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Diffuse Lung Diseases in Childhood

See also Chapter 427 . Inherited Disorders of Surfactant Metabolism Jennifer A. Wambach Lawrence M. Nogee F. Sessions Cole Aaron Hamvas Pulmonary surfactant is a mixture of phospholipids and proteins synthesized, packaged, and secreted by alveolar type II pneumocytes (AEC2s) that line the distal air spaces. This mixture forms a monolayer at the air–liquid interface that lowers surface tension at end-expiration of the respiratory cycle, preventing atelectasis and ventilation–perfusion mismatch.…

Primary Ciliary Dyskinesia (Immotile Cilia Syndrome, Kartagener Syndrome)

Primary ciliary dyskinesia (PCD) is an inherited disorder characterized by impaired ciliary function leading to diverse clinical manifestations, including chronic sinopulmonary disease, persistent middle ear effusions, laterality defects, and infertility. The estimated frequency of PCD is 1 in 12,000 to 1 in 20,000 live births, but its prevalence in children with repeated respiratory infections has been estimated to be as high as 5%. Normal Ciliary Ultrastructure…

Cystic Fibrosis

Cystic fibrosis (CF) is an inherited multisystem disorder of children and adults; it is the most common life-limiting recessive genetic trait among whites. Dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, the primary defect, leads to a wide and variable array of presenting manifestations and complications. CF is responsible for most cases of exocrine pancreatic insufficiency in early life and is the major cause…

Pulmonary Abscess

Lung infection that destroys the lung parenchyma, resulting in cavitations and central necrosis, can result in localized areas composed of thick-walled purulent material, called lung abscesses. Primary lung abscesses occur in previously healthy patients with no underlying medical disorders and are usually solitary. Secondary lung abscesses occur in patients with underlying or predisposing conditions and may be multiple. Lung abscesses are much less common in children…

Bronchiectasis

Bronchiectasis is characterized by irreversible abnormal dilation and anatomic distortion of the bronchial tree and represents the common end stage of many nonspecific and unrelated antecedent events. Its incidence has been decreasing overall in industrialized countries, but it persists as a problem in lower- and middle-income countries and among some ethnic groups in industrialized nations (particularly in aboriginal children). Females are afflicted more frequently than males.…

Pleurisy, Pleural Effusions, and Empyema

Pleurisy is the inflammation of the pleura; it may be accompanied by an effusion. The most common cause of pleural effusion in children is bacterial pneumonia (see Chapter 428 ); heart failure (see Chapter 469 ), rheumatologic causes, and metastatic intrathoracic malignancy are also common causes. A variety of other diseases account for the remaining cases, including tuberculosis (see Chapter 242 ), lupus erythematosus (see Chapter…

Community-Acquired Pneumonia

Epidemiology Pneumonia, defined as inflammation of the lung parenchyma, is the leading infectious cause of death globally among children younger than 5 yr, accounting for an estimated 920,000 deaths each year ( Fig. 428.1 ). Pneumonia mortality is closely linked to poverty. More than 99% of pneumonia deaths are in low- and middle-income countries, with the highest pneumonia mortality rate occurring in poorly developed countries in Africa…

Immune and Inflammatory Lung Disease

Hypersensitivity Pneumonia Kevin J. Kelly Michelle L. Hernandez Keywords hypersensitivity pneumonia (HP) extrinsic allergic alveolitis acute HP recurrent subacute HP chronic progressive HP pet birds thermophilic organisms Hypersensitivity pneumonia (HP), aptly called extrinsic allergic alveolitis because the inciting agent is almost uniformly inhaled from the environment, is a complex immunologic-mediated syndrome of the pulmonary alveoli and interstitium. There are numerous specific disease names based on the origin of…

Chronic Recurrent Aspiration

Etiology Repeated aspiration of even small quantities of gastric, nasal, or oral contents can lead to recurrent bronchitis or bronchiolitis, recurrent pneumonia, atelectasis, wheezing, cough, apnea, and/or laryngospasm. Pathologic outcomes include granulomatous inflammation, interstitial inflammation, fibrosis, lipoid pneumonia, and bronchiolitis obliterans. Most cases clinically manifest as airway inflammation and are rarely associated with significant morbidity. Table 426.1 lists underlying disorders that are frequently associated with recurrent…

Aspiration Syndromes

Aspiration Syndromes Aspiration of material that is foreign to the lower airway produces a varied clinical spectrum ranging from an asymptomatic condition to acute life-threatening events, such as occur with massive aspiration of gastric contents or hydrocarbon products. Other chapters discuss mechanical obstruction of large- or intermediate-size airways as occurs with foreign bodies (see Chapter 414 ) and infectious complications of aspiration and recurrent microaspiration (see…

Pulmonary Edema

Pulmonary edema is an abnormal fluid collection in the interstitium and air spaces of the lung resulting in oxygen desaturation, decreased lung compliance, and respiratory distress. The condition is common in the acutely ill child. Pathophysiology Although pulmonary edema is traditionally separated into two categories according to cause ( cardiogenic and noncardiogenic ), the end result of both processes is a net fluid accumulation within the…

Congenital Disorders of the Lung

Pulmonary Agenesis and Aplasia Joshua A. Blatter Jonathan D. Finder Etiology and Pathology Pulmonary agenesis differs from hypoplasia in that agenesis entails the complete absence of a lung. Agenesis differs from aplasia by the absence of a bronchial stump or carina that is seen in aplasia. Bilateral pulmonary agenesis is incompatible with life, manifesting as severe respiratory distress and failure. Pulmonary agenesis is thought to be an autosomal…

Other Distal Airway Diseases

Bronchiolitis Obliterans Steven R. Boas Keywords Bronchiolitis obliterans Bronchiolitis obliterans syndrome Bronchiolitis obliterans organizing pneumonia Cryptogenic organizing pneumonia Epidemiology Bronchiolitis obliterans (BO) is a histopathologic diagnosis characterized by chronic obstructive lung disease of the bronchioles and smaller airways, resulting from an insult to the lower respiratory tract leading to inflammation and fibrosis of the small airways. In the nontransplant patient, BO most commonly occurs in the pediatric…

α 1 -Antitrypsin Deficiency and Emphysema

Homozygous deficiency of α 1 -antitrypsin (α 1 -AT) rarely produces lung disease in children, but it is an important cause of early-onset severe panacinar pulmonary emphysema in adults in the 3rd and 4th decades of life and a significant cause of liver disease in children (see Chapter 384.5 ). It is associated with panniculitis and vasculitis in adults. Pathogenesis The type and concentration of α…

Emphysema and Overinflation

Pulmonary emphysema consists of distention of air spaces with irreversible disruption of the alveolar septa. It can involve part or all of a lung. Overinflation is distention with or without alveolar rupture and is often reversible. Compensatory overinflation can be acute or chronic and occurs in normally functioning pulmonary tissue when, for any reason, a sizable portion of the lung is removed or becomes partially or…

Plastic Bronchitis

Plastic bronchitis is a rare condition characterized by recurrent episodes of airway obstruction secondary to the formation of large proteinaceous branching casts that take on the shape of and obstruct the tracheobronchial tree. It is not a single disease entity, but rather represents a state of altered respiratory epithelial function and is most frequently encountered in the setting of underlying pulmonary or cardiac disease, although plastic…

Wheezing, Bronchiolitis, and Bronchitis

Wheezing in Infants: Bronchiolitis Samantha A. House Shawn L. Ralston Keywords Bronchiolitis Wheezing Respiratory Syncytial Virus (RSV) General Pathophysiology of Wheezing in Infants Wheezing, the production of a musical continuous sound that originates in narrowed airways, is heard on expiration as a result of airway obstruction. Infants are more likely to wheeze than are older children, as a result of differing lung mechanics. Obstruction of airflow is affected…

Neoplasms of the Larynx, Trachea, and Bronchi

Vocal Nodules Saied Ghadersohi James W. Schroeder Keywords Vocal nodules Vocal abuse Voice therapy Vocal nodules , which are not true neoplasms, are the most common cause of chronic hoarseness in children. Chronic vocal abuse or misuse (i.e., frequent yelling and screaming) produces localized vascular congestion, edema, hyalinization, and epithelial thickening in the bilateral vocal cords. This grossly appears as nodules that disrupt the normal vibration of the…

Bronchomalacia and Tracheomalacia

Tracheomalacia and bronchomalacia refer to chondromalacia of a central airway, leading to insufficient cartilage to maintain airway patency throughout the respiratory cycle. These are common causes of persistent wheezing in infancy. Tracheomalacia and bronchomalacia can be either primary or secondary ( Table 416.1 ). Primary tracheomalacia and bronchomalacia are often seen in premature infants, although most affected patients are born at term. Secondary tracheomalacia and bronchomalacia…

Laryngotracheal Stenosis and Subglottic Stenosis

Laryngotracheal stenosis is the second most common cause of stridor in neonates and is the most common cause of airway obstruction requiring tracheostomy in infants. The glottis (vocal cords) and the upper trachea are compromised in most laryngeal stenosis, particularly those that develop following endotracheal intubation. Subglottic stenosis is a narrowing of the subglottic larynx, which is the space extending from the undersurface of the true…