Aquifer - Pulmonary Flashcards
26
DDx - wheezing (infants and toddlers)
Most common: viral bronchiolitis, asthma, foreign body aspiration, gastroesophageal reflux
Less common: tracheomalacia, extrinsic compression (adenopathy, mass, vascular ring/sling, other anatomic lesion), CF
Important history questions to ask when investigating wheezing in infants and toddlers?
- Timing of wheeze
- Association with feeding
- Change with position or activity
- Other exacerbating factors
- History of wheezing in the past + response to treatment (bronchodilator or steroids)
True or false - for a first episode of wheezing, diagnoses other than asthma need to be higher on the differential.
True
What are two observations to consider when initially looking for signs of respiratory distress?
Can the patient speak in full sentences? Do they appear short of breath while talking?
List 6 signs of respiratory distress.
- Paradoxical breathing
- Tachypnea
- Retractions
- Nasal flaring
- Grunting
- Head bobbing
What is paradoxical breathing?
Occurs when the force of contraction generated by the diaphragm exceeds the ability of the chest wall muscles to expand the rib cage. As a result, the chest is drawn inward with inspiration, and the abdomen rises due to downward displacement of abdominal contents.
(Seen more in younger children/infants due to greater compliance of the chest wall)
Almost always a sign of very severe respiratory distress due to respiratory muscle fatigue
What is the difference between hyperpnea and hypopnea?
Hyperpnea - increased depth and rate of breathing (without respiratory distress, may suggest a non-pulmonary condition such as fever, acidosis, or extreme anxiety - hyperventilation syndrome)
Hypopnea - reduced tidal volume (increases the proportion of each breath used to ventilate dead space, so may result in hypoventilation even in the setting of a normal or elevated RR)
What are retractions and what causes them?
Abnormal use of accessory muscles to augment breathing during respiratory distress
Reflect increased WOB due to decreased lung compliance (primary pathology or edema)
Suprasternal and intercostal retractions occur due to excessive negative pleural pressure
Subcostal retractions occur when the diaphragm is flattened during inward pulling on the chest wall
May be seen in severe obstructive airway disease, including asthma, bronchiolitis, and foreign body obstruction
What does nasal flaring indicate?
Accessory muscles are being used for respiration
What does grunting indicate?
Seen in infants
Audible sound of air being expelled through a partially closed glottis, is thought to help infants generate the positive pressure necessary to stent airways open, increase lung volumes, and improve gas exchange
What causes head bobbing?
Seen in young infants
Due to the use of accessory muscles (neck strap muscles) - in synchrony with each inspiration, the head is noted to bob forward due to neck flexion caused by the use of neck strap mucsles (best observed in sleep)
What may reduce signs of respiratory distress even though a patient’s condition is deteriorating?
Respiratory muscle fatigue (check a blood gas in this situation for possible elevated PCO2 indicative of hypoventilation)
If a patient is hypoxemia, what should be done?
Oxygen therapy as soon as indicated; can be administered via a variety of methods including blow-by, nasal cannula, facemask, or endotracheal tube (most serious)
True or false - oxygen should be withheld in cases of severe hypoxemia in patients with chronic hypercarbia.
False - although some patients with chronic hyeprcarbia depend on their hypoxemia for their respiratory drive, oxygen should never be withheld in cases of severe hypoxemia. These patients should be monitored closely and given only as much oxygen as they need to maintain reasonable saturation.
What are the most common infectious causes of respiratory diseases in children?
Viruses
Discuss the triphasic course of pertussis.
- Catarrhal (1-2 weeks) - URI symptoms
- Paroxysmal (4-6 weeks) - repetitive, forceful coughing episodes followed by massive inspiratory effort, resulting in the characteristic “whoop.” Of note, infants do not usually develop a whoop due to relative weakness of their inspiratory effort
- Convalescent - paroxysms of cough gradually decrease in frequency and severity; episodic cough may persist for months
Complications of pertussis?
Infants > older children
Difficulty feeding (due to cough), CNS complications (e.g., apnea)
Discuss immunization against pertussis.
Acellular pertussis vaccine recommended for all children; even with full immunization, it is only 70-90% effective. Protection also wanes with time such that many adolescents are unprotected unless reimmunized.
What is the most common cause of epiglottitis historically? Now?
H. influenza type b (Hib); staph and strep
What ages is epiglottitis most likely to present?
2-5 years
Presentation of epiglottitis?
Fever, stridor, drooling, dysphonia, dysphagia, respiratory distress
Toxic-appearing, sniffing position
When suspected on clinical grounds, what should be done for epiglottitis?
Prompt intervention in a controlled environment to secure the airway - most often done in the OR - while waiting, do not disturb or examine the child due to risk of acute deterioration
How does epiglottitis appear on XR?
Thumb sign (thickening of the epiglottis and the aryepiglottic folds)
When should diphtheria be considered?
Child with pharyngitis and a low-grade fever, particularly if stridor or hoarseness is present + characteristic gray pseudomembrane seen in the pharynx
What is asthma?
Chronic disorder of the airways that involves a complex interaction of airflow obstruction, bronchial hyperresponsiveness, and underlying inflammation
What is the most common chronic disease in children in developed countries?
Asthma
List 3 risk factors for asthma.
- Gender (M>F)
- Race/ethnicity (non-Hispanic black children)
- Lower SES
Discuss the pathophysiology of asthma.
Infiltration of inflammatory cells into the airway mucosa, mucus hypersecretion, and mucosal edema , accomopanied by bronchoconstriction
How is asthma diagnosed?
Diagnosis requires:
- Symptoms of recurrent airway obstruction by H&P
- Demonstration that airway obstruction is at least partially reversible (Children >5 should do spirometry; younger children should do a trial of bronchodilator treatment)
- Exclusion of other causes of obstruction
CXR can help exclude other causes of wheezing, but would not be essential in establishing a diagnosis
Presentation of asthma? Acute and chronic
Acute - cough, wheezing, tachypnea, dyspnea, wheezing (typically diffuse, but can be focal in the setting of mucus plugging)/diminished air exchange on chest exam
More severe exacerbation - minimal air exchange, absence of wheezing due to poor airflow, cyanosis, and pulsus paradoxus
Chronic - recurrent episodes of dyspnea and/or cough
Discuss the asthma classification system.
During initial presentation, emphasis is on assessment of severity as a guide to starting therapy. Once treatment is initiated, emphasis is on assessment of control as a guide to maintaining or adjusting therapy.
What elements are used to assess severity and control of asthma?
Frequency of daytime symptoms Frequency of nighttime awakenings related to asthma Interference with activity Pulmonary function Use of SABAs
What is the difference between intermittent and persistent asthma?
Intermittent - daytime symptoms for 2 or fewer days/week, nighttime awakening less than 2x/month, no interference with activity (Rx with SABA prn)
Persistent: more frequent symptoms, more interference witha activity (Rx with daily controller + SABA prn)
Radiographic findings of asthma?
Hyperinflation due to air trapping, increased interstitial markings, patchy atelectasis
What are the primary goals of therapy in treating asthma?
Reduce airway inflammation
Dilate the airways
How is an acute asthma exacerbation treated?
Anti-inflammatory therapy (corticosteroids) + bronchodilation with SABAs + supportive care for hypoxemia or dehydration
Most commonly prescribed inhaled steroids?
Beclomethasone, fluticasone, and budesonide
When do inhaled steroids become beneficial?
After several weeks of daily use
Which population of children with asthma may require daily use of anti-inflammatory medications for a limited period of time?
Children with only seasonal symptomatlogy; may start several weeks before the expected exposure
Children receiving long-term inhaled corticosteroid therapy should be routinely monitored for what?
Elevation in BP, serum blood sugar, growth delay, and cataract development
What does spirometry measure?
Active lung volume (i.e., air volumes that a patient actively blows into the spirometer while the rate of air flow is measured)
Describe the process of obtaining a volume-time spirogram.
- Tidal breaths to determine tidal volume
- Slow and forced vital capacity breath performed to determine the maximum amount of air that can be inspired (TLC) and released
- Forced exhalation (rate of airflow) - FEV1
Measurements are obtained before and after bronchodilator use
Spirometry findings in obstructive lung disease?
Reduction in airflow and trapping of air inside the thorax behind tight, plugged airways lowers the FEV1 more than the FVC, leading to a low FEV1/FVC ratio
Spirometry findings in restrictive lung disease?
Low FEV1 + proportionately reduced FCV - normal FEV1/FVc ratio
What is the most common cause of wheezing in infants?
Acute bronchiolitis (viral disease of the lower respiratory tract)
Pathophysiology of bronchiolitis? Most common cause?
Bronchiolar obstruction due to edema, mucus, and cellular debris
RSV is the most common cause, but other viruses such as influenza and parainfluenza may cause bronchiolitis as well
Signs and symptoms of bronchiolitis?
Wide spectrum - most children have mild URI symptoms and often a fever of 38.5-39 C. Symptoms can progress to cough, wheezing, and dyspnea
(typically <2 years old, peak 2-8 months, more severe in babies 1-3)
(Winter)
(Risk factors - heart disease, BPD, prematurity, smoking in home)
CXR findings in bronchiolitis?
Hyperinflation, increased interstitial markings, peribronchial cuffing, and scattered atelectasis from bronchial obstruction
Treatment of bronchiolitis?
Supportive aimed at maintaining adequate oxygenation and hydration
Use of additional therapies such as corticosteroids, bronchodilators, and hypertonic saline is controversial. Antibiotics may be indicated if there is evidence of secondary bacterial infection.
Pathophysiology of pneumonia?
Inflammation of the lung parenchyma, generally due to microorganisms, although non-infectious causes include aspiration of gastric contents or hydrcarbons
Most common cause of pneumonia in children? Other causes?
Respiratory viruses (adenovirus, RSV, parainfluenza, influenza)
Bacterial infections - less common but more severe
Discuss the most common causes of pneumonia in neonates, infants-toddlers, and school-aged/older children.
Neonates: GBS, E. Coli, Klebsiella (from maternal genital tract), chlamydia pneumonia is also possible
Infants-toddlers up to 5-6 years: S. pneumonia
School-aged and older children: Mycoplasma pneumonia, S. pneumonia
Unique presenting feature of Chlamydia pneumonia?
Staccato cough presenting between 4-12 weeks
Signs and symptoms of viral pneumonia?
Prodrome of URI symptoms including cough and rhinorrhea; cough progresses and is accompanied by fever, tachypnea, and crackles on exam
CXR findings in viral vs. bacterial pneumonia?
Viral - variable, may show diffuse or patchy interstitial infiltrates, hyperinflation, and small pleural effusions
Bacterial - airspace disease with lobar or segmental consolidation and air bronchograms
Lab findings in viral vs. bacterial pneumonia?
Viral - normal or slightly elevated peripheral WBC count; viral antigen testing of respiratory secretions may be helpful but is not usually necessary
Bacterial - elevated peripheral WBC counts with a neutrophilic predominance
Treatment of viral vs. bacterial pneumonia?
Viral - supportive, majority of children recover without sequelae
Bacterial - appropriate antibiotics and supportive care
What is croup (laryngotracheobronchitis)?
Viral disease of the UR tract (and lower respiratory tract leading to erythema and edema of the tracheal walls and narrowing of the subglottic region); common cause of cough and stridor in children with a peak age of incidence of 2 years
(Winter months)
Most common and other causes of croup + pathophysiology?
Most common - parainfluenza
Other viruses - rhinovirus, RSV, influenza, adenovirus
Inflammation and edema of the pharynx and upper airways, with maximal airway narrowing occurring in the subglottic region
Presentation of croup?
Cold-like symptoms (congestion, coryza, sore throat, cough, fever); may progress to inspiratory stridor and a seal-like or barky cough
Croup - CXR?
Steeple sign (narrowing in the subglottic region)
Treatment of croup?
Generally supportive; breathing humidifed air or mist therapy can improve laryngospasm. Racemic epinephrine can be used for acute improvement, and oral or IM dexamethasone can reduce the severity of symptoms
List the 9 major findings on lung exam.
- Stridor
- Wheezing
- Rhonchi
- Crackles
- Air entry
- Bronchial breath sounds
- Tracheal deviations
- Retractions
- Egophany
What is stridor, what causes it, and when is it seen?
High-pitched inspiratory noise (can be biphasic)
Due to airway narrowing/partial obstruction of the extrathoracic airways such as the larynx or trachea (above the thoracic inlet)
DDx - croup (most often), inhaled foreign body with partial obstruction, laryngomalacia
What is wheezing, what causes it, and when is it seen?
Expiratory only - mild obstruction
May be biphasic or disappear completely with increasing obstruction
Typically diffuse, but may be focal with mucus plugging
Polyphonic (multiple pitches) - asthma
Monophonic (single pitch) - focal airway obstruction
Due to airway narrowing below the thoracic inlet
DDx - intraluminal obstruction (edema, mucus, foreign object) or external compression (lymphadenopathy, neoplasm)
What are rhonchi and what causes them?
Coarse, continuous, polyphonic, low-pitched rattling sounds - heard best in expiration, may be biphasic
Due to secretions/mucus and narrowing of the airways
What are crackles and what causes them?
Finer, discontinuous breath sounds typically heard on inspiration
Associated with fluid in the alveoli or small airway conditions such as pneumonia, pulmonary edema, and bronchitis, or with opening and closing of stiff alveoli as in interstitial disease
Coarse - purulent secretions (pneumonia)
Fine - pulmonary edema or interstitial lung idsease
When is decreased air entry seen?
Consolidation, atelectasis, pneumothorax, pleural effusion, airway obstruction
What are bronchial breath sounds and what causes them?
Lower pitched, more hollow-sounding
Caused by air moving through areas of consolidated lung
What can cause tracheal deviation?
Mediastinal mass, pneumothorax, or foreign body aspiration
What happens to the I:E ratio in obstructive disorders?
Ratio of time for full inspiration to full expiration is normally 1:1 or 1:2; expiration is prolonged in obstructive disorders, leading to a decrease in the ratio
What can cause hyperresonance and dullness to percussion?
Hyper - localized air trapping behind a mucus plug, foreign body, or mass
Dullness - lobar consolidation form pneumonia or atelectasis
What is egophany and what causes it?
Patient says “ee,” examiner hears “ay” through the stethoscope; suggests lobar consolidation (airless lung)
How is concern for foreign body aspiration worked up?
- PA/lateral chest films in the setting of asymmetric breath sounds - CXR helps account (or not account) for asymmetry
- Bilateral decubitus or inspiratory/expiratory films - helps evaluate for a larger airway obstruction
- Chest fluoroscopy - dynamic evaluation that visualizes the airways over several breaths
- Bronchoscopy - not the initial test - used to visualize the ariways
In an aspiration obstructing the right airway, what is seen on PA film (sitting position) and right and left decubitus?
PA - right hemidiaphragm flattening (unilateral hyperexpansion on the right
R - mediastinal structures remain in the midline rather than shifting toward the right lung due to gravity (fixed hyperinflation)
L - mediastinal structures shift toward L lung as expected
Most common aspirated foods?
Hot dogs, hard candy, nuts, grapes, popcorn
Pathophysiology of cough?
Protective action
Can be initiated both voluntarily and via stimulation of cough receptors located throughout the respiratory tract (ear, upper/lower airways, pleura, pericardium, and diaphragm)
Receptors signal the cough center in the medulla -> vagus, phrenic, and spinal motor nerves to produce cough
Acute vs. chronic cough?
Acute - <4 weeks
Chronic >4 weeks
Typical causes of acute cough?
Most commonly due to infectious cause (viral URI vs. viral or bacterial pneumonia) or a clear precipitating event like trauma or choking
Typical causes of chronic cough?
Infection, inflammation, irritation, anatomic, psychogenic; rarely due to cardiac or GI causes
Usually benign resulting from a viral URI, which can induce airway reactivity in a healthy host of weeks
Infants are more likely to have anatomic malformations (congenital vocal cord dysfunction, laryngotracheomalacia, vascular ring, laryngeal web, tracheal stenosis, or TE fistula)
Toddlers - consider foreign body aspiration
Differentiating causes of dry vs. wet cough?
Dry - environmental irritant, asthma
Wet/productive - lower respiratory tract infection, post-nasal drip, GER, bronchictatic disease like CF
Differentiating causes of barking vs. brassy/honking cough?
Barking - croup, subglottic disease, foreign body
Brassy/honking - habitual cough, tracheitis
Differentiating causes of paroxysmal vs. worse at night vs. disappears at night cough?
Paroxysmal - pertussis, chlamydia, mycoplasma, foreign body
Worse at night - asthma, sinusitis, allergic or vasomotor rhinitis (postnasal drip)
Disappears at night - habitual cough
Cough associated with gagging or choking?
GER
Clues for a school-aged child with cough - change in voice (dysphonia or hoarseness)
Laryngeal irritation due to chronic rhinitis or GER
Clues for a school-aged child with cough - chest pain
Probe for evidence of GI causes, not cardiac conditions. True cardiac chest pain is rare in children
While rare, CHF (most commonly due to infectious myocarditis) can present in school-aged children with cough and wheezing and can be mistaken for a common pulmonary condition
Clues for a school-aged child with cough - fever?
Suggests infectious etiology, primarily pneumonia and sinusitis
Lobar pneumonia may also present with abdominal pain, mimicking appendicitis
Clues for a school-aged child with cough - headaches?
Frontal or orbital headaches may suggest sinusitis (common cause of persistent cough in children due to the associated post-nasal drip, which is often worse at night when supine)
Clues for a school-aged child with cough - sore throat?
Post-nasal drip and pharyngeal irritation due to allergies or sinusitis
What are some environmental effects of coughing in children?
Exposure to secondhand smoke, wood smoke, air pollution, and a dry dusty environment (typically present with chronic cough WITHOUT wheeze)
DDx - cough?
Many conditions
Viral URI pneumonia Post-nasal drip due to allergies and/or sinusitis Foreign body aspiration GER
What is used to diagnose CF?
Sweat chloride test
Sensitivity and specificity of sweat chloride test? Causes of false negatives and false positives?
Sensitivity - 99%
Specificity - 90%
False negative - specific rare CF mutation
False positive - metabolic disorders including adrenal insufficiency and hypothyroidism
What does the neonatal screening detect to diagnose CF?
Immunoreactive trypsinogen in blood
Most common mutation of the CFTR gene associated with CF?
Delta-F508
Inheritance pattern of CF?
AR
Components of CF treatment?
Nutritional management, with enzymes, vitamins, and extra calories
Airway clearance
Treatment of airway infections
Signs of CF?
Pancreatic insufficiency (steatorrhea and malabsorption Chronic cough Chronic sinusitis Poor weight gain Abnormal stools
Presentation can be variable
The age at diagnosis of CF has a major impact on ___ of the child.
Nutritional status
DDx - Tachypnea in a newborn
- Respiratory distress syndrome (RDS)
- Transient tachypnea of the newborn (TTN)
- Pneumothorax
- Meconium aspiration
- Hypoglycemia
- Hypothermia
- Cardiac abnormalities
- Neonatal sepsis
- Congenital diaphragmatic hernia
Most common cause of respiratory distress in premature infants?
Respiratory distress syndrome
Cause of respiratory distress syndrome?
Deficiency of lung surfactant and delayed lung maturation
specifically increased risk in infants of diabetic mothers due to a delay of sufficient surfactant production
Cause of transient tachypnea of the newborn (TTN)?
Delayed clearance of fluid from the lungs following birth; more common in infants born to diabetic mothers and those born by C-section
Cause of pneumothorax and common risk factors?
Collection of gas in the pleural space with resultant collapse of lung tissue
Mechanical ventilation or underlying lung disease (especially meconium aspiration or severe RDS in a premature infant)
Common congenital heart defects can cause tachypnea - which ones and why?
VSD, PDA, AVC, due to pulmonary overcirculation
Presentation of tachypnea due to cardiac abnormalities in infants?
Typically not present in the newborn period
Develops as the pulmonary resistance falls, typically by 6-8 weeks of age
Coarctation of the aorta can lead to tachypnea - why and when does this occur?
Pulmonary venous congestion from left heart obstruction
Around 3-7 days of age as the PDA closes
What happens in congenital diaphragmatic hernia?
Malformation resulting from a defect in the development of the diaphragm, allows the passage of organs from the abdomen into the chest cavity and severely impairs lung development
Most congenital diaphragmatic hernias occur on which side? Most common type?
Left side; Bochdalek hernia (located posterolaterally)
Compare CXR findings in RDS vs. TTN vs. neonatal pneumonia.
RDS: diffuse reticulogranular appearance of the lung fields (ground glass appearance) and air bronchograms
TTN: wet-looking lungs, no consolidation, no air bronchograms
Neonatal pneumonia: similar to TTN or RDS, but clinical findings more concerning for sepsis
CXR findings of a diaphragmatic hernia?
Air-filled loops of bowel in the chest most often on the left side displacing the heart and mediastinum contralaterally
What is persistent pulmonary hypertension of the newborn?
Abnormal transition to extrauterine life resulting from elevated pulmonary vascular resistance to the point that venous blood is diverted to various degree through fetal channels into the systemic circulation and bypasses the lungs, resulting in systemic arterial hypoxemia.
What can cause PPHN?
Several conditions including meconium aspiration syndrome, diaphragmatic hernia, hypoplastic lungs, and in utero asphyxia.
How should infants in respiratory distress be fed?
No evidence from controlled studies that feeding a tachypneic infant by mouth is contraindicated
Many infants with RR of 60-80 tolerate oral feeds, but some may need NG feeding or IV fluids if respiratory distress worsens with feeding
