PHARM: Otitis Media Flashcards
Acute otitis media (AOM) Cause? Bacterial pathogens?
Typically a pediatric condition
Can be caused by both bacteria and viruses and co-infection is common, especially in those who experience chronic, recurrent otitis media
The most common bacterial pathogens are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis
AOM: Prevention?
Preventative factors include:
Vaccination (influenza and S. pneumoniae) as viral upper respiratory tract infections often precede AOM
Public health measures may reduce virus transmission leading to a reduction in AOM cases
Avoiding exposure to tobacco smoke
Breastfeeding
Watchful waiting
Spontaneous resolution is seen in a number of cases caused by the top 3 bacterial pathogens
S. pneumoniae – 20%
H. influenzae- 50%
M. catarrhalis – 75%
Withhold antibiotic prescriptions for 48 hours in children over 6 months of age provided they have:
Nonsevere illness (mild pain and fever < 39°C)
Uncomplicated AOM (no episode in the preceding month, no acute facial nerve palsy, mastoiditis, meningitis, or labyrinthitis)
No craniofacial abnormalities, immunodeficiencies, cardiac or pulmonary disease, Down syndrome, or history of complicated AOM.
Parents are capable of recognizing worsening illness with ready access to medical care
Exceptions
Infants under 6 weeks of age should be immediately referred to the nearest emergency department
Patients aged 6 weeks to 6 months should begin antibiotic therapy immediately
Patients with 3 or more episodes in 6 months or 4 or more within a year should begin antibiotic therapy immediately
Antibiotic therapy
Antibiotic resistance is common among the three pathogens
S. pneumoniae resistance is a result of the alteration of penicillin-binding cell wall proteins leading to decreased drug affinity
This is overcome by doubling the dose of amoxicillin
H. influenzae and M. catarrhalis produce beta-lactamases which confer resistance
This is overcome by using a beta-lactamase inhibitor called clavulanate
When antibiotics are used, treatment failure should be considered if symptoms do not improve after 72 hours of treatment
Amoxicillin is considered first-line therapy in the treatment of AOM
There is disagreement about the ideal dose and available evidence had not demonstrated superiority of one approach over others
In most areas of Canada, susceptibility of S. pneumoniae to amoxicillin is >90%
S. pneumoniae as the causative pathogen for AOM has been decreasing steadily with vaccination programs
Standard dose amoxicillin is a reasonable first-line option in children without risk factors for resistance
Alternatives to amoxicillin
The combination of amoxicillin and clavulanate is typically used for treatment failure or recurrence
Diarrhea is commonly noted as an adverse effect of combination therapy
All other treatment options discussed later are less favourable but may be necessary depending on the patient
Cephalosporins
Cefuroxime axetil and Cefprozil
Second-generation cephalosporins have reasonable activity against H. influenzae and M. catarrhalis as they are more resistant to bacterial beta-lactamases
Less effective against S. pneumoniae
Considered second-line agents
Macrolides
Azithromycin and Clarithromycin should be reserved for patients with type 1 hypersensitivity reactions to beta-lactam antibiotics
Resistance to macrolides is common and treatment failure is common
Lincosamides
Clindamycin can be used for patients with type 1 hypersensitivity reactions to beta-lactam antibiotics
It does not cover H. influenzae or M. catarrhalis
Supportive therapy
Antibiotics do not reduce pain within the first 24 hours of therapy and do little in the following days compared to placebo
Analgesics are recommended during watchful waiting and with antibiotic therapy
Analgesics
Acetaminophen
10 – 15 mg/kg every 4 – 6 hours to a maximum of 75 mg/kg/day and not to exceed 4000 mg/day
Ibuprofen
10 mg/kg every 6 – 8 hours to a maximum of 40 mg/kg/day and not to exceed 2400 mg/day
Aspirin should never be given to children or teenagers recovering from chickenpox or with flu-like symptoms
Has been linked to Reye syndrome – a rare but serious condition that causes swelling of the liver and brain
The resistance mechanism produced by H. influenzae can be overcome by which of the following strategies?
A. Doubling the dose of amoxicillin
B. Giving amoxicillin and clavulanate together
C. Using clindamycin as an alternative to amoxicillin
D. Giving cefprozil and clavulanate together
B. Giving amoxicillin and clavulanate together
Increases half life of amoxicillin by adding clavulanate
