Pulmonary Disorders
Apnea
Katie Ward
Background/Definition
Cessation of airflow through the respiratory tract for 20 seconds or longer or shorter respiratory pause associated with bradycardia or cyanosis significant enough to cause arterial hypoxemia and hypercapnia.
Types
Central.
Disruption of afferent (cessation of output) or efferent (inability of peripheral nerves or respiratory muscles to receive input) signals of the central respiratory center.
Inappropriate response to hypercapnia and hypoxemia.
Obstructive.
Reduced airway patency secondary to some form of obstruction causing poor or no air movement through passage.
Usually results in significant respiratory effort that is ineffective.
Etiology
Central: immaturity of the respiratory center (premature infants), head trauma, toxin-mediated.
Obstructive: obstructive sleep apnea (OSA), mucopolysaccharidosis, craniofacial anomalies, obesity, adenoid or tonsillar hypertrophy, aspirated foreign body, vocal cord paralysis.
Mixed: obstructive and central.
Pathophysiology
Within the transition from awake to nonrapid eye movement (NREM) sleep.
Reduced amplitude in the electrical activity of medullary inspiratory neurons, diaphragm, and abductor muscles.
Accompanied by mild hypoventilation and increased airway resistance.
Exaggerated pattern is noted in children with apnea disorders.
Clinical Presentation
At time of evaluation, patient may appear clinically well.
History may include poor sleep patterns, fatigue, daytime sleepiness, or difficulty concentrating.
Examination during apneic episode: no respiratory effort, breath sounds, or chest wall movement; potential hypoxia, cyanosis, and bradycardia.
Diagnostic Evaluation
Polysomnography
Echocardiography and/or electrocardiography (EKG) to evaluate for cardiac sequelae.
Management
If adenotonsillar hypertrophy, referral to an otolaryngologist for possible adenotonsillectomy
If obese, weight management, including nutrition, exercise, and behavioral elements.
Noninvasive positive pressure ventilation (NIPPV): continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP).
PEARL
Always consider an acute life-threatening event in a young infant presenting with apnea
Acute Respiratory Distress Syndrome
Katie Ward
Background
Result of lung injury, specifically to the alveolar capillary barrier (alveolar epithelium, capillary endothelium), which is vital in maintaining lung fluid balance.
Diagnostic Criteria
Acute onset.
Bilateral infiltrates on chest radiograph (see Figure 3.1).
FIGURE 3.1 • ARDS Radiographic Images. Nonuniform parenchymal involvement in ARDS. Anterior-posterior chest X-ray and CT scans corresponding to lung apex, hilum, and base from a patient with sepsis and ARDS. Images are taken with the patient in supine position, at a PEEP of 5 cm H2O. The CT scans illustrate the influence of the gravitational axis on the pattern of alveolar consolidation in ARDS: Nondependent regions are aerated, while dependent regions remain consolidated.
Pao2/Fio2 ratio of <200.
Noncardiogenic origin: pulmonary artery wedge pressure <18 mmHg or absence of clinical evidence of left atrial hypertension.
Etiology
Direct lung injury as a result of pneumonia, aspiration, pulmonary contusion, pulmonary embolism, submersion injury, or inhalational injury.
Indirect lung injury as a result of sepsis, shock, burn injury, pancreatitis, exposure to cardiopulmonary bypass, transfusionrelated acute lung injury (TRALI), or cardiopulmonary arrest.
Pathophysiology
Exudative phase: Injury to the alveolar capillary barrier causes disruption of fluid balance, leading to capillary permeability and pulmonary edema, in turn leading to a disruption of gas exchange and resulting in decreased pulmonary compliance and arterial hypoxemia.
Acute inflammatory response: follows with adherence of neutrophils to damaged epithelium and resultant release of proinflammatory cytokines (TNF-α, interleukins).
Proliferative phase: Resolution of ARDS begins.
Chronic/fibrotic phase: If complete resolution does not occur after phase 1, it may progress to fibrosing alveolitis, persistent hypoxemia, increased alveolar dead space, decreased pulmonary compliance, and pulmonary hypertension, which may lead to right ventricular (RV) failure.
Clinical Presentation
Tachypnea, labored breathing.
Hypoxia, labored breathing.
Hypocarbia followed by hypercarbia.
Rales/crackles, decreased breath sounds.
Diagnostic Evaluation
Chest radiography: bilateral infiltrates.
Arterial blood gas (ABG): Pao2/Fio2 ratio <200.
Complete blood count (CBC): evaluation for infectious process as well as hemoglobin level to calculate arterial oxygen content.
ECHO: evaluation for cardiogenic etiology of pulmonary disease.
Bronchoalveolar lavage (BAL): neutrophil activation, culture for infectious origin.
Oxygen index calculation ([Fio2 × MAP]/Pao2): If >20, consider high-frequency oscillatory ventilation (HFOV); if >40, consider extracorporeal membrane oxygenation (ECMO).
Management
Supplemental O2
Noninvasive ventilation (CPAP, BiPAP): may reduce intubation; Recent studies have included high flow nasal cannula (HFNC) as an additional modality to provide oxygenation prior to intubation or for management.
Intubation and ventilation.
High positive end-expiratory pressure (PEEP) to achieve Fio2 <0.5-0.6, low tidal volume (7-8 mL/kg); avoid peak inspiratory pressure (PIP)>30 cm H2O.
Permissive hypercapnia (unless contraindicated).
Escalation of symptoms.
Titrate PEEP upward.
HFOV.
Smaller tidal volume.
Higher mean airway pressures.
Limited PIPs.
Additional management strategies may include the following:
Surfactant.
Reduces alveolar surface tension.
Dosing: 50 to 100 mg/kg administered 1 to 2 times within 12 to 48 hours of initiation of mechanical ventilation.
Nitric oxide.
Results in capillary and pulmonary dilation.
Dose: 20-80 ppm continuous inhalation.
Requires methemoglobin level monitoring.
Conservative fluid management.
Neuromuscular blockade.
Bronchoscopy.
Corticosteroid administration.
No evidence in pediatrics.
Typically initiated 7 to 10 days into course of ARDS.
If oxygen index is not improving on conventional ventilator or HFOV, consider ECMO.
PEARLS
ARDS is a clinical syndrome with multiple etiologies
Management focuses on lung-protective strategies
Air Leak Syndromes
Katie Ward
Background/Definition
Any condition in which air is present within a thoracic space that is otherwise normally closed.
Defined by the location/space where air has abnormally infiltrated.
Pneumothorax: air in pleural space.
Pneumomediastinum: air in mediastinum.
Pneumopericardium: air in the pericardial space.
Subcutaneous and interstitial emphysema.
Etiology
Spontaneous.
Trauma.
Underlying lung disease.
Ventilator-induced.
Pathophysiology
Normally, pressure gradients within thoracic cavity maintain alveolar ventilation and lung expansion in areas throughout the thoracic cavity where air does not normally exist.
Disturbances of normal thoracic barriers cause disruption of pressure gradients with movement of gas from areas of high pressure to areas of lower pressure for the purpose of equalizing pressures.
Le Chatelier’s principle of chemical equilibrium: If a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.
Clinical Presentation
Depends on the location of air.
Pneumothorax.
Chest pain, dyspnea, tachycardia.
Ipsilateral hyperresonance to percussion, decreased air entry, decreased vocal fremitus.
Hypoxia: increased PIP on mechanical ventilation.
Tension pneumothorax: tracheal deviation (contralateral), hypotension, tachycardia, cyanosis—medical emergency.
Pneumomediastinum.
Chest pain, dyspnea, neck pain, subcutaneous emphysema, Hamman’s sign (i.e., crunching sound noted over the precordium space that is noted concurrent with heart tones rather than respirations; represents the sound of the heart beating against an air-filled space).
Pneumopericardium.
Tachycardia, tachypnea, mill wheel murmur, muffled heart sounds, hypotension.
Diagnostic Evaluation
Chest radiography.
Pneumothorax: thin line where lung is separated from chest wall.
Tension pneumothorax: shift of the mediastinum to the contralateral side (see Figure 3.2).
FIGURE 3.2 • Tension Pneumothorax Chest Radiograph. Left tension pneumothorax produces collapse of the left lung and mediastinal shift to the right.
FIGURE 3.3 • Pneumomediastinum Chest Radiograph. Asthmatic child with pneumomediastinum with air surrounding the small triangular thymus gland, extending as linear sheaths into the neck and superior mediastinum (upper arrows) and extending along the lower left cardiac edge (lower arrows).
Pneumomediastinum: radiolucent streaks in mediastinum (see Figure 3.3).
Pneumopericardium: air in pericardial sac and “halo” sign (see Figure 3.4).
EKG.
Pneumopericardium: ST-segment elevations and low voltage.
Management
Depends on clinical symptomatology and patient’s clinical status.
Goal is to remove pathologic air and restore normal pressure gradient.
Needle decompression.
May require thoracostomy tube placement; most common in pneumothorax.
Limiting PIP, if requiring mechanical ventilation.
Surgical evacuation is rare.
Observation.
PEARLS
Pneumomediastinum may be associated with subcutaneous emphysema on clinical examination
Pneumomediastinum and pneumopericardium typically do not require intervention unless associated with marked cardiopulmonary compromise
 FIGURE 3.4 • Pneumopericardium Chest Radiograph. In this chest X-ray, air can be seen within the pericardial sac surrounding the heart (pneumopericardium), and in the right hemithorax. |
Pneumothorax
Anne Vasiliadis
Definition
A pneumothorax is an abnormal collection of air between the visceral and parietal pleura in the thoracic cage.
Traumatic pneumothorax.
Caused by blunt, crush, or penetrating trauma to the chest.
Iatrogenic.
Caused by injury from a diagnostic or therapeutic procedure, or as a consequence of mechanical ventilation.
Spontaneous.
Primary spontaneous: occurs in patients with no underlying lung disease.
Secondary spontaneous: occurs as a complication of underlying lung disease such as asthma, cystic fibrosis (CF), connective tissue disorders, infections, malignancies, and interstitial lung disease.
Etiology
Spontaneous pneumothorax is very rare but more common in males.
Risk Factors
Tall, thin males aged 10 to 30 years.
Smoking.
Underlying lung disease or connective tissue disorder.
Pathophysiology
Acute increase in transpulmonary pressure that causes alveolar overdistention and rupture.
Defects in visceral pleura, generally caused by underlying lung disease.
Catamenial pneumothorax.
Spontaneous pneumothorax triggered by menstruation and thought to be associated with thoracic endometriosis.
Clinical Presentation
History: typically no inciting event for spontaneous pneumothorax.
Patient may report symptoms occurring after a maneuver that increases intrathoracic pressure, including Valsalva maneuver or other type of straining.
Patients with traumatic pneumothorax will generally report a history of blunt injury such as a trauma or fall.
Symptoms
May be asymptomatic.
Pleuritic chest pain (e.g., sharp and worse with inspiration) and dyspnea.
Chest pain usually resolves or changes to a dull pain within 1 to 3 days despite the persistence of the pneumothorax.
Physical Examination
Ipsilateral hyperresonance to percussion, decreased air entry, and decreased vocal fremitus.
Clinical Findings
Hypoxia, which can be acute.
Tachycardia.
Increased PIP or decreased expired tidal volume on mechanical ventilator.
Tension pneumothorax.
May result in tracheal deviation, decreased cardiac output leading to hypotension, tachycardia, and hypoxemia.
Medical emergency requiring immediate intervention.
Diagnostic Evaluation
Diagnosis typically confirmed with a posterior-anterior chest radiograph.
A lateral decubitus film may be needed if suspicion is high, but PA film is normal.
CT may help identify underlying blebs/bullae or very small pneumothoraces not detected by radiography.
There are multiple equations for calculating size of pneumothorax in adults, but these methods are not accurate in the pediatric population.
Laboratory evaluation: ABG may reveal decreased Pao2.
Management
Treatment is determined by type and size of pneumothorax and the clinical condition of the patient.
Observation.
Stable patients may only require observation with pulse oximetry and cardiorespiratory monitoring.
During observation, patient should receive 100% oxygen delivered via face mask to “wash out” nitrogen from pleural space.
Needle aspiration: Air is aspirated via a temporary needle inserted at the second intercostal space at the midclavicular line.
Thoracostomy tube: Catheter is placed in the pleural space at fourth, fifth, or sixth intercostal space at the midaxillary line and connected to water seal or suction.
Surgical intervention: video-assisted thoracoscopic surgery (VATS) and/orpleurodesis.
PEARLS
Conservative and noninvasive treatment options should be considered first in the clinically stable patient
Tension pneumothorax is diagnosed by clinical findings and is considered a medical emergency
Asthma
Megan Trahan
Definition
A chronic disorder that results in airway inflammation.
Characterized by episodes of cough, wheeze, dyspnea, and chest tightness.
Associated with airflow obstruction.
Status asthmaticus results from progressively worsening bronchospasm and airflow obstruction that is unresponsive to conventional therapy for asthma.
Etiology/Types
Triggers.
Extrinsic: allergic/immunologic factors.
Intrinsic: Infectious process, very common trigger for status asthmaticus.
Exercise-induced bronchospasm.
Severity classification.
Intermittent asthma.
Symptoms (difficulty breathing, wheezing, chest tightness, and coughing).
Occur fewer than 2 days per week.
Do not interfere with normal activities.
Nighttime symptoms occur fewer than 2 days per month.
Mild persistent asthma.
Symptoms occur more than 2 days a week, but do not occur every day; they interfere with daily activities.
Nighttime symptoms occur 3 to 4 times per month.
Lung function tests are normal when there are no symptoms.
Lung function tests are ≥80% of the expected value and may vary slightly (peak expiratory flow [PEF] varies 20%-30%) from morning to afternoon.
Moderate persistent asthma.
Symptoms occur daily and interfere with daily activities.
Inhaled short-acting asthma medication is used daily.
Nighttime symptoms occur more than 1 time per week, but do not happen daily.
Lung function tests are abnormal (e.g., ≥60% and <80% of the expected value); PEF varies more than 30% from morning to afternoon.
Severe persistent asthma.
Symptoms occur every day and severely limit daily physical activities.
Nighttime symptoms occur often, sometimes every night.
Lung function tests are abnormal (≤60% of expected value); PEF varies >30% from morning to afternoon.
Acute asthma exacerbation.
Mild symptoms: Tachypnea without accessory muscle use.
Heart rate is <100 beats per minute.
Pulsus paradoxus is not present.
Auscultation of chest reveals moderate wheezing, which is often end-expiratory.
Oxygen saturation in room air is >95%.
Moderate symptoms: Tachypnea and accessory muscles use are common.
Loud expiratory wheeze with suprasternal retractions present.
Pulsus paradoxus may be present (e.g., 10-20 mmHg).
Oxygen saturation in room air is 91% to 95%.
Severe symptoms.
Tachypnea; respiratory rate >30 breaths per minute, based on age and activity.
Accessory muscles use with suprasternal retractions common.
Heart rate >120 beats per minute.
Wheezing; biphasic (e.g., expiratory and inspiratory); usually loud.
Pulsus paradoxus, common (e.g., 20-40 mmHg). Oxygen saturation <91% in room air.
TABLE 3.1 Asthma Presentation by Severity | ||||||||
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Pathophysiology
Processes of asthma: triad.
Bronchoconstriction.
Airway hyperresponsiveness.
Airway inflammation.
Phases of asthma exacerbation.
Initial phase: Mast cells, eosinophils, T lymphocytes, macrophages, neutrophils, and epithelial cells initiate inflammatory process.
Mast cells cause histamine release, resulting in mucosal edema, mucous production, and bronchospasm.
Late phase: Infiltration and congestion of airways leads to obstruction and respiratory insufficiency.
Alterations in epithelium, smooth muscle, and bronchial blood vessels may lead to airway remodeling.
Clinical Presentation
Common symptoms include wheezing, shortness of breath, chest or abdominal pain, and cough which is often at night.
Symptomatology is often related to trigger.
Viral trigger: fever, rhinorrhea, sick contact exposure.
IgE-mediated trigger: strong patient or family history of atopy/allergies (Table 3.1).
Other signs and symptoms.
Forced or prolonged expiratory phase.
Hypoxia related to ventilation/perfusion (V/Q) mismatch.
Pulsus paradoxus, especially when severe asthma exacerbation is combined with hypovolemia.
Diagnostic Evaluation
Laboratory
ABG (not required in mild/moderate exacerbations).
Hypoxemia and hypocarbia with early or mild asthma exacerbation (e.g., respiratory alkalosis).
Worsening air trapping results in an inability to clear carbon dioxide, leading to normal or elevated Paco2 (e.g., respiratory acidosis).
Serum lactate level; elevated.
Electrolyte panel.
Evaluates Degree of dehydration and acidosis.
Hypokalemia; intracellular shifts of potassium are associated with β-agonist therapy
Magnesium level; in anticipation of magnesium sulfate therapy.
Imaging: chest radiography.
Not required for all children with asthma.
Evaluates for suspected pneumonia, pneumothorax and other air leak syndromes, cardiomegaly pulmonary edema.
Common findings:
Hyperinflation with flattened diaphragms.
Peribronchial thickening.
Narrowed cardiac silhouette.
Acute Management
Initial interventions.
Supplemental oxygen—first priority.
IV fluids.
Increased insensible losses with tachypnea.
Avoid overhydration; risk for pulmonary edema.
β-agonists (e.g., albuterol, levalbuterol).
Sympathomimetic medication, result in bronchial smooth muscle relaxation.
Intermittent dosing with inhaled nebulization (usually three doses in the first hour) or metered-dose inhaler.
Continuous nebulization for refractory asthma exacerbation; typically 10 to 20 mg/hour.
Corticosteroids target underlying airway inflammation.
IV formulation recommended in severe exacerbations or with high doses of β-agonist; a 3- to 5-day course typically recommended.
Taper dosing is recommended for steroid therapy >5 days.
Anticholinergics (e.g., ipratropium bromide).
Promotes bronchodilation without affecting mucociliary clearance.
Used most frequently in the emergency department to prevent hospitalization; data limited on inpatient use.
Admission criteria.
Symptoms after observation for 60 minutes.
Oxygen requirement.
Short-acting β-agonist required more than every 2 to 3 hours.
Prior ICU admissions.
Adjunct Therapies
Magnesium sulfate is classified as bronchodilator which inhibits calcium-mediated smooth muscle contraction.
Usually given as a rapid bolus (over 30 minutes) or as a continuous infusion.
Most common adverse reaction is hypotension.
Cardiac dysrhythmias noted with very high magnesium levels (10-12 mg/dL).
Terbutaline and epinephrine are β-agonists delivered through intravenous or subcutaneous route.
Terbutaline.
Administered as a bolus with or without infusion.
Monitor EKG and cardiac enzymes for myocardial ischemia.
Methylxanthines (e.g., theophylline, aminophylline).
Promote bronchial smooth muscle relaxation by unknown mechanism.
Used for patients with status asthmaticus refractory to steroids and inhaled/IV β-agonists.
Narrow therapeutic window; monitor drug levels.
Therapeutic level 10 to 20 mcg/mL.
High side-effect profile (e.g., nausea, vomiting, abdominal discomfort, arrhythmias, seizures).
Antimicrobials.
Common coinfections include pneumonia or acute sinusitis.
Macrolides have anti-inflammatory properties, although studies do not recommend empiric macrolide use.
Helium-oxygen mixture (Heliox): inhaled (no definitive evidence that this works).
Helium: low-density gas that reduces airflow resistance and allows laminar flow.
Enhances inhaled β-agonist delivery.
Mixtures include 60/40 (i.e., 60% helium, 40% oxygen), 70/30, and 80/20.
Can also be entrained into ventilator or noninvasive ventilator circuits.
Lowers peak airway pressures, facilitates weaning, but limited use if severe hypoxemia.
Noninvasive mechanical ventilation: includes CPAP and BiPAP.
Used for hypoxemia or increased work of breathing.
Reduces work of breathing and dyspnea.
Limited by patient cooperation.
High-flow nasal cannula can be used as a noninvasive method of respiratory support.
Mechanical ventilation (used in cases refractory to other therapies).
Increased risk for barotrauma, air leak syndromes, nosocomial infection, pulmonary edema, circulatory dysfunction, steroid/muscle relaxant-associated myopathy, and death.
Anticipate hypotension with onset of positive pressure ventilation (PPV) related to dehydration combined with the effects of PPV on preload.
Allow permissive hypercapnia, long expiratory phase with slow ventilator rates.
ECMO or inhaled anesthesia may be considered in extreme cases.
Chronic Management
Controllers: stepwise therapy; based on National Heart, Lung, and Blood guidelines.
β-agonist: monitor usage; >2 canisters per month requires reevaluation.
Asthma Action Plan: details when to use medications, call providers, and seek emergency care. Provided to each patient on every encounter.
Identify and avoid triggers; consider allergy evaluation.
PEARLS
Assess risk factors for asthma severity
Previous PICU admissions
History of respiratory failure requiring mechanical ventilation
Previous sudden deterioration
For acute exacerbation, primary intervention is oxygen, followed by inhaled β-agonists
For respiratory acidosis, lowering the ventilator rate will prolong the exhalation phase and facilitate carbon dioxide removal in acute status asthmaticus
Follow National Institute of Health guidelines: National Heart, Lung, and Blood Institute, National Asthma Education and Prevention Program, 2007, Expert Panel 3: Guidelines for the diagnosis and management of asthma
Every child should have Asthma Action Plan, required by Joint Commission for hospital discharge, and includes environmental controls, algorithm for use of long-term and rescue medications, medication regimens and rescue medications, and steps to take when treatment is not effective/emergent care
Bronchiolitis
Danielle Mashburn
Background/Definition
Viral infection of bronchiolar epithelium usually occurs in children <2 years of age.
Typical pathogens include respiratory syncytial virus (RSV), adenovirus, influenza, parainfluenza, and human metapneumovirus (hMPV).
Etiology
Risk factors for severe disease include:
Prematurity, infants <6 months of age, underlying cardio-pulmonary disease, and immunodeficiency.
Pathophysiology
Usually begins as upper respiratory tract infection that spreads to lower respiratory tract (bronchioles) within the first few days of illness.
Characterized by submucosal edema, increased mucus production, and increased airway resistance/wheezing.
Bronchiolar changes cause airway obstruction leading to:
Air trapping resulting in hyperinflation.
V/Q mismatch resulting in hypoxemia.
Clinical Presentation
Upper respiratory tract symptoms (e.g., rhinorrhea, congestion, low-grade fever).
FIGURE 3.5 • Bronchiolitis Chest Radiographs. Chest radiographs of 6-month-old infant with hMPV bronchiolitis, showing hyperinflation and diffuse perihilar infiltrates.
Lower respiratory tract symptoms (cough, tachypnea, dyspnea, decreased oral intake).
Physical examination findings: hypoxia, respiratory distress, diffuse crackles/rhonchi, expiratory wheeze, prolonged expiratory phase, irritability.
Diagnostic Evaluation
Majority of cases can be diagnosed based on history and physical examination.
Laboratory testing, if indicated (or if needed for isolation purposes).
Respiratory viral culture or polymerase chain reaction.
Blood gas analysis: moderate/severe cases.
Chest radiography.
Patchy atelectasis, peribronchial thickening, perihilar prominence, airspace disease, hyperinflation (see Figure 3.5).
Management
Supportive therapy is mainstay.
Oxygen supplementation, rehydration, secretion clearance.
Routine use of corticosteroids, racemic epinephrine, and bronchodilators is not recommended.
In severe cases, patient may require initiation of:
High-flow nasal cannula therapy, NIPPV or mechanical ventilation.
Chronic Lung Disease (Bronchopulmonary Dysplasia)
Danielle Mashburn
Risk Factors
Prematurity, intrauterine growth restriction, extremely low birth weight, family history of lung disease, ventilator-associated volutrauma or barotrauma, oxygen toxicity, increased pulmonary blood flow, infection.
Pathophysiology
Preterm birth leads to an arrest of normal development of lung airways and vasculature.
Dysfunction of terminal respiratory units.
Higher elastic recoil.
Postnatal injury results in disordered repair of the underdeveloped lung tissue.
Causes of postnatal injury include oxygen toxicity, ventilator-associated trauma, infection.
Mediators of epithelial lung injury cause chronic inflammation and fibrosis.
Clinical Presentation
Premature infant born with severe respiratory distress syndrome.
Tachypnea, retractions, scattered rales, hypoxemia, periods of apnea, cyanosis, hypercarbia, increased anterior-posterior chest diameter.
Long-standing oxygen requirement (>28 days postnatally), chronic diuretic and bronchodilator dependence.
Diagnostic Evaluation
Chest radiography.
Initial findings: pulmonary edema, atelectasis, hyperinflation.
FIGURE 3.6 • Bronchopulmonary Dysplasia Chest Radiograph. This 2-month-old child was treated with mechanical ventilation during the first days of life for hyaline membrane disease. The chest radiograph shows generalized overaeration and course modularity with multiple cyst-like areas throughout both lung fields.
Chronic findings: hyperexpansion (air trapping), areas of focal hyperlucency (cystic changes), linear stranding (fibrosis) (see Figure 3.6).
Blood gas analysis: evaluates the ability to oxygenate and ventilate.
Respiratory acidosis usually present.
ECHO: evaluates for congenital heart disease (CHD) as cause of respiratory distress.
Otolaryngology evaluation: to exclude anatomic airway abnormalities.
Management
Therapies to avoid preterm birth.
Supportive care.
Goal: Promote neonatal growth while supporting respiratory needs and minimizing further injury through:
Lung-protective ventilator strategies or use of NIPPV as able.
Maintaining functional residual capacity by using optimal PEEP levels.
Judicious use of diuretic and bronchodilators.
Use of antibiotics until pulmonary infection excluded.
Prevent gastroesophageal reflux disease.
Nutritional support: may require nasogastric or gastrostomy tube feedings.
Use of steroids remains controversial and is not currently recommended (Table 3.2).
Congenital Central Hypoventilation Syndrome
Danielle Mashburn
Definition
Inadequate respiratory drive as a result of a genetic defect in the autonomic nervous system’s control of breathing.
Etiology
Mutation of PHOX2B gene.
Gene is essential for embryologic development of the autonomic nervous system in the neural chest.
Majority of cases are a result of spontaneous gene mutation.
In a small percentage of cases, congenital central hypoventilation syndrome is inherited (autosomal dominant).
Pathophysiology
PHOX2B gene defect results in an abnormality of integration of chemoreceptors responsible for autonomic control of breathing.
Leads to abnormal function of ventilatory muscles and inadequate ventilation.
Patients fail to produce an appropriate ventilatory response to hypercarbia and hypoxemia.
TABLE 3.2 Etiology of Pediatric Chronic Lung Disease | ||||||||||||||||
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Clinical Presentation
Usually presents in the newborn period.
Apnea, respiratory arrest, hypopnea, cyanosis, tachycardia, diaphoresis, lethargy, hypercarbia, hypoxemia.
Patients who present outside of newborn period.
Learning disabilities, growth failure, cor pulmonale.
Develop worsening symptoms with sleep.
Do not show classic signs of respiratory distress (e.g., tachypnea, retractions).
Exhibit monotonous respiratory rate and work of breathing despite hypoxemia and hypercarbia.
Diagnostic Evaluation
Genetic testing for PHOX2B gene mutation.
Polysomnography.
Findings include hypoventilation, hypoxemia, decreased minute ventilation, and frequent arousal.
Studies to evaluate for underlying metabolic, pulmonary, cardiac, or brainstem disease.
ECHO, chest radiography, brain MRI, urine amino and organic acids.
Management
Normalization of ventilation.
Tracheostomy with mechanical ventilation.
Chronic NIPPV.
Diaphragmatic pacing.
Supplemental oxygen is not adequate because it does not address hypoventilation.
Need continuous pulse oximetry and end-tidal CO2 monitoring.
Early intervention may improve long-term neurodevelopmental outcome.
Congenital Diaphragmatic Hernia
Danielle Mashburn
Definition
Congenital defect of diaphragm resulting in herniation of gastrointestinal contents into thoracic cavity.
Typically occurs on the left side of the chest.
Etiology
Failure of pleuroperitoneal folds to close at 6 to 8 weeks gestation.
Pathophysiology
Abdominal viscera herniate through diaphragmatic defect into thoracic cavity.
The resultant mass effect causes lung hypoplasia.
Primarily occurs on ipsilateral side, but contralateral lung can also be hypoplastic.
Reduction in pulmonary mass impairs oxygenation and ventilation, resulting in respiratory insufficiency or failure.
Clinical Presentation
Signs of respiratory failure in immediate newborn period.
Hypercarbia, hypoxia.
Physical examination findings: retractions, tachypnea, grunting, cyanosis, absent breaths, increased chest diameter, sounds on ipsilateral side, heart sounds shifted to contralateral side, scaphoid abdomen, presence of bowel sounds in thorax.
Diagnostic Evaluation
Antenatal ultrasound.
Commonly occurs in infants with a history of polyhydramnios.
Often diagnosed prior to birth: allows for counseling and postnatal planning.
Chest radiography.
Fluid-filled loops of bowel seen in thoracic cavity.
Associated mediastinal shift (see Figure 3.7).
ECHO.
Allows ability to evaluate for cardiac dysfunction and measures systemic and pulmonary pressures.
Chromosomal evaluation as disorder is frequently associated with anomalies.
Management
Cardiorespiratory stabilization.
Immediate intubation, sedation, and stomach decompression.
Bag-mask ventilation should be avoided as this will introduce air into gastrointestinal tract, worsening lung compression.
Lung-protective strategies (when stable) and pulmonary hypertension management.
Consider ECMO if conventional ventilation fails.
Delayed surgical intervention to repair defect.
Can be considered after hemodynamic stabilization and resolution of pulmonary hypertension.
Ongoing pulmonary care.
Chronic lung disease is common source of morbidity for survivors of congenital diaphragmatic hernia (CDH).
 FIGURE 3.7 • Diaphragmatic Hernia. A: Abdominal surface of the diaphragm and the derivation of the components during development. The pleuroperitoneal membranes, the septum transversum, and the esophageal mesentery form the diaphragm. A Bochdalek hernia forms when there is a posterolateral defect. Morgagni hernias are less common and are present anteriorly. B: Chest radiograph of a child with a congenital posterolateral (Bochdalek) diaphragmatic hernia on the left. The mediastinum is displaced to the right by the intestinal loops present in the left chest. |
Laryngotracheobronchitis/Croup
Andrea M. Kline-Tilford
Background/Definition
An infection involving the subglottic airway, larynx, trachea, and bronchi.
Most common in children 6 months to 3 years of age, affects males > females.
Peak incidence is late fall.
Etiology/Types
Most commonly caused by parainfluenza types 1 and 2.
Less commonly caused by RSV, influenza types A and B, and parainfluenza type 3.
Infrequently caused by Mycoplasma pneumoniae.
Pathophysiology
Mucosal airway edema from infectious pathogen.
Subsequent epithelial necrosis.
Reduced airway diameter results in increased resistance to airflow and increased work of breathing.
Poiseuille’s law: Resistance = 8 × viscosity × length/π × radius4.
Decreasing airway diameter dramatically increases airway resistance and increases the flow rate—Venturi effect.
Clinical Presentation
Diagnostic Evaluation
Westley croup score (published symptom scoring tool).
Provides an objective measure for disease severity.
Generally diagnosed on history and physical examination.
Consider lateral neck films.
Haziness or narrowing of subglottic area.
Distention of hypopharynx.
Consider chest radiography.
Narrowing of subglottic area (e.g., “steeple sign”) (see Figure 3.8).
Positive findings noted only in approximately 50% of studies.
Management
Supportive care.
Humidified or cooled air/gas.
Provides soothing vasoconstriction of airway tissue.
Steroids: dexamethasone 0.6 mg/kg IV/IM.
Oxygen and additional respiratory support/maneuvers, as needed.
Consider nebulized epinephrine solution.
Results in vasoconstriction of mucosal vasculature.
FIGURE 3.8 • Steeple Sign. Viral croup in an 18-month-old boy. A: Lateral view of the neck shows marked subglottic tracheal narrowing (arrow) and distension of the hypopharynx (*). B: Frontal view in another patient shows narrowing of the subglottic trachea (arrows).
Antipyretics, if febrile, and consider IV fluid administration.
Consider heliox administration.
Increases laminar flow of gas, improves airway mechanics, and reduces respiratory workload.
Consult otolaryngology if patient fails to improve with standard medical therapy.
PEARLS
Symptoms typically more prominent at night, peak in 48 hours and can last up to 1 week
Accounts for up to 90% of infectious airway obstruction
Cystic Fibrosis
Ruth DeVoogd
Background/Definition
An inherited chronic disease affecting multiple body systems, primarily the lungs and pancreas.
Most common in Caucasians.
Life expectancy is increasing; median life expectancy approximately 37 years.
Etiology/Types
Autosomal recessive disorder.
Over 1,500 gene mutations identified which cause CF; some mutations cause more mild disease.
Pathophysiology
Defective gene makes an abnormal protein, which impairs movement of salt and water across the epithelial cell wall in the exocrine glands, leading to thick sticky secretions.
Body systems affected include:
Lungs.
Sticky mucus traps bacteria in the airways and causes a cycle of infection and inflammation, leading to airways destruction and eventually respiratory failure and death.
Pancreas.
Sticky mucus blocks the pancreatic ducts, impairing the excretion of pancreatic enzymes and bicarbonate (which are necessary for digestion of nutrients), in turn leading to malabsorption and malnutrition.
Majority of individuals are pancreatic insufficient and require pancreatic enzyme replacement therapy.
CF-related diabetes may develop due to impaired insulin production.
Pancreatitis may develop in small number of individuals who are pancreatic sufficient.
Intestines.
Fat and protein malabsorption lead to poor growth and large, oily, foul-smelling stools. Risk for constipation and obstruction.
Liver.
Thick secretions block bile ducts and may lead to liver damage.
Sinuses.
Sticky mucus builds up and leads to poor drainage. Sinus disease, infection, and nasal polyps are common.
Reproductive tract.
98% of males are infertile due to damage to vas deferens; some females have difficulty getting pregnant due to thick cervical mucus.
Sweat glands.
Abnormally high levels of sodium and chloride are lost through sweat, leading to increased risk for dehydration.
Clinical Presentation
Traditional signs: poor growth, large foul-smelling and oily stools, increased appetite, and frequent respiratory infections.
Since newborn screening for CF provides an early diagnosis, infants may present well-nourished without any respiratory involvement.
Pulmonary: cough, increased sputum, crackles, wheezing, shortness of breath, hemoptysis, chest pain, and hypoxemia; occasionally pneumothorax.
Gastrointestinal tract: periumbilical or right lower quadrant (RLQ) pain, constipation, loose stools, flatus, abdominal distention, vomiting. RLQ pain mimics appendicitis; however, is usually due to constipation or distal intestinal obstruction syndrome (DIOS).
Weight loss.
Dehydration: Hypochloremic and hyponatremic alkalosis.
Hyperglycemia: If has impaired glucose tolerance or CF-related diabetes.
Diagnostic Evaluation
Sweat chloride test: noninvasive test. Sweat chloride ≥60 mmol/L (>30 mmol/L in infants).
Genotype: positive for combination of mutations.
Pulmonary exacerbation: Chest radiography (may or may not show acute process), decline in pulmonary function test (FEV1), oxygen saturation, sputum or throat culture, high-resolution chest CT scan may be indicated.
Gastrointestinal complications: abdominal radiography to evaluate for constipation, DIOS, abdominal ultrasound.
Laboratory Testing
CBC with differential, electrolytes, BUN, creatinine, glucose, liver panel with γ-glutamyl transferase, prothrombin time (PT)/international normalized ratio (INR).
Hemoglobin A1C if history of CF-related diabetes or weight loss.
Culture for CF pathogens: expectorated sputum (preferred), throat culture, or BAL.
Management
Pulmonary exacerbation.
Airway clearance (e.g., high-frequency chest wall oscillation [vest therapy], handheld device, intrapulmonary percussive ventilator).
Airway hydrators (e.g., Dornase alpha [Pulmozyme], hypertonic saline).
Antibiotics to cover typical CF pathogens.
Pseudomonas aeruginosa: aminoglycosides, antipseudomonal penicillins, β-lactams, cephalosporins (third and fourth generations), and fluoroquinolones.
CF patients usually clear aminoglycosides more rapidly, necessitating a higher mg-per-kg dose than normal.
Staphylococcus aureus: antistaphylococcal penicillins, cephalosporins, TMP/SMX, some fluoroquinolones.
Methicillin-resistant Staphylococcus aureus (MRSA): TMP/SMX, linezolid, vancomycin, clindamycin.
Burkholderia cepacia complex: meropenem, plus one other (e.g., aminocycline, amikacin, ceftazidime, chloramphenicol, TMP/SMX).
Aerosolized antibiotics: tobramycin (Tobi), aztreonam (Cayston).
Oral antibiotics: depending on airway culture results and susceptibilities.
Abdominal pain.
DIOS: laxative, polyethylene glycol (Miralax, GoLytely), enema (saline or Gastrografin), stool softener.
Acute abdomen: surgery consult to evaluate for severe obstruction, appendicitis, intussusception.
Hyperglycemia.
Monitor blood glucose levels, treat if indicated.
Risk in CF-related diabetes is that patient will become hypoglycemic because of the production of insulin.
PEARLS
Consider the diagnosis of CF in any patient with poor growth and frequent respiratory infections
Newborn screening is not a diagnostic procedure and may not detect all individuals with CF
If airway culture results are unknown or patient quite ill, treat for Pseudomonas initially while waiting for culture results
Cepacia syndrome, which occurs in patients who culture Burkholderia cepacia complex, is life-threatening. Syndrome involves rapid decline, fever, bacteremia, and necrotizing pneumonia
Appendix is often enlarged in CF, even without appendicitis. An abdominal CT may show this enlargement, but patient may not require surgical intervention
A child who presents with hyponatremia and hypochloremia should always be suspected of having CF
Foreign Body Aspiration
Andrea M. Kline-Tilford
Background/Definition
A complete or near complete obstruction of the larynx or trachea with a foreign object.
Complete airway obstruction can result in immediate asphyxia and death if not immediately dislodged.
Partial airway obstruction symptoms can vary depending on the size and location of the foreign object.
Children with underlying neurologic disease are at increased risk of foreign body aspiration (FBA).
Children/adolescents under the influence of alcohol or drugs are at increased risk for FBA.
Epidemiology
Common in children, with approximately 160 annual pediatric deaths.
Accounts for >17,000 emergency department visits in children <14 years of age.
Etiology/Types
Food items are common in all pediatric age groups.
Nonfood items more common in older pediatric patients (e.g., pen caps, paperclips).
Pathophysiology
Aspirated objects passing the level of the carina will lodge in a location determined by the size of the child, characteristics of the object aspirated, underlying anatomy, and position of the child during the aspiration event.
Clinical Presentation
Acute complete obstruction results in asphyxiation and death.
Acute noncomplete obstruction.
Symptoms can vary based on size and location of partial obstruction, but often include a combination of the following: coughing, gagging, choking, wheezing, respiratory distress.
Decreased breath sounds over affected lung (if foreign body is in the bronchial tree position).
Late noncomplete obstruction.
Paroxysmal cough, fever and local inflammation, edema, and granulation tissue formation.
Three stages in noncomplete obstruction FBA.
Initial event.
Asymptomatic period.
Symptoms of ensuing complications.
Diagnostic Evaluation
History is most important.
Chest radiography.
Most helpful views include:
Posterior-anterior views.
Lateral decubitus.
Inspiratory and expiratory (may be difficult to obtain in infants and young children).
Chest fluoroscopy.
Chest CT scan.
Bronchoscopy (rigid): may be used to visualize and retrieve the object.
Management
Prompt diagnosis and management are critical.
Acute presentation.
Back blows/chest compressions (infant).
Abdominal thrusts (child).
Direct visualization and manual retrieval (bronchoscopy).
PEARLS
Care with transportation of the child with suspected FBA is important as the object can shift to occlude the airway completely
Caregivers commonly believe that the object has been relieved when coughing resolves
A delay in diagnosis is not uncommon
Symptoms of cough, wheezing, and decreased breath sounds can be similar to common childhood diseases (e.g., asthma, bronchiolitis, and pneumonia)
Lung Transplantation
Carole A. Branch
Etiology
Most common indications in children 0 to 18 years.
CF.
Baseline FEV1 <30% of predicted value.
Pao2 <55 mmHg at rest.
Worsening severity of hypercapnia.
Female pediatric patient with rapid decline in lung function.
Frequent respiratory exacerbations requiring hospitalization and IV therapy with no improvement in lung function.
Pulmonary hypertension.
New York Heart Association/World health Organization functional class III or IV: rapidly progressive disease, elevated right arterial pressures >15 mmHg, cardiac index <2 L/minute/m2, failing medical therapy.
Other indications for lung transplantation include surfactant dysfunction syndromes, CHD, chronic lung disease, bronchiolitis obliterans (BO), and pulmonary fibrosis.
Evaluation/Referral
Referral for transplant is usually made by a pulmonologist.
Evaluation process.
Series of diagnostic tests, procedures, and assessments.
Evaluation of support system and ability to follow rigorous therapy, daily monitoring, and reevaluation schedule following transplant.
Prescribed medical regimen.
Tiered allocation scores (lung allocation score).
Age <12 years is listed as Priority I or II based on medical condition.
Priority I: Respiratory failure or supplemental O2 to achieve Fio2 >50% in order to maintain O2 levels >90% OR arterial or capillary Pco >50 mmHg or a venous Pco2 >56 mmHg or pulmonary hypertension.
Priority II: All other candidates that do not meet criteria for Priority I.
Age >12 years.
Score from 0 to 100 calculated: based on evaluation criteria.
Higher score receives higher priority, based on age, diagnosis, indicators of disease severity, likelihood of successful transplant.
Other factors in listing for transplant include blood type, height weight, and geographical area.
Contraindications for lung transplant: absolute or relative.
Absolute contraindications include malignancy within past 2 years, immunodeficiency syndrome, hepatitis B or C with liver disease, severe neuromuscular disease, multiorgan system dysfunction.
Relative contraindications include pleurodesis, renal insufficiency, markedly abnormal body mass index (BMI), chronic airway infection with specified organisms, severe scoliosis, active collagen disease, mechanical ventilation, among others.
Diagnostic Transplant Evaluation
Organs matched by height, weight, blood type.
HLA antibody screening is performed.
Specific antibodies can be avoided if recipient has elevated antibody levels.
Postoperative Considerations
ICU settings with mechanical ventilation and chest tubes for first 24 to 48 hours.
IV antibiotics to cover previous organisms, donor organisms, and current cultures.
Pulmonary rehabilitation.
Immunosuppressive therapy: triple therapy per International Pediatric Lung Transplant Consortium.
Potential Postoperative Complications
Early complications can include hyperacute rejection, primary graft dysfunction, acute rejection, ectopic atrial tachycardia, airway complications, infection, damage to phrenic nerve resulting in diaphragmatic paralysis.
Late complications include acute or chronic rejection, bronchiolitis obliterans syndrome (BOS), infection, diabetes, hypertension, kidney failure, posttransplant lymphoproliferative disease, osteoporosis.
Infection: major cause of morbidity and mortality during the first 6 months after transplant.
Prevention: prophylactic antimicrobial against bacterial, fungal, and viral causes. Cytomegalovirus (CMV) is the most commonly encountered serious viral infection.
CMV pneumonitis is linked to the development of BO.
CMV prophylaxis is used at all transplant centers.
Fungal infections: Candida albicans and Aspergillus are most common.
Rejection
Acute rejection: Cellular rejection is highest in the first few weeks following transplant.
May be difficult to distinguish between rejection and infection.
Transbronchial biopsy with BAL surveillance performed on a regular basis based on institutional protocol.
Acute rejection graded from A0 (none) to A4 (severe) Grades A2 and higher are treated with high-dose pulse steroids.
Refractory acute rejection may be treated with augmentation of immunosuppression with monoclonal or polyclonal T-cell antibodies.
Chronic rejection/BO.
Leading cause of morbidity and late mortality 1 year after lung transplant.
Approximately half of all lung transplant patients are diagnosed with BO by 5 years after transplant.
BOS is the clinical correlate of BO.
Symptoms of BOS: unexplained drop in FEV1 or the forced expiratory flow (FEF) 25% to 75% on pulmonary function tests (PFTs) which does not respond to bronchodilators, plus dyspnea, wheezing.
Treatment: no consistently effective treatment; often consists of augmentation of immunosuppression,
photopheresis, total lymphoid irradiation, azithromycin for anti-inflammatory effect or retransplantation.
Life expectancy: 1-year survival is close to 85%; median 4.3 years with better outcomes when children are 1 to 10 years of age.
Obstructive Sleep Apnea
Andrea M. Kline-Tilford
Background/Definition
Intermittent upper airway obstruction during sleep.
Affects 2% to 3% of school-aged children.
Peak prevalence 2 to 8 years of age.
Children with obesity, craniofacial abnormalities, cerebral palsy, and neuromuscular disease are at increased risk for OSA.
Etiology/Types
Most commonly due to hypertrophy of adenoids and tonsils in relation to airway diameter.
Also may be due to nasal obstruction, fat deposition in the pharynx, cranial facial abnormalities, or abnormal neuromotor tone.
Pathophysiology
Obstruction arises from an anatomically narrow upper airway and/or abnormal upper airway neuromotor tone, partially or completely occluding the airway.
Ineffective gas exchange occurs, resulting in hypoxia or hypercarbia.
Events are terminated through arousal from stimulation of the central nervous system and respiration is resumed.
Results in fragmented sleep.
Clinical Presentation
Varies with age, but typical age is toddler/preschool.
Loud snoring, gasping, and labored breathing during sleep.
May also have agitated/mobile sleep.
Signs of hyperactivity and inattentiveness during wakefulness.
School-age.
Agitated sleep, difficult morning arousal, daytime sleepiness, and learning problems.
Diagnostic Evaluation
Polysomnogram.
Quantifies the number and duration of airway obstructions during sleep.
Determines presence of hypoxia and/or hypoventilation during sleep.
Identifies sleep fragmentation.
Additional diagnostic tests to be considered:
ABG.
EKG.
Echocardiography.
Lateral neck radiography.
Management
Referral to otolaryngology for consideration of adenoidectomy/tonsillectomy.
Monitor postoperatively for hypoxia, persistent oxygen requirement, and postobstructive pulmonary edema.
Counsel family to monitor for return of symptoms.
Consider noninvasive ventilation: CPAP or BiPAP.
PEARLS
Not all snoring results in OSA
History and physical examination alone are not reliable in distinguishing primary snoring from OSA
OSA should be considered in children evaluated for attention-deficit disorder
Long-term, untreated OSA has been associated with neurocognitive impairment, behavior problems, and cor pulmonale
Pneumonia
Viswanath Gajula
Background/Definition
Pneumonia is an infection and inflammation of lower respiratory tract.
Typically associated with fever, cough, adventitious breath sounds, and alveolar-interstitial changes on chest radiograph.
Etiology
Community-acquired pneumonia.
Most common organisms by age group.
Neonate: group B streptococcus, Escherichia coli, Staphylococcus aureus, herpes simplex virus, Ureaplasma urealyticum.
Infants up to 1 year of age: RSV is most common cause.
1 to 3 months of age: Streptococcus pneumoniae, Chlamydia trachomatis, Bordetella pertussis, RSV, influenza and parainfluenza virus.
3 months to 5 years of age: viral, Mycoplasma, C. trachomatis, Strep. pneumoniae.
>5 years of age: Strep. pneumoniae, Mycoplasma pneumoniae, C. trachomatis.
Aspiration pneumonia.
Most commonly associated with oral anaerobes.
Health-care-associated or hospital-acquired pneumonia.
Most commonly associated with gram-negative bacilli, Staph. aureus.
Opportunistic infections in immunocompromised host.
Most commonly associated with Staph. aureus, gram-negative bacilli, Legionella pneumophila, Aspergillus, Pneumocystis jirovecii, CMV, herpes simplex virus.
Radiographic Patterns of Pneumonia
Pathophysiology
Inflammatory response to infection includes neutrophil and/or lymphocyte localization, complement activation, and production of toxic free radical species.
Leads to vasodilation and capillary leak with interstitial edema, epithelial and interstitial damage, with airway obstruction and alveolar filling.
Clinical Signs
Tachypnea, fever, cough, respiratory distress, grunting in younger children, retractions, and hypoxemia.
Focal diminished breath sounds, rales (crackles), and tactile fremitus.
Diagnostic Evaluation
Clinical diagnosis in most cases.
Clinical presentation often precedes radiographic findings.
Complications
Parapneumonic effusion, empyema, pulmonary abscess, necrotizing pneumonia.
Pneumatocele and hyponatremia are possible.
Management
Antibiotics based on suspected organism and age; tailored to pathogen if specimen obtained.
Oxygen and other respiratory support maneuvers, as needed.
Monitor for complications and treatment failures.
Pertussis
Viswanath Gajula
Background/Definition
Commonly known as whooping cough.
Caused by B. pertussis, which is a nonmotile, aerobic gram-negative coccobacillus.
Transmitted by aerosol droplets.
Pathophysiology
Initial exposure, organism-specific adhesion proteins allow adherence to the mucosa of the upper respiratory tract.
Organisms multiply and progress down the lower respiratory tract to induce cascade of inflammatory processes.
Mucopurulent exudate leads to airway obstruction, loss of surfactant, pneumonia, and small airway disease.
Presentation
Commonly in children <5 years of age.
May be severe in infancy, especially <6 months of age.
Presentation occurs in three main stages.
Initial symptoms (catarrhal stage: 1-2 weeks) can include rhinorrhea and cough. Fever may be mild or absent. Progression to paroxysms of cough.
Paroxysmal phase (1-2 weeks): often associated with a “whoop” upon inspiration, followed by a convalescent stage with persistent cough.
Disease in infants is often atypical and characterized by shortened or absent catarrhal stage. Gagging, gasping, and/or apnea occur often around feedings and may be life-threatening.
Severe pneumonia and hypoxemic respiratory failure may also occur.
Classic duration of cough is 6 to 10 weeks, but may be longer in older children and adults.
Diagnostic Evaluation
Direct fluorescent antibody testing, polymerase chain reaction testing, bacterial culture (confirmatory).
CBC: lymphocyte-predominant leukocytosis (WBC counts may be elevated to 50-80,000/cm3).
Chest radiography: Radiographic findings may be absent, or may be suggestive of small airway disease.
Management
Antibiotics: Macrolides including azithromycin and erythromycin are the treatment for pertussis. In young infants, azithromycin is recommended as first-line therapy.
Antibiotic treatment after catarrhal stage does not significantly reduce longevity or severity of disease, except possibly in cases of pneumonia.
Treatment is most important for preventing spread of disease.
Supportive Care
Hospitalization of infants with evidence of pneumonia or who are at risk for apnea.
Monitor and maintain adequate hydration.
Mechanical ventilation may be necessary in infants with significant apnea or with alveolar disease.
PEARLS
American Academy of Pediatrics recommends antimicrobial prophylaxis for all exposed close contacts regardless of their immunization status
Suspect pertussis in infants <4 months of age if paroxysmal cough is present
Pleural and Parapneumonic Effusions
Viswanath Gajula
Background
Inflammation of pleura secondary to adjacent pneumonia is common and often associated with pleural effusion.
In early stages, effusion may be transudative, but becomes exudative due to leakage of protein and inflammatory cells.
Empyema is accumulation of pus in the pleural space due to overgrowth of bacteria.
Etiology
Transudative and exudative pleural effusions.
Transudative: Serous, acellular fluid collection due to increased hydrostatic pressure across the vascular membrane.
Often associated with congestive heart failure, pericarditis, hypoalbuminemia, nephrotic syndrome, peritoneal dialysis.
Exudative: Due to leakage of protein and inflammatory cells, secondary to inflammatory cascade.
Often associated with infectious process, chylothorax, neoplasm, connective tissue disease, immunodeficiency.
Pathophysiology of parapneumonic effusion—three stages:
Exudative stage: fibrinous, uncomplicated fluid; common in the first 24 to 72 hours of effusion.
Fibrinopurulent stage: loculated, thick, cellular-rich fibrinous exudates; complicates to bronchopleural fistula or pyopneumothorax if left untreated; usually occurs in 5 to 10 days, may occur sooner.
Organizational stage: “parietal peel” formation due to fibroblast overgrowth on the parietal and visceral pleura. May compromise lung function, causes restrictive lung disease; occurs 1 to 4 weeks after the initial presentation.
Clinical Presentation
Similar to pneumonia or can occur as a complication of pneumonia.
Pleuritic pain exacerbated by deep breaths and coughing; worsening respiratory distress, persistent fevers, expiratory friction rub, diminished or “distant” breath sounds, and dullness to percussion are suggestive of effusion.
Diagnostic Evaluation
Chest radiography, anterior-posterior.
Blunted costophrenic angle (see Figure 3.9).
Chest radiography decubitus (affected side positioned down).
Evaluates mobility of fluid and layering of fluid.
Ultrasound or CT of chest.
Pleural fluid sampling for cellular and microbiological analysis.
Management (Based on Presentation, Severity, and Indications)
Simple effusions.
Medically managed (e.g., antibiotics) under close observation.
See section on pneumonia for typical pathogens.
Complicated effusions and empyema.
Procedural or surgical intervention; thoracentesis and thoracostomy tube placement.
Antibiotic administration.
FIGURE 3.9 • Pleural Effusion Chest Radiograph. Pneumonia with large pleural effusion. This child presented with bacterial pneumonia and respiratory distress, presumed to be caused in part by the large pleural effusion. In the emergency department, a pleural catheter (“pigtail”) was placed for drainage.
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