Acceleration in linear growth after splenectomy for hypersplenism in homozygous sickle cell disease

Hypersplenism Affects Growth and Haematology in HbSS: Observations from the Jamaican Birth Cohort

In 296 patients with homozygous sickle cell disease (HbSS) detected during the screening of 100,000 deliveries between 1973-1981, chronic hypersplenism defined as a spleen measuring ≥4 cm below the costal margin with evidence of prolonged red cell sequestration occurred in 30 (10.1%) subjects, 23 resolved by splenectomy and 7 resolved spontaneously. Median age at splenectomy was 4.8 years and following splenectomy, median values for hemoglobin increased by 2.3 g/dL, reticulocytes fell by 8.3%, total nucleated cells fell by 2.2%, and platelets increased by 29,813 × 109/dL. Mean splenic weight at splenectomy was 340 g representing 0.5%-4.9% of post-splenectomy body weight. Following splenectomy, height increased at a greater rate than in a matching period for controls (95% CI 0.11-4.06. p = 0.04). Risk factors for hypersplenism, did not differ among commonly used determinants of sickling, fetal hemoglobin (HbF), α globin gene number, or β globin haplotype. A history of acute splenic sequestration preceded hypersplenism more commonly among splenectomized cases (20/23 compared with 0 of 7 resolving spontaneously (Fishers exact test p < 0.001). Factors causing hypersplenism remain largely unknown but splenectomy after a period of monitoring for spontaneous regression, improves hematology and growth.

[Splenic dysfunction in sickle cell disease: An update]

The spleen filters blood cells and contributes to the immune defense. The red pulp clears the blood from altered red blood cells via its unique microcirculatory network ; while the white pulp is a secondary lymphoid organ, directly connected to the bloodstream, whose specificity is the defense against encapsulated bacteria through the production of "natural" IgM in the marginal zone. Various health conditions can cause acquired impairment of the splenic function (or hyposplenism) directly and/or through therapeutic splenectomy. Hypo/asplenia is complicated by an increased susceptibility to encapsulated germ infections, but an increased risk of thrombosis and pulmonary hypertension has also been reported after surgical splenectomy. Homozygous sickle cell disease is the most common disease associated with functional asplenia. The latter appears early in childhood likely through repeated ischemic alterations caused by the sickling of red blood cells. In addition, specific complications such as hypersplenism and acute splenic sequestration can occur and may be life-threatening. We provide here an update on the role and physiology of the spleen, which will allow a better understanding of the pathophysiology of spleen damage and its consequences in sickle cell disease.

Spleen size in homozygous sickle cell disease: trends in a birth cohort using ultrasound

OBJECTIVES

To provide ultrasound baselines for spleen length in homozygous sickle cell disease (HbSS) and in normal controls with a HbAA genotype.

METHODS

The Jamaican cohort study identified 311 babies with HbSS and 246 matched HbAA controls during the screening of 100,000 consecutive deliveries in Kingston, Jamaica from 1973 to 1981. Ultrasonography commenced in 1988 when the youngest patients were aged 6 years at which time deaths, emigrations and default had reduced the numbers to 206 HbSS and 89 controls. It continued annually until 2000.

RESULTS

The spleen was visualized in all HbAA controls but in only 1103/2138 (52%) scans in HbSS. Where available, mean splenic lengths were significantly lower in HbSS (77-103 mm in males, 70-83 mm in females) compared to normal controls (89-101 mm in males, 86-95 mm in females). Assessed by statistical modelling after adjusting for body height, the splenic ratio (splenic length/body height) declined over the age range 12-20 years in HbSS, consistent with progressive splenic fibrosis. Genetic factors known to inhibit sickling, α thalassemia and fetal hemoglobin level (HbF) significantly reduced the decline in splenic ratio. Clinical splenomegaly was an insensitive measure of splenic enlargement as only 50% of patients aged 18 years and above with spleens measuring ≥150 mm on ultrasonography had palpable spleens.

CONCLUSIONS

An age-related decline in splenic length occurred in HbSS and occurred more slowly with genetic factors known to inhibit sickling. The standards provided may be of value in assessing minor degrees of subclinical acute splenic sequestration.

ADVANCES IN KNOWLEDGE

These are the first standards available for splenic length in HbSS. They may be useful in detecting red cell sequestration, not apparent from clinical splenomegaly and also provide a model for identifying factors inhibiting vaso-occlusion.

Splenectomy in Jamaican children with sickle cell disease: Outcome of selective blood transfusion

We reviewed the post-operative morbidity and mortality of open splenectomy undertaken in conjunction with selective blood transfusion in Jamaican children with sickle cell disease. Data were collected on 150 splenectomies performed between November 1994 and October 2017. Selective blood transfusion involved raising haemoglobin levels to approximately 100 g/L in patients with admission haemoglobin ≥10 g/L below steady state. There was no mortality. Mean post-operative stay was 3.2 days with a median of three days. Total morbidity was 19/150 cases (12.7%), with acute chest syndrome accounting for 11/19 (57.9%). Among the non-transfused, acute chest syndrome occurred in 10/117 cases (8.5%), while among transfused, acute chest syndrome occurred in 1/33 cases (2.9%). We recommend this selective blood transfusion protocol for patients with sickle cell disease to surgeons who undertake splenectomies in settings where blood bank reserves are perennially low.

The spectrum of splenic complications in patients with sickle cell disease in Africa: a systematic review

The majority of the global population of sickle cell disease (SCD) patients resides in Africa. Individuals with this condition are at great risk of serious infections and early mortality secondary to splenic dysfunction without preventative measures. This review investigated the spectrum of splenic complications encountered in SCD among populations in Africa. We systematically searched several databases for all articles published through March 3, 2020. We included 55 studies from 14 African countries. This review reveals the difference in frequency of splenic complications in SCD in Africa when compared with their counterparts in the United State and Europe. While several studies (n = 45) described splenomegaly with a prevalence of 12% to 73% among children, and 4% to 50% among adults with HbSS, the reported prevalence for acute splenic sequestration crisis (n = 6 studies) and hypersplenism (n = 4 studies) was <10% and <5% respectively. A total of 30 surgical splenectomy was reported across eight studies. Only two (3.7%) studies provided data on spleen function. A conflicting pattern was observed amongst studies that evaluated the relationship between splenomegaly and the presence of bacterial and malaria infections. This review reveals the paucity of studies describing the role of SCD-induced splenic dysfunction in morbidity and infection related mortality in Africa.

Considering the spleen in sickle cell disease

Introduction: In human physiology, the spleen is generally neglected, and its role is considered anecdotal. In sickle cell disease, splenic dysfunction is the main cause of life-threatening complications, particularly in early childhood with the risk of pneumococcal overwhelming sepsis and acute splenic sequestration crisis, notably. During the course of the disease, the spleen functionally declines and anatomically disappears, albeit with great individual variability depending on modulating genetic and environmental factors. Areas covered: The present review aims to provide an overview of spleen structure and function in order to highlight its role in sickling disorders. The clinical features of spleen damage in sickle cell disease, as well as complications and short- and long-term consequences, are reviewed, along with the main therapeutic options. Expert opinion: Management of acute splenic sequestration recurrence and timing of splenectomy in children with sickling disorders are two main areas in which clinical studies are needed.

Evolving locally appropriate models of care for indian sickle cell disease

The sickle cell gene in India represents a separate occurrence of the HbS mutations from those in Africa. Sickle cell disease in India occurs against different genetic and environmental backgrounds from those seen in African patients and there is evidence of clinical differences between the populations. Knowledge of the clinical features of African disease was drawn from the Jamaican Cohort Study, based on prospective follow up of all cases of sickle cell disease detected by the screening of 100,000 consecutive newborns in Kingston, Jamaica, and supplemented by observations from the Cooperative Study of Sickle Cell Disease in the US. Defining the principal causes of early morbidity in African sickle cell disease led to successful interventions including pneumococcal prophylaxis, parental education in the early diagnosis of acute splenic sequestration, and the early detection by trans-cranial Doppler of cerebral vessel stenosis predictive of stroke but their success depended on early diagnosis, ideally at birth. Although reducing mortality among patients with African forms of SS disease, the question remains whether these interventions are appropriate or justified in Indian patients. This dilemma is approached by comparing the available data in African and Indian forms of SS disease seeking to highlight the similarities and differences and to identify the deficiencies in knowledge of Indian disease. These deficiencies could be most readily addressed by cohort studies based on newborn screening and since much of the morbidity of African disease occurs in the first five years of life, these need not be a daunting prospect for Indian health care personnel. Newborn screening programmes for sickle cell disease are already underway in India and appropriate protocols and therapeutic trials could quickly answer many of these questions. Without this knowledge, Indian physicians may continue to use possibly unnecessary and expensive models of care.

Comparative effectiveness of different types of splenectomy for children with congenital hemolytic anemias

OBJECTIVE

To compare the effectiveness of different types of splenectomy in children with congenital hemolytic anemias.

STUDY DESIGN

We constructed key questions that addressed outcomes relevant to clinicians and families on effects of partial or total splenectomy, including hematologic effect, splenic function, and the risk of adverse events. We identified from Pubmed and Embase 703 studies that evaluated different types of splenectomy and accepted 93 studies that satisfied entry criteria. We graded the quality of each report and summarized the overall strength of research evidence for each key question.

RESULTS

We did not identify any randomized clinical trials. All types of splenectomy have favorable clinical outcomes in most diseases. We did not identify any hematologic advantage of laparoscopy compared with laparotomy. Adverse events are uncommon in most studies and are minimized with use of laparoscopy.

CONCLUSIONS

There is a need for randomized clinical trials and improved data collection of different types of splenectomy in congenital hemolytic anemias. Outcomes studied should address the concerns of families and clinicians to assess the risks and benefits of various treatments.

Growth in children and adolescents with sickle cell disease in Yemen

BACKGROUND

Physical growth is known to be impaired in children with sickle cell disease (SCD) and the prevalence and severity vary with geographical location. The factors which contribute to this sub-optimal growth are poorly understood.

OBJECTIVES

To describe the growth status of children and adolescents with SCD in Yemen using the new WHO reference values and to assess correlation of growth indicators with disease severity and with haematological and biochemical parameters.

METHODS

A cross-sectional study of children <16 years with SCD was conducted at Al-Wahda General Teaching Hospital, Aden. Anthropometric measurements of weight, length/height, mid-upper-arm circumference (MUAC) and body mass index (BMI) were collected. Disease severity was assessed using a severity index (SI) score.

RESULTS

A total of 102 children (56 male) were included and their mean age was 7.2 years (range 6 months to 15 years). Low weight, height and BMI-for-age Z-scores (<-2 SD) were observed in 45%, 54% and 35% of children, respectively. Regression analyses indicated an association of low height-for-age with male gender (p=0.02), low weight-for-age and weight-for-height with increased age (both p<0.001), low weight-for-age with raised alkaline phosphatase (p=0.04), and low BMI with reduced plasma albumin (p=0.04). There was no correlation between growth deficits and SI or anaemia severity.

CONCLUSION

Growth is severely impaired in children and adolescents with SCD in Yemen. Growth monitoring and nutritional support should be included in their comprehensive care package.

Growth and nutritional status of children with homozygous sickle cell disease

BACKGROUND

Poor growth and under-nutrition are common in children with sickle cell disease (SCD). This review summarises evidence of nutritional status in children with SCD in relation to anthropometric status, disease severity, body composition, energy metabolism, micronutrient deficiency and endocrine dysfunction.

METHODS

A literature search was conducted on the Medline/PUBMED, SCOPUS, SciELO and LILACS databases to July 2007 using the keywords sickle cell combined with nutrition, anthropometry, growth, height and weight, body mass index, and specific named micronutrients.

RESULTS

Forty-six studies (26 cross-sectional and 20 longitudinal) were included in the final anthropometric analysis. Fourteen of the longitudinal studies were conducted in North America, the Caribbean or Europe, representing 78.8% (2086/2645) of patients. Most studies were observational with wide variations in sample size and selection of reference growth data, which limited comparability. There was a paucity of studies from Africa and the Arabian Peninsula, highlighting a large knowledge gap for low-resource settings. There was a consistent pattern of growth failure among affected children from all geographic areas, with good evidence linking growth failure to endocrine dysfunction, metabolic derangement and specific nutrient deficiencies.

CONCLUSIONS

The monitoring of growth and nutritional status in children with SCD is an essential requirement for comprehensive care, facilitating early diagnosis of growth failure and nutritional intervention. Randomised controlled trials are necessary to assess the potential benefits of nutritional interventions in relation to growth, nutritional status and the pathophysiology of the disease.

Effects of delayed pubertal development, nutritional status, and disease severity on longitudinal patterns of growth failure in children with sickle cell disease

Previous studies of children with sickle cell disease (SCD) reported poor growth and delayed maturation. However, the prevalence, magnitude, and correlates of suboptimal growth remain poorly understood. A prospective longitudinal study was undertaken to determine the effects of disease severity and nutritional status on growth, an indicator of childhood well-being. Children, birth to 18 y of age, with SCD-SS were evaluated annually for 4 y. Growth, nutritional status, skeletal and sexual maturation, disease severity, dietary intake, and maternal education were assessed. In this sample of 148 children (78 females), growth in height, weight, or body mass index declined in 84% of subjects; 38% fell below the 5th percentile in one or more measures. Puberty was delayed 1 to 2 y, and median age at menarche was 13.2 y. Skeletal age was delayed by 0.7 +/- 1.4 y overall and by 1.3 +/- 1.5 y in children 10 to 15 y old. Height status declined over time and was positively associated with advancing puberty and hematological measures in girls, and nutritional status in girls and boys. Growth failure and maturational delay remain significant chronic problems in children with SCD-SS and are related to potentially modifiable factors such as nutritional status.

Is splenectomy for massive splenomegaly safe in children?

PURPOSE

To study and analyze the causes, etiology, morbidity, mortality and therapeutic value of splenectomy performed for massive splenomegaly in children.

METHODS

The medical records of 115 children less than 18 years old who had splenectomy for various hematological disorders were reviewed. Twenty of them had splenectomy for massive splenomegaly (spleen weight > or =1,000 g). The records of these were reviewed for age at operation, gender, hematological diagnosis, indication for splenectomy, operative procedures, postoperative complications, and outcome.

RESULTS

Twenty children had splenectomy for massive splenomegaly. There were 16 males and 4 females. Their ages ranged from 4 to 15 years (mean 11.2). Twelve had sickle cell disease, 5 had sickle-beta-thalassemia, 1 had beta-thalassemia major, 1 had thalassemia intermediate, and 1 had chronic myeloid leukemia. The indications for splenectomy were hypersplenism in 11, recurrent splenic sequestration crisis in 8, and splenic abscess in 1. The transfusion requirements in the patient with beta-thalassemia major decreased markedly postoperatively from 18 transfusions/year to only 4 transfusions/year; and for those with hypersplenism, there was a marked improvement in their blood parameters following splenectomy. The patient with thalassemia intermediate required no more blood transfusions. There was no mortality. The immediate postoperative morbidity was 10% for those with massive splenomegaly compared with 6.3% for those with splenomegaly <1,000 g.

CONCLUSIONS

With good perioperative management, splenectomy in children with massive splenomegaly is both safe and effective.

Postsplenectomy course in homozygous sickle cell disease

OBJECTIVE

To determine whether children with homozygous sickle cell (SS) disease and splenectomy are at greater risk of death, overwhelming septicemia, or other complications.

METHODS

A total of 130 patients with SS treated by splenectomy (46 recurrent acute splenic sequestration, 84 chronic hypersplenism) over a 22.5-year period at the Sickle Cell Clinic of the University Hospital of the West Indies, Kingston, Jamaica, were compared with a control group matched for sex, age, and duration of follow-up in a retrospective review. Deaths and bacteremias were examined over the whole study period. Painful crises, acute chest syndromes, and febrile episodes were compared in the 90 patients completing 5 years of postsplenectomy follow-up.

FINDINGS

Mortality and bacteremic episodes did not differ between the splenectomy and control groups. Painful crises were more common in the splenectomy group than in the control group (P =.01) but did not differ between splenectomy indications. Acute chest syndrome was more common in the splenectomy group than in the control group (P <.01) and was more common in the acute splenic sequestration group than in the hypersplenism group (P =.01). Febrile events did not differ between the groups or between the indications for splenectomy.

CONCLUSION

Splenectomy does not increase the risk of death or bacteremic illness in patients with SS disease and, if otherwise indicated, should not be deferred for these reasons.

Factors affecting prepubertal growth in homozygous sickle cell disease

OBJECTIVE

To investigate the role of haematological indices, socioeconomic status, and morbidity in prepubertal growth in homozygous sickle cell (SS) disease.

METHOD

Height, weight, and haematology were serially recorded in a cohort study of 315 children with SS disease from birth to 9 years at the sickle cell clinic of the University Hospital of the West Indies, Kingston, Jamaica.

RESULTS

Height increment between 3 and 9 years correlated positively with total haemoglobin at age 7 years in boys but not girls. Attained height and weight at age 7 years correlated positively with haemoglobin and fetal haemoglobin in boys but not girls. Only the correlation between haemoglobin and weight showed a significant gender difference. Partial correlation analysis suggested that the effect of haemoglobin was accounted for by the effect of fetal haemolglobin and further analysis indicated that height correlated with F reticulocyte count (a measure of fetal haemoglobin production) in both sexes but not with the ratio of F cells to F reticulocytes (a measure of F cell enrichment). Growth was not significantly related to mean red cell volume, proportional reticulocyte count, alpha thalassaemia, socioeconomic status, or morbidity.

CONCLUSION

A high concentration of fetal haemoglobin in boys with SS disease is associated with greater linear growth. It is postulated that in boys, low concentrations of fetal haemoglobin increase haemolysis and hence metabolic requirements for erythropoiesis, putting them at greater risk of poor growth. Differences in the relationship of haematology and growth between boys and girls with SS disease dictate that future analyses of growth take gender into account.