How I treat hypoxia in adults with hemoglobinopathies and hemolytic disorders.

Hemoglobinopathies are caused by genetic mutations that result in abnormal hemoglobin molecules, resulting in hemolytic anemia. Chronic complications involving the lung parenchyma, vasculature, and cardiac function in hemoglobinopathies result in impaired gas exchange, resulting in tissue hypoxia. Hypoxia is defined as the deficiency in the amount of oxygen reaching the tissues of the body and is prevalent in patients with hemoglobinopathies, and its cause is often multifactorial. Chronic hypoxia in hemoglobinopathies is often a sign of disease severity and is associated with increased morbidity and mortality. Therefore, a thorough understanding of the pathophysiology of hypoxia in these disease processes is important in order to appropriately treat the underlying cause and prevent complications. In this article, we discuss management of hypoxia based on three different cases: sickle cell disease, ß-thalassemia, and hereditary spherocytosis. These cases are used to review the current understanding of the disease pathophysiology, demonstrate the importance of a thorough clinical history and physical examination, explore diagnostic pathways, and review the current management.

Sickle cell disease increases high mobility group box 1: a novel mechanism of inflammation.

High mobility group box 1 (HMGB1) is a chromatin-binding protein that maintains DNA structure. On cellular activation or injury, HMGB1 is released from activated immune cells or necrotic tissues and acts as a damage-associated molecular pattern to activate Toll-like receptor 4 (TLR4). Little is known concerning HMGB1 release and TLR4 activity and their role in the pathology of inflammation of sickle cell disease (SCD). Circulating HMGB1 levels were increased in both humans and mice with SCD compared with controls. Furthermore, sickle plasma increased HMGB1-dependent TLR4 activity compared with control plasma. HMGB1 levels were further increased during acute sickling events (vasoocclusive crises in humans or hypoxia/reoxygenation injury in mice). Anti-HMGB1 neutralizing antibodies reduced the majority of sickle plasma-induced TLR4 activity both in vitro and in vivo. These findings show that HMGB1 is the major TLR4 ligand in SCD and likely plays a critical role in SCD-mediated inflammation.

Comparison of WHO and CDC growth charts in predicting pulmonary outcomes in cystic fibrosis.

OBJECTIVES: The relation of weight-for-length (WFL) and weight-for-age (WFA) measurements with pulmonary function in patients with cystic fibrosis (CF) using the World Health Organization (WHO) growth standards has not been evaluated. The objective of the present study was to show that the relation of WFL and WFA measurements at 2 years with forced expiratory volume in 1 second (FEV1) at 6 to 8 years differs when using the WHO versus the Centers for Disease Control and Prevention (CDC) growth charts. METHODS: We assessed 1155 patients in the CF Foundation Patient Registry born between 2001 and 2004. Comparisons were made between the CDC and WHO growth charts. RESULTS: The WFL percentiles are significantly higher for the WHO growth standards compared with those for the CDC growth charts (median and interquartile range [IQR] WHO--64.8 [41.7-84.9], CDC--48.1 [23.7-75.7], P < 0.0001). WFL and WFA percentiles at 2 years on both charts are strongly associated with FEV1 at 6 to 8 years of age. The FEV1 at 6 to 8 years was statistically significantly lower for children who were classified as reaching a WFL ≥ 50 th percentile at 2 years by WHO standards alone versus those who qualified by both growth charts (median and IQR 103 [94-115] vs 107 [96-117], P < 0.05). Continued weight gain between 2 and 6 years was associated with a higher lung function at age 6 to 8 years. CONCLUSIONS: Although children attaining the 50th WFL percentile on the WHO growth chart by age 2 years have a lower FEV1 at 6 years than children attaining the same percentile on the CDC chart, both groups of children attain clinically normal FEV1. Further studies are needed to determine whether this difference is clinically meaningful.

Nasal nitric oxide May not differentiate primary ciliary dyskinesia from certain primary immunodeficiencies.

The diagnosis of primary ciliary dyskinesia (PCD) is made through a combination of clinical features supported by a panel of diagnostic tests. Our cases highlight the similarities in the clinical presentation of patients with the specific immunodeficiency activated phosphatidylinositol 3-kinase delta syndrome 1 (or PIK3CD-related disorder) and PCD. We highlight the importance of repeating nasal nitric oxide testing when PCD has not been confirmed by genetic or ciliary electron micrograph analysis in the setting of an expanded suppurative lung disease differential that includes considerations for immunodeficiency as well as PCD.

Respiratory Distress in the Newborn with Primary Ciliary Dyskinesia.

Primary ciliary dyskinesia (PCD) is inherited in a predominantly autosomal recessive manner with over 45 currently identified causative genes. It is a clinically heterogeneous disorder that results in a chronic wet cough and drainage from the paranasal sinuses, chronic otitis media with hearing impairment as well as male infertility. Approximately 50% of patients have situs inversus totalis. Prior to the development of chronic oto-sino-pulmonary symptoms, neonatal respiratory distress occurs in more than 80% of patients as a result of impaired mucociliary clearance and mucus impaction causing atelectasis and lobar collapse. Diagnosis is often delayed due to overlapping symptoms with other causes of neonatal respiratory distress. A work up for PCD should be initiated in the newborn with compatible clinical features, especially those with respiratory distress, consistent radiographic findings or persistent oxygen requirement and/or organ laterality defects.

Lung clearance index in children with sickle cell disease.

INTRODUCTION: The lung clearance index (LCI) derived from the multiple breath washout test (MBW), is both feasible and sensitive to early lung disease detection in young children with cystic fibrosis and asthma. The utility of LCI has not been studied in children with sickle cell disease (SCD). We hypothesized that children with SCD, with or without asthma or airway hyperreactivity (AHR), would have an elevated LCI compared to healthy controls. METHODS: Children with SCD from a single center between the ages of 6 and 18 years were studied at baseline health and completed MBW, spirometry, plethysmography and blood was drawn for serum markers. Results were compared to healthy controls of similar race, age, and gender. RESULTS: Healthy controls (n = 35) had a significantly higher daytime oxygen saturation level, weight and body mass index but not height compared to participants with SCD (n = 34). Total lung capacity (TLC) z-scores were significantly higher in the healthy controls compared to those with SCD (0.87 [1.13] vs. 0.02 [1.27]; p = .005) while differences in forced expiratory volume in 1 s z-scores approached significance (0.26 [0.97] vs. -0.22 [1.09]; p = .055). There was no significant difference in LCI between the healthy controls compared to participants with SCD (7.29 [0.72] vs. 7.40 [0.69]; p = .514). CONCLUSION: LCI did not differentiate SCD from healthy controls in children between the ages of 6 and 18 years at baseline health. TLC may be an important pulmonary function measure to follow longitudinally in the pediatric SCD population.

Novel insights into the diagnostic and therapeutic challenges of the CFTR metabolic syndrome/CF screen positive indeterminate diagnosis.

The growth of cystic fibrosis newborn screening (CF NBS) has led to an increased number of infants with a positive NBS test but inconclusive CF diagnostic testing. In the USA this condition is called CFTR related metabolic syndrome (CRMS), while in Europe the term CF screen positive, inconclusive diagnosis (CFSPID) is used. Recent advances in CF genetics and epidemiologic studies of CRMS/CFSPID have provided new insights into the prevalence and outcomes associated with this condition. Pediatr Pulmonol. 2016;51:S45-S48. © 2016 Wiley Periodicals, Inc.

Apical Lung Herniation Associated with Continuous Positive Airway Pressure in a 4-Year-Old Girl.

ABSTRACT: We report a case of apical lung herniation through the superior thoracic aperture of an obese child using nocturnal CPAP. Lung herniation has been described in association with congenital thoracic abnormalities and elevated intra-thoracic pressure, such as trauma. This patient was hospitalized with community acquired pneumonia and required nocturnal CPAP for treatment of concurrent obstructive sleep apnea. Her lung hernia was discovered incidentally on routine follow-up chest radiography and resolved with cessation of CPAP treatment. Lung herniation in association with the use of continuous positive airway pressure (CPAP) has not been previously described.

A case of tracheal varices in an adolescent patient with cyanotic heart disease.

Tracheal varices and bronchial varices are infrequently reported in adults as a complication of an underlying vascular obstruction, including portal hypertension, pulmonary arterial hypertension, or pulmonary venous hypertension. Tracheal varices and bronchial varices have been reported in adults with failing Fontan physiology, but this occurrence is rare in children. We report the unusual presentation of tracheal-bronchial varices due to veno-venous collaterals in an adolescent patient with Glenn physiology for double-inlet left ventricle and portal hypertension secondary to cardiac cirrhosis. We document complete resolution of these varices after heart and liver transplantation.