS: Eight (15.1%) of the 53 children receiving prednisone and 2 (8%) of the 25 who did not were readmitted within 2 weeks (P=0.33), usually for treatment of pain. Patients with moderate-to-severe ACS were more likely to receive prednisone. There was no difference in the duration of stay or the need for blood transfusion between the 2 groups; 21.8% of all the patients received blood. CONCLUSION: A short course of prednisone did not significantly increase readmission rate after discharge. Larger prospective studies are needed to confirm safety and to establish efficacy.

The pediatric hydroxyurea phase III clinical trial (BABY HUG): challenges of study design.

Evidence of the laboratory benefits of hydroxyurea and its clinical efficacy in reducing acute vaso-occlusive events in adults and children with sickle cell anemia has accumulated for more than 15 years. A definitive clinical trial showing that hydroxyurea can also prevent organ damage might support widespread use of the drug at an early age. BABY HUG is a randomized, double-blind placebo-controlled trial to test whether treating young children ages 9-17 months at entry with a liquid preparation of hydroxyurea (20 mg/kg/day for 2 years) can decrease organ damage in the kidneys and spleen by at least 50%. Creation of BABY HUG entailed unique challenges and opportunities. Although protection of brain function might be considered a more compelling endpoint, preservation of spleen and renal function has clinical relevance, and significant treatment effects might be discernable within the mandated sample size of 200. Concerns about unanticipated severe toxicity and burdensome testing and monitoring requirements were addressed in part by an internal Feasibility and Safety Pilot Study, the successful completion of which was required prior to enrolling a larger number of children on the protocol. Concerns over recruitment of potentially vulnerable subjects were allayed by inclusion of a research subject advocate, or ombudsman. Finally, maintenance of blinding of research personnel was aided by inclusion of an unblinded primary endpoint person, charged with transmitting endpoint data and monitoring blood work locally for toxicity (ClinicalTrials.gov number, NCT00006400).

Transcranial doppler ultrasonography (TCD) in infants with sickle cell anemia: baseline data from the BABY HUG trial.

BACKGROUND: Transcranial Doppler ultrasonography (TCD) is used to predict stroke risk in children with sickle cell anemia (SCA), but has not been adequately studied in children under age 2 years. PROCEDURE: TCD was performed on infants with SCA enrolled in the BABY HUG trial. Subjects were 7-17 months of age (mean 12.6 months). TCD examinations were successfully performed in 94% of subjects (n = 192). RESULTS: No patient had an abnormal TCD as defined in the older child (time averaged maximum mean TAMM velocity > or =200 cm/sec) and only four subjects (2%) had velocities in the conditional range (170-199 cm/sec). TCD velocities were inversely related to hemoglobin (Hb) concentration and directly related to increasing age. CONCLUSION: Determination of whether the TCD values in this very young cohort of infants with SCA can be used to predict stroke risk later in childhood will require analysis of exit TCD's and long-term follow-up, which is ongoing (ClinicalTrials.gov number, NCT00006400).

Urine concentrating ability in infants with sickle cell disease: baseline data from the phase III trial of hydroxyurea (BABY HUG).

BACKGROUND: A urine concentrating defect is quite common in sickle cell anemia, has its onset in early childhood, and may be reversible with transfusion. The Pediatric Hydroxyurea Phase III Clinical Trial (BABY HUG) is a double-blind, placebo-controlled trial to assess efficacy of hydroxyurea in preventing organ damage in young children with sickle cell anemia. PROCEDURES: Enrolled infants were subjected to parent-supervised fluid deprivation, and urine and serum osmolality were determined. RESULTS: Of 185 infants age 7.5-17.9 months (mean 13.0 +/- 2.7) and fluid-deprived 7.4 +/- 2.4 hr (range 4-13), 178 had concurrent determinations of urine and serum osmolality. Mean serum osmolality was 286 +/- 6 mOsm/kg H(2)O (range 275-312) and independent of age, height, weight, or duration of fluid deprivation. Urine osmolality (mean 407 +/- 151, range 58-794 mOsm/kg H(2)O) was greater than serum (P < 0.0001) and correlated with duration of fluid deprivation (P = 0.001). Of 142 (77.2%) who concentrated urine, 54 (29.4%) had urine osmolality >500 mOsm/kg H(2)O. Urine osmolality correlated with (99m)Tc-DTPA clearance (P = 0.02) and serum urea nitrogen (P < 0.0001), but not with serum osmolality, gender, age, height, weight, or serum creatinine. Infants able to produce urine with osmolality >500 mOsm/kg H(2)O had higher mean fetal hemoglobin concentrations than did those who could not (P = 0.014). CONCLUSIONS: Even with often limited fluid deprivation, 77.2% of young infants with sickle cell anemia were able to concentrate urine. Preservation of concentrating ability was associated with higher fetal hemoglobin concentration. Assessment will be repeated after 2 years of hydroxyurea or placebo treatment (ClinicalTrials.gov number, NCT00006400).

A prospective appraisal of pulmonary hypertension in children with sickle cell disease.

OBJECTIVES: Pulmonary hypertension (PHT) is a life-threatening complication of sickle cell disease that occurs in 20% to 40% of adults. Measurement of maximal tricuspid regurgitant jet velocity (TRV) by echocardiography provides a noninvasive screening tool; TRV values > or =2.5 m/s are correlated with PHT and increased mortality. Our objective was to estimate the prevalence of PHT in our pediatric sickle cell population and its possible association with various clinical and laboratory findings, including obstructive sleep apnea and/or pulmonary dysfunction. STUDY DESIGN: Eligible children had measurement of the TRV. Clinical data were collected, including detailed history with a standardized sleep apnea questionnaire; those with suggestive histories had polysomonography. Pulmonary function was assessed using whole body plethysmography. RESULTS: Of 48 subjects (79% homozygous sickle cell anemia; median age 12 y; 11 receiving chronic transfusion) enrolled in the study, 4 (8.3%) had TRV >2.5 m/s; all had homozygous sickle cell anemia and 1 was receiving hydroxyurea after 3 years of transfusion for secondary stroke prevention. Subjects with elevated TRV had higher indirect bilirubin levels; we found no association between elevated TRV and obstructive apnea or pulmonary function abnormalities. CONCLUSIONS: Elevation of TRV was relatively uncommon in our pediatric patients as compared with prevalence reported in adults and may be associated with increased hemolysis. There was no association with obstructive sleep apnea or abnormal pulmonary function.

Intra-individual variation in blood flow velocities in cerebral arteries of children with sickle cell disease.

BACKGROUND: Children with sickle cell disease (SCD) are at elevated risk of stroke. Risk increases with blood flow velocity in selected cerebral arteries, as measured by transcranial Doppler (TCD) ultrasound, and use of TCD to screen these patients is widely recommended. Interpretation of TCD results should be based on knowledge of intra-individual variation in blood flow velocity, information not currently available for sickle cell patients. PROCEDURES: Between 1995 and 2002, 4,141 subjects, 2-16 years old, with homozygous SCD or Sbeta0-thalasemmia and no history of stroke were screened with TCD, including 2,018 subjects screened in one clinical trial (STOP), 1,816 screened in another (STOP 2), and 307 screened in an interim ancillary prospective study. The 812 subjects with >or=2 examinations<6 months apart were selected for analysis, including 242 (29.8%) subjects with normal average velocities (i.e., <170 cm/sec), 350 (43.1%) subjects with conditional velocities (i.e., 170-199 cm/sec), and 220 (27.1%) subjects with abnormal velocities (i.e., >or=200 cm/sec). The intra-subject standard deviation of TCD velocity was estimated from the difference between velocities at the first two interpretable examinations on each subject. RESULTS: An intra-subject standard deviation of 14.9 cm/sec was obtained. Seven (0.9%) subjects had unusually large and unexplained differences between velocities at the two examinations (range of absolute differences: 69-112 cm/sec). CONCLUSIONS: While stroke risk is well demonstrated to increase with increasingly abnormal TCD velocity, given the relatively large intra-subject variability, one TCD examination is generally not sufficient to characterize stroke risk in this patient population.

Risk factors and prediction of outcomes in children and adolescents who have sickle cell anemia.

This article discusses risk factors and prediction in children and adolescents who have sickle cell anemia.

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.

Systemic lupus erythematosus in children with sickle cell disease.

Coexistence of sickle cell disease (SCD) and systemic lupus erythematosus (SLE) has been reported in 11 patients. The authors describe five additional patients with SCD and symptoms initially attributable to SCD who were later found to have SLE. Patients were identified over a 10-year period (1991-2001) in a pediatric sickle cell population numbering approximately 350. All patients are African-American. Age at diagnosis of SLE was 9 to 17 years (median 11 years), and follow-up after diagnosis ranged from 6 months to 10 years (median 3 years). SLE cerebritis (n = 3), serositis (n = 4), and nephritis (n = 2) were common findings. Physicians should be alerted to the possible development of SLE in patients with SCD.