IMPORTANCE Sickle cell disease (SCD) is a life-threatening genetic disorder affecting nearly 100 000 individuals in the United States and is associated with many acute and chronic complications requiring immediate medical attention. Two disease-modifying therapies, hydroxyurea and long-term blood transfusions, are available but underused.OBJECTIVE To support and expand the number of health professionals able and willing to provide care for persons with SCD.EVIDENCE REVIEW Databases of MEDLINE (including in-process and other nonindexed citations), EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, CINAHL, TOXLINE, and Scopus were searched using prespecified search terms and keywords to identify randomized clinical trials, nonrandomized intervention studies, and observational studies. Literature searches of English-language publications from 1980 with updates through April 1, 2014, addressed key questions developed by the expert panel members and methodologists.FINDINGS Strong recommendations for preventive services include daily oral prophylactic penicillin up to the age of 5 years, annual transcranial Doppler examinations from the ages of 2 to 16 years in those with sickle cell anemia, and long-term transfusion therapy to prevent stroke in those children with abnormal transcranial Doppler velocity (Ն200 cm/s). Strong recommendations addressing acute complications include rapid initiation of opioids for treatment of severe pain associated with a vasoocclusive crisis, and use of incentive spirometry in patients hospitalized for a vasoocclusive crisis. Strong recommendations for chronic complications include use of analgesics and physical therapy for treatment of avascular necrosis, and use of angiotensin-converting enzyme inhibitor therapy for microalbuminuria in adults with SCD. Strong recommendations for children and adults with proliferative sickle cell retinopathy include referral to expert specialists for consideration of laser photocoagulation and for echocardiography to evaluate signs of pulmonary hypertension. Hydroxyurea therapy is strongly recommended for adults with 3 or more severe vasoocclusive crises during any 12-month period, with SCD pain or chronic anemia interfering with daily activities, or with severe or recurrent episodes of acute chest syndrome. A recommendation of moderate strength suggests offering treatment with hydroxyurea without regard to the presence of symptoms for infants, children, and adolescents. In persons with sickle cell anemia, preoperative transfusion therapy to increase hemoglobin levels to 10 g/dL is strongly recommended with a moderate strength recommendation to maintain sickle hemoglobin levels of less than 30% prior to the next transfusion during long-term transfusion therapy. A strong recommendation to assess iron overload is accompanied by a moderate strength recommendation to begin iron chelation therapy when indicated.CONCLUSIONS AND RELEVANCE Hydroxyurea and transfusion therapy are strongly recommended for many individu...

Hydroxyurea and transfusion therapy are strongly recommended for many individuals with SCD. Many other recommendations are based on quality of evidence that is less than high due to the paucity of clinical trials regarding screening, management, and monitoring for individuals with SCD.

CUTE CHEST SYNDROME AND painful episodes are the most common precedents of death in adults with sickle cell anemia (SCA). 1 A randomized, doubleblinded, placebo-controlled trial, the

Sickle cell pain includes 3 types: acute recurrent painful crises, chronic pain syndromes, and neuropathic pain. The acute painful crisis is the hallmark of the disease and the most common cause of hospitalization and treatment in the emergency department. It evolves through 4 phases: prodromal, initial, established, and resolving. Each acute painful episode is associated with inflammation that worsens with recurrent episodes, often culminating in serious complications and organ damage, such as acute chest syndrome, multiorgan failure, and sudden death. Three pathophysiologic events operate in unison during the prodromal phase of the crisis: vaso-occlusion, inflammation, and nociception. Aborting the acute painful episode at the prodromal phase could potentially prevent or minimize tissue damage. Our hypothesis is that managing these events with hydration, anti-inflammatory drugs, aggressive analgesia, and possibly vasodilators could abort the crisis and prevent or minimize further damage. Chronic pain syndromes are associated with or accompany avascular necrosis and leg ulcers. Neuropathic pain is not well studied in patients with sickle cell disease but has been modeled in the transgenic sickle mouse. Management of sickle cell pain should be based on its own pathophysiologic mechanisms rather than borrowing guidelines from other nonsickle pain syndromes. (Blood. 2012;120(18): 3647-3656) IntroductionSickle cell disease (SCD) has been primarily considered a disease of children with a few patients surviving to adulthood. Between 1910 and 1950, the median survival of patients with SCD was Ͻ 20 years of age. 1 Sudden death occurred in ϳ 41% of the patients, whereas 29% deaths occurred within 24 hours after the onset of painful crises. 2 By 1980, 50% of children survived to 20 years of age; and by 2009, survival to age 20 years increased to 85% of children. 2 However, if we rewind the clock by more than a century when SCD was first described in the United States, we find that the first 4 SCD patients reported were adults with leg ulcers. [3][4][5][6] Before 1910, there were observations among adult African slaves suggestive of SCD with immunity to malaria and high prevalence of leg ulcers. 7 Moreover, autopsy on a slave with history of fever and respiratory illness in 1846 showed absence of the spleen. 8 The inevitable question then is: where were the children with SCD in the United States before 1910? There must have been children with SCD. The patient reported by Cook and Meyer 5 gave family history of brothers and sisters who died in early life of a disease associated with grave anemia. These children must have lived, suffered, and died prematurely, the dark side of the discovery of sickle cell anemia in the United States. 9 It was not until the early 1930s that children with SCD were recognized. Sickle cell pain between 1930 and 1960Between 1930 and 1960, the emphasis was on studying the basic science of SCD. This period witnessed quantum leaps in defining the specific molecular signature of SCD with the advent ...

A randomized, controlled clinical trial established the efficacy and safety of short-term use of hydroxyurea in adult sickle cell anemia. To examine the risks and benefits of long-term hydroxyurea usage, patients in this trial were followed for 17.5 years during which they could start or stop hydroxyurea. The purpose of this follow-up was to search for adverse outcomes and estimate mortality. For each outcome and for mortality, exact 95% confidence intervals were calculated, or tests were conducted at a 5 0.05 level (P-value <0.05 for statistical significance). Although the death rate in the overall study cohort was high (43.1%; 4.4 per 100 person-years), mortality was reduced in individuals with long-term exposure to hydroxyurea. Survival curves demonstrated a significant reduction in deaths with long-term exposure. Twenty-four percent of deaths were due to pulmonary complications; 87.1% occurred in patients who never took hydroxyurea or took it for <5 years. Stroke, organ dysfunction, infection, and malignancy were similar in all groups. Our results, while no longer the product of a randomized study because of the ethical concerns of withholding an efficacious treatment, suggest that long-term use of hydroxyurea is safe and might decrease mortality. Am. J. Hematol. 85:403-408, 2010. V

Sickle cell disease (SCD) is a pleiotropic genetic disorder of hemoglobin that has profound multi-organ effects. The low prevalence of SCD (~100,000/US) has limited progress in clinical, basic, and translational research. Lack of a large, readily accessible population for clinical studies has contributed to the absence of standard definitions and diagnostic criteria for the numerous complications of SCD and inadequate understanding of SCD pathophysiology. In 2005, the Comprehensive Sickle Cell Centers initiated a project to establish consensus definitions of the most frequently occurring complications. A group of clinicians and scientists with extensive expertise in research and treatment of SCD gathered to identify and categorize the most common complications. From this group, a formal writing team was formed that further reviewed the literature, sought specialist input, and produced definitions in a standard format. This manuscript provides an overview of the process and describes twelve body system categories and the most prevalent or severe complications within these categories. A detailed Appendix provides standardized definitions for all complications identified within each system. This report proposes use of these definitions for studies of SCD complications, so future studies can be comparably robust and treatment efficacy measured. Use of these definitions will support greater accuracy in genotype-phenotype studies, thereby achieving a better understanding of SCD pathophysiology. This should nevertheless be viewed as a dynamic rather than final document; phenotype descriptions should be reevaluated and revised periodically to provide the most current standard definitions as etiologic factors are better understood and new diagnostic options are developed.

Painful crises in patients with sickle cell anemia are caused by vaso-occlusion and infarction. Occlusion of blood vessels depends on (at least) their diameter, the deformability of red cells, and the adhesion of blood cells to endothelium. Deoxygenated sickle cells are rigid because they contain linear polymers of hemoglobin S (Hb S); polymerization is highly concentration dependent, and dilution of Hb S by a nonsickling hemoglobin such as fetal hemoglobin (Hb F) would be expected to lead ultimately to a decrease in the frequency of painful crises. It might also be expected to decrease the severity of anemia, although the pathogenesis of anemia in sickle cell anemia (SS disease) is not clearly understood. Reversion to production of fetal rather than adult hemoglobin became practical with the discovery that HU was an orally effective and relatively safe "switching agent." Preliminary dose-ranging studies led to a double-blind randomized controlled clinical trial, the Multicenter Study of Hydroxyurea in Sickle Cell Anemia (MSH), designed to test whether patients treated with HU would have fewer crises than patients treated with placebo. The MSH was not designed to assess the mechanism(s) by which a beneficial effect might be achieved, but it was hoped that observations made during the study might illuminate that question. The 2 MSH treatment groups were similar to each other and were representative of African-American patients with relatively severe disease. The trial was closed earlier than expected, after demonstration that median crisis rate was reduced by almost 50% (2.5 versus 4.5 crises per year) in patients assigned to HU therapy. Hospitalizations, episodes of chest syndrome, and numbers of transfusions were also lower in patients treated with HU. Eight patients died during the trial, and treatment was stopped in 53. There were no instances of alarming toxicity. Patients varied widely in their maximum tolerated doses, but it was not clear that all were taking their prescribed treatments. When crisis frequency was compared with various clinical and laboratory measurements, pretreatment crisis rate and treatment with HU were clearly related to crisis rate during treatment. Pretreatment laboratory measurements were not associated with crisis rates during the study in either treatment group. It was not clear that clinical improvement was associated with an increase in Hb F. Crisis rates of the 2 treatment groups became different within 3 months. Mean corpuscular volumes (MCVs) and the proportion of Hb F containing red cells (F cells) rose, and neutrophil and reticulocyte counts fell, within 7 weeks. When patients were compared on the basis of 2-year crisis rates, those with lower crisis rates had higher F-cell counts and MCVs and lower neutrophil counts. Neutrophil, monocyte, reticulocyte, and platelet counts were directly associated, and F cells and MCV were inversely associated, with crisis rates in 3-month periods. In multivariable analyses, there was strong evidence of independent association of lower neutr...

Pulmonary hypertension, as indicated by an NT-proBNP level of 160 pg/mL or greater, was very common in patients in the NIH study and in the MSH cohort. The MSH analysis suggests that rates of vaso-occlusive pain episodes in these patients were unrelated to risk of death; this risk was largely determined by occult hemolytic anemia-associated pulmonary hypertension.