Acute Otitis Media (AOM) Lecture PDF

ACUTE OTITIS MEDIA Dr. Adam Gratton NMT150 MSc ND January 19, 2023 LECTURE COMPETENCIES Describe patient factors that are necessary to safely recommend “watchful waiting” within the context of acute otitis media Describe the resistance mechanisms for Streptococcus pneumoniae, Hae...

ACUTE OTITIS MEDIA Dr. Adam Gratton NMT150 MSc ND January 19, 2023 LECTURE COMPETENCIES Describe patient factors that are necessary to safely recommend “watchful waiting” within the context of acute otitis media Describe the resistance mechanisms for Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis that require antibiotic prescription modification Describe patient factors that necessitate immediate antibiotic prescription within the context of acute otitis media Recall first-choice antibiotics for acute otitis media and the evidence-based options for patients with hypersensitivity reactions to penicillins Describe appropriate analgesic options for patients with acute otitis media REVIEW Many of the antibiotics used to treat otitis media are the same as those discussed for the treatment of streptococcal pharyngitis Recall mechanisms of action for beta-lactam antibiotics, macrolides, and lincosamides Antibiotic resistance mechanisms ACUTE OTITIS MEDIA (AOM) 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 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% WATCHFUL WAITING 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) WATCHFUL WAITING 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 ANTIBIOTIC THERAPY 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 ANTIBIOTIC THERAPY 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 ANTIBIOTIC THERAPY 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 ANALGESICS 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 PRACTICE QUESTION 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