Acute otitis media Flashcards
Acute Otitis media:
-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 preventative factors:
-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:
-Non-severe illness (mild pain and fever < 39Celcius)
-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 moths should begin antibiotic therapy immediately
-Patients with 3 or more episodes in 6 months 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 side effect of combination therapy
-All other treatment options discussed later are less favorable 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
-10mg/kg every 6-8 hours to a maximum of 40 mg/kg/day and not exceed 2400 mg/day
-Asprin should never be given to children or teenagers recovering from the chickenpox or with flu-like symptoms
-Has been linked to rye 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
