Sickle cell pain: a critical reappraisal

Burden of central nervous system complications in sickle cell disease: A systematic review and meta-analysis

Sickle cell disease (SCD) patients are at high risk of central nervous system (CNS) complications and may experience significant morbidity. The study was conducted to describe the comprehensive burden of SCD-related CNS complications and to identify patient-reported outcome (PRO) instruments for future research. The review included 32 studies published from January 2000 to 2020, evaluating humanistic and economic outcomes. Twenty-three studies reported humanistic outcomes, 16 of which measured cognitive function using Wechsler Intelligence Scales. A meta-analysis was conducted, finding full-scale intelligence quotient (IQ) was significantly lower in: overt stroke versus controls: -12.6 (p < .001); silent cerebral infarct (SCI) versus controls: -5.7 (p < .001); overt stroke versus SCI: -9.4 (p = .008); and any event versus controls: -7.6 (p < .001). This review quantified the cognitive deficits associated with CNS complications in pediatric SCD populations and highlights the need for improved prevention/treatment. As PRO evidence was limited, we discussed areas for future research.

Prevalence of neuropathic pain in adolescents with sickle cell disease: A single-center experience

BACKGROUND

Neuropathic pain (NP) has been previously explored in adolescents with sickle cell disease (SCD). This study aims to describe the prevalence of NP in adolescents with SCD at a single institution and to explore associated risk factors.

PROCEDURE

We used the painDETECT questionnaire, one of the few pain phenotyping questionnaires validated for adolescents. We also evaluated the relationships between painDETECT scores and frequency of acute care visits and admissions for pain in the previous 12 months, and age, respectively. Patients 12-18 years old were surveyed from June to July 2019. A retrospective approach was used to answer the remaining research questions.

RESULTS

Eighty-one and seven surveys were completed in the outpatient and inpatient settings, respectively. PainDETECT scores suggestive of NP were more prevalent in inpatient surveys than in outpatient surveys. The difference between the mean painDETECT scores of each group was significant when using a general linear mixed model. Most inpatients surveyed had ≥3 pain events in the previous 12 months. Further, older age and increased number of pain events in the previous 12 months were independently associated with higher painDETECT scores.

CONCLUSIONS

Overall, in our opinion, NP is not being evaluated for and treated sufficiently in pediatric SCD, especially in the setting of inpatient acute vaso-occlusive crisis. Age and number of acute pain events/admissions in the previous 12 months can be used to identify patients likely to be at risk for NP. It is important to continue to identify NP and develop NP-targeting treatment plans.

How Would You Treat This Patient With Acute and Chronic Pain From Sickle Cell Disease? : Grand Rounds Discussion From Beth Israel Deaconess Medical Center

Sickle cell disease is prevalent in large numbers of patients in the United States and has a significant global impact. Its complications span numerous organs and lead to reduced life expectancy. Acute and chronic sickle cell pain is a common cause of patient suffering. The American Society of Hematology published updated guidelines on management of acute and chronic pain from sickle cell disease in 2019. Several of the recommendations are conditional and leave specific decisions to the treating physician. These include conditional recommendations about the use of ketamine for acute pain and the initiation and discontinuation of long-term opioid therapy for chronic pain. Here, 2 hematologists discuss these guidelines and make contrasting recommendations for the management of acute and chronic pain for a patient with sickle cell disease.

Moving Toward a Multimodal Analgesic Regimen for Acute Sickle Cell Pain with Non-Opioid Analgesic Adjuncts: A Narrative Review

Purpose of Review

Sickle cell disease (SCD) is an inherited hemoglobinopathy with potential life-threatening complications that affect millions of people worldwide. Severe and disabling acute pain, referred to as a vaso-occlusive crisis (VOC), is a fundamental symptom of the disease and the primary driver for acute care visits and hospitalizations. Despite the publication of guidelines for VOC management over the past decade, management of VOCs remains unsatisfactory for patients and providers.

Recent Findings

Acute SCD pain includes pain secondary to VOCs and other forms of acute pain. Distinguishing VOC from non-VOC pain may be challenging for both patients and clinicians. Further, although opioids have been the gold-standard for VOC pain management for decades, the current highest standard of care for all acute pain is a multimodal approach that is less dependent on opioids, and, instead incorporates analgesics and adjuvants from different mechanistic pathways. In this narrative review, we focus on a multimodal pharmacologic approach for acute SCD pain management and explore the evidence for existing non-opioid pharmacological adjuncts. Moreover, we present an explanatory model of pain, which is not only novel in its application to SCD pain but also captures the multidimensional nature of the SCD pain experience and supports the need for such a multimodal approach. This model also highlights opportunities for new investigative and therapeutic targets - both pharmacological and non-pharmacological.

Summary

Multimodal pain regimens that are less dependent on opioids are urgently needed to improve acute pain outcomes for individuals with SCD. The proposed explanatory model for SCD pain offers novel opportunities to improve acute pain management for SCD patients.

Klotho Level as a Marker of Low Bone Mineral Density in Egyptian Sickle Cell Disease Patients

Bone involvement of sickle cell disease (SCD) patients varies from acute clinical manifestations of painful vaso-occlusive crises or osteomyelitis to more chronic affection of bone mineral density (BMD) and debilitating osteonecrosis and osteoporosis. Secreted klotho protein is involved in calcium (Ca) reabsorption in the kidney. This study aimed to measure serum klotho levels in children with SCD to determine the possibility of using it as a marker of low BMD in children with SCD in correlation with a dual-energy radiograph absorptiometry scan. This study included 60 sickle disease patients and 30 age-matched and sex-matched control participants without SCD. A highly statistically significant difference was found between patients with normal BMD and those with low BMD, with serum Ca and klotho levels being lower in the latter group. Klotho serum level correlated positively with both serum Ca and BMD. Serum klotho level showed 94.9% sensitivity and 95.2% specificity in the detection of low BMD. Both serum Ca and klotho serum levels may be useful markers for detection of low BMD related to SCD with high sensitivity and specificity; however, klotho may be a better indicator as it is less affected by the nutritional and endocrinal status of patients or by intake of Ca supplements.

Opioid Use in Patients With Sickle Cell Disease During a Vaso-Occlusive Crisis: A Systematic Review

Sickle cell disease (SCD) affects the red blood cells, which become sickle-shaped, leading to their adhesion to vascular walls, impeding blood flow and causing the unpredictable, abrupt onset of intense pain episodes in the form of vaso-occlusive crises (VOC) as well as affecting multiple organ systems. The primary aim of this review is to assess the effectiveness of opioid analgesic intervention for pain management in sickle cell disease during an acute painful crisis. A literature search was done electronically on PubMed Central (PMC), PubMed, and Google Scholar databases. The reports included in the study were from 2010 to 2021, and the bibliographies of retrieved studies are included in the references. This systematic review was undertaken as per the Preferred Reporting Items for Systematic Review and Meta-Analysis. This study included reports discussing opioid analgesics in SCD patients during VOC in different settings. After extensive research, there were no clear current opioid treatment patterns described, and our conclusion suggested conducting more evidence-based research to improve the quality of VOC management and outcome.

Communicating and understanding pain: Limitations of pain scales for patients with sickle cell disorder and other painful conditions

Pain communication in healthcare is challenging. We examine use of pain scales to communicate pain severity via a case study of people with sickle cell disorder (SCD). We show how pain communication involves complex social interactions between patients, healthcare professionals and significant others - none of which are included in pain ratings. Failure to account for relational aspects of pain may cause problems for any patient. For SCD, mutual distrust shapes pain communication, further complicating clinical assessments. Moreover, SCD pain is particularly severe, making ratings hard to interpret compared with ratings from non-SCD patients, potentially exacerbating problems in managing pain relief.

Hydroxyurea usage awareness among patients with sickle-cell disease in Saudi Arabia

BACKGROUND AND AIM

Hydroxyurea (HU) plays an essential role in the complex pathophysiology alteration of sickle-cell disease (SCD), which translates clinically into the enhanced quality of life and increased survival. This research examines adult patients with SCD's attitudes and awareness toward HU, as well as underutilization consequences.

METHOD

A cross-sectional research was performed in Saudi Arabia, and adult patients with SCD were interviewed. The survey includes patient demographics, attitudes, and knowledge of HU and clinical data. The chi-square was applied through SPSS version 23 for assessing any association with outcome variables and demographic characteristics.

RESULTS

HU is known to 72 (67.3%) of the 107 patients. The hydroxyurea treatment was initiated in 46 patients (63%). Of these, 23 (50%) discontinue HU, with the key factors being pregnancy preparation and side effects development. For those who were unaware of HU, 13 (37.1%) were admitted to the intensive care unit because of acute chest syndrome, 29 (82.8%) required a frequent blood transfusion and 12 (34.2%) with frequent hospitalizations. However, there was no significant relationship between awareness and education level (P value is .078 > .05). In addition, there was no significant relationship between the level of awareness and age and gender of participants (P value is .68 and .44, respectively).

CONCLUSION

HU is a long-established and effective disease-modifying agent for SCD patients, but it is underutilized. The causality of underuse is bidirectional between patients and healthcare providers. It is essential to educate healthcare providers and patients with SCD about hydroxyurea role in modifying disease severity, resolving adverse events, and achieving full benefits.

Vasoconstriction Response to Mental Stress in Sickle Cell Disease: The Role of the Cardiac and Vascular Baroreflexes

Recent studies have shown that individuals with sickle cell disease (SCD) exhibit greater vasoconstriction responses to physical autonomic stressors, such as heat pain and cold pain than normal individuals, but this is not the case for mental stress (MTS). We sought to determine whether this anomalous finding for MTS is related to inter-group differences in baseline cardiac and vascular autonomic function. Fifteen subjects with SCD and 15 healthy volunteers participated in three MTS tasks: N-back, Stroop, and pain anticipation (PA). R-R interval (RRI), arterial blood pressure and finger photoplethysmogram (PPG) were continuously monitored before and during these MTS tasks. The magnitude of vasoconstriction was quantified using change in PPG amplitude (PPGa) from the baseline period. To represent basal autonomic function, we assessed both cardiac and vascular arms of the baroreflex during the baseline period. Cardiac baroreflex sensitivity (BRSc) was estimated by applying both the "sequence" and "spectral" techniques to beat-to-beat measurements of systolic blood pressure and RRIs. The vascular baroreflex sensitivity (BRSv) was quantified using the same approaches, modified for application to beat-to-beat diastolic blood pressure and PPGa measurements. Baseline BRSc was not different between SCD and non-SCD subjects, was not correlated with BRSv, and was not associated with the vasoconstriction responses to MTS tasks. BRSv in both groups was correlated with mean PPGa, and since both baseline PPGa and BRSv were lower in SCD, these results suggested that the SCD subjects were in a basal state of higher sympathetically mediated vascular tone. In both groups, baseline BRSv was positively correlated with the vasoconstriction responses to N-back, Stroop, and PA. After adjusting for differences in BRSv within and between groups, we found no difference in the vasoconstriction responses to all three mental tasks between SCD and non-SCD subjects. The implications of these findings are significant in subjects with SCD since vasoconstriction reduces microvascular flow and prolongs capillary transit time, increasing the likelihood for vaso-occlusive crisis (VOC) to be triggered by exposure to stressful events.

Crizanlizumab for the Prevention of Vaso-Occlusive Pain Crises in Sickle Cell Disease

Objective: To review the efficacy and safety of crizanlizumab (Adakveo) in the prevention of vaso-occlusive pain crises in sickle cell disease. Data Sources: An English-language literature search of PubMed, MEDLINE, and Ovid (1946 to January 2021) was completed using the terms crizanlizumab, SEG101, SelG1, and sickle cell disease. Manufacturer prescribing information, article bibliographies, and data from clinicaltrials.gov were incorporated in the reviewed data. Study Selection/Data Extraction: All studies registered on clinicaltrials.gov were incorporated in the reviewed data. Data Synthesis: Crizanlizumab is the first monoclonal antibody approved for sickle cell disease to reduce the frequency of vaso-occlusive crises. One phase 2 clinical trial and a post hoc analysis of the trial have been published. Relevance to Patient Care and Clinical Practice: Crizanlizumab is a monthly intravenous infusion approved by the Food and Drug Administration for patients with sickle cell disease 16 years of age and older to reduce the frequency of vaso-occlusive crises. Conclusion: Crizanlizumab appears to be an efficacious therapy for patients with sickle cell disease to reduce the frequency of vaso-occlusive crises. Concerns include drug cost and administration. Long-term benefits and risks have not been determined.

American Society of Hematology 2021 guidelines for sickle cell disease: stem cell transplantation

BACKGROUND

Sickle cell disease (SCD) is a life-limiting inherited hemoglobinopathy that results in significant complications and affects quality of life. Hematopoietic stem cell transplantation (HSCT) is currently the only curative intervention for SCD; however, guidelines are needed to inform how to apply HSCT in clinical practice.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and health professionals in their decisions about HSCT for SCD.

METHODS

The multidisciplinary guideline panel formed by ASH included 2 patient representatives and was balanced to minimize potential bias from conflicts of interest. The Mayo Evidence-Based Practice Research Program supported the guideline development process, including performing systematic evidence reviews (through 2019). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE Evidence-to-Decision frameworks, to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 8 recommendations to help patients and providers assess how individuals with SCD should consider the timing and type of HSCT.

CONCLUSIONS

The evidence review yielded no randomized controlled clinical trials for HSCT in SCD; therefore, all recommendations are based on very low certainty in the evidence. Key recommendations include considering HSCT for those with neurologic injury or recurrent acute chest syndrome at an early age and to improve nonmyeloablative regimens. Future research should include the development of a robust SCD registry to serve as a comparator for HSCT studies.

Treatment of Acute Pain in Adults With Sickle Cell Disease in an Infusion Center Versus the Emergency Department : A Multicenter Prospective Cohort Study

BACKGROUND

Patients with sickle cell disease (SCD) have vaso-occlusive crises (VOCs). Infusion centers (ICs) are alternatives to emergency department (ED) care and may improve patient outcomes.

OBJECTIVE

To assess whether care in ICs or EDs leads to better outcomes for the treatment of uncomplicated VOCs.

DESIGN

Prospective cohort. (ClinicalTrials.gov: NCT02411396).

SETTING

4 U.S. sites, with recruitment between April 2015 and December 2016.

PARTICIPANTS

Adults with SCD living within 60 miles of a study site.

MEASUREMENTS

Participants were followed for 18 months after enrollment. Outcomes of interest were time to first dose of parenteral pain medication, whether pain reassessment was completed within 30 minutes after the first dose, and patient disposition on discharge from the acute care visit. Treatment effects for ICs versus EDs were estimated using a time-varying propensity score adjustment.

RESULTS

Researchers enrolled 483 participants; the 269 who had acute care visits on weekdays are included in this report. With inverse probability of treatment-weighted adjustment, the mean time to first dose was 62 minutes in ICs and 132 minutes in EDs; the difference was 70 minutes (95% CI, 54 to 98 minutes; E-value, 2.8). The probability of pain reassessment within 30 minutes of the first dose of parenteral pain medication was 3.8 times greater (CI, 2.63 to 5.64 times greater; E-value, 4.7) in the IC than the ED. The probability that a participant's visit would end in admission to the hospital was smaller by a factor of 4 (0.25 [CI, 0.18 to 0.33]) with treatment in an IC versus an ED.

LIMITATION

The study was restricted to participants with uncomplicated VOCs.

CONCLUSION

In adults with SCD having a VOC, treatment in an IC is associated with substantially better outcomes than treatment in an ED.

PRIMARY FUNDING SOURCE

Patient-Centered Outcomes Research Institute.

Nociceptors protect sickle cell disease mice from vaso-occlusive episodes and chronic organ damage

Sickle cell disease (SCD) is a common hereditary hematologic disorder. SCD patients suffer from acute vaso-occlusive episodes (VOEs), chronic organ damage, and premature death, with few therapeutic options. Although severe pain is a major clinical manifestation of SCD, it remains unknown whether nociception plays a role in SCD pathogenesis. To address this question, we generated nociceptor-deficient SCD mice and found, unexpectedly, that the absence of nociception led to more severe and more lethal VOE, indicating that somatosensory nerves protect SCD mice from VOE. Mechanistically, the beneficial effects of sensory nerves were induced by the neuropeptide calcitonin gene–related peptide (CGRP), which acted on hematopoietic cells. Additionally, oral capsaicin consumption, which can activate somatosensory nerves by binding to TRPV1, dramatically alleviated acute VOE and significantly prevented chronic liver and kidney damage in SCD mice. Thus, the manipulation of nociception may provide a promising approach to treat SCD.

A non-injected opioid analgesia protocol for acute pain crisis in adolescents and adults with sickle cell disease

Initial management of the acute pain crisis (APC) of sickle cell disease (SCD) is often unsatisfactory, and might be improved by developing a standardised analgesia protocol. Here, we report the first stages in developing a standard oral protocol for adolescents and adults. Initially, we performed a dose finding study to determine the maximal tolerated dose of sublingual fentanyl (MTD SLF) given on arrival in the acute care facility, when combined with repeated doses of oral oxycodone. We used a dose escalation algorithm with two dosing ranges based on patient’s weight (<50 kg or >50 kg). We also made a preliminary evaluation of the safety and efficacy of the protocol. The study took place in a large tertiary centre in London, UK. Ninety patients in the age range 14–60 years were pre-consented and 31 treatment episodes were evaluated. The first 21 episodes constituted the dose escalation study, establishing the MTD SLF at 600 mcg (>50 kg) or 400 mcg (<50 kg). Further evaluation of the protocol indicated no evidence of severe opioid toxicity, nor increased incidence of acute chest syndrome (ACS). Between 0 and 6 hours, the overall gradient of reduction of visual analogue pain score (visual analogue scale (VAS)) was 0.32 centimetres (cm) per hour (95% confidence interval (CI) = 0.20 to 0.44, p < 0.001). For episodes on MTD SLF, there was median (interquartile range (IQR)) reduction in VAS score of 2.8 cm (0–4.2) and 59% had at least a 2.6-cm reduction. These results are supportive of further evaluation of this protocol for acute analgesia of APC in a hospital setting and potentially for supervised home management.

Pain in sickle cell disease: current and potential translational therapies

Pain is a major comorbidity of sickle cell disease (SCD). Patients with SCD may suffer from both acute and chronic pain. Acute pain is caused by recurrent and unpredictable episodes of vaso-occlusive crises (VOC), whereas the exact etiology of chronic pain is still unknown. Opioids are the mainstay for pain treatment, but the opioid epidemic has significantly altered access to prescription opioids and has brought concerns over their long-term use into the forefront, which have negatively impacted the treatment of sickle pain. Opioids remain potent analgesics but growing opioid-phobia has led to the realization of an unmet need to develop nonopioid therapies that can provide relief for severe sickle pain. This realization has contributed to the approval of 3 different drugs by the Food and Drug Administration (FDA) for the treatment of SCD, particularly to reduce VOC and/or have an impact on the pathobiology of SCD. In this review, we outline the challenges and need for validation of side-effects of opioids and provide an update on the development of mechanism-based translational therapies, specifically targeting pain in SCD.

A systematic review of ketamine for the management of vaso-occlusive pain in sickle cell disease

Vaso-occlusive episodes (VOEs) are a common complication of sickle cell disease (SCD) and a significant cause of morbidity. Managing VOE pain can be difficult and complex. Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has been used to manage VOE pain. This systematic literature review synthesizes research published from 2010 to 2020 on the use of ketamine infusion to decrease VOE pain. The review demonstrates that ketamine, a safe and effective treatment for VOE pain, could be considered more widely. However, the significant variability among published clinical studies with regard to dosing, timing of initiation, duration of infusion, and timing of discontinuation highlights the need for standardized ketamine infusion protocols for the management of VOE pain. We conclude with a brief discussion of key components of a potential standardized protocol supported by the literature reviewed as well as areas for future investigation.

Clinical and Laboratory Predictors of Painful Vaso-Occlusive Crisis Among Sickle Cell Disease Patients: A Single-Center Study in Saudi Arabia

Introduction Vaso-occlusive crisis (VOC) episodes are considered to be the cause of 95% of hospitalizations for sickle cell disease (SCD) patients. The frequency of VOC is significantly associated with higher or lower lactate dehydrogenase levels, higher hemoglobin concentration, higher white blood cell, and neutrophil count, and lower platelet counts. In this study, we highlighted the association and predictors of VOC episodes in Saudi Arabia. Methods This is a retrospective observational study that was conducted in a period from January 2018 to December 2019 which included patients who were admitted and treated as sickle cell disease patients were included in this study. Retrieved data included patients' age, sex, and other demographic data items as well as the clinical history of SCD. The patients were divided into two groups. Those patients who developed one or two VOC episodes in the period between 2018-2019 were considered mild in severity and patients who developed three or more VOC episodes in the period between 2018-2019 were categorized as moderate to severe. Results A total of ninety-four patients (58 males and 36 females) with a male to female ratio of 1.6 were included in this study. The prevalence of patients who had severe vaso-occlusive crisis was 39.4% while mild-moderate were detected among 60.6% of the patients. It was found that there was no significant difference between the frequency of vaso-occlusive crisis and all the hematological parameters (all p>0.05). It was found that the risk of having vaso-occlusive crisis for those patients who were admitted more than three times was 30 times higher than those patients who were admitted by three times or less [adjusted odds ratio (AOR) = 30.081; 95% confidence interval (CI) = 8.204 - 110.3; p<0.001)]. Conclusion It was found that those patients who had three times VOC episodes in our studied period are more liable to have frequent episodes in the future which might necessitate urgent intervention for these patients.

Opioid Use in Adults With Sickle Cell Disease Hospitalized During Vaso-Occlusive Crisis: A Systematic Review

Background

While pain is the hallmark of sickle cell disease (SCD), healthcare personnel are often ill-equipped to adequately treat patients who present in vaso-occlusive crisis (VOC). Although symptom severity varies from individual to individual, SCD is characterized by intervallic pain as a result of oxygen deprivation in tissues and organs. Regardless of pain severity, SCD patients are often viewed as drug seekers by healthcare personnel who have concerns regarding patients’ dependence on opioids which may lead to addiction. The objective was to assess the types and amount of opioids used to treat VOC in comparison to Centers for Disease Control opioid prescription guidelines.

Methods

Literature search was conducted using CINAHL, PubMed, the Cochrane Library, Web of Science and hand search. Data were analyzed from 1999 to 2018. Randomized trials, observational, and case studies involved hospitalized adults with SCD who were prescribed opioids to treat VOC. Quality assessment was conducted using Downs and Black checklist. Meta-analysis was not conducted.

Results

Five studies were conducted in the USA, Arabia and the Netherlands, and the USA and Canada were included. Participants were treated with either morphine or morphine milligram equivalent (MME). No study used the same method of opioid administration.

Conclusions

Patients with SCD who are hospitalized secondary to VOC mostly received opioids for pain well within the Centers for Disease Control and Prevention prescription guidelines. No uniform method exists. Additional research is warranted.

Social support networks of adults with sickle cell disease

Sickle cell disease (SCD) can cause both physical and psychological complications, such as severe pain and depression. These effects often necessitate social and caregiving support. Few studies have assessed support networks within the adult SCD population. Here, we describe the support networks of adults with SCD and identify who in these networks (1) provides emotional support, (2) is dependable during crisis situations, including social and financial adversities, and (3) provides assistance in health crises. Forty-nine adults with SCD completed surveys and social network assessments through interview. Generalized mixed-effects linear regression models were fitted to investigate the composition of support provision within these personal networks. Our findings indicate that parents and 'other important people' (e.g., friends, spouses) play key roles in the support provided to those with SCD. Siblings with SCD appeared to be more emotionally supportive than unaffected siblings. With much research centered around the pediatric and adolescent SCD populations, focus needs to extend to adults and the individuals involved in their care and disease management. Understanding the flow of support within these networks can help genetic counselors and healthcare providers to better identify both social ties that serve as support resources and less supportive relationships for individuals living with SCD and other chronic genetic conditions that might be targeted for intervention.

P-Selectin Blockade in the Treatment of Painful Vaso-Occlusive Crises in Sickle Cell Disease: A Spotlight on Crizanlizumab

Microvascular vaso-occlusion driven pain crisis is the hallmark of sickle cell disease with profound morbidity and increased mortality. Selectins, most notably P-selectins have an integral role in this phenomenon. P-selection was first identified in 1989. In 2019, after 3 decades of basic, translational, and clinical work with this pathway, the US Food and Drug Administration approved a P-selectin antibody, crizanlizumab to reduce frequency of pain crisis in patients more than 16 years with sickle cell disease. We review the fundamentals of P-selectin pathobiology, P-selectin blocking agents, clinical data with the use of crizanlizumab and prospects of this novel class of drugs in the context of other treatments for painful vaso-occlusive episodes.

Microfluidics in Sickle Cell Disease Research: State of the Art and a Perspective Beyond the Flow Problem

Sickle cell disease (SCD) is the monogenic hemoglobinopathy where mutated sickle hemoglobin molecules polymerize to form long fibers under deoxygenated state and deform red blood cells (RBCs) into predominantly sickle form. Sickled RBCs stick to the vascular bed and obstruct blood flow in extreme conditions, leading to acute painful vaso-occlusion crises (VOCs) – the leading cause of mortality in SCD. Being a blood disorder of deformed RBCs, SCD manifests a wide-range of organ-specific clinical complications of life (in addition to chronic pain) such as stroke, acute chest syndrome (ACS) and pulmonary hypertension in the lung, nephropathy, auto-splenectomy, and splenomegaly, hand-foot syndrome, leg ulcer, stress erythropoiesis, osteonecrosis and osteoporosis. The physiological inception for VOC was initially thought to be only a fluid flow problem in microvascular space originated from increased viscosity due to aggregates of sickled RBCs; however, over the last three decades, multiple molecular and cellular mechanisms have been identified that aid the VOC in vivo. Activation of adhesion molecules in vascular endothelium and on RBC membranes, activated neutrophils and platelets, increased viscosity of the blood, and fluid physics driving sickled and deformed RBCs to the vascular wall (known as margination of flow) – all of these come together to orchestrate VOC. Microfluidic technology in sickle research was primarily adopted to benefit from mimicking the microvascular network to observe RBC flow under low oxygen conditions as models of VOC. However, over the last decade, microfluidics has evolved as a valuable tool to extract biophysical characteristics of sickle red cells, measure deformability of sickle red cells under simulated oxygen gradient and shear, drug testing, in vitro models of intercellular interaction on endothelialized or adhesion molecule-functionalized channels to understand adhesion in sickle microenvironment, characterizing biomechanics and microrheology, biomarker identification, and last but not least, for developing point-of-care diagnostic technologies for low resource setting. Several of these platforms have already demonstrated true potential to be translated from bench to bedside. Emerging microfluidics-based technologies for studying heterotypic cell–cell interactions, organ-on-chip application and drug dosage screening can be employed to sickle research field due to their wide-ranging advantages.

Integrative holistic approaches for children, adolescents, and young adults with sickle cell disease: A single center experience

CONTEXT

Painful vaso-occlusive crises (VOCs) associated with sickle cell disease (SCD) are the most common cause of morbidity, hospitalizations, and poor quality of life. Additional symptoms such as sleep disturbances, fatigue, and stress are also common. Non-traditional approaches are often used by families, but concerns remain that patients may forgo standard of care effective therapies in favor of dangerous unproven alternatives.

OBJECTIVES

To describe a single center experience related to a multidisciplinary integrative medicine clinic within the division of hematology dedicated to children and young adults with SCD.

METHODS

The Sickle Cell Integrative Clinic at Children's National Hospital services patients with SCD. The main goal of this clinic is to provide access to non-pharmacologic interventions, and to manage patients' symptoms in a holistic manner along with standard of care management of SCD. This IRB approved study evaluated experiences of both patients and parents who attended this clinic.

RESULTS

Thirty-seven unique patients attended this clinic over 2 years and 31 participated in the study. After attending the SCD integrative clinic, the majority of patients reported integrative therapies to be an acceptable way of treating pain and believed these to be effective. Overall, the vast majority (88 %) of patients reported having a positive experience with the therapies offered in the clinic. None of the patients experienced any adverse events related to integrative therapies provided in the clinic.

CONCLUSION

Our experience suggests that encouraging conversations and offering safe and potentially effective integrative therapies alongside conventional SCD therapies under medical guidance allows patients to have an open discussion about their beliefs and treatment goals, improves patient satisfaction and can improve outcomes.

Mechanisms of Bone Impairment in Sickle Bone Disease

Sickle bone disease (SBD) is a chronic and invalidating complication of Sickle cell disease (SCD), a multisystem autosomal recessive genetic disorder affecting millions of people worldwide. Mechanisms involved in SBD are not completely known, especially in pediatric age. Among the hypothesized pathogenetic mechanisms underlying SBD are bone marrow compensatory hyperplasia and bone ischemic damage, both secondary to vaso-occlusive crisis (VOC), which leads to cell sickling, thus worsening local hypoxia with a negative impact on osteoblast recruitment. Furthermore, the hypoxia is a strong activator of erythropoietin, which in turn stimulates osteoclast precursors and induces bone loss. Hemolysis and iron overload due to a chronic transfusion regimen could also contribute to the onset of bone complications. Vitamin D deficiency, which is frequently seen in SCD subjects, may worsen SBD by increasing the resorptive state that is responsible for low bone mineral density, acute/chronic bone pain, and high fracture risk. An imbalance between osteoblasts and osteoclasts, with a relative decrease of osteoblast recruitment and activity, is a further possible mechanism responsible for the impairment of bone health in SCD. Moreover, delayed pubertal growth spurt and low peak bone mass may explain the high incidence of fracture in SCD adolescents. The aim of this review was to focus on the pathogenesis of SBD, updating the studies on biochemical, instrumental, and biological markers of bone metabolism. We also evaluated the growth development and endocrine complications in subjects affected with SCD.

Diet and companionship modulate pain via a serotonergic mechanism

Treatment of severe chronic and acute pain in sickle cell disease (SCD) remains challenging due to the interdependence of pain and psychosocial modulation. We examined whether modulation of the descending pain pathway through an enriched diet and companionship could alleviate pain in transgenic sickle mice. Mechanical and thermal hyperalgesia were reduced significantly with enriched diet and/or companionship. Upon withdrawal of both conditions, analgesic effects observed prior to withdrawal were diminished. Serotonin (5-hydroxytryptamine, 5-HT) was found to be increased in the spinal cords of mice provided both treatments. Additionally, 5-HT production improved at the rostral ventromedial medulla and 5-HT accumulated at the dorsal horn of the spinal cord of sickle mice, suggesting the involvement of the descending pain pathway in the analgesic response. Modulation of 5-HT and its effect on hyperalgesia was also investigated through pharmaceutical approaches. Duloxetine, a serotonin-norepinephrine reuptake inhibitor, showed a similar anti-nociceptive effect as the combination of diet and companionship. Depletion of 5-HT through p-chlorophenylalanine attenuated the anti-hyperalgesic effect of enriched diet and companionship. More significantly, improved diet and companionship enhanced the efficacy of a sub-optimal dose of morphine for analgesia in sickle mice. These findings offer the potential to reduce opioid use without pharmacological interventions to develop effective pain management strategies.

Neuropathic Pain in Children with Sickle Cell Disease: The Hidden Side of the Vaso-Occlusive Crisis

The majority of hospitalizations of patients with sickle cell disease (SCD) are related to painful vaso-occlusive crises (VOCs). Although the pain of VOC is classically nociceptive, neuropathic pain (NP) has also been demonstrated in SCD patients. The aim of our study is to specify the prevalence of NP during VOCs in SCD children using a dedicated scale and to measure its characteristics. We performed a prospective study that included SCD children hospitalized for an acute VOC. The presence of NP was sought with the DN4 scale on the second and fourth days of hospitalization. A total of 54 SCD children were included in the study. Overall, 41% of the patients (n = 22) experienced neuropathic pain during the VOC, mostly at an early stage (Day 2). The median age, the sex ratio, the location of the pain, and the morphine consumption were similar for patients with and without NP. Our study shows that neuropathic pain is very common during VOCs in SCD children. The absence of identified risk factors should prompt us to be vigilant regardless of the patient's age, sex, and clinical presentation.

Pain in Youth With Sickle Cell Disease: A Report From the Sickle Cell Clinical Research and Intervention Program

OBJECTIVES

Pain is prevalent among youth with sickle cell disease (SCD). However, previous research has been limited by small sample sizes and lacked examinations of developmental differences in pain, which are critical to minimizing the development of chronic pain as youth transition into adulthood. The primary aim of the current study was to compare pain and pain interference across 4 developmental groups in a large sample of youth with SCD. The secondary aim was to identify risk factors for greater pain and pain interference.

MATERIALS AND METHODS

Utilizing a cross-sectional study design, the expression and predictors of pain and pain interference were compared across 4 developmental stages: toddlers/preschoolers (2 to 4 y), school-aged children (5 to 7 y), preadolescents (8 to 12 y), and adolescents (13 to 18 y). Participants included 386 youth with SCD and their caregivers.

RESULTS

Caregiver-reported pain and pain interference and youth-reported pain interference increased across developmental groups and plateaued approaching adolescence (multivariate analyses of variance P=0.002 for pain and P<0.001 for pain interference). Elevated fatigue, anxiety, and perceived difficulties with pain management were the most robust predictors of higher youth- and caregiver-reported pain (βs ranging from 0.15 to 0.68; P<0.001) and pain interference (βs ranging from 0.18 to 0.64; P<0.001).

DISCUSSION

Disease and treatment-related variables were not associated with pain. Self-reported pain was elevated in older versus younger developmental groups and was largely linked to anxiety, fatigue, and perceptions of pain management, thus highlighting the modifiable nature of factors influencing pain among youth with SCD.

Sickle Cell Disease

Sickle cell disease is an umbrella term for a group of hemoglobinopathies characterized by the presence of 2 β-globin gene mutations or deletions, at least 1 of which is the point mutation that leads to the production of hemoglobin S. Sickle cell disease is associated with hemolytic anemia, significant chronic end-organ damage, and early death. In high-income countries, at least 95% of children with the disease survive into adulthood, resulting in a growing population of affected adults with significant comorbidities, complex medical issues, and not enough specialists to provide care. Hydroxyurea is the primary therapy, and recent advances in understanding disease pathophysiology have led to new therapies; progress in bone marrow transplant and gene editing has resulted in cure in some patients. The purpose of this review is to provide an overview of the diagnosis, common acute and chronic clinical manifestations, and best practices for management of sickle cell disease.

Ketamine for Sickle Cell Vaso-Occlusive Crises: A Systematic Review

INTRODUCTION

Vaso-occlusive crisis (VOC) is one of the main causes of hospital admission in patients with sickle cell disease (SCD). Ketamine is often used as an adjuvant to opioids to control sickle cell crisis; however, there is a lack of evidence about its safety and efficacy for VOC in SCD patients.

OBJECTIVE

To synthesize evidence from published reports about the efficacy and safety of ketamine in the management of acute painful VOC in both pediatric and adult SCD patients.

METHODS

A systematic literature search of PubMed, Scopus, Web of Science, EBSCO and Cochrane Library was conducted, up to March 2019. Studies reporting the analgesic effects and side effects of ketamine in the management of acute painful VOC in pediatric and adult SCD patients were included. The primary outcome measure was improvement in pain scale, and the secondary outcomes were reduction in opioid utilization and side effects. Studies were narratively summarized in this review.

RESULTS

Fourteen studies (with a total of 604 patients) were included in the final analysis. Several case reports and case series showed that ketamine significantly reduced pain scales and opioid utilization in both populations. The only randomized controlled trial available showed that ketamine was noninferior to morphine in reducing pain scores, but had a higher incidence of nonlife-threatening, reversible adverse effects. However, a retrospective study of 33 patients showed a higher pain score in the ketamine group with an acceptable short-term adverse effect.

CONCLUSION

Ketamine has a potentially comparable efficacy with other opioids in reducing the pain during VOC in SCD patients. However, it also likely has a higher rate of transient adverse events. Owing to the lack of published randomized controlled trials, current evidence is not sufficient to confirm the safety and efficacy of ketamine. Future well-designed randomized controlled trials are strongly recommended.

Repurposing of genistein as anti-sickling agent: elucidation by multi spectroscopic, thermophoresis, and molecular modeling techniques

Sickle cell disease (SCD) is a major medical problem in which mono-therapeutic interventions have so far shown only limited effectiveness. We studied the repurpose of genistein, which could prevent sickle hemoglobin from polymerizing under hypoxic conditions in this disease. Genistein an important nutraceutical molecule found in soybean. The present study examines the repurposing genistein as an anti- sickling agent. Genistein shows inhibition of Hb S polymerization as well as a sickle reversal. Also, we have explored the interaction of the genistein with sickle hemoglobin (Hb S), using fluorescence, far-UV-CD spectroscopy, MicroScale Thermophoresis (MST), FTIR, combined with molecular modeling computations. The quenching constant decreases with increasing temperature, a characteristic that coincides with the static type of quenching mechanism. Temperature-dependent fluorescence measurements and molecular modeling studies reveal that apart from the hydrogen bonding, electrostatic interactions also play a crucial role in genistein and Hb S complex formation. In silico, distribution prediction of adsorption, digestion, metabolism, excretion, and toxicity (ADME/Tox) based on physical and chemical properties show that genistein is nontoxic and has ideal drug properties. The helicity and thermophoretic mobility of Hb S was a change in the presence of genistein, which leads to the destabilizing the Hb S polymer was examined using CD and MST, respectively. Our results open up the possibility for a promising therapeutic approach for the SCD by repurposed genistein as an anti-sickling agent.Communicated by Ramaswamy H. Sarma.

Nitric oxide and sickle cell disease-Is there a painful connection?

Sickle cell disease is the most common hemoglobinopathy and affects millions worldwide. The disease is associated with severe organ dysfunction, acute and chronic pain, and significantly decreased life expectancy. The large body of work demonstrating that hemolysis results in rapid consumption of the endogenous vasodilator nitric oxide, decreased nitric oxide production, and promotion of vaso-occlusion provides the basis for the hypothesis that nitric oxide bioavailability is reduced in sickle cell disease and that this deficit plays a role in sickle cell disease pain. Despite initial promising results, large clinical trials using strategies to increase nitric oxide bioavailability in sickle cell disease patients yielded no significant change in duration or frequency of acute pain crises. Further, recent investigations showed that sickle cell disease patients and mouse models have elevated baseline levels of blood nitrite, a reservoir for nitric oxide formation and a product of nitric oxide metabolism, regardless of pain phenotype. These conflicting results challenge the hypotheses that nitric oxide bioavailability is decreased and that it plays a significant role in the pathogenesis in sickle cell disease acute pain crises. Conversely, a large body of work demonstrates that nitric oxide, as a neurotransmitter, has a complex role in pain neurobiology, contributes to the development of central sensitization, and can mediate hyperalgesia in inflammatory and neuropathic pain. These results support an alternative hypothesis: one proposing that altered nitric oxide signaling may contribute to the development of neuropathic and/or inflammatory pain in sickle cell disease through its role as a neurotransmitter.

Considerations for Cannabis Use to Treat Pain in Sickle Cell Disease

Pain in Sickle Cell Disease (SCD) is a major comorbidity and unique with acute pain due to recurrent and episodic vaso-occlusive crises as well as chronic pain, which can span an individual's entire life. Opioids are the mainstay treatment for pain in SCD. Due to recent health crises raised by adverse effects including deaths from opioid use, pain management in SCD is adversely affected. Cannabis and its products are most widely used for pain in multiple conditions and also by patients with SCD on their own. With the availability of "Medical Cannabis" and approval to use cannabis as medicine across majority of States in the United States as well as over-the-counter preparations, cannabis products are being used increasingly for SCD. The reliability of many of these products remains questionable, which poses a major health risk to the vulnerable individuals seeking pain relief. Therefore, this review provides up to date insights into available categories of cannabis-based treatment strategies, their mechanism of action and pre-clinical and clinical outcomes in SCD. It provides evidence for the benefits and risks of cannabis use in SCD and cautions about the unreliable and unvalidated products that may be adulterated with life-threatening non-cannabis compounds.

Total hip arthroplasty for sickle cell osteonecrosis: guidelines for perioperative management

The prognosis of sickle cell disease (SCD) has greatly improved in recent years, resulting in an increased number of patients reporting musculoskeletal complications such as osteonecrosis of the femoral head. Total hip arthroplasty (THA) can be utilized to alleviate the pain associated with this disease.

Although it is well known that hip arthroplasty for avascular necrosis (AVN) in SCD may represent a challenge for the surgeon, complications are frequent, and no guidelines exist to prevent these complications. Because patients with SCD will frequently undergo THA, we thought it necessary to fulfil the need for guidance recommendations based on experience, evidence and agreement from the literature.

For all these reasons this review proposes guidelines that provide clinicians with a document regarding management of patients with SCD in the period of time leading up to primary THA. The recommendations provide guidance that has been informed by the clinical expertise and experience of the authors and available literature.

Although this is not a systematic review since some papers may have been published in languages other than English, our study population consisted of 5,868 patients, including 2,126 patients with SCD operated on for THA by the senior author in the same hospital during 40 years and 3,742 patients reported in the literature.

Cite this article: EFORT Open Rev 2020;5:641-651. DOI: 10.1302/2058-5241.5.190073

Outcomes of an Emergency Department Observation Unit-Based Pathway for the Treatment of Uncomplicated Vaso-occlusive Events in Sickle Cell Disease

STUDY OBJECTIVE

This was a prospective, pre-post, 13-year observational study documenting the multiyear implementation of an observation unit sickle cell pathway for patients with uncomplicated vaso-occlusive events.

METHODS

The sickle cell pathway begins with rapid triage to identify patients with uncomplicated vaso-occlusive events for immediate transfer to the observation unit and initiation of patient-controlled analgesia followed by repeated evaluations of pain and identification of other complications. Data were abstracted from the electronic medical record or observation unit database. The sickle cell pathway was initiated in April 2006. Major revisions of it were carried out in June 2009 (physician evaluation occurs in sickle cell pathway and only patient-controlled analgesia administration of medications) and October 2010 (multidisciplinary management and individual dosing).

RESULTS

Annual ED visits ranged between 287 and 528. The preimplementation hospital admission rate was 33% (123/368), 3-day return rate 16% (60/368), and 30-day return rate 67% (248/368). Refinements to the sickle cell pathway have resulted in a decrease in admission rate to 20% (258/1276); 3-day return rate, to 3.6% (46/1,276); and 30-day return rate, to 41% (525/1,276) for the past 3 years.

CONCLUSION

The use of a sickle cell pathway for the treatment of uncomplicated vaso-occlusive events has been effective in providing rapid treatment and reducing hospital admissions. However, it was not only the intervention and its refinement that made the sickle cell pathway successful. With the Consolidated Framework for Implementation Research, it was discerned that outer setting factors of organizational commitment to the care of patients with SCD, inner setting factors of learning climate and leadership engagement, individuals, and process contributed to the success of the sickle cell pathway.

Pain in Children and Adolescents With Sickle Cell Disease: Multidimensional Assessment

BACKGROUND

Patients with sickle cell disease (SCD) suffer from recurrent painful vaso-occlusive episodes with a significant impact on their quality of life. The aim of this study was to perform a multidimensional assessment of pain in Portuguese children and adolescents with SCD.

METHODS

Subjects were children and adolescents and their parents recruited from the outpatient pediatric hematology clinic in a Portuguese Hospital. Pain frequency and a broader multidimensional evaluation was performed using the Pediatric Pain Questionnaire (PedsQL) (that includes Visual Analog Scales, color indicators, qualitative descriptors of pain [open question] and body diagram) and a structured questionnaire (PQ2), that included a term list of the Adolescent Pediatric Pain Tool, among other questions.

RESULTS

Included 60 children and adolescents (36 boys and 24 girls) with a mean age of 11±4.0 years (range, 5 to 18). The majority of children (83.1%) reported no present pain and 57.6% reported pain last month, with several degrees of pain intensity. Abdomen, thorax, and limbs were the most frequent localizations. Red was the color most chosen to describe "severe pain," whereas blue and green were more used to describe "no pain." The number of pain descriptors is different using an open-ended question (2.1±1.5) than a given list of terms (15.3±8.1). The most frequent terms used in the open question were "strong/very strong," "hurts a lot," "makes cry," and "horrible." Parents used similar pain descriptors. "Makes cry," "horrible," "tiring," "unbearable," and "uncomfortable" were the most frequent terms chosen in the PQ2. Pain interfered variably with daily activities for most of the patients.

CONCLUSION

Pain experienced in SCD has a broad range of intensity levels, localization, and frequency. There are a number of pain descriptors and socio-emotional factors related to the pain experience. A comprehensive multidimensional assessment that includes both child's and parents' perspective seem to be the most adequate strategy to assess pain.

The association between hydroxyurea adherence and opioid utilization among Texas Medicaid enrollees with sickle cell disease

BACKGROUND: Individuals with sickle cell disease (SCD) suffer from recurrent catastrophic pain crises that are often managed by opioid analgesics. Being adherent to hydroxyurea has been associated with decreased health care resource use for pain; however, evidence of its association with opioid use is limited. OBJECTIVE: To determine if adherence to hydroxyurea is associated with opioid use among patients with SCD. METHODS: This retrospective study used Texas Medicaid data from September 1, 2011, to August 31, 2016 (study period). The index date was the date of hydroxyurea initiation. Patients who were aged 2-63 years at the index date, had ≥ 1 inpatient or ≥ 2 outpatient SCD diagnoses during the study period, had ≥ 1 hydroxyurea prescription during the identification period (September 1, 2011-August 31, 2015), had no diagnosis of other indications for hydroxyurea during the study period, and were continuously enrolled for at least 12 months after the index date were included. Hydroxyurea adherence was measured using medication possession ratio (MPR). The study outcomes (measured 1-year post-index) were (a) opioid use; (b) number of opioid prescriptions; (c) strong opioid use (morphine, hydromorphone, fentanyl, and methadone); (d) number of strong opioid prescriptions; (e) high-dose opioid use (≥ 50 mg morphine milligram equivalent [MME]); and (f) days supply for opioid prescriptions. Covariates included demographic (age and gender) and clinical (vaso-occlusive crisis [VOC], avascular necrosis, iron overload, acute chest syndrome, and blood transfusion) characteristics. Descriptive, bivariate (chi-square and Wilcoxon-Mann-Whitney tests), multiple logistic regression, and negative binomial regression analyses were performed. RESULTS: 1,146 patients (18.3 [12.3] years) met the inclusion criteria. Of these, 19.6% were adherent to hydroxyurea (defined as MPR ≥ 80%) and mean (SD) MPR was 48.3% (29.7%). In the 1 year following hydroxyurea initiation, 923 (80.5%) patients had ≥ 1 opioid prescription with 7.6 (9.4) opioid prescriptions per patient, while 259 (22.6%) patients had ≥ 1 strong opioid prescription with 1.5 (4.4) strong opioid prescriptions per patient. Average (SD) opioid dose was 41.7 (74.3) mg MME, and 27.1% had high daily MME doses (≥ 50 mg MME). Average (SD) opioid days supply was 83.1 (112.2) days. After adjusting for covariates, compared with being nonadherent, being adherent to hydroxyurea was associated with a 50.5% decreased risk of having strong opioids (OR = 0.495, 95% CI = 0.278-0.879, P = 0.0165). Additionally, SCD-related complications (VOC, avascular necrosis, and iron overload) and older age were significant factors associated with opioid use and higher MME. Post hoc analyses showed that being adherent to hydroxyurea was significantly associated with lower probabilities of experiencing SCD-related complications. CONCLUSIONS: Results showed that patients with SCD are moderately adherent to hydroxyurea. Being adherent to hydroxyurea was found to be associated with a lower risk of receiving a prescription for strong opioids. Findings suggest that close monitoring and interventions to improve adherence may help mitigate strong opioid use among these patients. DISCLOSURES: This research did not receive any specific funding. Barner and Kang report grants from Novartis Pharmaceuticals, unrelated to this work. A part of this study was presented as a poster at the American Pharmacists Association (APhA) 2019 Annual Meeting and Exposition (March 22-25, 2019, Seattle, WA) and received the 2019 APhA-APRS Presentation Award in the APhA-APRS Contributed Research Paper, Graduate Student/Fellow/Postdoctoral Scholar category.

Spatiotemporal Alterations in Gait in Humanized Transgenic Sickle Mice

Sickle cell disease (SCD) is a hemoglobinopathy affecting multiple organs and featuring acute and chronic pain. Purkinje cell damage and hyperalgesia have been demonstrated in transgenic sickle mice. Purkinje cells are associated with movement and neural function which may influence pain. We hypothesized that Purkinje cell damage and/or chronic pain burden provoke compensatory gait changes in sickle mice. We found that Purkinje cells undergoe increased apoptosis as shown by caspase-3 activation. Using an automated gait measurement system, MouseWalker, we characterized spatiotemporal gait characteristics of humanized transgenic BERK sickle mice in comparison to control mice. Sickle mice showed alteration in stance instability and dynamic gait parameters (walking speed, stance duration, swing duration and specific swing indices). Differences in stance instability may reflect motor dysfunction due to damaged Purkinje cells. Alterations in diagonal and all stance indices indicative of hesitation during walking may originate from motor dysfunction and/or arise from fear and/or anticipation of movement-evoked pain. We also demonstrate that stance duration, diagonal swing indices and all stance indices correlate with both mechanical and deep tissue hyperalgesia, while stance instability correlates with only deep tissue hyperalgesia. Therefore, objective analysis of gait in SCD may provide insights into neurological impairment and pain states.

Outcomes of multidisciplinary team interventions in the management of sickle cell disease patients with opioid use disorders. A retrospective cohort study

Objectives:

To identify the magnitude of opioid use disorder (OUD) among sickle cell disease (SCD) patients; emphasize on multidisciplinary team (MDT) role; estimate cost-effectiveness following the proper use of therapeutic guidelines; and facilitate the reduction of emergency room (ER) visits and the length of stay (LOS).

Methods:

This retrospective cohort study included SCD patients aged 14 years and above, who have OUD. Data was collected between January 2016 and December 2018. Data included ER visits, hospital LOS, opioid consumption, and narcotic prescription tracking. The target group was followed with a set of interventions for pain management and healthcare resource utilization.

Results:

Twenty one SCD patients were identified with OUD. Following the interventions, there was a statistically significant decrease in ER visits of these OUD patients (from 8709 visits in 2016 to only 94 in 2018). Morphine consumption decreased by 82% and meperidine by 60%, over the 3-year period. Moreover, there was a huge reduction in both ER and LOS costs for this cohort of patients.

Conclusion:

Establishing an MDT and a series of interventions for SCD patients with OUD, including educational activities for caregivers and patients; establishing a palliative/pain clinic and a SCD addiction clinic; and implementing an adequate opioid prescription tracking system resulted in a significant reduction in both the cost and number of ER visits and hospital LOS and dramatically decreased opioid consumption.

Ketamine and lidocaine infusions decrease opioid consumption during vaso-occlusive crisis in adolescents with sickle cell disease

PURPOSE OF REVIEW

Recurrent exposure to opioids can lead to development of opioid tolerance and opioid-induced hyperalgesia through activation of N-methyl-D-aspartate receptors. N-methyl-D-aspartate receptor antagonists ketamine and lidocaine can modulate development of opioid tolerance and OIH. This study evaluated the utility of ketamine and/or lidocaine in decreasing opioid consumption during acute pain episodes in adolescents with sickle cell disease. There has been an increased effort to promote opioid-sparing pain relieving methods given the ongoing opioid epidemic.

RECENT FINDINGS

There have been six studies published over the past decade that highlight the ability of ketamine to reduce opioid consumption in the management of sickle cell disease-related pain, primarily in adult patients. There has been one study (2015) that demonstrated a similar benefit with lidocaine, however this was also in adult patients.

SUMMARY

We retrospectively evaluated treatment with ketamine and/or lidocaine infusions in adolescents hospitalized for vaso-occlusive crisis (VOC). Patients served as self-controls using a comparison with a previous control admission for VOC. The use of ketamine and/or lidocaine as adjuncts to opioids resulted in lower daily opioid consumption in three of four patients. Our study suggests that ketamine and/or lidocaine infusions may be useful adjuncts in reducing opioid exposure during VOC pain.

Current and novel therapies for the prevention of vaso-occlusive crisis in sickle cell disease

Individuals with sickle cell disease (SCD) are living further into adulthood in high-resource countries. However, despite increased quantity of life, recurrent, acute painful episodes cause significant morbidity for affected individuals. These SCD-related painful episodes, also referred to as vaso-occlusive crises (VOCs), have multifactorial causes, and they often occur as a result of multicellular aggregation and vascular adherence of red blood cells, neutrophils, and platelets, leading to recurrent and unpredictable occlusion of the microcirculation. In addition to severe pain, long-term complications of vaso-occlusion may include damage to muscle and/or bone, in addition to vital organs such as the liver, spleen, kidneys, and brain. Severe pain associated with VOCs also has a substantial detrimental impact on quality of life for individuals with SCD, and is associated with increased health care utilization, financial hardship, and impairments in education and vocation attainment. Previous treatments have targeted primarily SCD symptom management, or were broad nontargeted therapies, and include oral or parenteral hydration, analgesics (including opioids), nonsteroidal anti-inflammatory agents, and various other types of nonpharmacologic pain management strategies to treat the pain associated with VOC. With increased understanding of the pathophysiology of VOCs, there are several new potential therapies that specifically target the pathologic process of vaso-occlusion. These new therapies may reduce cell adhesion and inflammation, leading to decreased incidence of VOCs and prevention of end-organ damage. In this review, we consider the benefits and limitations of current treatments to reduce the occurrence of VOCs in individuals with SCD and the potential impact of emerging treatments on future disease management.

How I Treat Acute and Persistent Sickle Cell Pain

Sickle pain is the hallmark of sickle cell disease (SCD). It could be acute, persistent/relapsing, chronic, or neuropathic. Although there is a general consensus that pain is a major manifestation of SCD, there is a controversy as to the types of pain and their interrelationship between acute, chronic, relapsing, persistent, etc. This report first reviews the general approach to the management of acute vaso-occlusive crisis (VOC) pain, including education, counseling, pharmacotherapy, non-pharmacotherapy, and fluid therapy. This is followed by the presentation of five patients that represent typical issues that are commonly encountered in the management of patients with SCD. These issues are: individualized treatment of pain, bilaterality of pain, use of illicit drugs, tolerance to opioids, opioid-induced hyperalgesia, and withdrawal syndrome. The clinical aspects and management of each of these issues are described. Moreover, such complications as tolerance and withdrawal may persist after discharge and may be mistaken as chronic pain rather than resolving, persistent or relapsing pain.

Investigation of Lipid Profile and Clinical Manifestations in SCA Children

Introduction

Clinical complications in sickle cell anemia (SCA) are heterogeneous and involve several molecules. It has been suggested that SCA individuals present a dyslipidemic phenotype and that lipid parameters are associated with severe clinical complications, such as pulmonary hypertension. We sought to investigate associations between lipid parameters and clinical manifestations, as well as other laboratory parameters in a population of pediatric SCA patients.

Methods

Our cross-sectional evaluation included 126 SCA patients in steady state and who were not undergoing lipid-lowering therapy. Hematological and biochemical parameters were characterized, and previous clinical manifestations were investigated.

Results

Total cholesterol and low-density lipoprotein cholesterol (LDL-C) levels were increased in patients with a previous history of pneumonia, which also positively correlated with HbS levels. Decreased LDL-C levels were also associated with leg ulcers and anemia. Elevated high-density lipoprotein cholesterol (HDL-C) levels were associated with pain crises, increased viscosity, and decreased hemolysis. Several studies have determined that lipids play a role in the vascular impairment seen in SCA, which was corroborated by our findings.

Conclusions

In sum, our results suggest that total cholesterol, HDL-C, and LDL-C levels are associated with hemolysis and anemia markers and, most importantly, with clinical complications related to vasculopathy in SCA.

Patient-Reported Outcomes and Economic Burden of Adults with Sickle Cell Disease in the United States: A Systematic Review

Purpose

To systematically estimate the patient-reported outcomes (PROs) and economic burden of sickle cell disease (SCD) among adults in the United States (US).

Patients and Methods

Two systematic literature reviews (SLRs), one each for the PROs and economic topics, were performed using MEDLINE and Embase to identify observational studies of adults with SCD. Included studies were published between 2007 and 2018 and evaluated health-related quality of life (HRQL), function, healthcare resource utilization (HCRU), or costs. Given the high degree of clinical and methodological heterogeneity, findings were summarized qualitatively.

Results

The SLRs identified 7 studies evaluating the PROs and 15 studies evaluating the economic burden meeting the pre-specified selection criteria. The PRO evidence showed the prevalence of depression and anxiety to be 21–33% and 7–36%, respectively, in adults with SCD. The mean SF-36 physical summary scores ranged from 33.6 to 59.0 and from 46.3 to 61.5 for the mental summary scores. Overall HRQL for adults with SCD was poor and significantly worse in those with opioid use. Adult SCD patients were found to have varying rates of emergency department (ED) utilization (0.3–3.5 annual ED visits), hospitalizations (0.5–27.9 per patient per year), and/or readmission (12–41%). Key factors associated with significant HCRU were age, dental infection, and SCD-related complications. SCD specialized care settings and SCD intensive management strategy were reported to significantly decrease the number of hospitalizations.

Conclusion

This systematic evidence synthesis found that disease burden measured by PROs and economic burden of SCD on adults in the US are substantial despite the availability of approved SCD treatments during 2007–2018. The use of hydroxyurea, optimal management with opioids, and employing intensive treatment strategies may help decrease the overall burden to patients and healthcare systems. Published data on costs associated with SCD are limited and highlight the need for more economic studies to characterize the full burden of the disease.

Neuropathic Pain and Sickle Cell Disease: a Review of Pharmacologic Management

PURPOSE OF REVIEW

Sickle cell disease (SCD) remains among the most common and severe monogenic disorders present in the world today. Although sickle cell pain has been traditionally characterized as nociceptive, a significant portion of sickle cell patients has reported neuropathic pain symptoms. Our review article will discuss clinical aspects of SCD-related neuropathic pain, epidemiology of neuropathic pain among individuals with SCD, pain mechanisms, and current and future potential pharmacological interventions.

RECENT FINDINGS

Neuropathic pain in SCD is a complicated condition that often has a lifelong and significant negative impact on life; therefore, improved pain management is considered a significant and unmet need. Neuropathic pain mechanisms are heterogeneous, and the difficulty in determining their individual contribution to specific pain types may contribute to poor treatment outcomes in this population. Our review article outlines several pharmacological modalities which may be employed to treat neuropathic pain in SCD patients.

Synthesis and evaluation of resveratrol derivatives as fetal hemoglobin inducers

Resveratrol (RVT) derivatives (10a-i) were designed, synthesized, and evaluated for their potential as gamma-globin inducers in treating Sickle Cell Disease (SCD) symptoms. All compounds were able to release NO at different levels ranging from 0 to 26.3%, while RVT did not demonstrate this effect. In vivo, the antinociceptive effect was characterized using an acetic acid-induced abdominal contortion model. All compounds exhibited different levels of protection, ranging from 5.9 to 37.3%; the compound 10a was the most potent among the series. At concentrations between 3.13 and 12.5 µM, the derivative 10a resulted in a reduction of 41.1-64.3% in the TNF-α levels in the supernatants of macrophages that were previously LPS-stimulated. This inhibitory effect was higher than that of RVT used as the control. In addition, the compound 10a and RVT induced double the production of the gamma-globin chains (γG + γA), compared to the vehicle, using CD34+ cells. Compound 10a also did not induce membrane perturbation and it was not mutagenic in the in vivo assay. Thus, compound 10a emerged as a new prototype of the gamma-globin-inducer group with additional analgesic and anti-inflammatory activities and proving to be a useful alternative to treat SCD symptoms.

Association between Vaso-occlusive Crises and Opioid Prescriptions among Patients with Sickle Cell Disease: A Retrospective Claims-based Study

BACKGROUND/OBJECTIVES

Among sickle cell disease (SCD) patients, vaso-occlusive crises (VOCs) are recurrent and unpredictable attacks of acute pain. These pain crises are often treated with analgesics, including opioids, which have been associated with misuse and overdose. The aim of this study was to examine the association between VOC events and opioid use and assess the association between opioid prescriptions and health care resource utilization among SCD patients.

METHODS

This was a retrospective cohort study using Texas Medicaid medical and prescription claims between September 2011 and August 2016. The index date was the first SCD diagnosis. Patients (2-63 years) with at least one inpatient or two outpatient SCD diagnoses, who were continuously enrolled during 12 months postindex, were included in the study. The primary outcome was number of opioid prescriptions, while the independent variable was number of VOC events. Covariates included age, gender, nonopioid medication use, nonstudy SCD-related medication (penicillin and folic acid) use, evidence of blood transfusions, number of SCD-related complications, number of SCD-related comorbid conditions, and Charlson Comorbidity Index score. Negative binomial regression analysis was used to address study objectives.

RESULTS

Of 3368 included patients, 1978 (58.7%) had at least one opioid prescription with a mean of 4.2 (SD=7.2). Overall, 2071 (61.5%) had at least one VOC event with an average of 2.9 (SD=4.4). The results from the negative binomial regression showed that for every increase in VOC events, the number of opioid prescriptions increased by 9.5% (Incidence rate ratio=1.095, 95% CI: 1.078-1.111; P ≤ 0.0001). Other significant covariates associated with higher opioid use included age (13 and older compared to 2-12) and increase in the number of nonopioid pain medications, nonstudy SCD-related medications, and SCD-related complications.

CONCLUSIONS

The majority of SCD patients had at least one VOC event and were prescribed opioids during the 12-month study period. We found that each VOC event was associated with a 9.5% increase in the use of opioids. SCD guidelines recommend opioids for the treatment of VOC-related pain. Payers and providers should be aware of opioid use in this population, consider appropriate VOC prevention measures, and provide SCD patients with access to appropriate pain management.

Integrative approaches to treating pain in sickle cell disease: Pre-clinical and clinical evidence

Sickle cell disease (SCD) is a genetic disorder characterized by hemolysis, end-organ damage, inflammation, and pain. Recurrent and unpredictable episodes of acute pain due to vaso-occlusive crises are a unique feature of SCD. Many patients also develop lifelong chronic pain. Opioids are the primary method of pain treatment in SCD; however, continued use is associated with several adverse effects. Integrative approaches to treating pain in SCD are increasingly being explored to prevent the side effects associated with opioids. In this review, we highlight the mechanisms of pain in SCD and describe mechanism-based integrative approaches for treating pain.

A Healthcare Improvement Initiative to Increase Multidisciplinary Pain Management Referrals for Youth with Sickle Cell Disease

BACKGROUND

Chronic pain is a complex integration of biological, psychological, and social variables. Multidisciplinary pain management experts design interventions that treat the multidimensional experience. Children and adolescents with sickle cell disease (SCD) are at risk for chronic pain. Increased risk is associated with multiple characteristics including sickle cell genotype, age, gender, frequency of hospitalization, duration of hospitalization, and certain comorbid diagnoses. Referral to pain management professionals for this population is often delayed.

AIMS

To increase multidisciplinary pain management referrals for youth with SCD identified to be at risk for chronic pain.

DESIGN

Implementation research.

SETTING

One pediatric, academic medical facility serving as a regional sickle cell treatment center in the Midwest.

PARTICIPANTS

Children greater than 2 years of age and less than 21 years of age with laboratory confirmed SCD.

METHODS

Implementation of an evidence-based screening tool using the consolidated framework for implementation research (CFIR) to guide project planning, design, and evaluation. The CFIR model was paired with the Plan-Do-Study-Act (PDSA) quality improvement methodology to operationalize workflow and sustain project aims.

RESULTS AND CONCLUSIONS

Eighty-four percent of all eligible patients were screened during their routine sickle cell appointments resulting in a 110% increase in multidisciplinary pain management referrals. Future interventions and PDSA cycles are targeted at improving attendance at scheduled appointments, reducing hospitalizations, decreasing 30-day readmissions, and shortening length of stay.