Temperature changes, temperature extremes, and their relationship to emergency department visits and hospitalizations for sickle cell crisis

Cold exposure induces vaso-occlusion and pain in sickle mice that depend on complement activation

Vaso-occlusive pain episodes (VOE) cause severe pain in patients with sickle cell disease (SCD). Vaso-occlusive events promote ischemia/reperfusion pathobiology that activates complement. We hypothesized that complement activation is linked to VOE. We used cold to induce VOE in the Townes sickle homozygous for hemoglobin S (HbSS) mouse model and complement inhibitors to determine whether anaphylatoxin C5a mediates VOE. We used a dorsal skinfold chamber to measure microvascular stasis (vaso-occlusion) and von Frey filaments applied to the plantar surface of the hind paw to assess mechanical hyperalgesia in HbSS and control Townes mice homozygous for hemoglobin A (HbAA) mice after cold exposure at 10°C/50°F for 1 hour. Cold exposure induced more vaso-occlusion in nonhyperalgesic HbSS mice (33%) than in HbAA mice (11%) or HbSS mice left at room temperature (1%). Cold exposure also produced mechanical hyperalgesia as measured by paw withdrawal threshold in HbSS mice compared with that in HbAA mice or HbSS mice left at room temperature. Vaso-occlusion and hyperalgesia were associated with an increase in complement activation fragments Bb and C5a in plasma of HbSS mice after cold exposure. This was accompanied by an increase in proinflammatory NF-κB activation and VCAM-1 and ICAM-1 expression in the liver. Pretreatment of nonhyperalgesic HbSS mice before cold exposure with anti-C5 or anti-C5aR monoclonal antibodies (mAbs) decreased vaso-occlusion, mechanical hyperalgesia, complement activation, and liver inflammatory markers compared with pretreatment with control mAb. Anti-C5 or -C5aR mAb infusion also abrogated mechanical hyperalgesia in HbSS mice with ongoing hyperalgesia at baseline. These findings suggest that C5a promotes vaso-occlusion, pain, and inflammation during VOE and may play a role in chronic pain.

Hospitalizations among children with sickle cell disease enrolled in the Kumasi Sickle Cell Pan African Consortium (SPARCo) database: A cross sectional study

Background and Aims

Sickle cell disease (SCD) is the commonest monogenic haemolytic disorder in Africa. Despite strides made in its management, a significant proportion of patients are hospitalized from the various complications of the disease. This study set out to describe the main causes and outcomes of hospitalizations among pediatric patients with SCD.

Methods

A cross-sectional study was conducted at the Pediatric Emergency Unit of Komfo Anokye Teaching Hospital within a period of 12 months to recruit pediatric SCD patients. This study looked at causes of admission, length of hospital stay (LOS), and outcome of admission.

Results

Of the 201 SCD patients recruited, 57.2% were males and majority were of SCD-SS phenotype 83.1%. The median age was 6 years. The three leading causes of hospitalization were Vaso-occlusive pain events (VOPE) (39.8%), acute chest syndrome (ACS) (25.9%), and infections (12.4%). Ten (5.0%) of the patients presented with a stroke. High admissions were observed in June (12.4%) and November (16.9%). The median (interquartile range [IQR]) LOS was 6 days (IQR: 4-10). Six (3.0%) of the patients died from complications of the disease during hospitalization.

Conclusion

VOPE, ACS, infections, and acute anaemia from hyperhaemolysis were observed as the most common causes of admissions among SCD patients. A good outcome of discharge was seen in most of the patients that were hospitalized with a median length of stay of 6 days. This study also strengthens the importance of a good SCD database with patient follow-ups for better outcomes in SCD patients.

Seasonal and socio-demographic patterns of self-reporting major disease groups in north-west Burkina Faso: an analysis of the Nouna Health and Demographic Surveillance System (HDSS) data

Background

Sub-Saharan Africa (SSA) is facing a rapid growth of non-communicable diseases (NCDs), while communicable diseases still prevail. For rural SSA, evidence for this development is scarce. We aimed at quantifying self-reported major disease groups according to season, and determining the associations with socio-economic factors in rural Burkina Faso.

Methods

This study used data of 4192 adults (age range: 18–101 years; male: 49.0%) from the Nouna Health and Demographic Surveillance System (HDSS) in north-west Burkina Faso, rainy season of 2010 and dry season of 2011. We assessed the proportions and their 95% confidence intervals (CIs) of self-reported major disease groups as defined by the World Health Organization. For their associations with socio-economic factors, odds ratios (OR), 95% CIs and p-values were calculated by logistic regression.

Results

The surveys were completed by 3949 adults in 2010 (mean age: 37.5 ± 14.9 years, male: 48.8%) and by 4039 adults in 2011 (mean age: 37.3 ± 16.2 years, male: 49.1%). The proportions of self-reported communicable diseases were 20.7% (95% CI: 19.4–21.9%) in the rainy season and 11.0% (10.0–11.9%; McNemar’s p < 0.0001) in the dry season. Self-reported NCDs amounted to 5.3% (4.6–6.0%) and 4.5% (3.8–5.1%; p = 0.08), respectively. In each year, less than 1% reported injuries (p = 0.57). Few individuals reported an overlap of communicable diseases and NCDs: 1.4% in 2010 and 0.6% in 2011. In the multiple-adjusted models, formal education (vs. lack of education) showed the strongest association with self-reporting of communicable diseases in both seasons. For NCD-reporting, non-manual occupation (vs. manual) was positively associated, only in the rainy season.

Conclusions

Self-reporting of communicable diseases is subject to seasonal variation in this population in north-west Burkina Faso. The exact reasons for the low overall self-reporting of NCDs and injuries, apart from a low socio-demographic position, require further investigation.

Opioid Prescription Filling Trends Among Children with Sickle Cell Disease After the Release of State-Issued Guidelines on Pain Management

OBJECTIVE

To assess the impact of Ohio's 2012, 2013, and 2016 opioid prescribing guidelines on opioid and nonsteroidal anti-inflammatory drug (NSAID) prescription filling and health care utilization for pain among children with sickle cell disease (SCD).

DESIGN

Quasi-experimental retrospective cohort study.

SETTING

Ohio Medicaid claims data from August 2011 to August 2016.

SUBJECTS

Medicaid beneficiaries under age 19 years with SCD.

METHODS

Interrupted time series analyses comparing population-level rates of opioids and NSAID prescriptions filled, standardized amounts of opioids dispensed, and acute health care utilization for pain before and after release of each guideline.

RESULTS

In our cohort of 1,505 children with SCD, there was a temporary but significant decrease in the opioid filling rate (-2.96 prescriptions per 100 children, P = 0.01) and in the amount of opioids dispensed (-31.39 milligram morphine equivalents per filled prescription, P < 0.001) after the 2013 guideline but a temporary but significant increase in the opioid filling rate (7.44 prescriptions per 100 children, P < 0.001) and in the amount of opioids dispensed (72.73 mg morphine equivalents per filled prescription, P < 0.001) after the 2016 guideline. The NSAID filling rate did not significantly change after any of the guidelines. Acute health care utilization rates for pain after the 2016 guideline were similar to those before the 2013 guideline (rate ratio = 1.04, P = 0.63).

CONCLUSIONS

Our results suggest that Ohio's 2013 and 2016 guidelines were associated with significant but nonsustained changes in opioid prescription filling among children with SCD. Additional studies are needed to confirm that opioid guidelines have a sustained impact on excessive opioid prescribing, filling, and misuse.

Risk factors associated with increased emergency department utilization in patients with sickle cell disease: a systematic literature review

Sickle cell disease (SCD), a genetic disorder affecting up to 100,000 patients in the USA, impacts multiple organ systems. The emergency department (ED) is frequently utilized by patients with SCD who have severe pain from vaso-occlusive crises. The goal of this systematic literature review is to identify predictors for ED use among patients with SCD in the USA, as high ED reliance is not ideal because of the potential for discontinuity of care as well as higher costs. PubMed and Embase were searched for articles containing the keywords "sickle cell disease" AND ("emergency" OR "acute care") AND ("utilization" OR "health care") published between 2000 and 26 September 2019. A total of 26 publications were identified meeting the following inclusion criteria: report of ED or acute care clinic use; report of health care utilization for SCD; and report of ED visits independent of hospital admission, ED revisits, inpatient care visits, and SCD care unit visits. Articles unavailable in English or those focused on populations outside the USA were excluded. Of the 26 articles included, 4 were prospective and the remainder were retrospective. Qualitative analysis of the articles revealed a higher rate of ED utilization among adults than children, patients with public insurance than private insurance, and patients with more comorbidities, complications, or pain. Age and pain levels were both commonly cited as predictors of ED utilization. Additional prospective and interventional studies are needed to further define predictors of ED utilization and to uncover treatments that decrease ED visits.

High levels of proinflammatory cytokines IL-6 and IL-8 are associated with a poor clinical outcome in sickle cell anemia

Sickle cell anemia (SCA) pathophysiology is characterized by the activation of sickle red blood cells, reticulocytes, leukocytes, platelets, and endothelial cells, and with the expression of several inflammatory molecules. Therefore, it is conceivable that variations in levels of proinflammatory cytokines may act as a signaling of differential clinical course in SCA. Here, we evaluated the clinical impact of proinflammatory cytokines interleukin 1-β (IL-1β), interleukin 6 (IL-6), and interleukin 8 (IL-8) in 79 patients with SCA, followed in a single reference center from northeastern Brazil. The main clinical/laboratory data were obtained from patient interview and medical records. The proinflammatory markers IL-1β, IL-6, and IL-8 were evaluated by using commercially available enzyme-linked immunosorbent assay kits. According to levels of the proinflammatory markers, we observed that patients who had a higher frequency of VOC per year (P = 0.0236), acute chest syndrome (P = 0.01), leg ulcers (P = 0.0001), osteonecrosis (P = 0.0006), stroke (P = 0.0486), and priapism (P = 0.0347) had higher IL-6 levels compared with patients without these clinical complications. Furthermore, increased levels of IL-8 were found in patients who presented leg ulcers (P = 0.0184). No significant difference was found for IL-1β levels (P > 0.05). In summary, the present study emphasizes the role of inflammation in SCA pathophysiology, reveals an association of IL-8 levels and leg ulcer occurrence, and indicates that IL-6 levels can be used as a useful predictor for poor outcomes in SCA.

Significant Quantitative Differences in Orexin Neuronal Activation After Pain Assessments in an Animal Model of Sickle Cell Disease

Sickle cell disease is a hemoglobinopathy that causes sickling of red blood cells, resulting in vessel blockage, stroke, anemia, inflammation, and extreme pain. The development and treatment of pain, in particular, neuropathic pain in sickle cell disease patients is poorly understood and impedes our progress toward the development of novel therapies to treat pain associated with sickle cell disease. The orexin/hypocretin system offers a novel approach to treat chronic pain and hyperalgesia. These neuropeptides are synthesized in three regions: perifornical area (PFA), lateral hypothalamus (LH), and dorsomedial hypothalamus (DMH). Data suggest that orexin-A neuropeptide has an analgesic effect on inflammatory pain and may affect mechanisms underlying the maintenance of neuropathic pain. The purpose of this study was to determine whether there are neuronal activation differences in the orexin system as a result of neuropathic pain testing in a mouse model of sickle cell disease. Female transgenic sickle mice that express exclusively (99%) human sickle hemoglobin (HbSS-BERK) and age-/gender-matched controls (HbAA-BERK mice; n = 10/group, 20-30 g) expressing normal human hemoglobin A were habituated to each test protocol and environment before collecting baseline measurements and testing. Four measures were used to assess pain-related behaviors: thermal/heat hyperalgesia, cold hyperalgesia, mechanical hyperalgesia, and deep-tissue hyperalgesia. Hypothalamic brain sections from HbAA-BERK and HbSS-BERK mice were processed to visualize orexin and c-Fos immunoreactivity and quantified. The percentage of double labeled neurons in the PFA was significantly higher than the percentage of double labeled neurons in the LH orexin field of HbAA-BERK mice (* p < 0.05). The percentages of double labeled neurons in PFA and DMH orexin fields are significantly higher than those neurons in the LH of HbSS-BERK mice (* p < 0.05). These data suggest that DMH orexin neurons were preferentially recruited during neuropathic pain testing and a more diverse distribution of orexin neurons may be required to produce analgesia in response to pain in the HbSS-BERK mice. Identifying specific orexin neuronal populations that are integral in neuropathic pain processing will allow us to elucidate mechanisms that provide a more selective, targeted approach in treating of neuropathic pain in sickle cell disease.

Cold External Temperatures and Sickle Cell Morbidity in Children: A Retrospective Analysis

BACKGROUND

Genetic and environmental factors affect the occurrence of vaso-occlusive crises (VOCs) in patients with sickle cell disease (SCD). Research provides inconsistent evidence on how environmental temperature affects SCD. Edmonton, Alberta, has an increasing SCD population and is the northern-most city in North America with a population of over a million.

OBJECTIVE

The objective of this study was to identify whether pediatric patients with SCD experience increased morbidity in cold external temperatures.

MATERIALS AND METHODS

This study was a retrospective case series. Emergency visits, phone calls, and admission data for VOC in children were recorded from July 2011 to June 2016. Temperatures were recorded and statistically analyzed using descriptive statistics, to determine the relation to VOC.

RESULTS

A total of 118 patients with 257 VOC events were reviewed. When analyzing the mean, minimum, and change in temperatures at presentation, the largest percentage of VOC events occurred at mild to moderate temperatures. Temperature data at 24 and 48 hours before the presentation had similar results. When accounting for the relative frequency of extreme weather days, there are increased VOC events with temperature fluctuations >20°C.

CONCLUSIONS

There was no correlation between mean and minimum temperature change. Fluctuation in temperature of >20°C was associated with increased relative VOC frequency, suggesting that large temperature variability should be avoided in SCD, but a prospective study is required to determine causality.

Sickle Cell Disease and Infections in High- and Low-Income Countries

Infections, especially pneumococcal septicemia, meningitis, and Salmonella osteomyelitis, are a major cause of morbidity and mortality in patients with sickle cell disease (SCD). SCD increased susceptibility to infection, while infection leads to SCD-specific pathophysiological changes. The risk of infectious complications is highest in children with a palpable spleen before six months of age. Functional splenectomy, the results of repeated splenic infarctions, appears to be a severe host-defense defect. Infection is the leading cause of death, particularly in less developed countries. Defective host-defense mechanisms enhance the risk of pneumococcal complications. Susceptibility to Salmonella infections can be explained at least in part by a similar mechanism. In high-income countries, the efficacy of the pneumococcal vaccine has been demonstrated in this disease. A decreased in infection incidence has been noted in SCD patients treated prophylactically with daily oral penicillin. Studies in low-income countries suggest the involvement of a different spectrum of etiological agents.

Children and adolescents with sickle cell disease have worse cold and mechanical hypersensitivity during acute painful events

Sickle cell disease (SCD) pain associates with cold temperature and touch. Patients and murine models with SCD have baseline thermal and mechanical pain. In SCD mice, the baseline hypersensitivity is exacerbated by experimental vaso-occlusive crises. We hypothesized that patients with SCD will similarly experience increased hypersensitivity to thermal and mechanical stimuli during acute painful events compared with baseline health. We conducted a prospective study of 24 patients with SCD aged 7 to 19 years. Patients underwent quantitative sensory testing to thermal (cold/heat) and mechanical stimuli on the thenar eminence of the nondominant hand (glabrous skin) and the lateral dorsum of the foot (hairy skin) during baseline health and within 48 hours of hospitalization for acute pain. Primary outcomes were changes in: (1) cold pain threshold (°C), (2) heat pain threshold (°C), and (3) mechanical pain threshold (g). Median age was 10.5 (interquartile range [IQR] 9-14.8) years, 67% were females, and 92% were on hydroxyurea. Patients with SCD had increased cold pain sensitivity in the hand during hospitalization compared with baseline (25.2°C [IQR 18.4-27.5°C] vs 21.3°C [IQR 4.9-26.2°C]; P = 0.011) and increased mechanical pain sensitivity in the foot during hospitalization (0.32 g [IQR 0.09-1.1 g] vs 1.7 g [IQR 0.4-8.3 g]; P = 0.003). There were no differences in heat pain sensitivity. The increased cold (P = 0.02) and mechanical (P = 0.0016) pain sensitivity during hospitalization persisted after adjusting for age, sex, hydroxyurea use, opioid consumption, and numeric pain score. Thus, cold and mechanical pain is significantly worse during an acute SCD painful event as compared to baseline health in patients with SCD.

AAAPT Diagnostic Criteria for Acute Sickle Cell Disease Pain

Acute pain episodes are the most common complication in patients with sickle cell disease (SCD). Classically attributed to vaso-occlusion, recent insights suggest that chronic pain may also contribute to the pathogenesis of acute pain episodes, which adds complexity to their diagnosis and management. A taxonomy, or classification system, for acute pain in patients with SCD would aid research efforts and enhance clinical care. To meet this need, the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks public-private partnership with the U.S. Food and Drug Administration, the American Pain Society, and the American Academy of Pain Medicine formed the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks-American Pain Society-American Academy of Pain Medicine Pain Taxonomy initiative. One of the goals of this initiative was to develop taxonomies for acute pain disorders, including SCD. To accomplish this, a working group of experts in SCD and pain was convened. Based on available literature and expert opinion, the working group used a 5-dimenional structure (diagnostic criteria, common features, modulating factors, impact/functional consequences, and putative mechanisms) to develop an acute pain taxonomy that is specific to SCD. As part of this, a set of 4 diagnostic criteria, with 2 modifiers to account for the influence of chronic pain, are proposed to define the types of acute pain observed in patients with SCD. PERSPECTIVE: This article presents a taxonomy for acute pain in patients with SCD. This taxonomy could help to standardize definitions of acute pain in clinical studies of patients with SCD.

Coping with Pain in the Face of Healthcare Injustice in Patients with Sickle Cell Disease

To evaluate the pain coping strategies of patients with sickle cell disease (SCD) who experience healthcare injustice from either physicians or nurses during medical visits for pain management. It is unknown how patients' coping with pain relates to their experiences of healthcare injustice from physicians or nurses. This descriptive comparative study included adult outpatients with SCD who completed the PAINReportIt^®, Healthcare Justice Questionnaire^©, and Coping Strategies Questionnaire-SCD. Data were analyzed using independent t tests. Frequent coping strategies of patients who experienced healthcare justice from physicians were praying-hoping and from nurses were praying-hoping, calming self-statements, diverting attention, and increasing behavioral activity. In contrast, frequent coping strategies of patients who experienced healthcare injustice from physicians were catastrophizing and isolation and from nurses were isolation. Patients who experienced healthcare justice used different sets of pain coping strategies than those who experienced healthcare injustice during medical visits for pain management.

Erythrocyte Aggregation and Blood Viscosity is Similar in Homozygous Sickle Cell Disease Patients with and without Leg Ulcers

Background  There is no consensus regarding the role of red blood cell (RBC) aggregation in the pathogenesis of leg ulcers (LUs) in sickle cell disease (SCD). Objectives  We sought to evaluate whether the cross-sectional determination of RBC aggregation and hematological indices were associated with the presence of LU in homozygous SCD. Methods  Twenty-seven patients with LU and 23 with no history of ulceration were recruited into the study. A laser-assisted rotational red cell analyzer (LoRRca) was used in the determination of the aggregation index (AI), aggregation half-time ( t_1/2 ), and the RBC aggregate strength (AMP). Hematological indices were determined using a CELL-DYN Ruby analyzer. Whole blood viscosity (WBV) and plasma viscosity (PV) were measured using a Vilastic bioprofiler. The data were presented as means ± standard deviation or median, interquartile range. Two-sample t -test was used to test for associations between the AIs, WBV, and PV in patients with and without LU. Statistical significance was taken as p  < 0.05. All analyses were conducted using Stata/SE v . 12.1 (StataCorp, College Station, TX). Results  The AI was comparable in the group with and without ulcers (68.6, 16.7 versus 67.7, 16.9; p  = 0.74); t_1/2 (1.7, 1.3 versus 1.8, 1.3; p  = 0.71); AMP (18.8, 14.5 versus 19.1, 13.3; p  = 0.84), WBV (3.8, 1.2 versus 3.8, 0.7; p  = 0.77); and the PV (1.3, 0.08 versus 1.4, 0.1; p  = 0.31) and were also not statistically different between the groups of participants. Conclusion  RBC aggregation and aggregate strength are not associated with leg ulceration in SCD.

Factors Associated with Growth Retardation in Children Suffering from Sickle Cell Anemia: First Report from Central Africa

Background. The aim of this study was to investigate and determine the risk factors associated with poor growth among SCA children. Methods. A cross-sectional study was conducted in Kinshasa, the capital's country. The nutritional status was assessed using the Z scores of the anthropometric indices. Results. We gathered data on the 256 patients, 138 females (53.9%), who entered the study. The mean age at presentation was 8.4 ± 4.9 years of age. Underweight, stunting, and wasting were found, respectively, in 47.7%, 10.5%, and 50.3% of SCA children. A history of hand-foot syndrome, more than 3 blood transfusions, being less than 12 months of age when receiving the first transfusion, more than two severe sickle crises per year, a medical history of severe infections, and the presence of hepatomegaly were associated with poor growth. When comparing sickle cell patients under 12 years of age (n = 159) to a group of 296 age-matched children with normal Hb-AA, a significantly higher proportion of subjects with stunting and underweight were found among SCA. Conclusion. Nutritional status encountered in Congolese sickle cell children has been described for the first time in this study. A high prevalence of poor growth in SCA children was found in our study.

Saudi SCD patients' symptoms and quality of life relative to the number of ED visits

Background

Individuals living with sickle cell disease (SCD) have significantly increased emergency department (ED) use compared to the general population. In Saudi Arabia, health care is free for all individuals and therefore has no bearing on increased ED visits. However, little is known about the relationship between quality of life (QoL) and frequency of acute care utilization in this patient population.

Methods

A cross-sectional study was conducted on 366 patients with SCD who attended the outpatient department at King Fahad Hospital, Hofuf, Saudi Arabia. Data were collected through self-administered surveys, which included: demographics, SCD-related ED visits, clinical issues, and QoL levels. We assessed the ED use by asking for the number of SCD-related ED visits within a 6-month period.

Results

The self-report survey of ED visits was completed by 308 SCD patients. The median number of SCD-related ED visits within a 6-month time period (IQR) was four (2-7 visits). According to the unadjusted negative binomial model, the rate of SCD-related ED visits increased by (46, 39.3, 40, and 53.5 %) for patients with fever, skin redness with itching, swelling, and blood transfusion, respectively. Poor QoL tends to increase the rate of SCD-related ED visits. Well education and poor general health positively influenced the rate of SCD-related ED visits. Well education tends to increase the rate of SCD-related ED visits by 50.2 %. The rate of SCD-related ED visits decreased by 1.4 % for every point increase in general health.

Conclusion

Saudi patients with sickle cell disease reported a wide range of SCD-related ED visits. It was estimated that six of 10 SCD patients had at least three ED visits within a 6-month period. Well education and poor general health resulted in an increase in the rate of SCD-related ED visits.

Environmental determinants of severity in sickle cell disease

Sickle cell disease causes acute and chronic illness, and median life expectancy is reduced by at least 30 years in all countries, with greater reductions in low-income countries. There is a wide spectrum of severity, with some patients having no symptoms and others suffering frequent, life-changing complications. Much of this variability is unexplained, despite increasingly sophisticated genetic studies. Environmental factors, including climate, air quality, socio-economics, exercise and infection, are likely to be important, as demonstrated by the stark differences in outcomes between patients in Africa and USA/Europe. The effects of weather vary with geography, although most studies show that exposure to cold or wind increases hospital attendance with acute pain. Most of the different air pollutants are closely intercorrelated, and increasing overall levels seem to correlate with increased hospital attendance, although higher concentrations of atmospheric carbon monoxide may offer some benefit for patients with sickle cell disease. Exercise causes some adverse physiological changes, although this may be off-set by improvements in cardiovascular health. Most sickle cell disease patients live in low-income countries and socioeconomic factors are undoubtedly important, but little studied beyond documenting that sickle cell disease is associated with decreases in some measures of social status. Infections cause many of the differences in outcomes seen across the world, but again these effects are relatively poorly understood. All the above factors are likely to account for much of the pathology and variability of sickle cell disease, and large prospective studies are needed to understand these effects better.

Heat Illnesses in the Emergency Department: A Hot Topic

The RESEARCH TO PRACTICE column is intended to improve the research critique skills of the advanced practice registered nurse (APRN) and to assist with the translation of research into practice. For each column, a topic and a particular research study are selected. The stage is set with a case presentation. The research article is then reviewed and critiqued, and the findings are discussed in relation to the case presented. Our current column discusses factors associated with heat-related hospitalizations and deaths with implications for APRN practice and public health prevention strategies using the following study: . Summertime acute heat illness in U.S. emergency departments from 2006 through 2010: Analysis of a nationally representative sample. Environmental Health Perspectives, 122(11), 1209-1215. Our case involves an adolescent athlete with sickle cell trait participating in athletic practice during the summer.

Correlation between the Lactate Dehydrogenase Levels with Laboratory Variables in the Clinical Severity of Sickle Cell Anemia in Congolese Patients

Background

Sickle cell anemia is an inflammatory disease and is characterized by chronic hemolysis. We sought to evaluate the association of lactate dehydrogenase levels with specific clinical phenotypes and laboratory variables in patients with sickle cell anemia.

Methods

The present cross-sectional study was conducted in Sickle Cell Centre of Yolo in Kinshasa, the Democratic Republic of Congo. Two hundred and eleven patients with Sickle Cell Anemia in steady state were recruited. Seventy-four participants with normal Hb (Hb-AA) were selected as a control group.

Results

The average rates of hemoglobin, hematocrit, and red blood cells tended to be significantly lower in subjects with Hb-SS (p<0.001). The average rates of white blood cells, platelets, reticulocytes and serum LDH were significantly higher in subjects with Hb-SS (p<0.001). The average rates of Hb, HbF, hematocrit and red blood cells of Hb-SS patients with asymptomatic clinical phenotype were significantly higher than those of the two other phenotypes. However, the average rates of white blood cells, platelets, reticulocytes, and LDH of Hb-SS patients with the severe clinical phenotype are higher than those of two other clinical phenotypes. Significant correlations were observed between Hb and white blood cell in severe clinical phenotype (r3 = -0.37 *) between Hb and red blood cells in the three phenotypes (r1 = 0.69 * r2 * = 0.69, r3 = 0.83 *), and finally between Hb and reticulocytes in the asymptomatic clinical phenotype and severe clinical phenotype (r1 = -0.50 * r3 = 0.45 *). A significant increase in LDH was observed in patients with leg ulcer, cholelithiasis and aseptic necrosis of the femoral head.

Conclusion

The increase in serum LDH is accompanied by changes in hematological parameters. In our midst, serum LDH may be considered as an indicator of the severity of the disease.

Environmental influences on daily emergency admissions in sickle-cell disease patients

Previous reports have suggested a role for weather conditions and air pollution on the variability of sickle cell disease (SCD) severity, but large-scale comprehensive epidemiological studies are lacking. In order to evaluate the influence of air pollution and climatic factors on emergency hospital admissions (EHA) in SCD patients, we conducted an 8-year observational retrospective study in 22 French university hospitals in Paris conurbation, using distributed lag non-linear models, a methodology able to flexibly describe simultaneously non-linear and delayed associations, with a multivariable approach. During the 2922 days of the study, there were 17,710 EHA, with a mean daily number of 6.1 ± 2.8. Most environmental factors were significantly correlated to each other. The risk of EHA was significantly associated with higher values of nitrogen dioxide, atmospheric particulate matters, and daily mean wind speed; and with lower values of carbon monoxide, ozone, sulfur dioxide, daily temperature (minimal, maximal, mean, and range), day-to-day mean temperature change, daily bright sunshine, and occurrence of storm. There was a lag effect for 12 of 15 environmental factors influencing hospitalization rate. Multivariate analysis identified carbon monoxide, day-to-day temperature change, and mean wind speed, along with calendar factors (weekend, summer season, and year) as independent factors associated with EHA. In conclusion, most weather conditions and air pollutants assessed were correlated to each other and influenced the rate of EHA in SCD patients. In multivariate analysis, lower carbon monoxide concentrations, day-to-day mean temperature drop and higher wind speed were associated with increased risk of EHA.

Summertime acute heat illness in U.S. emergency departments from 2006 through 2010: analysis of a nationally representative sample

BACKGROUND

Patients with acute heat illness present primarily to emergency departments (EDs), yet little is known regarding these visits.

OBJECTIVE

We aimed to describe acute heat illness visits to U.S. EDs from 2006 through 2010 and identify factors associated with hospital admission or with death in the ED.

METHODS

We extracted ED case-level data from the Nationwide Emergency Department Sample (NEDS) for 2006-2010, defining cases as ED visits from May through September with any heat illness diagnosis (ICD-9-CM 992.0-992.9). We correlated visit rates and temperature anomalies, analyzed demographics and ED disposition, identified risk factors for adverse outcomes, and examined ED case fatality rates (CFR).

RESULTS

There were 326,497 (95% CI: 308,372, 344,658) cases, with 287,875 (88.2%) treated and released, 38,392 (11.8%) admitted, and 230 (0.07%) died in the ED. Heat illness diagnoses were first-listed in 68%. 74.7% had heat exhaustion, 5.4% heat stroke. Visit rates were highly correlated with annual temperature anomalies (Pearson correlation coefficient 0.882, p = 0.005). Treat-and-release rates were highest for younger adults (26.2/100,000/year), whereas hospitalization and death-in-the-ED rates were highest for older adults (6.7 and 0.03/100,000/year, respectively); all rates were highest in rural areas. Heat stroke had an ED CFR of 99.4/10,000 (95% CI: 78.7, 120.1) visits and was diagnosed in 77.0% of deaths. Adjusted odds of hospital admission or death in the ED were higher among elders, males, urban and low-income residents, and those with chronic conditions.

CONCLUSIONS

Heat illness presented to the ED frequently, with highest rates in rural areas. Case definitions should include all diagnoses. Visit rates were correlated with temperature anomalies. Heat stroke had a high ED CFR. Males, elders, and the chronically ill were at greatest risk of admission or death in the ED. Chronic disease burden exponentially increased this risk.

Circulating cell-free DNA in sickle cell disease: is it a potentially useful biomarker?

CONTEXT

Vascular occlusion in sickle cell disease causes increased levels of plasma cell-free DNA as a result of cell death and tissue damage.

OBJECTIVES

This study investigates plasma cell-free DNA concentrations in sickle cell disease patients, and aims at exploring the significance of plasma cell-free DNA as a potential biomarker in predicting its complications.

DESIGN

Plasma cell-free DNA levels were measured using real-time quantitative polymerase chain reaction to quantitatively measure β-globin gene in blood samples from 57 sickle cell disease patients with acute vaso-occlusive crisis, 42 patients in steady state, 16 individuals with sickle cell trait, and 40 healthy controls.

RESULTS

Plasma cell-free DNA level was significantly elevated in samples from patients with acute vaso-occlusive crisis when compared with those in steady state (P = .002), and was significantly higher both in crisis and in steady state when compared with individuals with sickle cell trait and healthy controls (P < .001). There was no difference in cell-free DNA levels between individuals with sickle cell trait and healthy controls. There was no association between plasma cell-free DNA levels and various clinical complications of sickle cell disease and comorbidity.

CONCLUSIONS

Plasma cell-free DNA, as quantified by polymerase chain reaction amplification of the β-globin and human telomerase reverse transcriptase genes, is increased in sickle cell disease patients in vaso-occlusive crisis and in steady state compared with individuals with sickle cell trait and healthy controls, and may be used as a tool to diagnose and monitor the sickle cell crisis and differentiate post-packed red cell transfusion sickle cell disease patients from individuals with sickle cell trait.

Beyond the definitions of the phenotypic complications of sickle cell disease: an update on management

The sickle hemoglobin is an abnormal hemoglobin due to point mutation (GAG → GTG) in exon 1 of the β globin gene resulting in the substitution of glutamic acid by valine at position 6 of the β globin polypeptide chain. Although the molecular lesion is a single-point mutation, the sickle gene is pleiotropic in nature causing multiple phenotypic expressions that constitute the various complications of sickle cell disease in general and sickle cell anemia in particular. The disease itself is chronic in nature but many of its complications are acute such as the recurrent acute painful crises (its hallmark), acute chest syndrome, and priapism. These complications vary considerably among patients, in the same patient with time, among countries and with age and sex. To date, there is no well-established consensus among providers on the management of the complications of sickle cell disease due in part to lack of evidence and in part to differences in the experience of providers. It is the aim of this paper to review available current approaches to manage the major complications of sickle cell disease. We hope that this will establish another preliminary forum among providers that may eventually lead the way to better outcomes.

Optimism and Perceived Stress in Sickle-Cell Disease: The Role of an Afrocultural Social Ethos

Given its prevalence among African diasporic populations, sickle-cell disease (SCD) is an individual and global public health issue that is especially relevant to health psychologists. Despite evidence that sociocultural variables generally exert a significant influence on health outcomes, very little is known about the social and cultural contexts of adjustment to SCD. The present study explored whether specific variables representing an Afrocultural social ethos (i.e., spirituality, positive affect, and communalism) indirectly influenced the relation between optimism and perceived stress among individuals coping with SCD. Eighty-three African American adults attending an outpatient clinic completed a demographic profile and a brief survey assessing optimism, pain, stress, and the aforementioned Afrocultural domains. Multiple mediation analyses controlling for age and pain severity indicated that the relation between optimism and stress was unaffected by an Afrocultural ethos. The implications of these findings for research on psychosocial aspects of SCD are discussed.

Climatic and geographic temporal patterns of pain in the Multicenter Study of Hydroxyurea

No multi-site comparisons have tested whether seasonally cold temperature or climate exacerbate pain intensity in sickle cell disease (SCD). We examined seasonal SCD pain intensity and frequency patterns and compared them with concurrent climate conditions (temperature and barometric pressure) and geography of patient residence in the Multicenter Study of Hydroxyurea (MSH). We conducted a time series analysis of the monthly average daily pain intensity (0-9 scale) and pain frequency of the 299 MSH patients from December 1991 to December 1994. We used both an unobserved component model (UCM) and a nonparametric local regression (LOESS) to probe for a cycle and/or trend associated with the time series. We also examined base mixed regression models of season, monthly average temperature and barometric pressure, and geographic region as stand-alone predictors of pain intensity and frequency. Expanded models included additional predictor variables. UCM and LOESS analyses showed a cyclic pattern of pain intensity and frequency with peaks in late Fall/early Winter and troughs in Spring. Base regression models showed colder seasons were significantly associated with greater pain intensity (p = .0035) but not frequency (p = .07); higher monthly temperatures were significantly associated with both lower pain intensity and pain frequency, but higher monthly barometric pressures were significantly associated with greater pain intensity and frequency (all p's < .0001); and northern sites had nonsignificantly higher pain intensity (p = .40) and frequency (p = .07) than southern sites. This pattern of results did not change in expanded models including other predictors. Our results suggest that seasonably colder temperatures exacerbate sickle cell-related pain, but low barometric pressure does not, and geographic region of residence is not significantly related to pain in this sample.

Association between wind speed and the occurrence of sickle cell acute painful episodes: results of a case-crossover study

The role of the weather as a trigger of sickle cell acute painful episodes has long been debated. To more accurately describe the role of the weather as a trigger of painful events, we conducted a case-crossover study of the association between local weather conditions and the occurrence of painful episodes. From the Cooperative Study of Sickle Cell Disease, we identified 813 patients with sickle cell anaemia who had 3570 acute painful episodes. We found an association between wind speed and the onset of pain, specifically wind speed during the 24-h period preceding the onset of pain. Analysing wind speed as a categorical trait, showed a 13% increase (95% confidence interval: 3%, 24%) in odds of pain, when comparing the high wind speed to lower wind speed (P = 0.007). In addition, the association between wind speed and painful episodes was found to be stronger among men, particularly those in the warmer climate regions of the United States. These results are in agreement with another study that found an association between wind speed and hospital visits for pain in the United Kingdom, and lends support to physiological and clinical studies that have suggested that skin cooling is associated with sickle vasoocclusion and perhaps pain.

Windy weather and low humidity are associated with an increased number of hospital admissions for acute pain and sickle cell disease in an urban environment with a maritime temperate climate

Sickle cell disease (SCD) is characterised by intermittent episodes of acute severe pain, related to vaso-occlusion. Environmental factors are thought to play an important role, and studies in tropical countries have suggested that cold and rainy seasons are associated with increased episodes of acute pain. We have studied retrospectively the number of admissions with acute pain and SCD to King's College Hospital, London, together with daily meteorological records collected locally. Data from 1400 d and 1047 separate admissions were analysed. Increased admissions were significantly associated with increased wind speed and low humidity, but showed no relationship to temperature, rainfall or barometric pressure. The strongest effect was for (maximum wind speed)/humidity, with 464 admissions on days in the lowest two quartiles of this parameter and 582 in the highest quartiles. The effect of high wind and low humidity is likely to be related to skin cooling.