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
