alterations of pulmonary function in children chapter 34 mosby items and derived items © 2010, 2006...

Alterations of Pulmonary Function in Alterations of Pulmonary Function in ChildrenChildren

Chapter 34Chapter 34

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

22Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.

Structure and FunctionStructure and Function Upper airwayUpper airway

Conducting airways are present at birthConducting airways are present at birth Airways are smaller in diameter and increase in Airways are smaller in diameter and increase in

size throughout childhoodsize throughout childhood Lower airways and lung parenchymaLower airways and lung parenchyma

Major changesMajor changes• Loss of mesenchymal tissue, expansion of air spaces, Loss of mesenchymal tissue, expansion of air spaces,

capillary development, alveolarization, and functional capillary development, alveolarization, and functional maturationmaturation


Structure and FunctionStructure and Function


Structure and FunctionStructure and Function SurfactantSurfactant

Lipid-protein mixLipid-protein mix Produced by alveolar type II cellsProduced by alveolar type II cells Surfactant maintains alveolar expansionSurfactant maintains alveolar expansion

• Decreases alveolar surface tensionDecreases alveolar surface tension


Structure and FunctionStructure and Function Surfactant deficiency often in premature infantsSurfactant deficiency often in premature infants

Causes respiratory distress syndrome (RDS; hyaline Causes respiratory distress syndrome (RDS; hyaline membrane disease) membrane disease)

Reflects developmental immaturityReflects developmental immaturity Produced by 20 to 24 weeks of gestationProduced by 20 to 24 weeks of gestation Secreted into the fetal airways by 30 weeksSecreted into the fetal airways by 30 weeks



Chest wall dynamicsChest wall dynamics Metabolic characteristicsMetabolic characteristics Immunologic incompetenceImmunologic incompetence

IgG conveyed transplacentally beginning at 20 weeks IgG conveyed transplacentally beginning at 20 weeks of gestationof 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 respirationPhysiologic control of respiration


Pulmonary DisordersPulmonary Disorders Disorders of upper airwaysDisorders of upper airways

Acute upper airway obstructions: PATENCYAcute upper airway obstructions: PATENCY• Infections, foreign body aspiration, angioedema, and Infections, foreign body aspiration, angioedema, and

traumatrauma

Chronic upper airway obstructionsChronic upper airway obstructions• Congenital malformations, cartilaginous weakness, vocal Congenital malformations, cartilaginous weakness, vocal

cord paralysis, and subglottic stenosiscord paralysis, and subglottic stenosis


Pulmonary DisordersPulmonary Disorders Breathing soundsBreathing sounds

A snoring noise is common for nasopharyngeal A snoring noise is common for nasopharyngeal obstructionsobstructions

StridorStridor• Harsh, vibratory sound caused by turbulent flow through Harsh, vibratory sound caused by turbulent flow through

a partially obstructed airwaya partially obstructed airway• Inspiratory stridor is common with extrathoracic airway Inspiratory stridor is common with extrathoracic airway

obstructionsobstructions• Expiratory stridor is common with intrathoracic airway Expiratory stridor is common with intrathoracic airway

obstructionsobstructions


Breathing SoundsBreathing Sounds


Pulmonary DisordersPulmonary Disorders Breathing soundsBreathing sounds

A weak or hoarse voice suggests possible A weak or hoarse voice suggests possible laryngeal problemslaryngeal problems

A cough is an indicator of an irritative symptomA cough is an indicator of an irritative symptom


Upper Airway InfectionsUpper Airway Infections Bacterial tracheitisBacterial tracheitis Retropharyngeal abscessRetropharyngeal abscess Tonsillar infectionsTonsillar infections Peritonsillar abscessPeritonsillar abscess


CroupCroup Acute laryngotracheobronchitisAcute laryngotracheobronchitis Common in children from 6 months to 5 yearsCommon in children from 6 months to 5 years Commonly caused by a virus (parainfluenza, Commonly caused by a virus (parainfluenza,

influenza A, or RSV)influenza A, or RSV) Causes subglottic edemaCauses subglottic edema

Usually occurs after an episode of rhinorrhea, Usually occurs after an episode of rhinorrhea, sore throat, and feversore throat, and fever

Causes seal-like barking coughCauses seal-like barking cough Self-limiting conditionSelf-limiting condition Severe cases are treated with nebulized Severe cases are treated with nebulized

epinephrineepinephrine


Spasmodic CroupSpasmodic Croup Similar hoarseness, cough, and stridor to Similar hoarseness, cough, and stridor to

croupcroup Usually in older childrenUsually in older children Demonstrates sudden onset, usually at night, Demonstrates sudden onset, usually at night,

and with no previous viral illnessand with no previous viral illness Resolves quicklyResolves quickly


Acute EpiglottitisAcute Epiglottitis Severe, rapidly progressive, life-threatening Severe, rapidly progressive, life-threatening

infection of the epiglottis and surrounding areainfection of the epiglottis and surrounding area Caused by Caused by Haemophilus influenzaeHaemophilus influenzae type B type B

(Hib)(Hib) Decreased incidence due to Hib vaccinationDecreased incidence due to Hib vaccination

ManifestationsManifestations High fever, sore throat, inspiratory stridor, and High fever, sore throat, inspiratory stridor, and

severe respiratory distresssevere respiratory distress TreatmentTreatment

Emergency airway and antibioticsEmergency airway and antibiotics


Aspiration of Foreign BodiesAspiration of Foreign Bodies Foreign body aspiration in children occurs Foreign body aspiration in children occurs

frequently between ages 1 and 3frequently between ages 1 and 3 ManifestationsManifestations

Coughing, choking, gagging, and wheezingCoughing, choking, gagging, and wheezing Symptoms depend on foreign body sizeSymptoms depend on foreign body size

Aspirated foreign bodies can be removed by Aspirated foreign bodies can be removed by bronchoscopybronchoscopy


Other Upper Airway DisordersOther Upper Airway Disorders AngioedemaAngioedema Subglottic stenosisSubglottic stenosis Laryngomalacia and tracheomalaciaLaryngomalacia and tracheomalacia Vocal cord paralysisVocal cord paralysis Congenital malformationCongenital malformation


Obstructive Sleep ApneaObstructive Sleep Apnea Partial or complete upper airway obstruction Partial or complete upper airway obstruction

during sleepduring sleep Obstructive sleep apnea disrupts normal Obstructive sleep apnea disrupts normal

ventilation and sleep patternsventilation and sleep patterns The most common cause of childhood The most common cause of childhood

obstructive sleep apnea is adenotonsillar obstructive sleep apnea is adenotonsillar hypertrophy hypertrophy


Respiratory Distress Syndrome Respiratory Distress Syndrome (RDS) of the Newborn(RDS) of the Newborn

Also called hyaline membrane disease (HMD)Also called hyaline membrane disease (HMD) Poor lung structure and lack of adequate Poor lung structure and lack of adequate

surfactantsurfactant Primarily a disease of preterm infantsPrimarily a disease of preterm infants Causes widespread atelectasis, respiratory Causes widespread atelectasis, respiratory

distress, and pulmonary hypertensiondistress, and pulmonary hypertension



Pulmonary hypertension causes continued Pulmonary hypertension causes continued shunting of blood away from the lungs (ductus shunting of blood away from the lungs (ductus arteriosus)arteriosus)

Prolonged anaerobic metabolism causes Prolonged anaerobic metabolism causes metabolic acidosismetabolic acidosis



Symptoms Symptoms Tachypnea, expiratory grunting, nasal flaring, Tachypnea, expiratory grunting, nasal flaring,

dusky skindusky skin TreatmentTreatment

Mechanical ventilation, surfactant administration, Mechanical ventilation, surfactant administration, glucocorticoid administration to women in preterm glucocorticoid administration to women in preterm laborlabor


Bronchopulmonary DysplasiaBronchopulmonary Dysplasia Chronic disease; result of acute respiratory Chronic disease; result of acute respiratory

disease in the neonatal perioddisease in the neonatal period Caused by premature birth, immature lungs, Caused by premature birth, immature lungs,

infections, genetics, etc.infections, genetics, etc. ManifestationsManifestations

Hypoxemia, hypercapnia, elevated work of breathing, Hypoxemia, hypercapnia, elevated work of breathing, bronchospasm, mucus plugging, pulmonary bronchospasm, mucus plugging, pulmonary hypertensionhypertension

Not as common due to availability of exogenous Not as common due to availability of exogenous surfactant and antenatal glucocorticoidssurfactant and antenatal glucocorticoids


Respiratory InfectionsRespiratory Infections Infections: bronchioles, bronchi, alveoli, Infections: bronchioles, bronchi, alveoli,

interstitium, pleurainterstitium, pleura Cause and site related to age, seasonal Cause and site related to age, seasonal

variables, environmental exposuresvariables, environmental exposures Infants and young children: more viral infectionsInfants and young children: more viral infections Environmental factors: presence of siblings, Environmental factors: presence of siblings,

daycare exposuredaycare exposure


Respiratory InfectionsRespiratory Infections BronchiolitisBronchiolitis PneumoniaPneumonia

Bacterial pneumoniaBacterial pneumonia Viral pneumoniaViral pneumonia Atypical pneumoniaAtypical pneumonia

Aspiration pneumonitisAspiration pneumonitis


Respiratory InfectionsRespiratory Infections Bronchiolitis obliteransBronchiolitis obliterans AsthmaAsthma Acute respiratory distress syndromeAcute respiratory distress syndrome


Cystic FibrosisCystic Fibrosis Autosomal recessive multisystem diseaseAutosomal recessive multisystem disease Exocrine or mucus-producing glands secrete Exocrine or mucus-producing glands secrete

abnormally thick mucus due to defective abnormally thick mucus due to defective epithelial ion transportepithelial ion transport

In lungs, thick secretions obstruct bronchioles In lungs, thick secretions obstruct bronchioles and predispose the lungs to chronic infectionsand predispose the lungs to chronic infections

Chronic inflammation leads to hyperplasia of Chronic inflammation leads to hyperplasia of goblet cells, bronchiectasis, pneumonia, goblet cells, bronchiectasis, pneumonia, hypoxia, fibrosis, etc.hypoxia, fibrosis, etc.


Cystic FibrosisCystic Fibrosis


Sudden Infant Death Syndrome Sudden Infant Death Syndrome (SIDS(SIDS))

Disease of unknown causeDisease of unknown cause IncidenceIncidence

Lower during 1st month of life, increases in 2nd Lower during 1st month of life, increases in 2nd month, and peaks at 3 to 4 monthsmonth, and peaks at 3 to 4 months

More common in male infantsMore common in male infants Seasonal variationSeasonal variation

Possible relationship to respiratory infectionsPossible relationship to respiratory infections Wide range of risk factorsWide range of risk factors

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