Thoracic Emergencies 7.2

Chapter Thoracic Emergencies 7.2 L. Breysem, M.-H. Smet Contents accurate, and in many situations imaging plays an essential role in completing or confirming the clinical suspicion.The 7.2.1 Introduction . 601 older the patient, the more comparable with adults is the 7.2.2 The Chest and Respiratory Tract in Children: therapeutic management. Physiological Aspects and Differences with Adults . 601 In this chapter, we focus on some important physiological and anatomical aspects of the pediatric airway and dis- 7.2.3 Clinical Symptoms . 602 cuss the most encountered non-traumatic and traumatic 7.2.4 Imaging of Non-traumatic Pediatric thoracic emergencies in the pediatric age group. Thoracic Emergencies . 603 Reviewing the causes of non-traumatic acute respirato- 7.2.4.1 Extrathoracic Airway Obstruction . 603 ry pathology in the different pediatric age groups, we 7.2.4.2 Parenchymal Disease . 612 7.2.4.3 Pleural Collections . 612 choose to subdivide the pathologies inhibiting normal res- 7.2.4.4 Large Diaphragmatic Defects . 615 piratory function in six main groups. We acknowledge, 7.2.4.5 Chest Wall Pathology . 615 however, that some conditions can occur concomitantly: ● The airways can be obstructed and the pathology can 7.2.5 Imaging of Traumatic Pediatric Thoracic Emergencies . 617 anatomically be situated from the upper airways to the peripheral small airways. 7.2.6 Conclusion . 618 ● The most common cause of severe respiratory distress related to parenchymal disease is premature birth and References . 618 hyaline membrane disease, acquired pneumonitides coming second. ● Changes in normal pleural negative pressure can com- 7.2.1 Introduction promise pulmonary function and pleural fluid collections can be susceptible for infection. Respiratory distress accounts for almost 10% of pediatric ● Large diaphragmatic defects either congenital either ac- emergencies. Under 15 years of age, deaths from respirato- quired need surgical intervention on very short notice. ry disorders accounts for 30% of childhood morbidity and ● Chest wall involvement with mechanical impairment can almost 50% in those less than 1 year of age. play a role in compromising normal respiratory function, By definition, respiratory failure indicates an inability of especially with underlying cardiopulmonary disease. the respiratory system to provide sufficient oxygen for ● Since the airways and the esophagus have a common metabolic needs or to excrete the CO2 produced by the embryological origin, both arising from the foregut, body. When a child presents with signs of respiratory dis- pathology and especially in neonates and infants, symp- tress, diagnosis and therapeutic decisions have to be made, tomatology, can be associated. and in some cases within a very short time scale. Many different diseases may lead to acute respiratory failure,includ- ing disorders outside the respiratory tract. That children are not small adults is even truer regard- 7.2.2 The Chest and Respiratory Tract ing the airways and respiratory system. Consequently, chil- in Children: Physiological Aspects dren respond different to an insult (traumatic or non-trau- and Differences with Adults matic) than adults. These differences between a child and an adult respiratory tract are also reflected in the multidis- Children have a large tongue and the narrowest point of the ciplinary approach. The approach of the child has to be extrathoracic airway is the subglottic region. The airways done with special care in a child friendly way; specific ex- in children are smaller, more collapsible, and the air flow is perience in pediatric or emergency medicine makes the di- larger in the central airways than in the peripheral airways. agnosis and immediate stabilization of the patient more Since the acini are smaller and the mucus production is in- 602 L.Breysem,M.-H.Smet creased, more atelectasis and/or air trapping is present in cases of airway inflammation or foreign-body aspiration. 7.2.3 Clinical Symptoms The alveoli grow until 8 years. Collateral ventilation is un- derdeveloped until 8 years due to the decreased number of Thoracic emergencies in children often result in life- pores of Kohn, the increased thickness of the connective threatening changes in cardiorespiratory function, anxious tissue septa, and the smaller alveolar size. This also results moments for the child as well as for the parents. The caus- in more atelectasis compared with adults (Hedlund and es of these emergencies are often distinct in the pediatric Kirks 1990; Rotta and Wiryawan 2003). In emergency situ- patient; however, it is a problem of any age, it can occur as ations, intubation of a child needs special experience. The a “new” situation or in an already existing pathology, and it possibility of craniofacial malformations, such as the can be a medical or a surgical emergency. Non-traumatic Pierre-Robin sequence or Apert syndrome with retrognatia acute chest pathology is more frequent than thoracic trau- and micrognathia, has to be taken into account (Dinwiddie ma. Inspection of the child’s well-being is in many cases 2004; Levy and Helfaer 2000; Nicolai 2004). more informative than blood gases or respiratory rate. The Also traumatic injuries of the chest do not have the same patient presents with acute or more insidious onset of result in children as in the adult. Bony and cartilaginous sometimes specific, and sometimes non-specific, signs or structures are more deformable, the elasticity of mediasti- symptoms. Most frequently, symptoms are present since a nal vessels is greater (Sivit 2002). Bony injuries are uncom- few hours or days and are not always easy to appreciate, mon in children. If rib fractures are present, the likelihood especially in the baby or infant (Eber 2004; Hammer 2003; of marked chest distortion and injury to the intrathoracic Rotta and Wiryawan 2003). viscera is great (Fig. 1). Aortic and great vessel injury is un- Voice changes can help in refining the differential diag- common in children, even following severe injury. Evalua- nosis, but tachypnea, cyanosis, and difficult breathing, de- tion of the superior mediastinum, however, is more difficult fined as stridor or wheezing, are most frequently present. in children because of the thymus. The age of the child, the Associated inflammatory symptoms or a septic appearance absence of deviation of the midline structures, and, if pre- are alerting. More severe signs are pulsus paradoxus and sent, the “sail sign” or “wave sign,”must assure you that the symptoms of pulmonary edema. Other worrying but less large upper mediastinum is thymus. If the plain chest X-ray specific symptoms are apnea, cough, chest pain, and sore is doubtful, ultrasound can be very helpful. Using a superfi- throat (Eber 2004). Feeding problems, swallowing prob- cial high-resolution linear or convex probe, the thymus be- lems, or dysphagia can sometimes be the initial symptoms tween the ribs can be identified (Mendelson 2001). of a tracheobronchial anomaly. All these features of the pediatric chest wall and respira- Stridor and wheezing are defined as an abnormal sound tory system make the response to a thoracic trauma, infec- during breathing produced by turbulence of air flow through tion, a thoracic mass, or respiratory obstruction in a young a partial obstruction. The characteristics and timing of stri- child different than in an adult. dor can indicate the site of airway obstruction and the effect Fig. 1. Battered child with multiple rib fractures and a hemothorax on the right side. Posterior and lateral rib fractures are highly specific fractures for battered child (in a non-accidental clinical setting) Chapter 7.2 Thoracic Emergencies 603 of the obstruction will be the greatest when the airway is the Table 1 Most frequent causes of inflammatory and non-inflamma- narrowest. Obstruction in the extrathoracic airway will be of tory extrathoracic airway obstruction more significance in inspiration and the child presents with Inflammatory inspiratory stridor. Obstruction in the intrathoracic airway Viral laryngotracheobronchitis will be of more significance in expiration and the child pre- Epiglottitis sents with expiratory stridor or wheezing. The lumen of the Retropharyngeal abscess Bacterial tracheitis (or laryngeotracheobronchitis) subglottic airway is defined by rigid cricoids cartilage and Allergy/laryngeal edema obstruction at that site produces stridor in the in- and expi- Viral laryngotracheobronchitis ratory phase, a biphasic stridor (Swischuk 2000a,b). Epiglottitis Retropharyngeal abscess In first instance, it is obvious that the clinician has to be Bacterial tracheitis (or laryngeotracheobronchitis) sure that all immediate necessary respiratory care to stabi- Allergy/laryngeal edema lize the child is given and secondly imaging can lead to the Non-inflammatory definitive diagnosis. In an urgent situation, rapid diagnosis Acquired or congenital anomalies and therapeutic action are mandatory. Foreign body Angioneurotic edema Tumors: subglottic hemangioma; vallecular cyst (uncommon: aryepiglottic cysts or dermoid cysts, cysts of the thyroglossal duct and laryngeal cyst) 7.2.4 Imaging of Non-traumatic Pediatric Neck trauma Vocal cord paralysis Thoracic Emergencies Chronic stridor can become acute Airway obstruction is potentially life-threatening and the pathology can be situated from the upper airways to the peripheral small airways. Airway obstruction in a child is ing (MRI) for specific indications (Table 1; Damm et al. potentially life threatening and, depending on the cause of 1999; Rencken

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