Current Pediatric Reviews (v.7, #1)

Upper airway (UAW) is defined as the extra-thoracic portion of the airway extending from the nose to the intra-thoracicinlet. It is divided into distinct segments such as the nose, pharynx, larynx and trachea. UAW has an exoskeleton of bones andcartilages on which more than 20 pairs of muscles are attached either directly or indirectly. UAW participates in a number ofcomplex motor acts involving both the respiratory and alimentary systems. Although we take airway patency for granted, itssignificance is highlighted during cardio-pulmonary resuscitation. A patent upper airway is vital for survival. Peter Safar, aCPR pioneer, made the seminal observation which is the basis of UAW maintenance. He recognized the development of oropharyngealobstruction during general anesthesia [1]. In an elegant study Wilson et al. determined the passive characteristics ofthe UAW and suggested that the UAW patency is actively maintained in the neonate [2]. Loss of UAW muscle tone with theonset of sleep predisposes the airway to obstruction, especially in obese adults. Research interest in sleep apnea served asfurther impetus to our understanding of UAW maintenance.Intrapleural negative pressure generated during inspiration acts as an airway collapsing force to the UAW. Nasal resistance,which accounts for nearly one-half the pulmonary resistance, increases markedly in the neonate when a nasogastric tube isinserted. As airway resistance increases, UAW is subjected to even greater airway collapsing force. Although airwayobstruction occurs typically during sleep and anesthesia, UAW patency can also be compromised by other factors such as neckflexion or maldevelopment. Congenital airway disorders such as laryngomalacia, choanal atresia and Pierre Robin sequenceconstitute the major UAW disorders in the newborn. Airway resistance is increased in these disorders, often impairing gasexchange in severe cases and sometimes even threatening survival. Prompt investigations, diagnosis and intervention arerequired for optimal outcome. Endoscopic evaluation and non invasive imaging such as computerized tomography are veryuseful tools in this process. In a series of reviews we discuss key issues in these UAW disorders.The passive characteristics of the UAW, neural and chemical regulation of UAW muscles, and effect of sleep and arousalon muscle activity as well as basic pathophysiology of upper airway obstruction are discussed in the first article [3]. SomeUAW muscles such as the alae nasi, posterior cricoarytenoid (PCA) influence UAW lumen markedly because of their strategiclocation. Respiratory activity of these muscles is altered by chemical and mechanical factors. For example, laryngealmechanoreceptors responding to negative pressure changes promote UAW patency by increasing PCA and genioglosssalactivity [4].Bilateral choanal atresia which occurs as an isolated abnormality or as part of a syndrome (e.g., CHARGE syndrome)manifests clinically with airway obstruction, stridor, and cyanosis in the immediate neonatal period. In the vast majority ofpatients it is a mixed (bony/membranous) lesion. A temporizing measure such as an oral airway or intubation is often requiredprior to definitive surgical treatment. Surgical strategies include transnasal puncture, transpalatal resection and endoscopicresection. Typical post-operative management of choanal atresia includes a stenting period. Ramsden reviews in detail thediagnosis, etiology and surgical treatment of choanal atresia [5].Pierre Robin Sequence is a collection of symptoms and signs including micrognathia, glossoptosis, intermittent upperairway obstruction and typically cleft palate. A majority of the patients responds to prone positioning and careful oral feeding.If airway obstruction persists or growth is inadequate, surgical intervention is indicated: glossopexy, mandibular distractionosteogenesis or tracheostomy. Yu et al. address these critical issues in their review on Pierre Robin Sequence [6].Stridor in the neonate has multiple causes. A basic physiological approach is needed to establish a diagnosis. This includes adetailed assessment of the characteristics of stridor, its associated features and the levels of respiratory distress. The differentialdiagnosis includes laryngomalacia, tracheobronchomalacia, subglottic stenosis, cysts, clefts, webs, hemangiomas and masses.Diagnostic laryngoscopy and bronchoscopy are required for most cases. Management ranges from observation and parentaleducation in mild cases to relief of obstruction through surgical means. Masters addresses these and other important issues inhis review [7]. Laryngomalacia is the most common cause of stridor in the neonates. It follows a benign, self-limiting course inthe vast majority of cases. Surgical intervention is warranted only in a minority of patients. The surgical techniques haveevolved over the years to endoscopic supraglottoplasty; tracheotomy can be avoided in most infants. Clinical symptoms,evaluation and surgical approaches are discussed in detail by Bedwell and Zalzal [8]. Endotracheal intubation and mechanical ventilation often help to stabilize the infants with severe upper airway problems.However, subglottic stenosis in the neonate is often acquired and is caused by prolonged mechanical ventilation. The incidenceof acquired subglottic stenosis has decreased significantly in recent years. Prior to the introduction of airway reconstruction,tracheotomy was the primary treatment option. Endoscopic airway techniques have expanded the surgical options withlaryngotracheal reconstruction as the mainstay for moderate and cricotracheal resection for severe stenosis. Meier and Whitediscuss the management of subglottic stenosis with an emphasis on current surgical techniques [9].

Upper Airway Patency in the Neonate by Oommen P. Mathew (3-8).
Extrathoracic portion of the airway can be defined as the upper airway (UAW) which serves both alimentaryand respiratory functions. It accounts for a significant portion of the dead space and total airway resistance. Activation ofUAW muscles must be precisely coordinated to achieve the desired results in several complex motor acts such asrespiration, airway protection, phonation, mastication and swallowing. A patent UAW is vital for survival. This reviewcritically evaluates key factors that influence UAW patency with special emphasis on the neonate.

Choanal Atresia by James D. Ramsden (9-14).
Congenital narrowing of the nasal airway at the posterior choanae is an uncommon condition in pediatricpatients, which can be uni- or bilateral. The presentation of bilateral choanal atresia is a neonatal airway emergency,requiring prompt treatment. The repair of unilateral choanal atresia is often an elective surgical procedure of earlychildhood, for which a variety of techniques have been described. Choanal atresia occurs as an isolated abnormality, or as part of a syndrome, most commonly CHARGE syndrome.Choanal atresia, and associated abnormalities such as abnormal semicircular canals and cranial nerve abnormalities, areintegral part of the diagnosis of CHARGE syndrome. There is increasing understanding of the biology of choanal atresia,and aetiological risk factors are starting to become apparent.

Pierre Robin Sequence by Jack C. Yu, Renee Hilton, R. Gerry Magana (15-19).
This is a mini-review of the etiopathogenesis and management of Pierre Robin Sequence (PRS). PRS is thecombination of intermittent upper airway obstruction, glossoptosis, microgenia, and retrognathia, with or without cleftpalate. 70 to 75% of PRS babies can be managed by prone positioning. Failing conservative measures, classified asCaouette-Laberge Group III PRS patients, surgical airway management is necessary and includes tongue-lip adhesion,mandibular distraction, or tracheostomy. The objectives are to provide a comprehensive, practical, and updated synopsisfor health care professionals involved in the care of this group of patients, so that accurate diagnosis can be made, logicaltreatment plan can be formulated, and effective therapy can be carried out. Particular emphasis is placed on themanagement for Group III patients with focus on the technical aspects of the tongue-lip adhesion and distractionosteogenesis in this review.

Stridor in the Neonate by Ian Brent Masters (20-32).
Stridor in the neonate is a sign that necessitates a basic physiological approach to establish a diagnosis. Thisincludes a detailed assessment of the characteristics of the stridor; its associated features particularly voice quality,swallow, cough as well as general features and finally the levels of respiratory distress. The differential diagnosis is wideranging, the associated features are common and the associated distress is highly variable. Common disorders causingstridor in the neonate include laryngomalacia, tracheobronchomalacia disorders, subglottic stenosis, and cysts; while vocalcord immobility, clefts, webs, hemangiomas and masses are rare. Diagnostic laryngoscopy and bronchoscopy are requiredin many cases. Management ranges from observation and parental education in mild cases to relief of hypoxia, relief or removal ofobstruction and treatment of the specific causes through surgical means in the severe and potentially dangerous. Aspecialized chronic illness teamwork approach including medical, paramedical, psychological support for the child andfamily and otolaryngological and surgical teams is often required to ensure a satisfactory outcome.

Surgical Treatment of Laryngomalacia by Joshua Bedwell, George Zalzal (33-41).
Laryngomalacia is the most common cause of stridor in neonates. It generally presents as occasionalinspiratory stridor, but may be associated with feeding problems, failure to thrive, and significant respiratory distress. Themajority of patients are managed conservatively with watchful waiting and anti-reflux medication, and can expect to seesymptom resolution by 12-18 months of age. About 10% of patients require surgical treatment for their symptoms.Surgical management has evolved over the past century from tracheotomy to the modern endoscopic supraglottoplasty.Results of this surgery are excellent, and severe complications, such as supraglottic stenosis and aspiration, areuncommon.

The surgical options for children with subglottic stenosis (SGS) have evolved from primarily tracheotomy fiftyyears ago to open and endoscopic techniques today. Improved airway management in the neonatal intensive care unit andbetter understanding of gastroesophageal reflux and its impact in the neonatal airway have decreased the overall incidenceof subglottic stenosis. However, SGS remains a significant cause of morbidity in the neonatal population. Laryngotrachealreconstruction with cartilage grafting is the most common treatment for moderate subglottic stenosis. Cricotrachealresection is a more extensive operation but has achieved excellent results in children with severe subglottic stenosis.Developing endoscopic airway techniques using instruments such as balloon dilators, carbon dioxide lasers, andmicrodebriders, continue to expand the surgeon' s armamentarium in treating subglottic stenosis. This paper reviews theevaluation and management of subglottic stenosis with an emphasis on discussing current surgical techniques.

Tuberculin Skin Test: Revisiting the Reading Technique by Naharajakumar Naharajakumar, Carolyn J. McKay (49-51).
Tuberculin Skin Tests (TST) are widely used but its utility is compromised by variations in reading thereactions by different observers, as studies over time have consistently shown that health care providers do not alwaysfollow established recommendations. To help ensure consistency among TST readers, Centers for Disease Control andPrevention (CDC), Atlanta, USA recommends that the induration following administration of a TST must be measuredtransverse to long axis of the forearm. Existing literature on measurement of delayed skin test responses have allexamined the advantage of using the pen versus the palpation technique for measuring induration, and to the best of ourknowledge, none have factored in the role of superficial lymphatics that possibly can influence the vertical diameter of theinduration following a TST. Accurate measurement of a TST forms an important element in the continuum of standard ofcare between administration of a TST and its correct interpretation, and errors in interpretation can lead to institution ofinappropriate therapy. It is hoped that this mini-review provides a logical insight based on best available evidence into thepossible role of superficial lymphatics in influencing the vertical diameter of the induration along the long axis of theforearm thereby also reinforcing CDC's recommendation for measuring the induration of a positive TST transverse to thelong axis of the forearm.

Adolescent Suicide: Epidemiology, Psychological Theories, Risk Factors, and Prevention by Mirjami Pelkonen, Linnea Karlsson, Mauri Marttunen (52-67).
Suicide is one of the most common causes of death among young people worldwide. Adolescence is adevelopmentally important phase of age due to the growing risk for suicide and prevalence of psychiatric disorders, aswell as due to growing possibilities for prevention and treatments. Research findings in theoretical considerations, inpsychological autopsy studies as well as in selected follow-up studies of clinical populations and suicide attemptersanalyzing risk factors for youth suicides are reviewed emphasizing the most recent data. As youth suicides are rare,research on risk factors for youth suicidal ideation, deliberate self-harm behavior and attempted suicide are also brieflyreviewed. Family-related adversity, precipitating interpersonal problems, and particularly psychiatric disorders constituterisk factors for adolescent suicide. Mood disorders, substance abuse and prior suicide attempts are strongly related withyouth suicides. However, recent psychological autopsy studies in China have found substantially lower rates ofpsychiatric disorders among suicide victims compared with those in the Western countries. Recognition and effectivetreatment of psychiatric disorders, e.g. depression are essential in preventing adolescent suicides. As only seldom youngsuicide victims have received psychiatric care, broad prevention strategies are needed in health care and social services.Education of physicians to recognize youth at risk, and restricting access to lethal means are recommended to preventsuicides. For high-risk youth providing continuity of care is important. Recent treatment studies among suicidaladolescents have reported promising results on safety planning and increased therapeutic contact early in treatment.

Endocrine Disorders in Sickle-Cell Disease by Cresio Alves, Zilda Braid (68-72).
Background: Sickle cell disease is a hemoglobinopathy of global importance due to its worldwide highprevalence. Endocrine and metabolic disorders may be associated with this disease, aggravating its clinical course.Objective: Evaluate the current knowledge about metabolic and endocrine derangements related to sickle cell anemia.Source: Literature search was performed in MEDLINE and SciELO databases, in the last 20 years, combining in differentcompositions the following terms: sickle cell disease, short stature, delayed puberty, diabetes mellitus, osteoporosis,hypothyroidism and adrenal dysfunction. Results: Endocrine disorders in sickle cell disease have multifarious causes:tissue hypoxia, chronic anemia, iron overload, high energy demand, genetic influence and malnourishment. Slow speed ofgrowth and delayed puberty are frequent. The most common endocrine disorders in sickle cell disease are: growth delay,osteopenia and hypogonadism. Diabetes mellitus, thyroid and adrenal disorders are overall rare in this population.Conclusion: Recognition of an endocrine disturbance is of utmost importance in the follow-up of sickle cell diseasepatients. Thus, preventive measures, early diagnosis and replacement of specific hormonal deficiencies may beimplemented contributing to a better quality of life for these patients.