Mortality in sickle cell disease. Life expectancy and risk factors for early death

Incentive spirometry to prevent acute pulmonary complications in sickle cell diseases

BACKGROUND

This study was designed to determine the incidence of thoracic bone infarction in patients with sickle cell diseases who were hospitalized with acute chest or back pain above the diaphragm and to test the hypothesis that incentive spirometry can decrease the incidence of atelectasis and pulmonary infiltrates.

METHODS

We conducted a prospective, randomized trial in 29 patients between 8 and 21 years of age with sickle cell diseases who had 38 episodes of acute chest or back pain above the diaphragm and were hospitalized. Each episode of pain was considered to be an independent event. At each hospitalization, patients with normal or unchanged chest radiographs on admission were randomly assigned to treatment with spirometry or to a control nonspirometry group. Each patient in the spirometry group took 10 maximal inspirations using an incentive spirometer every two hours between 8 a.m. and 10 p.m. and while awake during the night until the chest pain subsided. A second radiograph was obtained three or more days after admission, or sooner if clinically necessary, to determine the incidence of pulmonary complications. Bone scanning was performed no sooner than two days after hospital admission to determine the incidence of thoracic bone infarction.

RESULTS

The incidence of thoracic bone infarction was 39.5 percent (15 of 38 hospitalizations). Pulmonary complications (atelectasis or infiltrates) developed during only 1 of 19 hospitalizations of patients assigned to the spirometry group, as compared with 8 of 19 hospitalizations of patients in the nonspirometry group (P = 0.019). Among patients with thoracic bone infarction, no pulmonary complications developed in those assigned to the spirometry group during a total of seven hospitalizations, whereas they developed during five of eight hospitalizations in the nonspirometry group (P = 0.025).

CONCLUSIONS

Thoracic bone infarction is common in patients with sickle cell diseases who are hospitalized with acute chest pain. Incentive spirometry can prevent the pulmonary complications (atelectasis and infiltrates) associated with the acute chest syndrome in patients with sickle cell diseases who are hospitalized with chest or back pain above the diaphragm.

Advances in the prenatal and molecular diagnosis of the hemoglobinopathies and thalassemias

Prenatal diagnosis is available for pregnancies at risk for virtually all inherited disorders of hemoglobin production. The field of reproductive genetics must confront many ethical, legal, and social concerns regarding its use, many of which derive from a woman's desire to bear children but legal right to abortion. The goal of more widespread utilization of prenatal diagnosis is sought in the context of questioning the ethical control to be exerted over the biological makeup of future generations. Its appropriate application would be facilitated greatly by the availability of reliable DNA markers of disease severity. Advances in fetal sampling and in detecting mutant globin genes have provided the safe, accurate methodology required for prenatal diagnosis. Chorionic villus sampling in the first trimester has become standard practice, but second trimester amniocentesis also is used for sampling fetal DNA. The use of preimplantation diagnosis and testing fetal cells from the maternal circulation will soon be practical. DNA-based detection of globin gene mutations has been facilitated greatly by the polymerase chain reaction revolution, and several reliable diagnostic methods are available. Polymerase chain reaction-based methods rely on restriction analysis, allele-specific hybridization or amplification, DNA sequence analysis, and new non-polymerase chain reaction methods for DNA amplification in vitro. These methods are available for detecting hemoglobinopathy, thalassemia, and thalassemic-hemoglobinopathy genes that affect alpha- or beta-globin loci.

Nursing management of children with sickle cell disease: an update

This article reviews current trends in managing children with sickle cell disease (SCD). The pathophysiology, medical and nursing management, and complications of SCD are discussed. Current trends and research findings related to improving the prognosis of children with SCD are offered. The importance of the nurse's role in educating the family about the disease process and clinical interventions to prevent or manage complications are stressed. Lastly, a nursing care plan is offered which focuses on pertinent nursing diagnosis.

Transplanted sickle-cell disease patients with autologous bone marrow recovery after graft failure develop increased levels of fetal haemoglobin which corrects disease severity

Bone marrow transplantation (BMT) is the only curative therapy for sickle-cell disease (SCD), but is not devoid of failure risk. Nine patients with severe SCD were grafted in our institution between 1988 and 1993. Six patients successfully engrafted, but three failed to engraft and had delayed autologous recovery. All patients had, prior to BMT, low levels of fetal haemoglobin (HbF < or = 3.5%). No change in HbF occurred in successfully grafted patients. In the three patients with graft failure HbF increased and remained persistently present at a high level (> or = 22%) 14 months, 16 months and 39 months post BMT, although two of the three patients were homozygous for either the Benin or the Central African Republic haplotype, a characteristic associated with low HbF level. Of interest, these three previously severely affected patients remain free of vaso-occlusive events. The mechanism responsible for the expression of high levels of HbF in our three patients with graft failure is not understood, but it protects them from the recurrence of severe vaso-occlusive crises.

A comparison of conservative and aggressive transfusion regimens in the perioperative management of sickle cell disease. The Preoperative Transfusion in Sickle Cell Disease Study Group

BACKGROUND

Preoperative transfusions are frequently given to prevent perioperative morbidity in patients with sickle cell anemia. There is no consensus, however, on the best regimen of transfusions for this purpose.

METHODS

We conducted a multicenter study to compare the rates of perioperative complications among patients randomly assigned to receive either an aggressive transfusion regimen designed to decrease the hemoglobin S level to less than 30 percent (group 1) or a conservative regimen designed to increase the hemoglobin level to 10 g per deciliter (group 2).

RESULTS

Patients undergoing a total of 604 operations were randomly assigned to group 1 or group 2. The severity of the disease, compliance with the protocol, and the types of operations were similar in the two groups. The preoperative hemoglobin level was 11 g per deciliter in group 1 and 10.6 g per deciliter in group 2. The preoperative value for hemoglobin S was 31 percent in group 1 and 59 percent in group 2. The most frequent operations were cholecystectomies (232), head and neck surgery (156), and orthopedic surgery (72). With the exception of transfusion-related complications, which occurred in 14 percent of the operations in group 1 and in 7 percent of those in group 2, the frequency of serious complications was similar in the two groups (31 percent in group 1 and 35 percent in group 2). The acute chest syndrome developed in 10 percent of both groups and resulted in two deaths in group 1. A history of pulmonary disease and a higher risk associated with surgery were significant predictors of the acute chest syndrome.

CONCLUSIONS

A conservative transfusion regimen was as effective as an aggressive regimen in preventing perioperative complications in patients with sickle cell anemia, and the conservative approach resulted in only half as many transfusion-associated complications.

Low-intensity oral anticoagulation in sickle-cell disease reverses the prethrombotic state: promises for treatment?

Increased plasma levels of prothrombin fragment 1 + 2 (F1 + 2) found in patients with sickle-cell disease reflect enhanced endogenous thrombin generation. We postulate that hypercoagulability contributes to vaso-occlusion. The intensity of acenocoumarol treatment required to reduce the F1 + 2 level to 50% of pretreatment level was investigated in seven patients with symptomatic sickle-cell anaemia during steady-state disease for a period of 2 months. All patients had increased levels of F1 + 2 compared with an age-matched control group. Normalization of the F1 + 2 was achieved at a median INR of 1.64 (range 1.18-2.2). It is concluded that low-intensity oral anticoagulation normalizes the hypercoagulability in sickle-cell disease.

Blood transfusion in sickle cell disease

Blood transfusion is used as a life-saving and prophylactic treatment in sickle cell disease. Despite the many complications associated with its use, few randomised controlled trials and careful research studies have been performed to fully define its role. This subjects is, therefore, discussed in the context of the current literature and authors' experience.

Gender and haplotype effects upon hematological manifestations of adult sickle cell anemia

In Africa, the beta-globin gene cluster haplotype may be associated with variation of Hb F levels in subjects with sickle cell anemia (SS). These observations have not yet been conclusively confirmed in SS out of Africa, perhaps because of small sample sizes, the predominance of haplotype heterozygotes, and diverse influences, including gender, upon Hb F levels. We studied 384 adult African-American SS patients (mean age, 31 years) and explored the relationship of gender, beta-globin gene cluster haplotype, and alpha thalassemia to hematological values and Hb F levels. Both haplotype and gender influenced Hb F concentration. In the total sample, Hb F was higher in females than in males (8.2 vs. 6.5%). In 35 males who were either homozygous for the Senegal chromosome or had the Senegal/Benin haplotype, the mean percent Hb F (8.0%) was equivalent to the Hb F level in females with Benin and Bantu haplotypes (approximately 7.5%). Both females and males homozygous for the Senegal haplotype chromosome or with the Senegal/Benin combination had a significant increase in Hb F compared to other groups. In 44 Senegal/Senegal or Senegal/Benin females the Hb F was 10.9%, or 1.0 g/dl, the highest value observed in all primary analysis groups. Preliminary analyses suggested that the presence of a Bantu chromosome blunted the gender-associated difference in Hb F, but Hb F differences between females with the Senegal/Benin haplotype (11.2%) and the Senegal/Bantu haplotype (8.8%) were not statistically significant. Hemoglobin concentrations were higher in males than in females except in subjects with at least one Senegal haplotype chromosome, where hemoglobin levels were equal. As expected, alpha thalassemia reduced the MCV, increased hemoglobin concentration, and lowered reticulocyte counts, regardless of haplotype. Hb F levels were not affected by the presence of alpha thalassemia in any group. We conclude that gender and beta-globin gene cluster haplotype interact significantly in the modulation of Hb F and anemia in adults with SS.

Effects of a long-term transfusion regimen on sickle cell-related illnesses

The efficacy of a long-term transfusion regimen in preventing sickle cell disease complications is unknown. We examined 17 patients before, during, and after transfusion for cerebral vascular accident and vaso-occlusive crisis. Total hospitalization rate, as well as admissions for vaso-occlusive crisis, cases of acute chest syndrome, and bacterial infections decreased while patients were on a transfusion regimen.

Isobutyramide, an orally bioavailable butyrate analogue, stimulates fetal globin gene expression in vitro and in vivo

Butyrate and other short-chain fatty acids stimulate fetal globin gene expression and have potential for ameliorating the beta globin disorders. Butyrate, however, is rapidly metabolized in vivo and reaches only micromolar concentrations in plasma. We report here that a branched-chain derivative of butyrate, isobutyramide, increases gamma globin gene expression in cultured human erythroid progenitors in vitro and stimulates activity from a minimal gamma globin gene promoter linked to a reporter gene in stable and transient expression assays, with slightly less activity in these in vitro assays than butyrate. In vivo, administration of isobutyramide to anaemic adult baboons rapidly stimulates fetal globin synthesis and F-reticulocyte production. Plasma concentrations at millimolar levels are achieved after a single intravenous or oral dose (500-600 mg/kg), and these concentrations are maintained for 9.5-10.5 h. These results indicate that although isobutyramide has slightly less activity than butyrate in vitro in enhancing fetal globin expression at the cellular and molecular level, its prolonged in vivo half-life may provide superior activity as a therapeutic agent for reactivating fetal globin gene expression in vivo.

Sickle cell anemia and fetal hemoglobin

Fetal hemoglobin, the predominant hemoglobin of the fetus, is good for sickle cell anemia. This hemoglobin inhibits the polymerization of sickle hemoglobin. Clinical studies have shown that at any level of fetal hemoglobin, the more that is present, the better off is the patient. We are now able to increase fetal hemoglobin levels by pharmacologic means. We should know shortly if this is associated with clinical benefit.