Alterations of Pulmonary Function in Children Chapter 34 Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.

2 Structure and Function Upper airway Upper airway Conducting airways are present at birth Conducting airways are present at birth Airways are smaller in diameter and increase in size throughout childhood Airways are smaller in diameter and increase in size throughout childhood Lower airways and lung parenchyma Lower airways and lung parenchyma Major changes Major changes Loss of mesenchymal tissue, expansion of air spaces, capillary development, alveolarization, and functional maturation Loss of mesenchymal tissue, expansion of air spaces, capillary development, alveolarization, and functional maturation

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 3 Structure and Function

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 4 Structure and Function Surfactant Surfactant Lipid-protein mix Lipid-protein mix Produced by alveolar type II cells Produced by alveolar type II cells Surfactant maintains alveolar expansion Surfactant maintains alveolar expansion Decreases alveolar surface tension Decreases alveolar surface tension

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 5 Structure and Function Surfactant deficiency often in premature infants Surfactant deficiency often in premature infants Causes respiratory distress syndrome (RDS; hyaline membrane disease) Causes respiratory distress syndrome (RDS; hyaline membrane disease) Reflects developmental immaturity Reflects developmental immaturity Produced by 20 to 24 weeks of gestation Produced by 20 to 24 weeks of gestation Secreted into the fetal airways by 30 weeks Secreted into the fetal airways by 30 weeks

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 6 Structure and Function Chest wall dynamics Chest wall dynamics Metabolic characteristics Metabolic characteristics Immunologic incompetence Immunologic incompetence IgG conveyed transplacentally beginning at 20 weeks of gestation IgG conveyed transplacentally beginning at 20 weeks of gestation Breast-feeding allows further transfer of IgG Breast-feeding allows further transfer of IgG Babies are able to make IgG, IgM, and IgA Babies are able to make IgG, IgM, and IgA Levels increase slowly with age Levels increase slowly with age Physiologic control of respiration Physiologic control of respiration

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 7 Structure and Function

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 8 Pulmonary Disorders Disorders of upper airways Disorders of upper airways Acute upper airway obstructions: PATENCY Acute upper airway obstructions: PATENCY Infections, foreign body aspiration, angioedema, and trauma Infections, foreign body aspiration, angioedema, and trauma Chronic upper airway obstructions Chronic upper airway obstructions Congenital malformations, cartilaginous weakness, vocal cord paralysis, and subglottic stenosis Congenital malformations, cartilaginous weakness, vocal cord paralysis, and subglottic stenosis

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 9 Pulmonary Disorders Breathing sounds Breathing sounds A snoring noise is common for nasopharyngeal obstructions A snoring noise is common for nasopharyngeal obstructions Stridor Stridor Harsh, vibratory sound caused by turbulent flow through a partially obstructed airway Harsh, vibratory sound caused by turbulent flow through a partially obstructed airway Inspiratory stridor is common with extrathoracic airway obstructions Inspiratory stridor is common with extrathoracic airway obstructions Expiratory stridor is common with intrathoracic airway obstructions Expiratory stridor is common with intrathoracic airway obstructions

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 10 Breathing Sounds

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 11 Pulmonary Disorders Breathing sounds Breathing sounds A weak or hoarse voice suggests possible laryngeal problems A weak or hoarse voice suggests possible laryngeal problems A cough is an indicator of an irritative symptom A cough is an indicator of an irritative symptom

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 12 Upper Airway Infections Bacterial tracheitis Bacterial tracheitis Retropharyngeal abscess Retropharyngeal abscess Tonsillar infections Tonsillar infections Peritonsillar abscess Peritonsillar abscess

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 13 Croup Acute laryngotracheobronchitis Acute laryngotracheobronchitis Common in children from 6 months to 5 years Common in children from 6 months to 5 years Commonly caused by a virus (parainfluenza, influenza A, or RSV) Commonly caused by a virus (parainfluenza, influenza A, or RSV) Causes subglottic edema Causes subglottic edema Usually occurs after an episode of rhinorrhea, sore throat, and fever Usually occurs after an episode of rhinorrhea, sore throat, and fever Causes seal-like barking cough Causes seal-like barking cough Self-limiting condition Self-limiting condition Severe cases are treated with nebulized epinephrine Severe cases are treated with nebulized epinephrine

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 14 Spasmodic Croup Similar hoarseness, cough, and stridor to croup Similar hoarseness, cough, and stridor to croup Usually in older children Usually in older children Demonstrates sudden onset, usually at night, and with no previous viral illness Demonstrates sudden onset, usually at night, and with no previous viral illness Resolves quickly Resolves quickly

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 15 Acute Epiglottitis Severe, rapidly progressive, life-threatening infection of the epiglottis and surrounding area Severe, rapidly progressive, life-threatening infection of the epiglottis and surrounding area Caused by Haemophilus influenzae type B (Hib) Caused by Haemophilus influenzae type B (Hib) Decreased incidence due to Hib vaccination Decreased incidence due to Hib vaccination Manifestations Manifestations High fever, sore throat, inspiratory stridor, and severe respiratory distress High fever, sore throat, inspiratory stridor, and severe respiratory distress Treatment Treatment Emergency airway and antibiotics Emergency airway and antibiotics

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 16 Aspiration of Foreign Bodies Foreign body aspiration in children occurs frequently between ages 1 and 3 Foreign body aspiration in children occurs frequently between ages 1 and 3 Manifestations Manifestations Coughing, choking, gagging, and wheezing Coughing, choking, gagging, and wheezing Symptoms depend on foreign body size Symptoms depend on foreign body size Aspirated foreign bodies can be removed by bronchoscopy Aspirated foreign bodies can be removed by bronchoscopy

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 17 Other Upper Airway Disorders Angioedema Angioedema Subglottic stenosis Subglottic stenosis Laryngomalacia and tracheomalacia Laryngomalacia and tracheomalacia Vocal cord paralysis Vocal cord paralysis Congenital malformation Congenital malformation

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 18 Obstructive Sleep Apnea Partial or complete upper airway obstruction during sleep Partial or complete upper airway obstruction during sleep Obstructive sleep apnea disrupts normal ventilation and sleep patterns Obstructive sleep apnea disrupts normal ventilation and sleep patterns The most common cause of childhood obstructive sleep apnea is adenotonsillar hypertrophy The most common cause of childhood obstructive sleep apnea is adenotonsillar hypertrophy

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 19 Respiratory Distress Syndrome (RDS) of the Newborn Also called hyaline membrane disease (HMD) Also called hyaline membrane disease (HMD) Poor lung structure and lack of adequate surfactant Poor lung structure and lack of adequate surfactant Primarily a disease of preterm infants Primarily a disease of preterm infants Causes widespread atelectasis, respiratory distress, and pulmonary hypertension Causes widespread atelectasis, respiratory distress, and pulmonary hypertension

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 20 Respiratory Distress Syndrome (RDS) of the Newborn Pulmonary hypertension causes continued shunting of blood away from the lungs (ductus arteriosus) Pulmonary hypertension causes continued shunting of blood away from the lungs (ductus arteriosus) Prolonged anaerobic metabolism causes metabolic acidosis Prolonged anaerobic metabolism causes metabolic acidosis

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 21 Respiratory Distress Syndrome (RDS) of the Newborn Symptoms Symptoms Tachypnea, expiratory grunting, nasal flaring, dusky skin Tachypnea, expiratory grunting, nasal flaring, dusky skin Treatment Treatment Mechanical ventilation, surfactant administration, glucocorticoid administration to women in preterm labor Mechanical ventilation, surfactant administration, glucocorticoid administration to women in preterm labor

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 22 Bronchopulmonary Dysplasia Chronic disease; result of acute respiratory disease in the neonatal period Chronic disease; result of acute respiratory disease in the neonatal period Caused by premature birth, immature lungs, infections, genetics, etc. Caused by premature birth, immature lungs, infections, genetics, etc. Manifestations Manifestations Hypoxemia, hypercapnia, elevated work of breathing, bronchospasm, mucus plugging, pulmonary hypertension Hypoxemia, hypercapnia, elevated work of breathing, bronchospasm, mucus plugging, pulmonary hypertension Not as common due to availability of exogenous surfactant and antenatal glucocorticoids Not as common due to availability of exogenous surfactant and antenatal glucocorticoids

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 23 Respiratory Infections Infections: bronchioles, bronchi, alveoli, interstitium, pleura Infections: bronchioles, bronchi, alveoli, interstitium, pleura Cause and site related to age, seasonal variables, environmental exposures Cause and site related to age, seasonal variables, environmental exposures Infants and young children: more viral infections Infants and young children: more viral infections Environmental factors: presence of siblings, daycare exposure Environmental factors: presence of siblings, daycare exposure

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 24 Respiratory Infections Bronchiolitis Bronchiolitis Pneumonia Pneumonia Bacterial pneumonia Bacterial pneumonia Viral pneumonia Viral pneumonia Atypical pneumonia Atypical pneumonia Aspiration pneumonitis Aspiration pneumonitis

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 25 Respiratory Infections Bronchiolitis obliterans Bronchiolitis obliterans Asthma Asthma Acute respiratory distress syndrome Acute respiratory distress syndrome

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 26 Cystic Fibrosis Autosomal recessive multisystem disease Autosomal recessive multisystem disease Exocrine or mucus-producing glands secrete abnormally thick mucus due to defective epithelial ion transport Exocrine or mucus-producing glands secrete abnormally thick mucus due to defective epithelial ion transport In lungs, thick secretions obstruct bronchioles and predispose the lungs to chronic infections In lungs, thick secretions obstruct bronchioles and predispose the lungs to chronic infections Chronic inflammation leads to hyperplasia of goblet cells, bronchiectasis, pneumonia, hypoxia, fibrosis, etc. Chronic inflammation leads to hyperplasia of goblet cells, bronchiectasis, pneumonia, hypoxia, fibrosis, etc.

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 27 Cystic Fibrosis

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 28 Sudden Infant Death Syndrome (SIDS ) Disease of unknown cause Disease of unknown cause Incidence Incidence Lower during 1st month of life, increases in 2nd month, and peaks at 3 to 4 months Lower during 1st month of life, increases in 2nd month, and peaks at 3 to 4 months More common in male infants More common in male infants Seasonal variation Seasonal variation Possible relationship to respiratory infections Possible relationship to respiratory infections Wide range of risk factors Wide range of risk factors