Chapter 9 - Pulm Flashcards
1
Q
Why are infants at higher risk for respiratory insufficiency than older patients?
A
- smaller caliber airways
- less compliant lungs and more compliant chest wall
- less efficient pulmonary mechanics
2
Q
What happens to pulmonary vascular resistance at birth?
A
the first breathes inflate the lungs and reduce pulmonary vascular resistance
3
Q
What is suggested by the following lung sounds:
- inspiratory stridor
- expiratory wheezing
- crackles or rales
A
- stridor: extrathoracic obstruction like croup or laryngomalacia
- wheezing: intrathoracic obstruction like asthma or bronchiolitis
- crackles or rales: parenchymal disease like pneumonia or pulmonary edema
4
Q
Laryngomalacia
A
- 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
5
Q
Epiglottitis
A
- 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.
6
Q
Croup (Laryngotracheobronchitis)
A
- 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
7
Q
Bacterial Tracheitis
A
- 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
8
Q
How can supraglottic disorders be differentiated form subglottic disorders? Give examples of these disorders.
A
- 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
9
Q
Bronchiolitis
A
- 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
10
Q
Viral Pneumonia
A
- 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
11
Q
Bacterial Pneumonia
A
- 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
12
Q
Chlamydia trachomatis Pneumonia
A
- 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
13
Q
Mycoplasma pneumoniae
A
- 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
14
Q
Pertussis
A
- 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
15
Q
Describe the pathogenesis of allergen-induced asthma.
A
- 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
16
Q
Name two important microscopic findings that can help identify asthmatics.
A
- Curschmann spirals (mucous plugs)
- Charcot-Leyden crystals (crystallized MBP)
17
Q
Asthma
A
- 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
18
Q
Cystic Fibrosis
A
- 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
19
Q
Bronchopulmonary Dysplasia
A
- 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
20
Q
Foreign Body Aspiration
A
- 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
21
Q
What is periodic breathing?
A
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
22
Q
What is an “apparent life-threatening event”?
A
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
23
Q
What are risk factors for SIDS?
A
- 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
24
Q
Vascular Rings
A
- 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
25
How do we define and treat the following types of asthma:
- intermittent
- mild persistent
- moderate persistent
- severe
- 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
26
Name two low-dose ICS and their adverse effects.
- beclomethasone and fluticasone
| - may cause thrush or vocal cord irritation
27
Name two LABAs.
- Salmeterol
| - Formoterol
28
How do we know when an asthmatic requires intubation?
if patient stops hyperventilating and PCO2 becomes normal or elevated, it is indicative of decompensation and a need for intubation
29
Congenital Cystic Adenomatoid Malformation
- 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
30
Kartagener's Syndrome
- 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
31
What is the general presentation of pneumonia?
- cough productive of yellow-green sputum
- low-grade fever
- decreased breath sounds with crackles
- increased white cell count
32
Compare and contrast the features and causes of typical and atypical community acquired pneumonia.
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
33
What are zanamivir and oseltamivir?
they are neuraminidase inhibitors which reduce release of influenza viral particles
34
What is palivizumab?
an antibody against the fusion protein of RSV, used for post-exposure prevention
35
What is ribavirin?
an inhibitor of guanine synthesis used to treat RSV
36
What etiologic agent causes pneumonia with a staccato cough?
C. trachomatis
37
What are the most common causes of typical and atypical pneumonia in children?
- 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
38
How should community acquired pneumonia be treated?
- 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
39
Hospital Acquired Pneumonia
- 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
