Immunization of children with Haemophilus influenzae type B (Hib) vaccine decreases the incidence of which of the following conditions?
A. Bronchiolitis
B. Laryngotracheobronchitis (LTB)
C. Epiglottitis
D. Pneumonia
Correct Answer: C. Epiglottitis
Epiglottitis is a bacterial infection of the epiglottis primarily caused by Hib. Administration of the vaccine has decreased the incidence of epiglottitis. By the early 1990s, the use of the Hib conjugate vaccine caused a 99% drop in infections caused by Hib. Widespread use of the Hib vaccine has also been shown to significantly decrease rates of epiglottitis, which usually occurs in children.
Option A: Bronchiolitis is usually caused by Respiratory Syncytial Virus (RSV). RSV accounts for the majority of cases, although in about 30% of infants, there may be 2 viruses present at the same time. It is important to know that the respiratory syncytial virus is just one cause of bronchiolitis. The infection can occur in individuals of any age, but overall, the most severe symptoms tend to be common in infants.
Option B: Acute LTB is of viral origin. Croup is most often a viral infection that affects the subglottic airway, commonly caused by the parainfluenza virus. Other viruses that are known to cause croup include the respiratory syncytial virus (RSV), rhinovirus, enterovirus, influenza, and adenovirus.
Option D: The most common bacterial organisms causing pneumonia in children are pneumococci, streptococci, and staphylococci. The etiology of pneumonia in the pediatric population can be classified by age-specific versus pathogen-specific organisms. Neonates are at risk for bacterial pathogens present in the birth canal, and this includes organisms such as group B streptococci, Klebsiella, Escherichia coli, and Listeria monocytogenes. Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus can be identified in late-onset neonatal pneumonia.