الثلاثاء، 5 فبراير 2013

MCQs In Pediatric Pulmonology


Q1 :

A 3-year-old boy was admitted to the hospital with respiratory distress after ingesting kerosene. Chest radiography revealed bilateral diffuse atelectasis. Although initially hypoxic, he gradually improved and never required ventilation.
Of the following, the MOST likely sequela for this patient is the long-term development of:

A.  cardiomyopathy
B.   encephalopathy
C.   esophageal stricture
D.   obstructive pulmonary disease
E.    pulmonary hemorrhage

answer

D


Because of their low viscosity and high volatility, hydrocarbons may be aspirated during ingestion and cause a secondary pneumonitis, although most children who ingest hydrocarbons do not develop respiratory difficulties. The onset of respiratory symptoms and radiographic findings may be delayed. Patients who are asymptomatic after 6 hours of observation and have negative radiographic findings are unlikely to develop symptoms. Those who do develop clinical pneumonitis may experience dyspnea and hypoxia and require oxygen treatment. Occasionally, ventilatory assistance is necessary. Rarely, there is a rapid progression to respiratory failure and death.

            Acute complications of pneumonitis include pneumothorax, subcutaneous emphysema of the chest wall, and pleural effusions. A secondary pneumonia may develop during the ensuing week. Pneumatoceles may be a late development, but they rarely require treatment. Most children survive hydrocarbon pneumonitis without complications or sequelae. They are at risk for obstructive pulmonary disease, although results of long-term pulmonary function studies have been inconclusive.

            Although ingestion of hydrocarbons may cause acute gastrointestinal irritation, esophagitis and subsequent esophageal stricture are not expected. Ingestion of corrosive household cleaning products is associated with acute esophagitis and long-term development of strictures.

            Pulmonary hemorrhage has not been described in hydrocarbon pneumonitis. Chronic inhalation abuse or “huffing” has been associated with the sequelae of cardiomyopathy and encephalopathy. An acute effect of inhalant abuse can be death due to cardiac arrhythmia.
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Q2



Your practice group has decided to create a comprehensive plan of action for your patients who have asthma. You have been assigned to create the new hospital discharge plan. The current plan includes the initiation of inhaled corticosteroids, as-needed short-acting beta agonists.

Of the following, The BEST option to add to the plan is:

A. an assessment of asthma triggers
B.  daily oral antihistamines
C.  excuse from gym class for 2 months
D.  pneumococcal vaccine for children
E.   weekly spirometry for the 2 months following discharge

Answer

A


Identifying the triggers of asthma exacerbations assists the clinician in planning discharge therapy, including future medications. For example, if an upper respiratory tract infection is found to be the trigger, the hospitalization may have been unavoidable. However, if there were no triggers and the admission was due to noncompliance with therapy, a change in management may be appropriate. If the trigger is an allergen, identification and removal of the allergen will be extremely helpful. Returning a child to an environment in which there is an allergen trigger may result in repeated hospitalizations despite appropriate medications. In contrast, elimination of a trigger, such as home remodeling, a new pet, or the addition of a feather pillow, may be the first step toward dramatic improvement in the child’s overall health.

            The use of daily oral antihistamines is an inappropriate part of a discharge plan unless the child has been identified as atopic. Excusing a child from gym is not helpful because asthmatic children need regular exercise. Only the rare child who has severe disease should be excused from activities.

 The pneumococcal vaccine is recommended for all children younger than age 2 years, but it is not normally included as part of a standard asthma plan. Although weekly spirometry would allow for charting a child’s slow improvement over time, it is of little clinical benefit.

 Peak flow meters generally are not used in children younger than 6 years of age.

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Q 3:



A 12-year-old boy who has cystic fibrosis is hospitalized for treatment of a pulmonary exacerbation. Gram stain of sputum reveals many polymorphonuclear leukocytes and gram-negative rods.
Of the following, the MOST appropriate antibiotic choice for this patient is an aminoglycoside plus:

A. azithromycin
B.  ceftriaxone
C. cefuroxime
D.  ticarcillin
E.  vancomycin

Answer :

D


Pseudomonas aeruginosa is found in the respiratory tracts of most patients who have cystic fibrosis. 

This bacterium is virtually specific for cystic fibrosis, and once acquired, generally is not eradicated from the respiratory tract.

            Antibiotics have been one of the cornerstones of treatment for the patient who has cystic fibrosis. Intravenous antipseudomonal antibiotic therapy is well tolerated and when used in pulmonary exacerbations, often results in improved lung function and reduced bacterial colonization of the airway. The most commonly used drugs include aminoglycosides, semisynthetic penicillins, and cephalosporins. Two-drug therapy is usually administered to patients who have a pulmonary exacerbation. The two agents act synergistically for enhanced bactericidal activity and may prevent the emergence of resistant organisms.

            Ticarcillin is a carboxypenicillin whose spectrum of activity includes P aeruginosa. It often is used in conjunction with an aminoglycoside for treatment of pulmonary exacerbations due to P aeruginosa.

            Second-generation cephalosporins, such as cefuroxime, have gram-positive activity, increased gram-negative activity, and beta-lactamase stability. The second-generation drugs may be active against some strains of Acinetobacter, Citrobacter, Enterobacter, Klebsiella, Neisseria, Proteus, Providencia, and Serratia sp as well as Escherichia coli, but they have no activity against Pseudomonas sp.

            Third-generation cephalosporins, such as ceftriaxone, are less active than first-generation cephalosporins against gram-positive cocci, but they are much more active against Enterobacteriaceae and beta-lactamase-producing strains of Haemophilus influenzae, Moraxella catarrhalis, and Neisseria gonorrhoeae. A subset of third-generation cephalosporins, such as ceftazidime, also has good antipseudomonal activity.

            Azithromycin is a macrolide antibiotic that is active against group A streptococci and Staphylococcus aureus as well as common pediatric pathogens such as pneumococcus, M catarrhalis, and H influenzae. Mycoplasma pneumoniae and Chlamydia pneumoniae also are susceptible. It has no activity against Pseudomonas sp.

            Vancomycin, a glycopeptide antibiotic, is selectively bactericidal against most gram-positive organisms, but it has no activity against gram-negative organisms such as Pseudomonas sp.

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Q 4


A 6-month-old previously healthy child presents in January with fever of 3 days' duration and wheezing that has increased in severity for 2 days. On physical examination, the child is awake and interactive. Respiratory rate is 60 breaths/min, and there are marked wheezes bilaterally and intercostal retractions. Because there is no improvement after two treatments with nebulized albuterol, you admit the child to the hospital. Upon re-evaluation 4 hours later, the child is agitated and has a respiratory rate of 80 breaths/min. Arterial blood gas while receiving 35% oxygen reveals pH of 7.24, Po2 of 65 mm Hg, and Pco2 of 60 mm Hg.
Of the following, the MOST appropriate next step in management is:

A.  administration of intramuscular dexamethasone
B.  administration of racemic epinephrine
C.  continuous albuterol nebulization
D.  immediate endotracheal intubation
E.   increase of inspired oxygen to 50%

Answer :

D


The agitation, significantly increased respiratory rate, and acute carbon dioxide retention described for the girl in the vignette indicate impending respiratory failure. The most appropriate management is immediate endotracheal intubation.

            Agitation is common in hypoxia; somnolence or tachycardia may be due to either carbon dioxide retention or severe hypoxemia. Bradycardia is an ominous development, usually indicating severe respiratory failure, hypoxemia, and impending cardiac arrest. Acute carbon dioxide retention (hypercapnia) often results in flushing, agitation, confusion, tachycardia, and headache.

            The child described in the vignette has symptoms of bronchiolitis. The wheezing results from necrosis and sloughing of the respiratory epithelium caused by the toxic effect of the virus on the cells. Partial airway obstruction ensues. Although bronchodilators may be of some benefit in affected children who have underlying reactive airways, they are of little to no benefit for most children.

            Steroids have no proven benefit in the management of bronchiolitis, although they may be beneficial in the respiratory distress caused by croup. Similarly, racemic epinephrine is of limited value in bronchiolitis. The initial management of hypoxemia is administration of oxygen at the highest concentration available, but increasing the inspired concentration of administered oxygen is not appropriate treatment of carbon dioxide retention.

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Q 5


You are asked to consult on a 9-month-old boy who has been hospitalized five times for
wheezing. His history reveals occasional coughing with feedings, but results of a pH probe
performed during his last admission were normal. His weight and height are at the 50th
percentile. Except for scattered wheezes with good aeration bilaterally, results of his physical
examination are normal.

Of the following, the test that is MOST likely to reveal the cause of his recurrent wheezing is

A. chest computed tomography scan
B. immunoglobulin panel
C. inspiratory and expiratory chest radiographs
D. pulmonary function testing
E. videofluoroscopic swallow study

Answer

E


Recurrent wheezing can be caused by many diseases, including reactive airway disease, cystic
fibrosis, extrinsic airway compression, and aspiration with and without gastroesophageal reflux.
The history of coughing with feedings described for the boy in the vignette should alert the
clinician to the possibility of swallowing dysfunction, with aspiration as the cause of his recurrent
symptoms. Accordingly, a videofluoroscopic swallow study is the best diagnostic procedure to
reveal the cause of his wheezing.


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