Chapter_034.ppt
Download
Report
Transcript Chapter_034.ppt
Chapter 34
Alterations of Pulmonary Function in
Children
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
Structure and Function
Upper airway
Conducting airways are present at birth
Airways are smaller in diameter and increase in
size throughout childhood
Lower airways and lung parenchyma
Major changes
• 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.
2
Structure and Function
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
3
Structure and Function
Surfactant
Lipid-protein mix
Produced by alveolar type II cells
Surfactant maintains alveolar expansion
• Decreases alveolar surface tension
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
4
Structure and Function
Surfactant deficiency often in premature infants
Causes respiratory distress syndrome (RDS; hyaline
membrane disease)
Reflects developmental immaturity
Produced by 20 to 24 weeks of gestation
Secreted into the fetal airways by 30 weeks
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
5
Structure and Function
Chest wall dynamics
Metabolic characteristics
Immunologic incompetence
IgG conveyed transplacentally beginning at 20 weeks
of gestation
Breast-feeding allows further transfer of IgG
Babies are able to make IgG, IgM, and IgA
• Levels increase slowly with age
Physiologic control of respiration
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
6
Structure and Function
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
7
Pulmonary Disorders
Disorders of upper airways
Acute upper airway obstructions: PATENCY
• Infections, foreign body aspiration, angioedema, and
trauma
Chronic upper airway obstructions
• 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.
8
Pulmonary Disorders
Breathing sounds
A snoring noise is common for nasopharyngeal
obstructions
Stridor
• Harsh, vibratory sound caused by turbulent flow through
a partially obstructed airway
• Inspiratory stridor is common with extrathoracic 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.
9
Breathing Sounds
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
10
Pulmonary Disorders
Breathing sounds
A weak or hoarse voice suggests possible
laryngeal problems
A cough is an indicator of an irritative symptom
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
11
Upper Airway Infections
Bacterial tracheitis
Retropharyngeal abscess
Tonsillar infections
Peritonsillar abscess
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
12
Croup
Acute laryngotracheobronchitis
Common in children from 6 months to 5 years
Commonly caused by a virus (parainfluenza,
influenza A, or RSV)
Causes subglottic edema
Usually occurs after an episode of rhinorrhea,
sore throat, and fever
Causes seal-like barking cough
Self-limiting condition
Severe cases are treated with nebulized
epinephrine
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
13
Spasmodic Croup
Similar hoarseness, cough, and stridor to
croup
Usually in older children
Demonstrates sudden onset, usually at night,
and with no previous viral illness
Resolves quickly
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
14
Acute Epiglottitis
Severe, rapidly progressive, life-threatening
infection of the epiglottis and surrounding area
Caused by Haemophilus influenzae type B
(Hib)
Manifestations
Decreased incidence due to Hib vaccination
High fever, sore throat, inspiratory stridor, and
severe respiratory distress
Treatment
Emergency airway and antibiotics
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
15
Aspiration of Foreign Bodies
Foreign body aspiration in children occurs
frequently between ages 1 and 3
Manifestations
Coughing, choking, gagging, and wheezing
Symptoms depend on foreign body size
Aspirated foreign bodies can be removed by
bronchoscopy
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
16
Other Upper Airway Disorders
Angioedema
Subglottic stenosis
Laryngomalacia and tracheomalacia
Vocal cord paralysis
Congenital malformation
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
17
Obstructive Sleep Apnea
Partial or complete upper airway obstruction
during sleep
Obstructive sleep apnea disrupts normal
ventilation and sleep patterns
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.
18
Respiratory Distress Syndrome
(RDS) of the Newborn
Also called hyaline membrane disease (HMD)
Poor lung structure and lack of adequate
surfactant
Primarily a disease of preterm infants
Causes widespread atelectasis, respiratory
distress, and pulmonary hypertension
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
19
Respiratory Distress Syndrome
(RDS) of the Newborn
Pulmonary hypertension causes continued
shunting of blood away from the lungs (ductus
arteriosus)
Prolonged anaerobic metabolism causes
metabolic acidosis
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
20
Respiratory Distress Syndrome
(RDS) of the Newborn
Symptoms
Tachypnea, expiratory grunting, nasal flaring,
dusky skin
Treatment
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.
21
Bronchopulmonary Dysplasia
Chronic disease; result of acute respiratory
disease in the neonatal period
Caused by premature birth, immature lungs,
infections, genetics, etc.
Manifestations
Hypoxemia, hypercapnia, elevated work of breathing,
bronchospasm, mucus plugging, pulmonary
hypertension
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.
22
Respiratory Infections
Infections: bronchioles, bronchi, alveoli,
interstitium, pleura
Cause and site related to age, seasonal
variables, environmental exposures
Infants and young children: more viral infections
Environmental factors: presence of siblings,
daycare exposure
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
23
Respiratory Infections
Bronchiolitis
Pneumonia
Bacterial pneumonia
Viral pneumonia
Atypical pneumonia
Aspiration pneumonitis
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
24
Respiratory Infections
Bronchiolitis obliterans
Asthma
Acute respiratory distress syndrome
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
25
Cystic Fibrosis
Autosomal recessive multisystem disease
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
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.
26
Cystic Fibrosis
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
27
Sudden Infant Death Syndrome
(SIDS)
Disease of unknown cause
Incidence
Seasonal variation
Lower during 1st month of life, increases in 2nd
month, and peaks at 3 to 4 months
More common in male infants
Possible relationship to respiratory infections
Wide range of risk factors
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
28