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Acute otitis media is an inflammatory condition of the middle ear that is usually caused by a bacterial etiology and is typically seen in children younger than 5 years.
The condition is characterized by the presence of ear pain which can be associated with conductive hearing loss due to the presence of middle ear effusion. While middle ear effusions are usually caused by viral etiologies in children, typical acute otitis media is more commonly caused by bacterial pathogens.
Epidemiology of Acute Otitis Media in Children
Acute otitis media is considerably more common in children compared to adults. Up to 15 % of pediatrics’ consultations are related to acute otitis media.
The estimated incidence of acute otitis media in infants younger than one year is around 85 %. The incidence of acute otitis media decreases significantly after 5 years of age.
The peak incidence of acute otitis media has been reported to be in children aged between 3 and 18 months. Boys are slightly more likely to develop acute otitis media compared to girls. African American children have a lower incidence of acute otitis media compared to white children while native Americans have the highest incidence.
The prognosis of acute otitis media in children after adequate antibiotic therapy is excellent. Hearing loss is usually reversible and most children show significant symptomatic treatment within 48 hours of initiation of antibiotic therapy.
Pathophysiology of Acute Otitis Media
Viral etiologies of acute otitis media include the respiratory syncytial virus and the influenza and parainfluenza viruses. Viral agents are responsible for around one third of the cases of acute otitis media in children and the remainder are caused by bacterial pathogens.
The most common bacterial pathogens identified as possible etiologies of acute otitis media in children are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. The percentage of cases of acute otitis media caused by each of these bacterial pathogens is equal in children younger than 5 years of age.
The most important pathologic change that is believed to trigger bacterial growth and the development of acute otitis media is the obstruction of the eustachian tube. The most common cause of the obstruction of the eustachian tube in children is viral upper respiratory tract infection.
Inflammation of the eustachian tube is responsible for creating stasis and elevating the pressure within the middle ear. Stasis also puts the child at an increased risk of bacterial colonization of the middle ear.
The previously described bacterial pathogens are usually unable to adhere to the mucus lining of the middle ear and are unable to cause inflammation on their own. Therefore, the presence of an ongoing viral infection is needed which usually results in impaired mucosal linings of the upper respiratory tract including the middle ear and the eustachian tube.
Another important key factor in the pathogenesis of acute otitis media in children is the status of the immune response. Children with impaired immunoglobulin G production, which is responsible for the neutralization of pathogens that have polysaccharide antigens such as Streptococcus pneumoniae are at an increased risk of developing acute otitis media.
On the other hand, children with excess production of immunoglobulin E are more prone to allergies and have been found to have an increased risk of eustachian tube dysfunction, hence are more likely to develop acute otitis media than normal children.
Clinical Presentation of Acute Otitis Media in Children
Children who are older than one year usually present with ear pain, purulent discharge from the ear and conductive hearing loss. Fever is usually present. Ear popping and the feeling of ear fullness are also common symptoms of acute otitis media in children.
Pneumatic otoscopy can be used to visualize the ear drum which is usually red in color, shows bulging and might have purulent discharge in case of acute otitis media. Tympanometry can show elevated middle ear pressure, a sign of eustachian tube obstruction.
The most important clinical features that can help establish the diagnosis of acute otitis media in children are bulging of the eardrum and clouding of the eardrum in addition to reduced mobility of the eardrum on pneumatic otoscopy examination. The presence of hearing loss is also very important in children and is usually present.
Diagnostic Workup for Acute Otitis Media in Children
Routine laboratory investigations are not useful in establishing the diagnosis of acute otitis media in children as the probability of finding leukocytosis on a complete blood count is low. A recent study has showed that children with acute otitis media caused by nontypeable Haemophilus influenzae might have elevated serum levels of protein S100A12 and interleukin-10. The value of these markers in the clinical practice has not been established.
Tympanocentesis is a procedure that allows for the aspiration of the fluid of the middle ear and the identification of the causative organism and its sensitivity profile. This is an invasive procedure that should be reserved for selected patients. Neonates who are younger than 6 weeks, immunocompromised children, or children who fail to respond to antibiotic therapy and develop sepsis should undergo a tympanocentesis.
Delayed diagnosis and inadequate treatment of acute otitis media in children can cause intracranial complications such as cerebral venous thrombosis and brain abscess formation.
Children with new-onset focal neurological signs suggestive of intracranial complications should undergo magnetic resonance imaging of the brain. Children with suspected acute rhinosinusitis should be evaluated clinically to confirm the diagnosis of acute rhinosinusitis. A computed tomography scan can help exclude sinusitis in children.
Treatment of Acute Otitis Media in Children
Symptomatic relief is important in the management of acute otitis media in children. Children usually have significant ear pain and a fever. Ibuprofen and acetaminophen have been shown to have similar efficacy in the management of the symptoms of acute otitis media.
Children who appear healthy despite having an acute otitis media should be offered conservative management and antibiotics are better withheld. A follow-up visit should be scheduled within two or three days and if no improvement is seen on the follow-up visit, antibiotic therapy should be initiated.
If the decision to start antibiotics is made, amoxicillin is the antibiotic of choice for the management of acute otitis media. Children who are allergic to amoxicillin should receive trimethoprim-sulfamethoxazole or erythromycin-sulfamethoxazole.
If antibiotic therapy is initiated, the recommended duration of treatment is usually five days. Antibiotic administration for ten days in children with acute otitis media failed to show any added benefits but was associated with a higher risk of developing side-effects and is therefore not recommended. The only drawback of 5-day course of antibiotic therapy instead of 10-day course is the increased risk of relapse with the former.