Chapter 9 - Pulm

Question 1

Why are infants at higher risk for respiratory insufficiency than older patients?

Answer 1

• smaller caliber airways
• less compliant lungs and more compliant chest wall
• less efficient pulmonary mechanics

Question 2

What happens to pulmonary vascular resistance at birth?

Answer 2

the first breathes inflate the lungs and reduce pulmonary vascular resistance

Question 3

What is suggested by the following lung sounds:

• inspiratory stridor
• expiratory wheezing
• crackles or rales

Answer 3

• stridor: extrathoracic obstruction like croup or laryngomalacia
• wheezing: intrathoracic obstruction like asthma or bronchiolitis
• crackles or rales: parenchymal disease like pneumonia or pulmonary edema

Question 4

Laryngomalacia

Answer 4

• a softening with weakness of the laryngeal cartilage that collapses into the airway, causing an extrathoracic obstruction
• most severe in children 4-8mo
• presents with inspiratory stridor worst in the supine position and improved when prone
• diagnose with laryngoscopy to visualize the collapse

Question 5

Epiglottitis

Answer 5

• inflammation and edema of the epiglottis or arytenoids
• usually caused by H. influenza, type b; other causes include group A strep, strep pneumo, and staph
• most common in children 2-7 years old, presenting with abrupt, rapidly progressive upper airway obstruction without prodrome
• associated symptoms include high fever, muffled speech and inspiratory stridor, dysphagia with drooling, and neck hyperextension
• the feared complication is complete airway obstruction with respiratory arrest occurring suddenly
• can typically visualize a cherry red, swollen epiglottis, labs show leukocytosis with left shift, and lateral radiograph of the neck shows a “thumbprint”
• treat with immediate intubation; offer humidified oxygen and minimize stimulation/examination because this may trigger respiratory arrest
• treat the underlying infection with 2nd or 3rd gen cephalosporin and an anti-Staph antibiotic; rifampin prophylaxis indicated for unimmunized household contacts younger than 4 y.o.

Question 6

Croup (Laryngotracheobronchitis)

Answer 6

• inflammation and edema of the subglottic larynx, trachea, and bronchi
• viral is usually caused by parainfluenza virus and is seen in children 6mo to 3yo in the winter and fall; spasmodic is secondary to hypersensitivity reaction
• viral begins with URI prodrome followed by inspiratory stridor, barky cough, and hoarse voice lasting 3-7 days; stridor worsens at night and with agitation, wheezing may occur, and AP radiograph demonstrates the “steeple sign” of subglottic narrowing
• spasmodic has an acute onset of stridor, usually at night and typically resolving without treatment
• mild disease (no stridor at rest) is treated with humidified air and corticosteroids; moderate to severe disease is treated with corticosteroids and nebulizer epinephrine, which vasoconstricts and reduces edema

Question 7

Bacterial Tracheitis

Answer 7

• an acute inflammation of the trachea
• most often caused by S. aureus, Streptococcus, or nontypeable H. influenza
• presentation resembles croup with inspiratory stridor but the treatment for croup fails
• treat with antistaphylococcal antibiotics and airway support

Question 8

How can supraglottic disorders be differentiated form subglottic disorders? Give examples of these disorders.

Answer 8

• supraglottic may include epiglottitis or a retropharyngeal abscess whereas subglottic would include bacterial tracheitis or viral croup
• supraglottic tend to have quiet stridor, no cough, muffled voice, dysphagia, high fever, and neck extension
• subglottic tend to have loud stridor, a barky cough, hoarse voice, no dysphagia, a range of fevers, and normal posture

Question 9

Bronchiolitis

Answer 9

• a viral infection, usually RSV, that causes inflammatory bronchiolar obstruction
• the most common lower resp. tract infection in the first two years of life with epidemics occurring in Nov-Apr
• onset is gradual with upper respiratory symptoms including rhinorrhea, nasal congestion, fever, and cough
• respiratory symptoms follow with tachypnea, rales, symmetric wheezing and pseudohepatosplenomegaly as hyperinflated lungs push the organs inferiorly; hypoxemia and apnea may occur
• may appear like asthma but will not reverse with B-agonist
• improvement should be noted within 2 weeks
• management is primarily supportive with careful handwashing to prevent spread; ribavirin can be considered for very ill infants and palivizumab may be given prophylactically during RSV season to those with chronic lung disease
• can admit if less than 3 months old or has saturations below 92

Question 10

Viral Pneumonia

Answer 10

• an infection and inflammation of lung parenchyma
• more commonly viral than bacterial, organisms include RSV, adenovirus, influenza A and B, and parainfluenza
• likely to present with upper respiratory complaints followed by fever, cough, and dyspnea
• diagnosis is supported by interstitial infiltrates on CXR and a white cell count less than 20K with lymphocytes predominated
• treatment is supportive

Question 11

Bacterial Pneumonia

Answer 11

• an infection and inflammation of the lung parenchyma
• less common than viral etiologies
• symptoms have a more rapid onset and greater severity, and the associated fever, cough, and dyspnea typically occur without a URI prodrome
• diagnosis is supported by lobar consolidation on CXR and a white cell count more than 20K with neutrophils predominating
• treatment is supportive with antibiotics

Question 12

Chlamydia trachomatis Pneumonia

Answer 12

• a common cause of afebrile pneumonia in those 1-3mo
• symptoms include a staccato-type cough, dyspnea, and absence of fever
• many have a history of conjunctivitis after birth and a diagnosis is supported by eosinophilia interstitial infiltrates on cxr
• treat with oral erythromycin or azithromycin

Question 13

Mycoplasma pneumoniae

Answer 13

• a common cause of pneumonia in older children and adolescents
• symptoms include a low-grade fever, chills, nonproductive cough, headache, pharyngitis, and malaise
• lung examination findings are often worse than expected based on the history
• diagnosed according to positive cold agglutinins, cxr with bilateral diffuse infiltrates, and elevated IgM serum titers for mycoplasma
• treated with erythromycin or azithromycin

Question 14

Pertussis

Answer 14

• an acute respiratory infection caused by Bordetella pertussis, which is highly contagious
• infants younger than 6mo are most at risk for severe disease whereas adolescents and adults with waning immunity are the major source
• the catarrhal stages lasts 1-2 weeks and is characterized by upper respiratory symptoms
• the paroxysmal stage lasts 2-4 weeks with fits of forceful coughing, often with an inspiratory gasp/whoop heard at the end of the fit and possible post-tussive vomiting
• the convalescent phase may last weeks to months with continued but declining paroxysmal cough
• diagnosed based on culture or DFA, supported by lymphocytosis
• treat with erythromycin for 14 days to prevent the spread but these do not alter the clinical course; isolation is need until antibiotics have been given for five days

Question 15

Describe the pathogenesis of allergen-induced asthma.

Answer 15

• an allergen induces Th2 differentiation in susceptible individuals
• these T cells secrete IL-4, mediating IgE class switching, IL-5, attracting eosinophils, and IL-10, inhibiting a Th1 response
• upon re-exposure, the allergen leads to IgE-mediated activation of mast cells
• histamine and leukotrienes mediate the early phase of bronchoconstriction, inflammation, and edema
• major basic protein damages cells and perpetuates bronchoconstriction in the late-phase

Question 16

Name two important microscopic findings that can help identify asthmatics.

Answer 16

• Curschmann spirals (mucous plugs)

- Charcot-Leyden crystals (crystallized MBP)

Question 17

Asthma

Answer 17

• chronic inflammation, variable airflow obstruction that is partially reversible, and airway hypersensitivity
• pathophysiology includes smooth muscle bronchoconstriction, airway mucosal edema, increased secretions with mucous plugging, airway remodeling, and production of inflammatory mediators
• exacerbations tend to present with tachypnea, dyspnea, nasal flaring, retractions, and wheezing with a prolonged expiratory phase
• CXR often reveals hyperinflation and PFTs show increased lung volumes with decreased expiratory flow rates (decreased FEV1 and FEV1/FVC ratio)
• can also diagnose with a greater than 20% decrease in FEV1 following methacholine challenge
• typically begin treatment with a short-acting B2 agonist; add an inhaled corticosteroid then a LABA and then an oral steroid
• cromolyn is a mast cell stabilizer that reduces the risk of attacks, anticholinergic agents are second line bronchodilators, montelukast is a leukotriene modifier, and theophyllines have declining use
• if patients enter respiratory failure/decompensate, endotracheal intubation may be necessary

Question 18

Cystic Fibrosis

Answer 18

• an autosomal recessive condition caused by a mutation of the CFTR gene on chromosome 7
• CFTR is an ATP-gated Cl- channel that secretes Cl- into the lungs and Gi tract and reabsorbs chloride ions in the sweat glands
• most common is a deletion of Phe508, which causes a misfiling of the protein, which is then retained in the RER and not transported to the cell membrane
• as a result, there is a rise in intracellular chloride ions and a compensatory increase in sodium reabsorption, which increases water reabsorption; water reabsorption causes the lung and GI tract secretions to become very thick; change in sodium causes a more negative trans epithelial potential difference
• abnormal secretions lead to a chronic productive cough, dyspnea, hyperinflation, digital clubbing, and progressive hypoxemia; eventually PFTs show decreased lung volumes
• newborn screening looks for an increase in immunoreactive trypsinogen
• diagnosed based on increase in chloride concentration on sweat test or based on fecal elastase; can also be seen as a contraction alkalosis and hypokalemia
• complications include recurrent pulmonary infections (S. aureus in early infancy, P. aeruginosa in adolescence); nasal polyps; chronic bronchitis and bronchiectasis; pancreatic insufficiency with malabsorption, steatorrhea, FTT, and fat-solute vitamin deficiencies; biliary cirrhosis and liver disease; meconium ileus in newborns; infertility in men; and sub fertility in women
• treatment involves chest physiotherapy, albuterol, aerosolized dornase alfa (a DNAse), N-acetylcysteine (a mucolytic which cleaves disulfide bonds) hypertonic saline for mucus clearance, azithromycin for prophylaxis, and pancreatic enzyme replacement

Question 19

Bronchopulmonary Dysplasia

Answer 19

• defined as oxygen dependency beyond 28 days of life resulting from acute lung injury and the resulting cycle of repair
• often, initial injury is due to barotrauma from mechanical ventilation, meconium aspiration, or infection; oxidants and proteases follow this injury, and lung tissue heals abnormally with an altered airway, parenchymal remodeling, tissue fibrosis, chronic airflow limitations, and diminished compliance
• may experience diminished oxygenation, hypercarbia, intermittent respiratory distress, frequent respiration tract infections, pulmonary hypertension, or airway hyperreactivity
• likely to also have greater caloric needs and delayed growth and development
• treat with supplemental oxygen; bronchodilators, diuretics, anti-inflammatories, and fluid restriction to optimize pulm function; optimize caloric intact; and prevent infection
• disease usually diminishes with time and growth though continued airway hyperreactivity is possible

Question 20

Foreign Body Aspiration

Answer 20

• history of choking episode is present in most cases
• laryngotracheal more dangerous than bronchial because it obstructs more airflow
• laryngotracheal foreign bodies result in cough, hoarseness, and inspiratory stridor
• bronchial foreign bodies present with asymmetric findings on auscultation, localized wheezing, persistent pneumonia, chronic cough, hemoptysis, and occasionally unilateral emphysema seen on cxr
• esophageal foreign bodies may compress the trachea and produce respiratory signs as well
• radiographs have limited utility depending on the foreign body, but consider inspiratory and expiratory films
• manage with basic life support as natural cough is the most effective mechanism; bronchoscopy may be necessary

Question 21

What is periodic breathing?

Answer 21

a breathing pattern with three or more respiratory pauses lasting at least 3 seconds each with less than 20 seconds of normal respiration in between

Question 22

What is an “apparent life-threatening event”?

Answer 22

a respiratory event characterized by some combination of apnea, color change, change in muscle tone, choking, or gagging in which recovery occurs only after stimulation or resuscitation

Question 23

What are risk factors for SIDS?

Answer 23

• peak age is 2-4mo
• prone sleeping position
• soft bedding, overbundling, and overheating
• prematurity
• being a twin of a sibling who died of SIDS
• low birth weight
• recent illness
• lack of breastfeeding
• maternal smoking, drug abuse, or infection

Question 24

Vascular Rings

Answer 24

• an upper airway obstruction caused by an abnormal aorta putting pressure on the tracheobronchial tree and esophagus
• presents as inspiratory stridor that improves with neck extension

Question 25

How do we define and treat the following types of asthma: - intermittent - mild persistent - moderate persistent - severe

Answer 25

- intermittent: less than twice a week and fewer than 2 awakenings per month; treat with albuterol PRN - mild persistent: more than twice a week; treat with low-dose ICS - moderate persistent: treat with either an ICS and LABA or medium dose ICS - severe: high-dose ICS and LABA

Question 26

Name two low-dose ICS and their adverse effects.

Answer 26

- beclomethasone and fluticasone | - may cause thrush or vocal cord irritation

Question 27

Name two LABAs.

Answer 27

- Salmeterol | - Formoterol

Question 28

How do we know when an asthmatic requires intubation?

Answer 28

if patient stops hyperventilating and PCO2 becomes normal or elevated, it is indicative of decompensation and a need for intubation

Question 29

Congenital Cystic Adenomatoid Malformation

Answer 29

- a large cystic lesion that can compress the lung, leading to pulmonary hypoplasia and a midline shift away from the lesion - realists from a disruption of embryogenesis before day 35, which causes improper development of bronchioles

Question 30

Kartagener's Syndrome

Answer 30

- a syndrome of bronchiectasis, male infertility or reduce female fertility, and recurrent sinusitis - due to a dynein arm defect, which leaves cilia immotile - associated with sinus inversus

Question 31

What is the general presentation of pneumonia?

Answer 31

- cough productive of yellow-green sputum - low-grade fever - decreased breath sounds with crackles - increased white cell count

Question 32

Compare and contrast the features and causes of typical and atypical community acquired pneumonia.

Answer 32

Typical - signs of consolidation with dullness to percussion, vocal remits, late crackles, and egophany - usually caused by GBS, E. coli, or Listeria in neonates less than 1 month old, polysaccharide-encapsulated strep pneumo is the most common cause in those older than 1 month Atypical - has a slower onset, no consolidation because it's interstitial, and milder symptoms - can't visualize the organism on gram stain or culture with standard agar - C. trachomatis is most common in 1-3 month olds and presents with a staccato cough, Mycoplasma pneumoniae is common after age five, chlamydia pneumoniae is second most common cause in young adults, RSV is the most common cause in infants, and influenza is a potential cause in those who are immunocompromised or have pre-existing lung disease

Question 33

What are zanamivir and oseltamivir?

Answer 33

they are neuraminidase inhibitors which reduce release of influenza viral particles

Question 34

What is palivizumab?

Answer 34

an antibody against the fusion protein of RSV, used for post-exposure prevention

Question 35

What is ribavirin?

Answer 35

an inhibitor of guanine synthesis used to treat RSV

Question 36

What etiologic agent causes pneumonia with a staccato cough?

Answer 36

C. trachomatis

Question 37

What are the most common causes of typical and atypical pneumonia in children?

Answer 37

- typical pneumonia in those < 1 mo: GBS, E. coli, Listeria - typical pneumonia in those > 1 mo: Strep pneumo, RSV is more common in those 4mo-5yo - atypical in infants: RSV is most common, chlamydia trachomatis is also common between 1 mo-3mo - atypical in kids > 5: mycoplasma pneumoniae most common but Chlamydia pneumoniae is second - atypical in immunocompromised and those with pre-existing lung disease: influenza

Question 38

How should community acquired pneumonia be treated?

Answer 38

- if it's uncomplicated, azithromycin or doxycycline will cover the most common typicals and atypicals - fluoroquinolones are used if there is comorbidity present - fluoroquinolone/ceftriaxone plus azithromycin is used in the hospital if hypoxic or hypotensive

Question 39

Hospital Acquired Pneumonia

Answer 39

- the most common cause is S. aureus secondary to influenza, which may form abscess or empyema - in those with cystic fibrosis it is likely to be caused by a gram-negative rod and should be treated with ceftazidime, cefepime (a pseudomonas), imipenem, or piperacillin/tazobactam