Peds respiratory disorders

Question 1

Neonatal Respiratory Distress Syndrome (RSD)

general

Answer 1

Also known as hyaline membrane disease
Condition caused by structural and functional immaturity of the lungs
Undeveloped parenchyma
Inadequate production of pulmonary surfactant (Type II pneumocytes)
Most common cause of respiratory distress in preterm infants
Frequent cause of morbidity and mortality in neonates

Question 2

Neonatal Respiratory Distress Syndrome (RSD)

Epidemiology

Answer 2

Risk is inversely related togestational ageat delivery
Highestincidencein babies born < 28 weeks of gestation
Higherincidencein white male infants

Question 3

RSD

etiology(3)

prematurity and surfactant

Answer 3

Conditions that cause fetalacidosis (may ↓surfactantsynthesisand/or activity)
Genetic mutations affecting production of surfactant proteins

Prematurity
Lack of mature type II alveolar cells → insufficientsurfactantproduction
Different lipid and protein composition ofsurfactantin an immature lung → less activesurfactant

Surfactantinactivation
Meconiumor blood inalveoli(more common in term infants)
Oxidative and mechanical stress such as from mechanicalventilation

Question 4

RSD

maternal and C section

Answer 4

Maternal diabetes
Maternal hyperglycemia→ fetalhyperinsulinemia
↑Insulinantagonizes the action ofcortisol, delaying lungsurfactantproduction

Cesarean delivery(CD) without labor
In the absence of labor,cortisolproduction (as well as other hormonal factors) is decreased
Altered fluid clearance from the fetal lung compared with vaginal delivery

Question 5

Normal Fetal Lungs
Surfactant surge

Answer 5

Fetallungs
Not functional forgas exchange, and are filled with fluid (amniotic fluid)
Theplacentaserves as the fetus’s respiratory organ

Surfactant
Lipid-dense secretion (~80% phospholipids)
Produced in fetal development to prepare for air-breathing at birth
Appears in amniotic fluid between 28-32 weeks gestation
Surge in surfactant levels after 36 weeks
Reducessurface tensionwithin thealveoli
Prevents alveolar collapse at the end of theexpiration
↓ Risk ofatelectasisand ventilatory-perfusion (V/Q) mismatch in thealveoli

Question 6

Question 7

Respiration at Birth and RDS

Answer 7

Question 8

Premature Lungs

Answer 8

Surfactant deficiency causing ↑ surface tension

↑ pressure is required for alveolar expansion

Lung instability at end-expiration
Low lung volume and ↓compliance
Collapse of portions of thelungs(atelectasis) → V/Q mismatch

Question 9

RDS

Clin man

S/Sx and on auscultation

Answer 9

Respiratory distress
Starts within minutes or hours after birth
Becomes progressively worse over the first 48–72 hours of life
Tachypnea
Nasal flaring
Retractions
Expiratorygrunting
Cyanosis(from right-to-left shunting)

On auscultation:
Breath sounds may be normal or diminished, with a harsh tubularquality
Bilateral fine basal crackles

Question 10

RDS

Cxray

Answer 10

ChestX-ray
Low lung volume
Bilateral, diffuse ground-glass appearance
Air bronchograms
Gas-filled bronchi surrounded by alveoli filled with fluid
Arterial blood gas(ABG)
Hypoxemia – improves with O2
Hypercapnia as disease progresses
Respiratoryacidosis

Question 11

RDS

Management pre delivery

Answer 11

Prevention
Most effective preventive method is to avoid preterm delivery, when possible

Determine fetal lung maturity by amniocentesis
Usually performed after 32 weeks
Assess surfactant levels
Lecithin-to-sphingomyelin (L/S) ratio
Presence or absence of phosphatidylglycerol

Question 12

RDS

management for preterm delivery and post delivery

Answer 12

If an early delivery cannot be avoided, treatment includes:

Antenatal corticosteroid therapy
Enhancessurfactantsynthesisandrelease
Accelerates lung maturity
Indicated for preterm delivery
Steroids are given 24-48 hours before delivery

Exogenoussurfactantreplacement therapy
Beneficial to preterm infants born < 30 weeks gestation
Provides support until endogenous production begins
Administration within 30–60 minutes of life provides the most benefit
Administered via endotracheal or less-invasive route (nebulization)

Question 13

RDS

resusitation

Answer 13

Resuscitation
Airway, breathing, andcirculation (ABCs)
Respiratory support especially for babies under 28 weeksgestational age
The goal is for effectiveventilationand oxygenation in the least invasive manner possible
Nasal continuous positiveairwaypressure (nCPAP)
Endotrachealintubationand assisted mechanicalventilation for respiratory failure
Extracorporeal membrane oxygenation (ECMO)
Treatment that uses a pump to circulate blood through an artificial lung back into the bloodstream

Question 14

Question 15

Kussmaul breathing

Answer 15

increased depth of ventilation, but the rate is rapid (diabetic ketoacidosis)

Question 16

Question 17

Croup

general

Answer 17

Also known as laryngotracheobronchitis
Characterized by severe inflammation of the upper airway and most commonly caused by a viral infection
Primarily affects children aged 6–36 months
Potential affected age range: 6 months to 15 years
More prevalent in the fall and early winter

Transmission:
Aerosol droplets released by sneezing and coughing or by contact with infected secretions

Question 18

Croup

Etiology

Answer 18

Etiology
Viral (75% of cases)
Most common: parainfluenza virus types 1 and 2
Second most common: respiratory syncytial virus (RSV)
Other causes: adenovirus, coronavirus, measles, influenza virus, rhinovirus, enterovirus, herpes simplex virus, metapneumovirus
Bacterial: usually present with high fever, look sicker than viral

Question 19

Croup

Patho

Answer 19

Virus/bacteria infects the nasal and pharyngeal mucosal epithelium through aerosol droplets
Infection spreads to the larynx and trachea via respiratory epithelium
Infection triggers the infiltration of white blood cells
Edema ensues inside the trachea, larynx, and large bronchi
Edema partially obstructs the airway

Question 20

Croup

S/Sx

Answer 20

Nasal discharge
Congestion
Coryza
Spasmodic, barking cough (common at night)
Inspiratory stridor – worsens with agitation
Fever
Hoarseness
Hoover’s sign (inward movement of the lower rib cage during inspiration)

Question 21

Croup

Typical course (viral croup)

Answer 21

Initial symptoms:coryza, nasal congestion
12–48 hours:fever, barking cough, hoarseness,stridor
As disease progresses, respiratory distress (noted bytachypnea,dyspneaat rest, thoracic retractions, mental status changes) can occur
Disease lasts around 3–7 days (self-limited)

Question 22

Croup

Dx

Answer 22

Clinical based on the presence of a“seal-like” barking cough and inspiratory stridor

for severe pts
Imaging
AP and lateral neck x-ray
Rule out other causes
Assess the severity of croup
AP neck x-ray usually shows a “steeple sign” which represents subglottic narrowing

Pearls & Pitfalls
Epiglottitis, retropharyngeal abscess, and bacterial tracheitis cause a more toxic appearance than croup and are not associated with a barking cough

Question 23

croup

Answer 23

Question 24

Croup

Westley Croup Score

Answer 24

Designed to measure severity of croup
Can be useful in determining treatment efficacy and patient disposition
Assesses 5 factors
Scores range: 0-17 points

Question 25

Croup

Tx

Answer 25

Antipyretics

Corticosteroids (high-dose dexamethasone)
Improvement in airway inflammation/symptoms in 6–8 hours
0.6 mg/kg IM, IV, or orally once

Racemic epinephrine given by nebulization (moderate and severe disease)
5 to 10 mg in 3 mL of saline every 2 hours
Observe 3–4 hours after initial treatment

Supplemental oxygen
Cough medicines with dextromethorphan or guaifenesin should be avoided
Antibiotics are only prescribed in cases of primary or secondary bacterial infection

Question 26

Question 27

croup

Requirements for Outpatient Management

Answer 27

Non-toxic appearance
3-4 hours since the last nebulized racemic epinephrine
Able to tolerate fluids
No stridor at rest
Normal pulse oximetry
Reliable parents with a good understanding of return precautions
Close follow-up for moderate or severe cases

Question 28

Croup

prognosis

Answer 28

Self-limiting disease that usually resolves within 3-7 days (80% of cases)
Life-threatening illness, but rarely progresses to death
Mortality occurs in <1% of intubated patients
Out-of-hospital cardiac arrest may occur

Question 29

croup

complications

Answer 29

Complications (uncommon)
Pneumonia
Secondary bacterial tracheitis (high fever, toxic appearance, mucopurulent exudates in the trachea)
Respiratory failure
Pneumothorax
Recurrent symptoms (5% of cases)

Question 30

Acute bronchiolitis

general

Answer 30

Acute inflammation of the small airways (bronchioles) most often secondary to viral infections
Common cause of hospitalization in infants in the United States
Peak incidence between 2-6 months of age
Seasonal preference:fall and winter

Question 31

Acute bronchiolitis

Etiology

Answer 31

Viral infection:
Respiratory syncytial virus (RSV) – 1/3 of cases
Rhinovirus
Less common:
Human metapneumovirus, Parainfluenza virus, Influenza virus, Adenovirus, Mycoplasma pneumoniae, Pertussis

Question 32

acute bronchilitis

RF

Answer 32

Prematurity (born < 34 weeks)
< 12 weeks of age
Low birth weight (< 2.5 kg)
Immunodeficiency
Congenital heart disease
Cystic fibrosis
Not breastfed
secondhand smoke

Question 33

acute bronchilitis

patho

Answer 33

Pathological changes occur within 24 hours of contact with a pathogen:

Virus enters epithelial cells of terminal bronchioles

Inoculation causes inflammation → edema, mucus secretion, and epithelium sloughing

Sloughing and edema → narrowing and obstruction of small airways

Narrowing results in atelectasis and symptoms appear
Alveoli can over-inflate and become trapped with air

look for kid with lots of secretion, runny nose like faucet

Question 34

acute bronciolitis

Sx

Answer 34

Symptoms vary based on the severity of the disease:
Initial 1–3 days (upper respiratory tract symptoms):
Cough
Congestion
Rhinorrhea
Peaks on day 3–5 (lower respiratory tract symptoms):
Wheezing and diffuse crackles on lung exam
Fever
Shortness of breath

Question 35

acute bronchiolitis

Sx severe cases

Answer 35

Severe cases:
Apnea in infants, especially during sleep
Tachypnea
Cyanosis
Nasal flaring
Grunting
Intercostal retraction
Hypoxia < 92% saturation

Question 36

acute bronchiolitis

Dx

Answer 36

Based onclinicalsuspicion:
Characteristic lower respiratory tract symptoms
Patients < 2 years
Presenting during the fall and winter seasons
Routine testing is discouraged → no therapeutic value

Further investigation:
Indications: high fever, severe presentation, history of comorbidities

Evaluate comorbid conditions or superimposed infection:
Complete blood count (CBC): leukocytosis
CXR: hyperinflation with atelectasis
RSV testing

Question 37

acute bronchiolitis

Tx mild/moderate cases

Answer 37

Mild-to-moderate cases
Upright positioning during sleeping and feeds
Use of cool-mist humidifier and antipyretic
Bulb suctioning of oral and nasal secretions
Maintain hydration and feeding
Follow-up if patient worsens

Question 38

acute bronchiolitis

Severe tx

Answer 38

Severe (< 28 days old, apnea, lethargic)
Hospital admission
Humidified oxygen and nebulized hypertonic saline
Suctioning of secretions
IV hydration

No evidence to support use of albuterol, epinephrine, or corticosteroids
Complications - pneumonia and respiratory failure

Question 39

RSV

general

Answer 39

RNA virus; paramyxovirus family
Transmission via droplets (coughing, sneezing, kissing, touching infected objects then touching mucus membranes)

Seasonal epidemiology
RSV seasonality was altered following the COVID-19 pandemic; it is unknown if or when RSV will return to normal seasonality

Question 40

RSV

presentation

Answer 40

Presentation:
Usually mild, cold-like symptoms
Serious illness (infants and older adults)

Highest risk among:
Premature infants
Young children with congenital heart or chronic lung disease
Young children who are immunocompromised
Adults 65 and older with compromised immune systems
Adults 65 and older with underlying heart or lung disease

Question 41

Diseases Caused by Respiratory Syncytial Virus (RSV)

Answer 41

Infants:
Acute bronchiolitis
Pneumonia
Acute otitis media
Respiratory failure
Immunocompromisedor elderly adults:
Pneumonia
Acute exacerbation of underlying chronic illness (COPD,asthma,congestive heart failure)

Question 42

RSV

Dx

Answer 42

Rapid antigen tests
Most common test
Nasal washings or nasal swabs
Results available in ~30 minutes

RSV RT-PCR
Molecular test that detects the genetic material of the virus
More sensitive than antigen testing or viral culture
Viral culture
Declining use
Costly and more difficult to perform
Several days to obtain a results

not normally done, does not change tx

Question 43

RSV

Tx
Prophylaxis

Answer 43

Self-limited
Supportive care

Passive prophylaxis- for high risk kids
Palivizumab
Indicated for high-risk infant
First dose just before the onset of RSV season
Subsequent doses given at 1-month intervals (total of 5 doses)

Question 44

whooping cough

general
What age is affected

Answer 44

Potentially life-threatening highly contagious bacterial infection of the respiratory tract caused by Bordetella pertussis (gram-negative coccobacillus)
Endemic worldwide

Incidence in the United States is affected by:
Immunity waning in previously vaccinated adolescents and adults
Anti-vaccination movement
Common and most severe in infants < 1 year of age

Transmission
Airborne droplets (coughing, sneezing, or speaking) or direct contact with oral or nasal secretions of an infected individual
Often affects 100% of non-immune household contacts

Question 45

whooping

RF

Answer 45

Individuals at risk for contracting pertussis and/or severe disease include:
Unvaccinated individuals
Infants (especially < 4 months)
Pregnant women
Patients with an immunodeficiency
Patients with an underlying respiratory condition (COPD)
Older adults (> 65 years of age)
Those caring for infants

Question 46

whooping

patho

Answer 46

Question 47

whooping

Catarrhal

Answer 47

Catarrhal – most infectious stage
Lasts 1–2 weeks
Presents with nonspecific symptoms of an upper respiratory tract infection:
Low-grade fevers
Coryza
Sneezing
Conjunctival injection

Question 48

whoopin

proxysmal

Answer 48

Paroxysmal
Lasts 2–8 weeks
Presents with the characteristic intense coughing (≥5 rapidly consecutive forceful coughs) followed by an inspiratory “whooping” sound
Frequently occurs at night
Whooping occurs ,ore frequently in older children and toddlers
Infants (< 6 months of age) may present with periods of choking orapnea(inability of the respiratory muscles to produce strong coughing)
Viscid (sticky) mucus from the nares
Post-tussive vomiting, shortness of breath (dyspnea), and cyanosis

Question 49

whooping

convalescent

Answer 49

Convalescent
Lasts 4 weeks on average, but may extend for months
Characterized by the progressive reduction of all symptoms

Question 50

whooping

Dx and prevention

Answer 50

Strong suspicion from a complete history and physical examination
Possible contact with other “whooping cough” cases
Vaccination status
Vaccine does not provide full protection; pertussis needs to be considered even in vaccinated children!

Laboratory confirmation is required
Nasopharyngeal swab → culture (gold standard) or PCR testing
Only reliable during the first 2-3 weeks of the infection
Serology testing
Can be used up to several weeks (2-8 weeks) after the onset of symptoms
A 2-fold rise in the antibody titer against pertussis is diagnostic

Question 51

whooping

Tx
Hospitalization

Answer 51

Supportive care
Suction to remove mucus from the throat
Azithro

Hospitalization with respiratory isolation:
Infants < 1
Hypoxia
Apnea
Respiratory distress
Superimposed pneumonia
Unable to hydrate orally

Oxygen administration may be required in severe cases

Question 52

whooping

Drug Tx

Answer 52

Macrolide
Catarrhal stage → ameliorate the disease
Paroxysmal stage → reduce the spread of pertussis, but do not affect the clinical course

Azithromycin 10 mg/kg PO once daily x 5 days
First-line choice for infants < 1 month of age

Erythromycin 10 mg/kg PO every 6 hours x 14 days (maximum 2 g/day)
Clarithromycin 7.5 mg/kg PO twice daily x 7 days (maximum 1 g/day)

Macrolide allergy → trimethoprim-sulfamethoxazole for patients > 2 months

Question 53

whooping

Postexposure Prophylaxis

Answer 53

Given to every household contacts within 21 days of the onset of cough in the positive patient, whether they have been vaccinated or not

Erythromycin 500 mg PO 4 times daily x 14 days
Erythromycin 10 mg/kg PO 4 times daily x 14 days
Alternative antibiotics:
Clarithromycin and Azithromycin
Azithromycinis preferred for infants < 1 month of age