Deck 67: Infections of the Lower Respiratory Tract

Question 1

One of the most common etiologic agents of lower respiratory tract infection among previously healthy patients 2 months to 5 years of age is:

A)C.pneumoniae.
B)M.pneumoniae.
C)S.pneumoniae.
D)respiratory syncytial virus.

Answer 1

D
Community-acquired pneumonia is a common and potentially serious infection that afflicts children.Among previously healthy patients 2 months to 5 years of age,respiratory syncytial virus,human metapneumovirus,parainfluenza,influenza,and adenoviruses are the most common etiologic agents of lower respiratory tract disease.

Question 2

Evaluation of the quality of the sputum specimen sent to the laboratory for bacterial culture is best performed by:

A)measuring the amount of mucus found.
B)checking for mucus or blood.
C)microscopically examining the Gram-stained smear for leukocytes.
D)microscopically examining the Gram-stained smear for squamous epithelial cells.

Answer 2

D
The respiratory secretions sent to the laboratory for bacterial culture should be microscopically examined via Gram-stained smear.One of the most important uses of the Gram stain is to evaluate the quality of expectorated sputum received for routine bacteriologic culture.An acceptable specimen yields less than 10 squamous epithelial cells per low-power field (100×).

Question 3

The nasal hairs,convoluted passages,and mucous lining of the nasal turbinates:

A)nonspecifically protect the respiratory tract from infection.
B)promote colonization of normal bacterial flora.
C)can aid adherence by potentially harmful bacteria.
D)reduce colonization of normal bacterial flora.

Answer 3

A
The human host has several mechanisms that nonspecifically protect the respiratory tract from infection: the nasal hairs,convoluted passages,and mucous lining of the nasal turbinates;secretory immunoglobulin A (IgA)and nonspecific antibacterial substances (lysozyme)in respiratory secretions;the cilia and mucous lining of the trachea;and reflexes such as coughing,sneezing,and swallowing.These mechanisms prevent foreign objects or organisms from entering the bronchi and gaining access to the lungs,which remain sterile in the healthy host.

Question 4

Adenoviruses are one of the most common etiologic agents of lower respiratory tract infection among:

A)previously healthy patients 2 months to 5 years of age.
B)adults younger than 30 years of age.
C)community-acquired pneumonia in adults.
D)school-age children.

Question 5

The most common etiologic agent of lower respiratory tract infection among adults younger than 30 years of age is:

A)Chlamydophila pneumoniae.
B)Mycoplasma pneumoniae.
C)Streptococcus pneumoniae.
D)Haemophilus influenzae.

Question 6

The most common etiologic agent of community-acquired pneumonia in adults older than 30 years of age is ___ pneumoniae.

A)Mycoplasma
B)Chlamydophila
C)Streptococcus
D)Klebsiella

Question 7

M.pneumoniae is detected as the most common agent of lower respiratory tract infection among:

A)previously healthy patients 2 months to 5 years of age.
B)adults younger than 30 years of age.
C)community-acquired pneumonia in adults.
D)school-age children.

Question 8

The most common cause of community-acquired pneumonia in adults,regardless of age,is:

A)Neisseria meningitidis.
B)S.pyogenes.
C)S.pneumoniae.
D)M.pneumoniae.

Question 9

One of the most important uses of the Gram stain of expectorated sputum received for routine bacteriologic culture is to:

A)give the physician a quick analysis of the type of organism causing the infection.
B)evaluate the quality of the specimen.
C)distinguish between the possibilities of bacterial and viral sources of infection.
D)begin appropriate antimicrobial therapy as soon as possible.

Question 10

One of the most common causes of bacterial pneumonia in school-age children (5 to 14 years of age)is:

A)H.influenzae type B.
B)Corynebacterium diphtheriae.
C)Streptococcus pyogenes.
D)M.pneumoniae.

Question 11

Of the various types of specimens collected to diagnose respiratory infections,which one is acceptable for the detection of anaerobic agents?

A)Tracheostomy aspirates
B)Bronchial washings
C)Gastric aspirates
D)Transtracheal aspirates (TTA)

Question 12

The sputum of a patient with acquired immunodeficiency syndrome (AIDS)is stained with Kinyoun's carbolfuchsin stain.Which organism would test positive using this stain?

A)Streptomyces spp.
B)Pneumocystis jiroveci
C)S.aureus
D)Cryptosporidium spp.

Question 13

Bacterial pneumonia in children is most commonly caused by:

A)M.pneumoniae.
B)Chlamydia pneumonia.
C)parainfluenza virus.
D)Staphylococcus aureus.

Question 14

Respiratory syncytial virus is one of the most common etiologic agents of lower respiratory tract infection among:

A)previously healthy patients 2 months to 5 years of age.
B)adults younger than 30 years of age.
C)community-acquired pneumonia in adults.
D)school-age children.