Environmental tobacco smoke and airway obstruction in children with sickle cell anemia

[Lung manifestations of sickle-cell disease]

Sickle-cell disease is an autosomal recessive genetic disorder of hemoglobin that causes systemic damage. Hypoxia is the main actor of sickle-cell disease. It initiates acutely the pathogenic cascade leading to tissue damages that in turn induce chronic hypoxia. Lung lesions represent the major risk of morbidity and mortality. Management of sickle-cell disease requires a tight collaboration between hematologists, intensivists and chest physicians. Recurrent episodes of thrombosis and hemolysis characterize the disease. New therapeutic protocols, associating hydroxyurea, transfusion program and stem cell transplantation in severe cases allow a prolonged survival until the fifth decade. However, recurrent pain, crisis, frequent hospital admissions due to infection, anemia or acute chest syndrome and chronic complications leading to organ deficiencies degrade the patients' quality of life. In low-income countries where the majority of sickle-cell patients are living, the disease is still associated with a high mortality in childhood. This paper focuses on acute chest syndrome and chronic lung manifestations.

Validation of the breathmobile case identification survey for asthma screening in children with sickle cell disease

Background: Asthma is a chronic airway disorder with variable/recurring symptoms, airflow obstruction, bronchial hyperresponsiveness, and an inflammation. The expert panel report of the National Heart Lung and Blood Institute recommends asthma screening in sickle cell disease (SCD); however, specific approach is not mentioned. We hypothesize that the breathmobile case identification survey (BCIS) is a valid asthma screening tool in children with SCD.Methods: This prospective, single-center study enrolled 129 SCD patients aged 5 to 18 years from March 2016 to March 2018. All patients completed BCIS, spirometry, and fractional exhaled nitric oxide (FeNO). A single pulmonologist blinded to the BCIS results evaluated patients for asthma.Results: Asthma prevalence was 41%. Male gender (60.4%; p = 0.041), allergic rhinitis (86.8%; p < 0.01), hydroxyurea usage (73.6%; p < 0.01), and family history of asthma (34%; p < 0.01) were higher but not self-reported parental asthma history, eczema, and tobacco smoke exposure in the asthma group compared to the nonasthma group. FEV₁ (p = 0.003), FVC (p = 0.02), FEV₁/FVC (p = 0.053), and FEF_25-75% (p = 0.02) were lower in asthma. FeNO levels were comparable in both groups. The sensitivity, specificity, positive predictive value, and negative predictive value of the abbreviated BCIS were 67.3%, 90.8%, 83.3%, and 80.2% for asthma; and 82.1%, 90.8%, 76.7%, and 93.2% for persistent asthma, respectively. Persistent asthma patients had a trend of higher hydroxyurea use (82.8% vs. 58.3%; p = 0.049) and tobacco smoke exposure (55.2% vs. 29.2%; p = 0.057) compared to intermittent asthma.Conclusion: We have validated the BCIS to screen for asthma in SCD. Spirometry but not FeNO may support an asthma diagnosis.

Identifying Clinical and Research Priorities in Sickle Cell Lung Disease. An Official American Thoracic Society Workshop Report

Background: Pulmonary complications of sickle cell disease (SCD) are diverse and encompass acute and chronic disease. The understanding of the natural history of pulmonary complications of SCD is limited, no specific therapies exist, and these complications are a primary cause of morbidity and mortality.Methods: We gathered a multidisciplinary group of pediatric and adult hematologists, pulmonologists, and emergency medicine physicians with expertise in SCD-related lung disease along with an SCD patient advocate for an American Thoracic Society-sponsored workshop to review the literature and identify key unanswered clinical and research questions. Participants were divided into four subcommittees on the basis of expertise: 1) acute chest syndrome, 2) lower airways disease and pulmonary function, 3) sleep-disordered breathing and hypoxia, and 4) pulmonary vascular complications of SCD. Before the workshop, a comprehensive literature review of each subtopic was conducted. Clinically important questions were developed after literature review and were finalized by group discussion and consensus.Results: Current knowledge is based on small, predominantly observational studies, few multicenter longitudinal studies, and even fewer high-quality interventional trials specifically targeting the pulmonary complications of SCD. Each subcommittee identified the three or four most important unanswered questions in their topic area for researchers to direct the next steps of clinical investigation.Conclusions: Important and clinically relevant questions regarding sickle cell lung disease remain unanswered. High-quality, multicenter, longitudinal studies and randomized clinical trials designed and implemented by teams of multidisciplinary clinician-investigators are needed to improve the care of individuals with SCD.

The etiologic origins for chronic obstructive pulmonary disease

COPD, characterized by long-term poorly irreversible airway limitation and persistent respiratory symptoms, has resulted in enormous challenges to human health worldwide, with increasing rates of prevalence, death, and disability. Although its origin was thought to be in the interactions of genetic with environmental factors, the effects of environmental factors on the disease during different life stages remain little known. Without clear mechanisms and radical cure for it, early screening and prevention of COPD seem to be important. In this review, we will discuss the etiologic origins for poor lung function and COPD caused by specific adverse effects during corresponding life stages, as well as try to find new insights and potential prevention strategies for this disease.

Preliminary exploration of secondhand smoke exposure in youth with Sickle Cell Disease: biochemical verification, pulmonary functioning, and health care utilization

Exposure to secondhand smoke (SHSe) can compound an already challenging set of health problems for youth with Sickle Cell Disease (SCD). Exposure to electronic cigarettes may also impact SCD symptomology and respiratory functioning. This study built on these previous findings by a) utilizing two objective measures of SHSe, salivary cotinine and exhaled carbon monoxide and b) examining the association of SHSe with emergency department utilization, physician-reported sickle cell crises, and pulmonary functioning. Caregivers (N = 31 dyads; Mage = 37.6 years; SD = 8.5 years) of youth with SCD (Mage = 9.0 years; SD = 4.5 years) completed self-report measures of tobacco/nicotine use. Youth provided a saliva sample to assess cotinine levels, and performed pulmonary function tests. Dyads provided breath samples for measurement of eCO. A chart review was conducted to obtain medical history and utilization. Majority of youth (88%) were exposed to SHS via salivary cotinine. Interestingly, no significant associations were observed between youth cotinine levels and emergency department utilization, physician-reported sickle cell crises, or pulmonary functioning. Present findings indicate a need to assess for SHSe using objective assessment measures. Future research should investigate which specific factors contribute to increase SHSe/SHVe in youth with SCD.

Tobacco Use and Smoke Exposure in Children: New Trends, Harm, and Strategies to Improve Health Outcomes

PURPOSE OF REVIEW

Every day in the USA, approximately 4000 adolescents begin smoking and the adolescent brain is particularly susceptible to nicotine addiction. We present current pediatric trends on tobacco use and exposures, various new products used by adolescents, the adverse biological and behavioral effects of tobacco use and exposures, and tobacco control strategies to eliminate tobacco-related illnesses and deaths in the pediatric population.

RECENT FINDINGS

Twelve-20% of women continue to smoke during pregnancy. New research reveals cognitive differences and behavior-control disorders are seen in elementary school children from prenatal and postnatal exposures. Traditional cigarette smoking has decreased in adolescents; novel and appealing tobacco products have captured their attention, particularly electronic cigarettes, and rates double and often triple from middle to high school. Children with asthma and those living in multi-housing units have higher rates of secondhand smoke exposure than non-asthmatics and children living in single-home dwellings. There is no "safe or risk-free" level of tobacco use or exposure. Tobacco use and exposure in childhood and adolescence must be decreased using evidenced-based strategies to improve child health.

Acute Chest Syndrome in Children with Sickle Cell Disease

Acute chest syndrome (ACS) is a frequent cause of acute lung disease in children with sickle cell disease (SCD). Patients may present with ACS or may develop this complication during the course of a hospitalization for acute vaso-occlusive crises (VOC). ACS is associated with prolonged hospitalization, increased risk of respiratory failure, and the potential for developing chronic lung disease. ACS in SCD is defined as the presence of fever and/or new respiratory symptoms accompanied by the presence of a new pulmonary infiltrate on chest X-ray. The spectrum of clinical manifestations can range from mild respiratory illness to acute respiratory distress syndrome. The presence of severe hypoxemia is a useful predictor of severity and outcome. The etiology of ACS is often multifactorial. One of the proposed mechanisms involves increased adhesion of sickle red cells to pulmonary microvasculature in the presence of hypoxia. Other commonly associated etiologies include infection, pulmonary fat embolism, and infarction. Infection is a common cause in children, whereas adults usually present with pain crises. Several risk factors have been identified in children to be associated with increased incidence of ACS. These include younger age, severe SCD genotypes (SS or Sβ⁰ thalassemia), lower fetal hemoglobin concentrations, higher steady-state hemoglobin levels, higher steady-state white blood cell counts, history of asthma, and tobacco smoke exposure. Opiate overdose and resulting hypoventilation can also trigger ACS. Prompt diagnosis and management with intravenous fluids, analgesics, aggressive incentive spirometry, supplemental oxygen or respiratory support, antibiotics, and transfusion therapy, are key to the prevention of clinical deterioration. Bronchodilators should be considered if there is history of asthma or in the presence of acute bronchospasm. Treatment with hydroxyurea should be considered for prevention of recurrent episodes. This review evaluates the etiology, pathophysiology, risk factors, clinical presentation of ACS, and preventive and treatment strategies for effective management of ACS.

Secondhand Smoke Is an Important Modifiable Risk Factor in Sickle Cell Disease: A Review of the Current Literature and Areas for Future Research

Sickle cell disease (SCD) is an autosomal recessive hemoglobinopathy that causes significant morbidity and mortality related to chronic hemolytic anemia, vaso-occlusion, and resultant end-organ damage. Tobacco smoke exposure (TSE) through secondhand smoke exposure in people with SCD of all ages and through primary smoking in adolescents and adults is associated with significantly increased morbidity, with increased rates of emergency department visits and hospitalizations for painful vaso-occlusive crises and acute chest syndrome (ACS). Secondhand smoke is also associated with pulmonary function abnormalities in children with SCD who are already at risk for pulmonary function abnormalities on the basis of SCD. TSE is emerging as one of the few modifiable risk factors of SCD. This review discusses the current state of the evidence with respect to TSE and SCD morbidity, discusses potential mechanisms, and highlights current gaps in the evidence and future research directions.

Pattern of Lung Function Is Not Associated with Prior or Future Morbidity in Children with Sickle Cell Anemia

RATIONALE

Patient factors associated with development of abnormal lung function in children with sickle cell anemia (SCA) have not been fully characterized.

OBJECTIVES

To characterize lung function abnormalities among children with SCA and to determine whether these steady-state lung function results were associated with morbidity before or after testing among children with SCA.

METHODS

This study was part of the prospective National Institutes of Health-funded Sleep and Asthma Cohort Study. Children with HbSS or Hb Sβ(o) (SCA) were enrolled without regard for sickle cell-related comorbidities or diagnosis of asthma. Lung function was measured by spirometry and plethysmography on the same day, when free of acute disease. Standardized asthma symptom questionnaires and review of the medical records were also performed.

MEASUREMENTS AND MAIN RESULTS

A total of 149 children aged 6 to 19 years completed lung function testing, of whom 139 participants had retrospective morbidity data from birth to the test date, and 136 participants were followed prospectively for a median of 4.3 years from the test date. At baseline, percentages with normal, obstructive, restrictive, nonspecific, and mixed lung function patterns were 70, 16, 7, 6, and 1, respectively. Neither retrospective rates of pain nor acute chest syndrome was associated with lung function patterns. Furthermore, baseline lung function pattern was not predictive of future pain or acute chest syndrome episodes.

CONCLUSIONS

The majority of children with SCA have lung function that is within the normal range. Abnormal lung function patterns were not associated with prior vasoocclusive pain or acute chest syndrome episodes, and baseline lung function patterns did not predict future vasoocclusive pain or chest syndrome episodes.

Secondhand smoke is associated with more frequent hospitalizations in children with sickle cell disease

Tobacco smoke exposure has been associated with more frequent hospitalizations in children with sickle cell disease (SCD), but previous studies have not quantified the exposure by objective methods. We enrolled 50 children and young adults with SCD in a retrospective and prospective cohort study and quantified tobacco smoke exposure by objective (salivary cotinine) and survey measures. We used a multivariable negative binomial regression model to evaluate the association between salivary cotinine and hospital admissions. Forty-five percent (22/49) of participants had significant elevation of salivary cotinine (≥ 0.5 ng/ml). The incidence risk ratio (IRR) for hospital admission for those with elevated cotinine was 3.7 (95% CI 1.8-8). Those exposed to secondhand smoke but not primary smokers (cotinine between 0.5 and 10 ng/ml) had a similarly increased risk of hospitalization [IRR 4.3 (95% CI 1.8-10)]. We show that an objective measure of tobacco smoke exposure, salivary cotinine, is strongly associated with the rate of hospital admissions in children and young adults with SCD. This association underscores the importance of screening for tobacco smoke exposure in people with SCD. Further investigation is warranted to determine the mechanisms of and to evaluate interventions to decrease tobacco smoke exposure.

Early-life origins of chronic respiratory diseases: understanding and promoting healthy ageing

Chronic obstructive respiratory disorders such as asthma and chronic obstructive pulmonary disease often originate early in life. In addition to a genetic predisposition, prenatal and early-life environmental exposures have a persistent impact on respiratory health. Acting during a critical phase of lung development, these factors may change lung structure and metabolism, and may induce maladaptive responses to harmful agents, which will affect the whole lifespan. Some environmental factors, such as exposure to cigarette smoke, type of childbirth and diet, may be modifiable, but it is more difficult to influence other factors, such as preterm birth and early exposure to viruses or allergens. Here, we bring together recent literature to analyse the critical aspects involved in the early stages of lung development, going back to prenatal and perinatal events, and we discuss the mechanisms by which noxious factors encountered early on may have a lifelong impact on respiratory health. We briefly comment on the need for early disease biomarkers and on the possible role of "-omic" technologies in identifying risk profiles predictive of chronic respiratory conditions. Such profiles could guide the ideation of effective preventive strategies and/or targeted early lifestyle or therapeutic interventions.

Lung function in sickle cell disease

Although some of the most severe complications of Sickle Cell Disease (SCD) tend to be acute and severe (e.g. acute chest syndrome, stroke etc.), the chronic ones can be equally debilitating. Prominent among them is the effect that the disease has on lung growth and function. For many years the traditional teaching has been that SCD is associated with the development of a restrictive lung defect. However, there is increasing evidence that this is not a universal finding and that at least during childhood and adolescence, the majority of the patients have a normal or obstructive pattern of lung function. The following article reviews the current knowledge on the effects of SCD on lung growth and function. Special emphasis is given to the controversies among the published articles in the literature and discusses possible causes for these discrepancies.

Mitochondria in lung diseases

Mitochondria are autonomous cellular organelles that oversee a variety of functions such as metabolism, energy production, calcium buffering and cell fate determination. Regulation of their morphology and diverse activities beyond energy production are being recognized as playing major roles in cellular health and dysfunction. This review is aimed at summarizing what is known regarding mitochondrial contributions to pathogenesis of lung diseases. Emphasis is given to understanding the importance of structural and functional aspects of mitochondria in both normal cellular function (based on knowledge from other cell types) and in development and modulation of lung diseases such as asthma, chronic obstructive pulmonary disease, cystic fibrosis and cancer. Emerging techniques that allow examination of mitochondria, and potential strategies to target mitochondria in the treatment of lung diseases are also discussed.