Neonatal Screening for Sickle Cell Disease in Western Andalusia: Results and Lessons Learnt after 3 Years of Implementation

OBJECTIVE

 The aim of this study was to present the results obtained in the Newborn Screening Program (NSP) for sickle cell disease (SCD) in western Andalusia and the autonomous city of Ceuta in the first 3 years of implementation, and to describe the discrepancies found in the diagnosis of hemoglobinopathies between the screening method and the confirmatory tests.

STUDY DESIGN

 A descriptive and retrospective study was carried out, and the findings obtained in the newborns included in the NSP between November 2018 and December 2021 were analyzed.

RESULTS

 A total of 111,205 samples were screened by high-performance liquid chromatography (HPLC). The birth prevalence of SCD, sickle cell trait, hemoglobin C carriers, and the compound heterozygosity Hb C/β-thalassemia was 1/12,356, 1/467, 1/1,278, and 1/55,602 newborns, respectively. Although there was a correlation between the first-line HPLC screening technique (VARIANTnbs HPLC analyzer, Bio-Rad) and the confirmatory tests in most cases, major discrepancies were found in detecting carriers of G-Philadelphia, D, E, and O-Arab hemoglobin variants, with the former having an incidence of 1/10,110 and the others 1/22,241. The carrier status of Hb G-Philadelphia produced an FAD pattern on the screening method that could be mistaken as Hb D, while Hb O-Arab was identified as an FA5 pattern. Hb D was initially recognized as Hb D in two cases.

CONCLUSION

 An NSP requires at least two different combined methods in order to identify the hemoglobin variant with sufficient certainty. Furthermore, even though software solutions for HPLC suggest a pattern, it must be confirmed with another technique to obtain a correct interpretation of the chromatograms.

KEY POINTS

· The NSPs are an essential activity in preventive medicine.. · At least two different combined methods are required to correctly identify hemoglobin variants.. · Different variants can produce a similar or identical pattern by a single method..

Splenic Subcapsular Hematoma from Commercial Air Travel: Case Report of a Unique Incident of Altitude-Associated Splenic Syndrome

BACKGROUND

Sickle cell trait (SCT), the heterozygous form of sickle cell disease, is generally thought of as a benign condition. However, it is possible for those with SCT to have serious complications, especially when they are exposed to high altitudes where oxygen levels are low.

CASE REPORT

We present a case of a 41-year-old man with a history of SCT who developed severe epigastric pain and nearly lost consciousness while traveling on a commercial airplane. His twin brother, who also has SCT, had a similar episode in the past and required a splenectomy. A splenic subcapsular hematoma was found in a computed tomography scan of the abdomen and pelvis with intravenous contrast. He was admitted and managed conservatively until his symptoms resolved. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Though SCT is prevalent in our population, the complications that can arise, such as altitude-associated splenic syndrome, have likely not been thoroughly investigated. Physicians should add this condition to their differential if they practice at locations near airports or in areas of higher altitude and if their patients have a past medical history of SCT.

Occlusive Retinal Vasculitis in a Pediatric Patient With Kikuchi-Fujimoto Disease and Sickle Cell Trait

A 13-year-old Black male patient with a history of Kikuchi-Fujimoto disease (KFD) and sickle cell trait presented with acute painless vision loss and no light perception vision (NLP) in his left eye. The examination was indicative of occlusive retinal vasculitis with near total central retinal artery occlusion (CRAO). He was started on oral steroids with dramatic reperfusion and improvement of the retinal hemorrhages. However, his vision remained at NLP. Oral steroids were tapered, and rituximab infusion was initiated. While ocular involvement is uncommon in KFD, vision-limiting complications, such as occlusive retinal vasculitis, ophthalmic artery occlusion, and CRAO can occur. Early systemic immunosuppression is key in achieving rapid remission. [Ophthalmic Surg Lasers Imaging Retina 2024;55:235-239.].

PARACENTRAL ACUTE MIDDLE MACULOPATHY WITH SICKLE CELL TRAIT

PURPOSE

To report a case of paracentral acute middle maculopathy in a pediatric patient with sickle cell trait.

METHODS

The patient was evaluated with a comprehensive ophthalmic examination, optical coherence tomography, optical coherence tomography angiography, and fluorescein angiography.

RESULTS

Acute loss of vision occurred immediately after an uneventful scleral buckling procedure for retinal detachment in a 16-year-old female patient. Retinal imaging studies confirmed the occurrence of paracentral acute middle maculopathy, an ischemic condition characterized by infarction of the inner nuclear layer of the retina caused by hypoperfusion of the intermediate and deep capillary plexuses. Laboratory evaluation was only remarkable for sickle cell trait. Over a course of 3 months after the loss of vision, visual acuity improved from 20/1,000 to 20/20, and optical coherence tomography lesion resolved to a parafoveal area of inner and middle retinal layer thinning. Paracentral scotoma corresponding to the atrophic area persisted.

CONCLUSION

Dehydration because of the presurgical nil-per-os status and transient increase in intraocular pressure during the buckling surgery may have predisposed this patient with sickle cell trait to a sickling event that caused localized ischemia in the middle retina's end-capillaries. Avoiding long nil-per-os status, being mindful of transient intraocular pressure elevation during scleral buckling procedures, and presurgical hemoglobin electrophoresis in at-risk populations are recommended to prevent sickling attacks during retinal surgeries in individuals with sickle cell trait.

Prevalence of sickle cell trait and needs assessment for uptake of sickle cell screening among secondary school students in Kampala City, Uganda

BACKGROUND

Sickle cell disease (SCD) is one of the most frequent and traumatizing genetic disease in Uganda, with the prevalence of the sickle cell trait (SCT) estimated at 13.3% leading to serious psycho-social and economic impact on the patients and their families.

AIM

This study aimed to determine the burden of SCT and factors influencing the uptake of screening services among secondary school students in Uganda.

METHODS

We used an analytical cross-sectional design with a multi-stage sampling approach. A total of 399 students from four secondary schools in Kampala City were enrolled in this study. Data were gathered using semi-structured questionnaires and blood screening. We used the sickling test to determine the presence of sickle cell alleles among the participants and hemoglobin electrophoresis as a confirmatory test. Data gathered using the questionnaire were analyzed using descriptive and inferential statistics.

RESULTS

In total, 5.8% of participants who were tested during this study had SCT. Most (80.2%) participants were not in an intimate relationship at the time of data collection. The majority (60.4%) had moderate knowledge about SCT screening and obtained information about screening from the school. Only 29 (7.3%) participants knew of a family member with sickle cell. Overall, participants had a negative attitude toward SCT screening (67%), although 41.6% believed that most people who were sickle cell carriers did not live long and were often sick. Statistically significant associations were found between testing for SCT and knowing a partner's sickle cell status (odds ratio [OR] 2.112, p = 0.043) and Anglican religion (OR 2.075, p = 0.047).

CONCLUSION

Despite the moderate level of knowledge and negative attitudes, a relatively large number of participants had SCT. This highlights the need for a comprehensive health education package targeting adolescents to promote SCD/SCT screening.

COVID-19 Infection and Outcomes in Newborn Screening Cohorts of Sickle Cell Trait and Sickle Cell Disease in Michigan and Georgia

The sickle cell mutation increases morbidity in those with sickle cell disease (SCD) and potentially sickle cell trait, impacting pulmonary, coagulation, renal, and other systems that are implicated in COVID-19 severity. There are no population-based registries for hemoglobinopathies, and they are not tracked in COVID-19 testing. We used COVID-19 test data from 2 states linked to newborn screening data to estimate COVID outcomes in people with SCD or trait compared with normal hemoglobin. We linked historical newborn screening data to COVID-19 tests, hospitalization, and mortality data and modeled the odds of hospitalization and mortality. Georgia's cohort aged 0 to 12 years; Michigan's, 0 to 33 years. Over 8% of those in Michigan were linked to positive COVID-19 results, and 4% in Georgia. Those with SCD showed significantly higher rates of COVID-19 hospitalization than the normal hemoglobin Black cohort, and Michigan had higher rates of mortality as well. Outcomes among those with the trait did not differ significantly from the normal hemoglobin Black group. People with SCD are at increased risk of COVID-19-related hospitalization and mortality and are encouraged to be vaccinated and avoid infection. Persons with the trait were not at higher risk of COVID-related severe outcomes.

Reconsidering sickle cell trait testing of red blood cell units allocated to children with sickle cell disease

BACKGROUND

Sickle cell trait (SCT) testing of red blood cell (RBC) units is sometimes performed to identify and divert units containing hemoglobin S (HbS). Recipients strategically guarded against this exposure include fetuses, neonates, and children with sickle cell disease (SCD). The clinical necessity of this practice is unclear.

STUDY DESIGN AND METHODS

A one-year audit (2018) was performed at a pediatric tertiary care hospital that tests for SCT in RBC units prescribed to children with SCD and neonates. The impact of incorporating varying numbers of SCT RBC units in a single-unit top-up, partial-manual red cell exchange, and automated erythrocytapheresis was modeled in four typical-parameter age scenarios (2, 5, 10, and 18 years) sharing a high baseline HbS. Additionally, a survey assessing SCT testing practices was administered to Canadian pediatric hospital transfusion laboratories serving hemoglobinopathy programs.

RESULTS

Of 2268 donor RBC units tested, one was positive for SCT (0.04% [95% CI: 0.01%-0.24%]), at a cost of $19,384.56 CAD. The impact of SCT unit incorporation on lost HbS reduction was modest (Δ1%-3% [automated erythrocytapheresis] and Δ4%-15% [top-up/partial manual exchange]). The survey (with all 13 sites responding) showed variable SCT testing practice; four (31%) do not test, four (31%) test for children with SCD, and six (46%) test for neonates.

CONCLUSION

RBC SCT testing may be more costly than beneficial or necessary in children with SCD. As of 2019, our transfusion service has ceased SCT testing for this population. Further research in the fetal/neonatal populations is needed to overturn this entrenched practice.

Sickle cell trait screening in students in a Ugandan university: a cross-sectional study

OBJECTIVE

To determine the uptake, knowledge level and attitude towards sickle cell trait screening in students aged 18 to 35 years in a Ugandan university.

METHODS

This was a university-based, cross-sectional study of students aged 18 to 35 years who were students at the Busitema University Faculty of Health Sciences. We used a simple random sampling technique to recruit participants. We conducted multivariable logistic regression to establish the association between factors such as age, year of study, marital status and uptake of sickle cell trait screening (SCTS) services.

RESULTS

A total of 315 students participated in the study. The uptake rate of SCTS was 24.4%. The knowledge level regarding sickle cell disease/SCTS was 93.7%, and 73.3% of respondents had a positive attitude towards SCTS, with a mean score of 23.32 ± 5.84. A multivariate analysis showed that those aged 25 to 29 years were 7.8 times more likely to have SCTS, while married respondents were 1.3 times more likely to be screened.

CONCLUSION

The uptake of SCTS services was low relative to the total number of participants recruited in this study. Therefore, the uptake of SCTS needs to be encouraged in students at universities.

Optical absorbance-based rapid test for the detection of sickle cell trait and sickle cell disease at the point-of-care

People afflicted with sickle cell disease (SCD) experience severe deterioration in quality of life. The disease is characterized by debilitating pain, anemia, and increased susceptibility to life threatening infections. This genetic disorder is endemic to many parts of the world. Extensive and accurate screening of individuals with sickle cell trait (SCT) in the population, coupled with genetic counselling can inhibit the propagation of the disease. The gold-standard techniques for the detection of sickle hemoglobin, such as capillary electrophoresis, HPLC, and genetic testing, are prohibitively expensive and time-consuming. Mass screening is usually conducted with a low-cost test called the solubility test, which does not offer high specificity. This study proposes a game-changing single-step low-cost method for rapidly yet accurately screening and diagnosing SCD and SCT. This method relies on the hitherto unexplored differences in the optical absorbance between diseased, trait, and normal blood samples, under deoxygenated conditions. The proposed method was tested in two phases of clinical validation: a pilot study and a blind study. A total of 438 patient samples were tested using the proposed method across the two phases. The proposed method offers an average accuracy, sensitivity, and specificity of 97.6%, 96.9%, and 98.6%, respectively. The proposed test has the potential to obliviate the conventional two-step process of screening and diagnostic tests as it can be used at the point-of-care with minimal training and yet yield results reliable enough to assess disability benefit claims.

Sudden Death in Diabetic Ketoacidosis Complicated by Sickle Cell Trait

ABSTRACT

In a sudden death investigation of a service member with sickle cell trait (SCT), evidence of sickle cell crisis further complicated by coexisting, undiagnosed diabetic ketoacidosis called into question the synergistic effects of diabetic ketoacidosis on red blood cell sickling. Sickle cell trait affects more than 4 million people in the United States (US) with the highest prevalence in non-Hispanic Blacks (7%-9%; Mil Med 2017;182(3):e1819-e1824). The heterozygous state of sickled hemoglobin was previously considered a benign condition causing sickling during hypoxic, high-stress conditions such as exercise and high altitude ( Am Assoc Clin Chem 2017). However, research within the last decade shows evidence of sudden death among SCT patients ( J Forensic Sci 2011;56(5):1352-1360). It has been shown that the presence of sickled hemoglobin artificially lowers levels of hemoglobin A1c making it a less effective biomarker for red blood cell glycosylation over time in sickle cell patients ( JAMA 2017;317(5):507-515). The limited scope of medical understanding of the effects of SCT in combination with other comorbidities requires further investigation and better diagnostic criteria. The uniqueness of the US Military and its screening program for sickle cell disease (SCD) and SCT allows for more detection. Since May 2006, newborn screening for SCD/SCT has been a national requirement; however, anyone older than 14 years may not know their SCD/SCT status ( Semin Perinatol 2010;34(2):134-44). The previous absence of such national screening makes it more challenging to identify SCT and SCD patients even within high-risk populations. Furthermore, patients may not know or understand the results of their SCD/SCT status testing. International standards for the autopsy of decedents with SCD and SCT exist ( R Coll Pathol 2017). Within the US, testing of vitreous electrolytes is a common practice in suspected natural death cases, but a review of the US literature did not demonstrate any autopsy standards or recommendations for persons with SCT or high-risk persons for sickling pathologies. The identification of a new diagnosis of type 2 diabetes mellitus, as the cause of death, is not uncommon; however, this case indicates that type 2 diabetes mellitus was not the sole contributing factor. It further illustrates that the US may be underestimating the impact of SCD and SCT as a cause of death, a contributing factor to death, and its synergistic effects with other pathologic processes. We propose a stringent literature review in conjunction with a review of international autopsy standards to develop national autopsy standards and possible SCT/SCD screening recommendations for high-risk persons at the time of autopsy.

National Audit of Criteria For Pre-Operative Sickle Cell Screening in Children

Aim We set out to identify the current practice in the anaesthesiology departments of Ireland's public hospitals that deliver paediatric anaesthesia with regard to pre-operative screening for sickle cell disease (SCD) and Sickle cell trait (SCT). Methods The Departments of Anaesthesiology at 14 public HSE-funded hospitals that deliver paediatric anaesthesia were contacted over a three month period in 2020. Any existing policies regarding pre-operative screening of paediatric patients for Sickle cell disease or trait were sought. Comparisons were made between any screening policies in place. Results A response was received from 11 of the 14 hospitals. Three out of 11 of the Anaesthesiology Departments have formal policies in place. The ethnicities identified for pre-operative screening varied across these three hospitals. Conclusion Despite a significant increase in the number of people of African, middle Eastern & Indian descent living in Ireland in recent years, no neonatal screening programme for Sickle cell exists here, and no national policy exists with criteria to guide the practice of pre-operative screening of patients for SCD/SCT (trait). Our survey highlights a lack of standardisation in the approach to pre-operative sickle cell screening of children across Ireland's public hospital system. In view of the increasing multiculturalism in Ireland we recommend a national review of the merits of the introduction of developing a targeted national guideline for pre-operative screening for sickle cell in at-risk children.

Parents' Experiences and Needs Regarding Infant Sickle Cell Trait Results

BACKGROUND AND OBJECTIVE

Sickle cell trait (SCT) has reproductive implications and can rarely cause health problems. SCT counseling improves parent knowledge but is infrequently received by children with SCT compared with children with cystic fibrosis carrier status. There are no national guidelines on SCT disclosure timing, frequency, or counseling content. Parents' experiences with SCT disclosure and counseling are poorly understood but could inform the development of guidelines. We explored parents' experiences with and desires for SCT disclosure and counseling for their infants with SCT identified via newborn screening.

METHODS

Parents of infants 2 to 12 months old with SCT were recruited through a state newborn screening program for semistructured interviews to explore their experiences with and desires for SCT disclosure and counseling. Inductive thematic analysis was conducted.

RESULTS

Sixteen interviews were completed from January to August 2020. Most parents reported that SCT disclosure occurred soon after birth, in person, and by the child's physician. Five themes were identified: parent knowledge before child's SCT disclosure, family planning, the dynamics of SCT disclosure and counseling, emotions and actions after SCT disclosure, and parent desires for the SCT disclosure and counseling process. Two primary parent desires were revealed. Parents want more information about SCT, particularly rare symptomatology, and they want SCT counseling repeated once the child approaches adolescence.

CONCLUSION

Parents report receiving their child's SCT diagnosis in the early newborn period from their child's doctor but indicate they receive incomplete information. Opportunities exist in primary care pediatrics to better align SCT disclosure timing and counseling content with parent desires.

Newborn Screening and Clinical Profile of Children With Sickle Cell Disease in a Tribal Area of Gujarat

OBJECTIVE

To present the result of newborn sickle cell disease (SCD) screening and clinical profile of SCD newborns in a tribal area of Gujarat.

METHODS

We screened all newborns of sickle cell trait (SCT) and SCD mothers for SCD using high-performance liquid chromatography (HPLC) within two days of birth at a secondary care hospital in a tribal area in Gujarat from 2014 to 2019. Newborns with SCD were registered under an information technology based platform for hospital-based comprehensive care. Neonates were followed prospectively every 3 months. If they missed the clinic visit, a medical counsellor visited them at home to collect the required information.

RESULTS

Out of 2492 newborns screened, 87 (3.5%) were diagnosed with SCD. Among the 67 newborns screened for alpha-thalassemia deletion, 64 (95.4%) of babies had alpha-thalassemia deletion. We recorded total 554 clinic visits over the period of 221.5 person-years. The rates of acute febrile illness, painful crisis, hospitalization and severe anemia were 42.9, 14.9, 14.9 and 4.5 per 100 person-year, respectively. Two deaths were recorded, and 5 babies (5.7%) had severe SCD.

CONCLUSION

We found a high prevalence of alpha thalassemia deletion among newborn SCD cohort in tribal area of Gujarat, and 70% babies had atleast one clinical complication on follow-up.

Sudden Death in High School Athletes: A Case Series Examining the Influence of Sickle Cell Trait

ABSTRACT

Athletes with sickle cell trait (SCT) have up to a 37-fold increased risk of exercise-related death. Exertional collapse associated with sickle cell trait (ECAST) is uncommon but can lead to exercise-related death due to exertional sickling. We present a case series of fatal ECAST in high school athletes aged 14 to 16 years. All 3 athletes experienced collapse during practice sessions with muscle pain or weakness. Upon evaluation at the hospital, the athletes had a significant metabolic acidosis that did not respond as expected to fluid resuscitation. Admitting diagnoses for the athletes included exertional heat stroke or dehydration. All 3 athletes had profound rhabdomyolysis leading to acute renal failure, worsening metabolic acidosis, and hyperkalemia. They rapidly progressed to disseminated intravascular coagulation, multiorgan system failure, and death. The autopsies of all 3 athletes showed extensive sickle cell vaso-occlusion involving the spleen liver, and muscles. Final clinical and pathologic diagnosis supported ECAST with fatal exertional rhabdomyolysis. Exertional collapse associated with sickle cell trait is an uncommon but potentially deadly condition that is often underrecognized or misdiagnosed as exertional heat stroke. The development of ECAST is thought to be multifactorial with exercise intensity, recent illness, and exercising conditions (ie, heat and altitude). Prevention should be the primary goal for athletes with SCT through exercise modification, education of precipitation factors, and cessation of exercise with recent illness. Athletes with suspected ECAST should undergo aggressive resuscitation with a low threshold for early transfer to a tertiary care facility for further management and potential hemodialysis.

Atypical Presentations of Exertional Collapse

ABSTRACT

Exertional collapse associated with sickle trait (ECAST) is an underrecognized cause of exertional collapse triggered by complex mechanisms involving acidosis, rhabdomyolysis, and arrhythmias, all of which create sickling, vaso-occlusive problems, and ultimately end organ failure. Three cases are described in young athletes, as well as 12 other examples of ECAST noted in case reports and news sources. Exertional collapse associated with sickle trait can be differentiated from other common causes of collapse (exertional heat syndrome, acute cardiac events, and asthma) because it is a conscious collapse without neurological changes, occurs early in workout with only mildly elevated body temperature, and involves muscle pain and weakness but not cramping. Aggressive early management and transport to care facilities can reverse ECAST in certain cases. This article discusses tips for early recognition, initial treatment in the emergency department, and precautions that can be taken to prevent sickling collapse in athletes with sickle cell trait (SCT).

An investigation of sickle cell trait, body mass index, and fitness in relation to venous thromboembolism among African American adults

BACKGROUND

The relationships of sickle cell trait (SCT), body mass index (BMI), and physical fitness to venous thromboembolism (VTE) in young adults have received little attention.

OBJECTIVES

To test for associations among SCT, BMI, fitness, and VTE.

PATIENTS/METHODS

We conducted a retrospective cohort study of 48,316 SCT-tested, African American individuals in the US Army during 2011-14. We used Cox proportional hazards models to compute adjusted hazards of deep vein thrombosis (DVT) and pulmonary embolism (PE) associated with selected factors.

RESULTS

Incidence rates of DVT and PE were 1.09 and 0.91 cases per 1000 person-years, respectively. Adjusted hazard ratios (aHRs) for DVT for men and women with SCT were 0.9 (95% confidence interval [CI]: 0.4-2.0; P = .711) and 1.51 (CI: 0.7-3.2; P = .274), respectively. aHRs for PE for SCT+ men and women were 1.1 (CI: 0.5-2.4; P = .773) and 1.2 (CI: 0.5-3.1; P = .650), respectively. Low physical fitness was associated with DVT and PE in women (DVT aHR =3.1; CI: 1.4-6.5; P = .004; PE aHR =4.6; CI: 2.1-9.9; P < .001) and DVT in men (aHR =2.2; CI: 1.0-4.6; P = .048). Recent weight gain of 1 or more BMI points was associated with DVT in men (aHR =1.8; CI: 1.1-2.8; P = .017).

CONCLUSIONS

We found no evidence of increased VTE risk associated with SCT in this population. However, lower fitness levels and BMI increases were so associated.

Triglyceride/HDL-cholesterol ratio and plasminogen activator inhibitor-1 independently predict high pulse pressure in sickle cell trait and disease

We hypothesised that TG/HDL-C ratio and PAI-1 would be associated with high pulse pressure (PP) in young adults with sickle cell trait (SCT) and sickle cell disease (SCD). We compared the clinical, biochemical, and cardiometabolic parameters among individuals with normal genotype (HbAA; n = 60), SCT (HbAS; n = 60), and SCD (HbSS; n = 60), all in steady state. Using multivariate linear regression analysis, high PP was positively related to TG/HDL-C ratio in SCT (β = 0.307; p = .014) and PAI-1 (β = 0.499; p = .001) in SCD. The curve of receiver operating characteristic also showed that TG/HDL-C ratio and PAI-1 are efficient predictors of high PP in SCT carriers and SCD patients, respectively. This study suggests that increased levels of TG/HDL-C ratio and PAI-1 may be salient risk factors that would promote the development of arterial stiffness and other CVD in SCT carriers and SCD patients.

Sickle cell carriers' unmet information needs: Beyond knowing trait status

Benefits of identifying sickle cell disease (SCD) carriers include detection of at-risk couples who may be informed on reproductive choices. Studies consistently report insufficient knowledge about the genetic inheritance pattern of SCD among people with sickle cell trait (SCT). This study explored perspectives of adults with SCT on the information needed to make an informed reproductive decision and the recommendations for communicating SCT information. Five focus groups (N = 25) were conducted with African Americans with SCT ages 18-65 years old. Participants were asked about their knowledge of SCT, methods for finding information on SCT, impact of SCT on daily living, and interactions with healthcare providers. An inductive-deductive qualitative analysis was used to analyze the data for emerging themes. Four themes emerged, highlighting the unmet information needs of African American sickle cell carriers: (a) SCT and SCD Education; (b) information sources; (c) improved communication about SCT and SCD; and (d) increased screening strategies. Future studies are needed to determine effective strategies for communicating SCT information and to identify opportunities for education within community and medical settings. Identifying strategies to facilitate access to SCT resources and education could serve as a model for meeting unmet information needs for carriers of other genetic conditions.

Sickled erythrocytes in urine as a clue to the diagnosis of sickle cell trait

Sickled erythrocytes in patients of sickle cell trait with microscopic hematuria have rarely been reported so far. A 30-year-old female underwent delivery of a healthy full-term baby by cesarean section. However, postcesarean, she had pain in abdomen and fever, for which she was advised blood and urine examination. The hemogram suggested mild leukocytosis with neutrophilia and the urine showed red blood cells, some of which were sickled. The patient was advised hemoglobin electrophoresis which suggested sickle cell trait (Hb-AS). We conclude that sickled erythrocytes should not be ignored in a sample of urine as it may serve as an important clue to the diagnosis of sickle cell trait or disease.

Venous thromboembolism in adults screened for sickle cell trait: a population-based cohort study with nested case-control analysis

OBJECTIVE

To determine whether sickle cell carriers ('sickle cell trait') have an increased risk of venous thromboembolism (VTE).

DESIGN

Cohort study with nested case-control analysis.

SETTING

General population with data from 609 UK general practices in the Clinical Practice Research Datalink (CPRD).

PARTICIPANTS

All individuals registered with a CPRD general practice between 1998 and 2013, with a medical record of screening for sickle cell between 18 and 75 years of age.

MAIN OUTCOMES MEASURES

Incidence of VTE per 10 000 person-years (PY) among sickle cell carriers and non-carriers; and adjusted OR for VTE among sickle cell carriers compared with non-carriers.

RESULTS

We included 30 424 individuals screened for sickle cell, with a follow-up time of 179 503 PY, identifying 55 VTEs in 6758 sickle cell carriers and 125 VTEs in 23 666 non-carriers. VTE incidence among sickle cell carriers (14.9/10 000 PY; 95% CI 11.4 to 19.4) was significantly higher than non-carriers (8.8/10 000 PY; 95% CI 7.4 to 10.4). Restricting analysis to confirmed non-carriers was non-significant, but performed on a small sample. In the case-control analysis (180 cases matched to 1775 controls by age and gender), sickle cell carriers remained at increased risk of VTE after adjusting for body mass index, pregnancy, smoking status and ethnicity (OR 1.78, 95% CI 1.18 to 2.69, p=0.006), with the greatest risk for pulmonary embolism (PE) (OR 2.27, 95% CI 1.17 to 4.39, p=0.011).

CONCLUSIONS

Although absolute numbers are small, in a general population screened for sickle cell, carriers have a higher incidence and risk of VTE, particularly PE, than non-carriers. Clinicians should be aware of this elevated risk in the clinical care of sickle cell carriers, or when discussing carrier screening, and explicitly attend to modifiable risk factors for VTE in these individuals. More complete primary care coding of carrier status could improve analysis.

Association among sickle cell trait, fitness, and cardiovascular risk factors in CARDIA

The contribution of sickle cell trait (SCT) to racial disparities in cardiopulmonary fitness is not known, despite concerns that SCT is associated with exertion-related sudden death. We evaluated the association of SCT status with cross-sectional and longitudinal changes in fitness and risk for hypertension, diabetes, and metabolic syndrome over the course of 25 years among 1995 African Americans (56% women, 18-30 years old) in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Overall, the prevalence of SCT was 6.8% (136/1995) in CARDIA, and over the course of 25 years, 46% (738/1590), 18% (288/1631), and 40% (645/1,611) of all participants developed hypertension, diabetes, and metabolic syndrome, respectively. Compared with participants without SCT, participants with SCT had similar baseline measures of fitness in cross-section, including exercise duration (535 vs 540 seconds; P = .62), estimated metabolic equivalent of tasks (METs; 11.6 vs 11.7; P = .80), maximum heart rate (174 vs 175 beats/min; P = .41), and heart rate at 2 minutes recovery (44 vs 43 beats/min; P = .28). In our secondary analysis, there was neither an association of SCT status with longitudinal changes in fitness nor an association with development of hypertension, diabetes, or metabolic syndrome after adjustment for sex, baseline age, body mass index, fitness, and physical activity. SCT is not associated with reduced fitness in this longitudinal study of young African American adults, suggesting the increased risk for exertion-related sudden death in SCT carriers is unlikely related to fitness. SCT status also is not an independent risk factor for developing hypertension, diabetes, or metabolic syndrome.

Sickle cell trait: what are the costs and benefits of screening?

INTRODUCTION

Eight percent of African Americans are carriers of the sickle cell trait. Some regard this as a benign anomaly, but others point to incidents of sudden exercise-related death, calling for a preliminary screening of either all athletes or those of African-American ancestry. This brief review considers the costs and benefits of such screening.

EVIDENCE ACQUISITION

The Ovid/Health Star data-base was searched from 1996 to June 2015. 2014. The terms "exercise", "exercise therapy", "sports", "athletes", "physical activity/motor activity" and "physical fitness" were combined to yield 227,120 citations. Likewise, the terms "sickle cell trait", "sickle cell disease", "splenic infarction", "hemoglobin S" and "rhabdomyolysis" identified 12,325 citations. A combination of the 2 searches yielded 416 abstracts.

EVIDENCE SYNTHESIS

Excluding items relating to animal research or forms of rhabdomyolysis other than sickling left 375 abstracts; 115 papers merited full examination. This material covered the risks of sickle cell trait and of screening (55 items), effects upon physical performance (31 items), cellular mechanisms (23 items), nutrition (4 items), and other topics (2 items). Supplemented material was drawn from reference lists and personal files. The tendency to sickling was provoked by excessive exercise relative to physical condition in hot or hypoxic conditions, and by local tissue acidosis, conditions that were best avoided by all athletes. The condition had little impact upon physical performance, but the relative risks of heat illness, exertional rhabdomyolysis, splenic infarction and sudden death were all increased by the sickle cell trait. The absolute number of critical incidents was nevertheless small, calling for close assessment of the costs and putative benefits of widespread screening.

CONCLUSIONS

Sports physicians should be aware of the clinical picture of sickling and be prepared to treat it. Screening may be cost-effective if targeted to black athletes involved in certain sports, although it has yet to be demonstrated how far the diagnosis of sickle cell trait reduces the risk of death when exercising in an adverse environment. A better tactic may be to reduce risks for all competitors by educating athletes and their coaches to adopt an intensity of training appropriate to the individual's physical condition, to maintain full hydration, and to avoid exposure to excessive heat and hypoxia.

A rapid, inexpensive and disposable point-of-care blood test for sickle cell disease using novel, highly specific monoclonal antibodies

Sickle cell disease (SCD) is a significant healthcare burden worldwide, but most affected individuals reside in low-resource areas where access to diagnostic testing may be limited. We developed and validated a rapid, inexpensive, disposable diagnostic test, the HemoTypeSC™ , based on novel monoclonal antibodies (MAbs) that differentiate normal adult haemoglobin (Hb A), sickle haemoglobin (Hb S) and haemoglobin C (Hb C). In competitive enzyme-linked immunosorbent assays, each MAb bound only its target with <0·1% cross-reactivity. With the HemoTypeSC™ test procedure, the sensitivity for each variant was <5·0 g/l. The accuracy of HemoTypeSC™ was evaluated on 100 whole blood samples from individuals with common relevant haemoglobin phenotypes, including normal (Hb AA, N = 20), carrier or trait (Hb AS, N = 22; Hb AC, N = 20), SCD (Hb SS, N = 22; Hb SC, N = 13), and Hb C disease (Hb CC, N = 3). The correct haemoglobin phenotype was identified in 100% of these samples. The accuracy of the test was not affected by Hb F (0-94·8% of total Hb) or Hb A2 (0-5·6% of total Hb). HemoTypeSC™ requires <1 μl of whole blood and no instruments or power sources. The total time-to-result is <20 min. HemoTypeSC™ may be a practical solution for point-of-care testing for SCD and carrier status in low-resource settings.

Sickle Cell Trait: A Benign State?

BACKGROUND

Sickle cell trait (SCT) is the heterozygous form of sickle cell disease and expectedly should be a benign state with no complications ascribed to it. There are numerous reports challenging its being a benign condition, though this is controversial.

METHODS AND RESULTS

A review of the results of the accompanying investigations done on some of the patients show that beta thalassemia may be responsible for many of the ascribed symptoms and complications. These patients may therefore have sickle cell beta thalassemia, a compound heterozygous form of sickle cell disease.

CONCLUSION

It is important to screen for beta thalassemia using red cell indices and quantitation of the different hemoglobin fractions before attributing any symptoms to SCT. DNA analysis, though useful in ascertaining the presence of the sickle cell gene, is not sufficient. There is the need to exclude the presence of mutations for beta thalassemia, which often is geographical region-specific.

Sickle cell trait is not associated with chronic kidney disease in adult Congolese patients: a clinic-based, cross-sectional study

OBJECTIVE

The aim of this study was to evaluate the determinants of chronic kidney disease (CKD) with special emphasis on sickle cell trait (SCT).

METHODS

Three hundred and fifty-nine patients (171 men and 188 women), aged 18 years or older, with reduced kidney function (eGFR < 90 ml/min/1.73 m(2)) and seen at secondary and tertiary healthcare in Kinshasa were consecutively recruited in this cross-sectional study. Serum creatinine and haemoglobin electrophoresis were performed in each patient. CKD was defined as < 60 ml/min/1.73 m(2). Logistic regression analysis was used to assess determinants of CKD with a special emphasis on SCT. A p-value < 0.05 defined the level of statistical significance.

RESULTS

SCT was present in 19% of the study population; its frequency was 21 and 18% (p > 0.05) in patients with and without CKD, respectively. In multivariate analysis, sickle cell trait was not significantly (OR: 0.38; 95% CI: 0.559-1.839; p = 0.235) associated with CKD; the main determinants were dipstick proteinuria (OR: 1.86; 95% CI: 1.094-3.168; p = 0.02), the metabolic syndrome (OR: 1.69; 95% CI: 1.033-2.965; p = 0.03), haemoblobin ≥ 12 g/dl (OR: 0.36; 95% CI: 0.210-0.625; p = 0.001), and personal history of hypertension (OR: 2.16; 95% CI: 1.202-3.892; p = 0.01) and of diabetes mellitus (OR: 2.35; 95% CI: 1.150-4.454; p = 0.001).

CONCLUSION

SCT was not an independent determinant of CKD in the present case series. Traditional risk factors emerged as the main determinants of CKD.

Sickle cell trait diagnosis: clinical and social implications

The sickle hemoglobin (HbS) point mutation has independently undergone evolutionary selection at least five times in the world because of its overwhelming malarial protective effects in the heterozygous state. In 1949, homozygous Hb S or sickle cell disease (SCD) became the first inherited condition identified at the molecular level; however, since then, both SCD and heterozygous Hb S, sickle cell trait (SCT), have endured a long and complicated history. Hasty adoption of early mass screening programs for SCD, recent implementation of targeted screening mandates for SCT in athletics, and concerns about stigmatization have evoked considerable controversy regarding research and policy decisions for SCT. Although SCT is a largely protective condition in the context of malaria, clinical sequelae, such as exercise-related injury, renal complications, and venous thromboembolism can occur in affected carriers. The historical background of SCD and SCT has provided lessons about how research should be conducted in the modern era to minimize stigmatization, optimize study conclusions, and inform genetic counseling and policy decisions for SCT.

Prospective study of sickle cell trait and venous thromboembolism incidence

BACKGROUND

Sickle cell trait may increase risk of venous thromboembolism, but this is not fully established.

OBJECTIVES

We sought to determine the association of sickle cell trait with deep vein thrombosis and pulmonary embolism.

METHODS

Middle-aged African Americans participating in a prospective, population-based cohort investigation, the Atherosclerosis Risk in Communities Study, were followed from 1987 through 2011 for incident hospitalized pulmonary embolism (n = 111) or isolated deep vein thrombosis (n = 138), verified by physician review of medical records. Sickle cell trait (heterozygosity for hemoglobin S, n = 268) was compared with no sickle cell trait (n = 3748).

RESULTS

Over a median of 22 years of follow-up, 249 participants had an incident venous thromboembolism. The hazard ratio of venous thromboembolism was 1.50 (95% confidence interval [CI] 0.96-2.36) for participants with vs. without sickle cell trait, after adjustment for age, sex, ancestry, hormone replacement therapy (women), body mass index, diabetes, and estimated glomerular filtration rate. This hazard ratio was 2.05 (95% CI 1.12-3.76) for pulmonary embolism and 1.15 (95% CI 0.58-2.27) for deep vein thrombosis without pulmonary embolism.

CONCLUSIONS

Sickle cell trait in African Americans carries a 2-fold increased risk of pulmonary embolism but does not elevate deep vein thrombosis risk. Because neonatal screening for sickle hemoglobin is being conducted in the United States, consideration should be paid to the increased pulmonary embolism risk of individuals with sickle cell trait.

Using formative research to develop a counselor training program for newborn screening in Ghana

Sickle cell disease (SCD), sickle cell trait (SCT) and related conditions are highly prevalent in sub-Saharan Africa. Despite the public health implications, there is limited understanding of the unique needs regarding establishing and implementing extensive screening for newborns and appropriate family counseling. We sought to gain understanding of community attitudes and beliefs about SCD/SCT from counselors and potential counselors in Ghana; obtain their input about goals for counseling following newborn screening; and obtain guidance about developing effective counselor education. Five focus groups with 32 health care providers and health educators from 9 of 10 regions in Ghana were conducted by trained facilitators according to a structured protocol. Qualitative data were coded and categorized to reflect common themes. Saturation was achieved in themes related to genetics/inheritance; common complications of SCD; potential for stigmatization; marital strain; and emotional stress. Misconceptions about SCT as a form of SCD were prevalent as were cultural and spiritual beliefs about the causes of SCD/SCT. Potential positive aspects included affected children's academic achievement as compensation for physical limitations, and family cohesion. This data informed recommendations for content and structure of a counselor training program that was provided to the Ministry of Health in Ghana.

Vitreoretinal management and surgical outcomes in proliferative sickle retinopathy: a case series

PURPOSE

To report the outcomes of current vitreoretinal surgical management of proliferative sickle retinopathy and to compare current methods to previous studies.

DESIGN

A retrospective, interventional case series.

METHODS

Fifteen eyes of 14 patients with proliferative sickle retinopathy were managed with vitreoretinal surgery over a 12-year period at a single institution.

RESULTS

Nine patients had a sickle cell-hemoglobin C (SC) profile, 1 was sickle cell-beta(+) thalassemia (S beta(+)-thal), and 4 were sickle cell trait (AS). All 15 eyes underwent pars plana vitrectomy (PPV): 6 for vitreous hemorrhage (VH), 1 for epiretinal membrane (ERM), and an additional 8 for tractional retinal detachment (RD) and/or rhegmatogenous RD. In addition, an encircling scleral buckle (SB) was used in 2 cases. In 7 cases, 20 gauge PPV was used; 23 gauge was used in 3; and 25 gauge was used in 5. All 7 eyes with VH or ERM had improved vision postoperatively. Four of the 8 patients with traction and/or rhegmatogenous RD developed recurrent detachments and required a second operation. All retinas were attached at last follow-up, and visual acuity was 20/400 or better in all eyes. No cases of anterior segment ischemia were encountered.

CONCLUSIONS

Anterior segment ischemia is no longer a common occurrence in eyes undergoing surgery for proliferative sickle retinopathy. Although PPV has replaced the use of SB in many situations, an encircling SB may still be used in this population when necessary. Surgery for VH and ERM generally results in favorable outcomes, but eyes undergoing surgery for traction/rhegmatogenous RD carry a more guarded prognosis.

Athletes' perceptions of National Collegiate Athletic Association-mandated sickle cell trait screening: insight for academic institutions and college health professionals

OBJECTIVE

The study objective was to explore athletes' perspectives of National Collegiate Athletic Association (NCAA)-mandated sickle cell trait (SCT)-screening policy by examining race- and gender-related differences in athletes' perceptions regarding risk of having SCT and concern about loss of playing time.

PARTICIPANTS

Participants were 259 athletes at a southeastern United States campus during April-August of 2010.

METHODS

Athletes completed a 21-question survey.

RESULTS

The majority of athletes (81.7%) perceived that they would have a high level of concern if found to carry the SCT. African Americans were 9.07 times more likely than Caucasians to perceive risk of having the SCT. The majority of athletes disagreed (38.4%) or did not know (50.8%) if they would lose playing time related to carrying the SCT.

CONCLUSION

Campus health professionals must be aware of athletes' perspectives on NCAA's SCT screening so that athletes are not unnecessarily subjected to stress or harm.

Effort required to contact primary care providers after newborn screening identifies sickle cell trait

People with heterozygous status for sickle cell disease (also called sickle cell trait) are essentially healthy, but evidence of rare health problems has increased interest in screening adolescents and young adults prior to enlisting in athletics or military service. Ironically, almost everyone with sickle cell trait is already identified during routine newborn screening for sickle cell disease, but this identification may never reach the parents. As part of a larger statewide study of communication after newborn screening, we decided to document the amount of labor required to connect sickle cell trait screening results with primary care providers (PCPs). Case review methods examined records and call logs from the first 150 cases in a 42-month project. Our study procedures identified PCPs for 136 of 150 infants (90.6%); a total of 266 phone calls were needed. We identified 9 categories of experiences, ranging from incorrect baby names to restrictions on accepting Medicaid patients. Cases demonstrate that it is possible to connect with most PCPs after newborn screening despite warnings about difficulties with this population. Success was due to persistence, relationships with clinics and hospitals, and Internet search capabilities. If sickle cell trait identification is necessary to protect health, then only modest increases in effort will be needed to reduce disparities in service.

ACSM and CHAMP summit on sickle cell trait: mitigating risks for warfighters and athletes

INTRODUCTION

An estimated 300 million people worldwide have sickle cell trait (SCT). Although largely benign, SCT has been associated with exertional rhabdomyolysis and exercise-related sudden death in warfighters/athletes (WA). The National Collegiate Athletic Association's policy to confirm a student athlete's SCT status during their preparticipation medical examination prompted reaction from some organizations regarding the rationale and ethical justification of the policy.

METHODS

On September 26 and 27, 2011, a summit, composed of military and civilian experts in sports medicine and SCT, was convened at the Uniformed Services University in Bethesda, MD. The expert panel was charged with two objectives: 1) to provide specific recommendations to further mitigate the apparent risk with strenuous exercise in WA with SCT and 2) to develop clinical guidelines to identify, treat, and return to duty/play WA suspected to have incurred nonfatal sickle cell collapse.

RESULTS

New terminology is introduced, areas of current controversy are explored, consensus recommendations for mitigating risk and managing the WA with SCT are reviewed, and important areas for future research are identified.

CONCLUSION

Further research is needed before conclusions can be drawn regarding the etiology of the increased death rate observed in WA with SCT, and the possibility exists that SCT is a surrogate for as yet another contributing factor for the unexplained deaths.

Haemoglobin SD disease--rare case of jaundice

A 15 years old Muslim female presented with moderate anaemia, mild jaundice and hepatosplenomegaly with no history of blood transfusion in the past. Routine examination was suggestive of haemolytic jaundice. High pressure liquid chromatography (HPLC) electrophoresis of the patient's blood showed haemoglobin (Hb) SD disease. As it is a double heterozygous disease, family screening was done. It showed that the father was sickle cell trait. Mother was Hb D trait. Both the brothers were sickle cell trait and the only sister was normal. Hb SD disease is a very rare variety of haemoglobinopathy and the case is presented here due to its rarity.

A fatal case of acute chest syndrome in a patient with undiagnosed sickle cell trait

We report a fatal case of acute chest syndrome in an African-American male. The patient was hospitalized for respiratory distress, fevers, and pulmonary infiltrates after working in an attic space on a summer day. An extensive work-up failed to reveal an etiology for his respiratory failure. He died of respiratory failure two weeks after admission. Autopsy findings suggested the patient had clinically unrecognized sickle cell trait exacerbated by working in the heat, causing acute chest syndrome with a fatal outcome. Clinicians should consider acute chest syndrome and sickle cell trait in the differential diagnosis of patients with unexplained respiratory failure and pulmonary infiltrates.

Novel test method (sickle confirm) to differentiate sickle cell anemia from sickle cell trait for potential use in developing countries

The objective of this study was to develop a diagnostic testing method to detect HbS, distinguish sickle cell homozygotes from heterozygotes, and overcome testing barriers encountered in laboratories in underdeveloped countries. Blood samples positive and negative for sickle cell were subjected to the standard hemoglobin solubility test followed by a variety of centrifugation and filtration procedures. Each procedure was evaluated for the ability to remove insoluble HbS from the sample. The hemoglobin types that remain (HbA, HbA2 and HbF) were measured spectrophotometrically or estimated visually allowing samples to be categorized into three genotypes (AA, AS and SS) as confirmed by hemoglobin electrophoresis. De-identified EDTA blood samples were obtained from Saint Louis University and Cardinal Glennon Children's hospitals and tested in the Department of Clinical Laboratory Science at Saint Louis University. The main outcome measures were turbidity of the solubility solution; color of the supernatant and the material on the surface of the solution following centrifugation; precipitate trapped on the filter paper; absorbance of the filtrate; and hemoglobin electrophoresis patterns. Centrifugation and filtration successfully separated HbS from HbA/A2/F allowing for the differentiation of seven sickle cell homozygotes from sixteen heterozygotes with a sensitivity and specificity of 100%. This method has the potential to reliably distinguish homozygous from heterozygous sickle cell patients and it is fast, inexpensive, and simple. These characteristics make Sickle Confirm a desirable method in developing countries like Haiti and Africa where sickle cell anemia is prevalent and modern diagnostic methods like electrophoresis, HPLC and nucleic acid testing are impractical.

Sickle cell considerations in athletes

This article highlights the exertional-sickling collapse syndrome in athletes with sickle cell trait (SCT). It covers all aspects of this syndrome, including pathophysiology, new research on microcirculatory changes, clinical features, differential diagnosis, prevention, and treatment. Also covered in this article are other clinical concerns for athletes with SCT, including lumbar myonecrosis, splenic infarction, hematuria, hyposthenuria, and venous thromboembolism. The final section offers practical points on athletes with sickling hemoglobinopathies more serious than SCT.