Acute Otitis Media

Acute otitis media (AOM) is a frequent disease in childhood with over 90% of children over three years old having had at least one episode. It is a difficult diagnosis and the major cause of antibiotic misuse and abuse. (AOM is the most common indication for antibiotic prescription).

Definition:
Rapid onset of signs and symptoms of acute infection within the middle ear with evidence of effusion.
(recurrent OM: 3 or more episodes of AOM in the previous six months or 4 or more in the last 12 months)

Why so common:
It is to do with the eustachian tube in children being smaller and more horizontal than in adults (<10degrees, in the adult >60degrees angle). The nasopharnyx is a carrier site for many pathogens and their virulence is increased after a viral illness typical of the winter season such as influenza or rhinovirus. This explains why AOM rates are increased after the winter season and in children that attend daycare (lots of children mixing viruses).

Etiology:
the so called infernal trio is responsible for majority of AOM cases through all pediatric ages:
Streptococcus pneumonia
Haemophilius influenze (non typeable (NOT HiB!!))
Moraxella Catarrhalis
(could add Group A Beta Hemolytic Streptococcus as the fourth agent).

Complications and consequences:
Potential for developmental delays
Chronis effusion requiring tympanostomy tube insertion (30% will undergo repeat infection within 5years)
Mastoiditis! The rates are increasing now, this means admission to hospital with IV antibiotics and can result in severe CNS complications

Risk factors:
Daycare (six children appears to be the cutt off), tobacco smoke exposure (dont forget 3rd hand exposure parents!), seasonality (more in winter and spring), bottle feeding, use of push-pull top bottles (negative pressure in the middle ear draws bacteria up), pacifier use, obesity, cleft palate, Male more,
African americans more.
(exclusive breastfeeding upto 6months reduces AOM rates compared to formula fed)

Diagnosis:
Correct diagnosis is essential, do not treat unless the diagnosis is sure
Acute onset of symptoms
Inflammation of tympanic membrane (assess with penumatic otoscope)
Presence of effusion (will appear as bulging tympanic memebrane on otoscope)

Symptoms:
Classically earache, fever and irritability
The symptoms of AOM are often nonspecific and no one symptoms is present in more than 50% of cases, look at the ear!
Use the COMPLETES mnemonic in assessing the ear: Colour, Other, Mobility, Position, Lighting, Entire surface, Translucency, External ear, Seal.
About half the children will have obstructing cerumen which can be a problem.

Treatment:
Pain managment with paracetomol or ibruprofen
(Paracetomol 10mg/kg/does max 4grams)
Antibiotic therapy is based on Age, laterality and severity
give antibiotics to: all children under six months, all children between 6months and 24months unless unilateral and mild and to over 24months only for severe bilateral disease. in all other cases use the watch and wait approach.
Amoxicillin 80-90mg/kg/day divided in 2 doses max 3grams/day
Up to date with vaccinations, note: Pneuomcoccal vaccine has decreased AOM RATES