Protective role of hemoglobin and fetal hemoglobin in early kidney disease for children with sickle cell anemia

Patients with sickle cell anemia are at risk for organ damage including kidney disease. Microalbuminuria may be an early marker of disease progression. This retrospective review analyzed laboratory and clinical findings in children with sickle cell anemia according to the presence or absence of MA during well clinic sickle cell visits. Results were analyzed in sum as well as by therapeutic intervention (not on therapy,hydroxyurea therapy, or chronic transfusion therapy). Thirty two of 144(22%) children had MA, including 20 of 82 (24%) children not on a therapeutic intervention (chronic transfusion or hydroxyurea). In children not on therapy, low hemoglobin, low fetal hemoglobin and high lactate dehydrogenase were associated with MA. Frequency of positive screens for MA for the different treatment groups were: Hydroxyurea 13%; chronic transfusion 26% and children on no treatment 24%. However,the difference between the hydroxyurea group and the chronic transfusion or no treatment groups did not reach statistical significance.Increased hemoglobin and fetal hemoglobin may provide protection against kidney disease in sickle cell anemia and should be evaluated in a randomized, prospective clinical trial.     

Sustained long-term hematologic efficacy of hydroxyurea at maximum tolerated dose in children with sickle cell disease

Hydroxyurea improves hematologic parameters for children with sickle cell disease (SCD), but its long-term efficacy at maximum tolerated dose (MTD) has not been determined. Between 1995 and 2002, hydroxyurea therapy was initiated for 122 pediatric patients with SCD including 106 with homozygous sickle cell anemia (HbSS), 7 with sickle hemoglobin C (HbSC), 7 with sickle/beta-thalassemia (HbS/ beta-thalassemia [6 HbS/beta0, 1 HbS/beta+]), and 2 with sickle hemoglobin OArab (HbS/OArab). Median age at initiation of therapy was 11.1 years. Hydroxyurea was escalated to MTD, with an average dose of 25.4 +/- 5.4 mg/kg per day; the average duration of hydroxyurea therapy has been 45 +/- 24 months (range, 6-101 months). Hydroxyurea was discontinued for 15 (12%) children with poor compliance. Mild transient neutropenia occurred, but no hepatic or renal toxicity was noted. Hydroxyurea therapy led to significant increases in hemoglobin level, mean corpuscular volume, and fetal hemoglobin (HbF) level, whereas significant decreases occurred in reticulocyte, white blood cell, and platelet counts and serum bilirubin levels. Children with variant SCD genotypes also had hematologic responses to hydroxyurea. HbF induction has been sustained for up to 8 years without adverse effects on growth or increased numbers of acquired DNA mutations. Long-term hydroxyurea therapy at MTD is well tolerated by pediatric patients with SCD and has sustained hematologic efficacy with apparent long-term safety.     

The Effect of Hydroxyurea Therapy in Bahraini Sickle Cell Disease Patients

Hydroxyurea (HU) is used as a disease-modifying agent in sickle cell disease (SCD). Its beneficial effects have been ascribed to inhibition of the sickling process through increase of fetal hemoglobin (HbF) levels and influence on multiple factors affecting adhesion of erythrocytes to vascular endothelium. The present study investigates the effect of HU in SCD patients who were grouped on the basis of association with α- and β-thalassemia using routine laboratory methods. A retrospective cross-sectional chart-review was done of 51 adult Bahraini SCD patients attending Salmaniya Medical Complex, Bahrain. Four sub-groups of cases were identified: (i) homozygous sickle cell anemia, 24 cases; (ii) SCD with microcytosis, 16 cases; (iii) sickle α-thalassemia, seven cases; and (iv) sickle β thalassemia, four cases. Documented laboratory and clinical data included hemoglobin level (Hb), hematocrit (Hct), red cell indices, hemoglobin fractions, hospital admissions (frequency), number of inpatient-days, pain episodes (frequency) and red cell transfusion requirement (number of units). Pre- and post-treatment data were compared. Hydroxyurea treatment led to highly significant reduction of HbS % and pain crisis episodes in all patient groups. Other changes such as increases of total hemoglobin, Hct and HbF and reduction of hospital admissions, inpatient days and red cell units transfused also occurred but with less consistent levels of significance within patient sub-groups. Treatment with HU is beneficial for all subgroups of Bahraini SCD patients, without or with α- and β-thalassemia interactions.     

Principles and problems of transfusion in sickle cell disease

Sickle cell disease (SCD) is associated with red blood cell (RBC) abnormalities and moderate to severe anemia, and blood transfusion is naturally a mainstay of treatment. However, transfusion therapy for SCD may incur special and distinctive adverse effects. Thus, it is important to understand the indications for and goals of transfusion therapy and to be aware of the potential side effects of therapy. Years of unsystematic clinical observations, followed by more carefully designed and in some cases randomized studies, have contributed substantially to our knowledge of transfusion therapy in SCD. However, much remains unknown and areas of controversy persist. In addition, serologic barriers pose enduring roadblocks to the optimization of transfusion therapy for patients with SCD, and the syndrome of massive hemolytic transfusion reactions and hyperhemolysis in SCD persists as a life-threatening complication for which appropriate clinical management is not yet defined.     

A cautionary note regarding hydroxyurea in sickle cell disease

Hydroxyurea can increase fetal hemoglobin (HbF) and improve the clinical course of sickle cell disease (SCD) patients. However, several issues of hydroxyurea therapy remain unresolved, including differences in patients' drug clearance, predictability of drug response, reversibility of sickle cell disease-related organ damage by hydroxyurea, and the efficacy of elevated HbF. We treated two patients with hydroxyurea for periods of 1 to 4 years, monitoring clinical course and laboratory parameters at regular intervals. The first patient (patient A) had a history of chronic pain and extensive hospitalizations. The second patient (patient B) had a history of stroke and refused to continue with chronic transfusion therapy and chelation. Both patients showed a fivefold to tenfold increase in HbF (5% to 25%, 3% to 31%). However, patient A developed an acute chest syndrome, despite an HbF level of 20%. After red blood cell transfusions for hypoxia, the HbF level decreased to 5%. When hydroxyurea dosage was increased, pancytopenia developed and was not resolved until 2 months after hydroxyurea was discontinued; Patient B developed a cerebral hemorrhage on hydroxyurea; he died shortly thereafter. His HbF level was 21% before death. We noted an increase in HbF and a general improvement in the two patients. However, both experienced major SCD-related complications despite HbF levels over 20%. Our findings also suggest that the progressive vascular changes associated with SCD are unlikely to be dramatically affected by increased HbF levels. Because neither the efficacy nor the toxicity of hydroxyurea have been thoroughly investigated, physicians should be cautious in prescribing hydroxyurea for patients with SCD before completion of the National Clinical Trial.     

How we manage iron overload in sickle cell patients

Blood transfusion plays a prominent role in the management of patients with sickle cell disease (SCD), but causes significant iron overload. As transfusions are used to treat the severe complications of SCD, it remains difficult to distinguish whether organ damage is a consequence of iron overload or is due to the complications treated by transfusion. Better management has resulted in increased survival, but prolonged exposure to iron puts SCD patients at greater risk for iron‐related complications that should be treated. The success of chelation therapy is dominated by patient adherence to prescribed treatment; thus, adjustment of drug regimens to increase adherence to treatment is critical. This review will discuss the current biology of iron homeostasis in patients with SCD and how this informs our clinical approach to treatment. We will present the clinical approach to treatment of iron overload at our centre using serial assessment of organ iron by magnetic resonance imaging.     

How we treat delayed haemolytic transfusion reactions in patients with sickle cell disease

Transfusion therapy is effective in the prevention and treatment of many complications of sickle cell disease (SCD). However, its benefits must be balanced against its risks, including delayed haemolytic transfusion reactions (DHTR). Not only is the relative rate of alloimmunization higher in patients with SCD than in other patient populations, but attendant risks associated with DHTR are even greater in SCD. Clinicians' awareness of DHTR events is poor because symptoms of DHTR mimic acute vaso‐occlusive pain and immunohaematology findings are often negative. Transfusions delivered in the acute rather than elective setting appear to confer a higher risk of DHTR. Management of DHTR in SCD depends on the clinical severity, ranging from supportive care to immunosuppression, and optimization of erythropoiesis. DHTR must be considered in any recently transfused patient presenting with acute sickle cell pain. Meticulous documentation of transfusion and immunohaematology history is key. We anticipate an increase in DHTR events in SCD patients with the increasing use of red blood cell transfusion therapy.     

COVID-19 outcomes in sickle cell disease and sickle cell trait

Throughout the Coronavirus Disease 2019 (COVID-19) pandemic, understanding the effects of COVID-19 on persons with Sickle Cell Disease (SCD) and Sickle Cell Trait (SCT) has garnered interest. Patients with SCD diagnosed with COVID-19 utilize the emergency department and are hospitalized at significantly higher rates compared to the general population, with vaso-occlusive crisis and acute chest syndrome as the leading presentations. Whether SCD alone increases the likelihood of severe COVID-19 illness remains uncertain; however, potential risk factors for severe disease among patients with SCD include older age, frequent acute care visits for pain, haemoglobin SC disease, and pre-existing end-organ disease. SCT status may also influence COVID-19 outcomes, particularly among those with pre-existing co-morbidities. Corticosteroids in patients with SCD and COVID-19 should be used with extreme caution given strong associations between corticosteroid exposure and severe vaso-occlusive crisis, with prophylactic transfusion administered if corticosteroids are deemed necessary. Hydroxyurea may be protective in COVID-19.     

Red Cell Transfusion Practices in Neonatal Intensive Care Unit: An Experience from Tertiary Care Centre

Red cells are the most often transfused blood components during the neonatal period. The aim of the present study was to obtain information regarding the relationship of red cell transfusion with clinical outcomes and to evaluate red cell transfusion practices in neonatal centre of a tertiary care centre. The clinical history, blood component details and laboratory parameters were evaluated with clinical outcomes. The neonates requiring transfusion of red cells were then followed up in the Blood bank for various laboratory parameters. Clinical parameters and clinical outcome were noted from case files. During the study period, 291 neonates were admitted in NICU. 2 neonates were excluded as they were congenitally malformed. Out of 289 admitted neonates, 61 neonates (21.1%) received blood and blood component transfusions. Out of 61 neonates, 20 received red cell transfusions. Mean donor exposure of red cells was 1.2. The mean volume of transfused red cell was 39.6 ml with mean age of red cells was 3.6 days. The mean pre- and post-transfusion Hct was 25.3 and 30.4%, respectively. The most common indication for red cell transfusion was low haemoglobin. There was a significant increase in lactate level and decrease in base excess in transfused neonates. However, no statistically significant correlations were found between transfusions and neonatal weight gain, apnoea, respiratory support and mortality. Transfusion of red cells has significant effect on laboratory parameters as compared to clinical parameters such as weight gain, episodes of apnoea and respiratory support.     

Cerebral hemodynamics in children with sickle cell disease in India: An observational cohort study

India has the second highest number of cases of sickle cell disease (SCD) and affects the most socioeconomically disadvantaged communities living in a horizontal belt from Gujarat to Odisha state. Despite high prevalence, information about cerebral hemodynamics among children with SCD in India remains scarcely described.We performed transcranial Doppler (TCD) to assess cerebral hemodynamics among Indian children with SCD and evaluated their association with clinical and hematological parameters.Children aged 3-18years, diagnosed with SCD living in Raipur in Chhattisgarh and Ahmedabad in Gujarat state were recruited. TCD was performed to obtain flow velocities from middle cerebral (MCA), intracranial internal carotid (ICA) and basilar artery. Associations were evaluated between timed-average-mean-maximum velocities (TAMMV) and various clinical and hematological parameters.Our prospective study included 62 consecutive children with known SCD. Mean ± SD age of the study population was 9.8 ± 3.9 years and 31 (50%) were male. Mean ± SD hemoglobin was 8.64 ± 1.34 Gm/dL while the mean HbSS ± SD was 70.25 ± 15.27%. While 6 (9.6%) children had suffered from stroke during previous 2 years, 7 (11%) demonstrated abnormal TAMMV. Higher HbSS level along with history of iron chelation therapy, blood transfusion and/or stroke showed a trend towards having higher TAMMV.Stroke and cerebral hemodynamic alterations are common among Indian children with SCD. Larger studies with detailed neuroimaging and genetic evaluations are needed for better understanding, characterization, risk stratification as well as optimization of the timing of blood transfusion to reduce physical disabilities among Indian children with SCD.     

Rituximab for prevention of delayed hemolytic transfusion reaction in sickle cell disease

Delayed hemolytic transfusion reaction (DHTR), a life-threatening transfusion complication in sickle cell disease (SCD), is characterized by a marked hemoglobin drop with destruction of both transfused and autologous red blood cells (RBCs) and exacerbation of SCD symptoms. One mechanism of RBCs destruction is auto-antibody production secondary to transfusion. As rituximab specifically targets circulating B cells, we thought that it could be beneficial in preventing this immune-mediated transfusion complication. We report the case of a SCD patient who previously experienced DHTR with auto-antibodies and who needed a new transfusion. DHTR recurrence was successfully prevented by rituximab administration prior transfusion, supporting the safe use of rituximab to prevent DHTR in SCD patients as a second line approach when other measures failed.     

The role of religious leaders and faith organisations in haemoglobinopathies: a review

Background  

Sickle cell disease (SCD) is now the most common genetic condition in the world including the UK with an estimate of over 12,500 affected people and over 300 new births per year. Blood transfusion therapy plays a very important role as a disease-modifying strategy in severe SCD e.g. primary and secondary stroke prevention and other acute life-threatening complications such as acute chest infections and acute multi-organ failure. Blood transfusion, however, carries a number of risks including alloimmunisation. There is the need to increase the level of awareness and education about SCD and also to increase blood donation drive among affected communities. These communities are mostly ethnic minority populations who are recognised to have poor access to health care services. Due to the strong impact of religion on these populations, faith organisations may provide potential access for health promotion and interventions.     

A Case Report of Darbepoetin Treatment in a Patient With Sickle Cell Disease and Chronic Renal Failure Undergoing Regular Hemodialysis Procedures That Induce a Dose-Dependent Extension of Blood Transfusion Intervals

Abstract: In this case, a female Nigerian patient suffered from sickle cell disease (SCD, hemoglobin SS)-induced chronic renal failure and was undergoing hemodialysis treatment. Due to SCD crisis and renal anemia the patient received regular blood transfusions when the hemoglobin concentration fell below 5.0 g/L. Blood transfusion associated iron-overload was noticed. To reduce the iron-overload side effects, we started an erythropoietin therapy (darbepoetin) to extend the blood transfusion interval, using 30–150 µg/week. As a result of our investigation we observed that darbepoetin can significantly extend blood transfusion intervals without increasing SCD crisis. To substantiate our observation, further investigations are needed with more SCD patients undergoing regular hemodialysis treatment.     

Hemoglobinopathies and Stroke: Strategies for Prevention and Treatment

OPINION STATEMENT: Current treatment options for stroke in sickle cell disease (SCD) and thalassemia are limited. Hypercoagulation occurs in both diseases partly due to activated platelets and red blood cell dysmorphology and dysfunction, resulting in chronic anemia. This overlapping pathophysiology of the nervous system promotes the role of some common treatment modalities for these similar diseases. The current evidence suggests that chronic exchange transfusion and stem cell transplantation/bone marrow transplant (BMT) can be used in both diseases. Exchange transfusion is the mainstay of therapy of acute stroke in SCD whereas blood transfusions and hydroxyurea appear to be the most effective current treatments. However, evidence suggests that exchange transfusion should be initiated in acute ischemic stroke (AIS) and chronic transfusion continued in both diseases after AIS. Exchange transfusion can also be used acutely in AIS with thalassemia as this disorder is also associated with hypervolemia at baseline, occurring secondary to chronic anemia. The ideal length of chronic transfusions for both primary and secondary stroke prevention still needs to be better defined. Stem cell transplant or BMT is the only curative treatment for both diseases. However, timing needs to be further investigated. If transplantation is effective, it may need to be done before the child with SCD expresses disease, such as in infancy. However, in infancy, we cannot predict the severity of the phenotype in SCD with certainty, so an individual decision about transplantation is difficult to make. In thalassemia, transplantation may be effective later because vasculopathy is not the problem as in SCD. Furthermore, cerebrovascular disease occurs later in thalassemia than in SCD. Finally, aspirin is a treatment modality that also warrants further investigation. There are limited studies on the effectiveness of aspirin in SCD and thalassemias. Few studies have demonstrated clinical improvement of stroke in patients with hemoglobinopathies. Given the successful use of aspirin in the treatment and prevention of recurrent cardioembolic events in patients without hemoglobinopathies, diseases with hypercoagulability, such as SCD and thalassemia, may also benefit from the use of aspirin for treatment and prevention. However, the evidence available is based on case and retrospective studies, necessitating future larger and more valid studies to evaluate safety and effectiveness.     

Treatment with hydroxyurea in thalassemia intermedia with paravertebral pseudotumors of extramedullary hematopoiesis

Excessive ineffective erythropoiesis in thalassemia intermedia may cause paravertebral pseudotumors of extramedullary hematopoiesis. Due to the proximity to the spinal canal, these paravertebral masses carry the risk of severe neurological damage. Treatment strategies include hypertransfusion, radiotherapy, and laminectomy. Hydroxyurea, stimulating fetal hemoglobin synthesis, may represent an alternative therapeutic approach. We report on a 26-year-old patient suffering from thalassemia intermedia with progressive anemia symptoms and presenting multiple intrathoracic paravertebral pseudotumors of extramedullary hematopoiesis. Hypertransfusion therapy and splenectomy were followed by regular transfusion (baseline hemoglobin 10 g/dl) and chelation with desferrioxamine. With this treatment, clinical symptoms disappeared, paravertebral hematopoietic masses did not progress, but severe hemosiderosis developed within a few years. Hydroxyurea therapy was initiated to increase the efficacy of erythropoiesis, thereby reducing the required transfusion volume but suppressing concomitantly further expansion of extramedullary hematopoiesis, and finally leading to a reduction of transfusional iron load. Treatment was started with 4 mg/kg per day and stepwise increased to 12.5 mg/kg per day. The fetal hemoglobin concentration increased from 4.5 to 5.5 g/dl after 1 year and to 9.9 g/dl after 2 years of treatment. The yearly transfusion volume was halved during the 1st year of treatment. At present, after 26 months of treatment, the patient has been transfusion-independent for 10 months. Serum ferritin levels decreased from 2844 to 1335 ng/ml. Size and shape of paravertebral hematopoietic pseudotumors remained stable. No side effects of hydroxyurea have been observed. In thalassemia intermedia patients with extramedullary hematopoiesis, hydroxyurea may lead to independence from regular transfusion therapy without further expansion of ectopic hematopoietic tissue.     

Five years of experience with hydroxyurea in children and young adults with sickle cell disease

The short-term beneficial effect of hydroxyurea (HU) in sickle cell disease (SCD) has been proven by randomized studies in children and adults. The Belgian registry of HU-treated SCD patients was created to evaluate its long-term efficacy and toxicity. The median follow-up of the 93 patients registered is 3.5 years; clinical and laboratory data have been obtained for 82 patients at 1 year, 61 at 2 years, 44 at 3 years, 33 at 4 years, and 22 after 5 years. On HU, the number of hospitalizations and days hospitalized dropped significantly. Analysis of the 22 patients with a minimum of 5 years of follow-up confirm a significant difference in the number of hospitalizations (P =.0002) and days in the hospital (P <.01), throughout the treatment when compared to prior to HU therapy. The probabilities of not experiencing any event or any vaso-occlusive crisis requiring hospitalization during the 5 years of treatment were, respectively, 47% and 55%. On HU, the rate per 100 patient-years of severe events was estimated to be 3.5% for acute chest syndrome, 1.2% for aplastic crisis, 0.4% for splenic sequestration; it was 0% for the 9 patients with a history of stroke or transient ischemic attack followed for an average of 4 years. No important adverse effect occurred. Long-term chronic treatment with HU for patients with SCD appears feasible, effective, and devoid of any major toxicity; in patients with a history of stroke, HU may be a valid alternative to chronic transfusion support. (Blood. 2001;97:3628-3632)     

Sudden Cardiac Death Unresponsive to Implantable Defibrillator Therapy: An Urgent Target for Clinicians,Industry and Government

A major expansion in utilization of implantable cardioverter-defibrillators (ICDs) is anticipated based on the results of randomized clinical trials (RCT) that demonstrate increased survival in a sizable population of patients with reduced left ventricular function. However, if RCT accurately reflect clinical practice, then a substantial proportion of patients will die suddenly despite ICD implantation. ICD-unresponsive sudden cardiac death (SCD) has been recognized since the initial ICD experience. Yet, despite 25 years of technical advances, the frequency of ICD-unresponsive SCD has not declined. Pooled analysis of RCT indicates a crude rate of ICD-unresponsive SCD of 5%. This may not cause alarm in an average practice, but it comprises about 30% of cardiac deaths. Meta-analyses of RCT show that ICD therapy is associated with a relative risk reduction of SCD of approximately 60%, far less than the greater than 90% efficacy that many expect. The suboptimal performance of ICD therapy accounts for the failure of some RCT to achieve statistically significant effects on survival. The number of patients with ICD-unresponsive SCD is highly correlated with the number of cardiac deaths among control patients as well as ICD recipients. Otherwise, no definite patterns have emerged that clearly distinguish this mode of demise from other modes of cardiac death. Retrospective post-hoc analyses have not revealed distinguishing characteristics of patients with ICD-unresponsive SCD with respect to clinical variables, pre-terminal symptoms or to the setting of the terminal event. Despite advanced storage capabilities of implanted devices, almost no information has become available from RCT regarding the terminal rhythm or the response of the ICD. These observations have implications for clinical management and research. Candidates for ICD implantation based on RCT should be accurately informed about the residual risk of SCD. Investigators seeking to identify populations likely to benefit from ICD therapy based on SCD incidence should recognize that a significant fraction may not respond to ICD therapy. Reducing the incidence of ICD-unresponsive SCD would substantially improve survival and cost-effectiveness related to ICD therapy. Close cooperation between clinicians, investigators and representatives of industry and government is urgently needed to develop strategies to identify patients prone to ICD-unresponsive SCD, to determine its mechanisms and to develop methods of prevention and treatment.     

Plasma glial fibrillary acidic protein levels in a child with sickle cell disease and stroke

A 12-year-old boy with HbSS sickle cell disease (SCD) was admitted with an acute febrile illness and developed overt stroke 3 days later. Plasma glial fibrillary acidic protein levels were elevated, as compared to pediatric controls, 32 h prior to the clinical diagnosis of stroke, peaked immediately prior to the exchange transfusion, and remained elevated 1 year later despite chronic transfusion therapy. Stroke in SCD can occur in the setting of acute illness, and a biomarker that could predict the onset and triage ill children to therapeutic intervention more quickly would be useful.     

Indications for red cell transfusion in sickle cell disease

Transfusion of red blood cells is an important therapeutic method employed in the care of people with sickle cell disease (SCD). There are several clinical situations in which patients with SCD clearly need red cell transfusion (RCT). In other situations, the indication for RCT is doubtful, controversial, or ill-advised. RCT is used on either an episodic or chronic basis in the management of SCD. Episodic transfusions are usually applied in a patient who has already developed a serious complication of SCD or are used to reduce the chances for the development of a complication. Chronic transfusion therapy is often used to prevent the recurrence of a major complication such as a stroke. Recently, chronic transfusion has been applied to patients with evidence of cerebrovascular disease to prevent the first occurrence of stroke.     

Retinopathy in Egyptian patients with sickle cell disease: A cross-sectional study

Sickle cell disease (SCD) is a disorder that causes red blood cells to become sticky and rigid. Sickle cells can block blood flow in small blood vessels depriving the eye of oxygen and cause damage. This is called sickle retinopathy that can progress to severe proliferative sickle cell retinopathy, bleeding into the eye, detachment of the retina or even loss of vision.To assess ocular manifestations and detect frequency of retinopathy in patients with SCD.Cross-sectional study was conducted on 32 patients with SCD. They were 22 males and 10 females with mean age of 12 years. Routine investigations as well as ophthalmological examination including visual acuity, fluorescein angiography and optical coherence tomography were done.We found that 8 patients (25%) suffered from proliferative retinopathy, 10 patients (31%) showed tortuous retinal veins, while 14 patients (44%) were normal. All patients showed macular thinning on optical coherence tomography examination.We concluded that frequency of retinopathy in patients with SCD is more than expected and it was higher in patients who started transfusion at a later age. More attention should be paid for this problem and close observations and follow up is strongly needed.