Acute otitis media: Antimicrobial treatment or the observation option?

The “observation option” was a recommendation cited in the American Academy of Pediatrics/American Academy of Family Physicians clinical practice guideline for the diagnosis and management of acute otitis media (AOM) in 2004. This option’s premise is that antibiotic treatment of some uncomplicated AOM cases can be deferred if certain criteria are met, including diagnostic certainty and disease severity. Although this recommendation was controversial, physicians expressed relief at its publication because they felt that not all cases of AOM needed treatment with antibiotics. Studies of the guideline’s acceptability, practicality, applicability, and effectiveness have been positive. The Centers for Disease Control and Prevention support it wholeheartedly. Nevertheless, reluctance persists, and the medical community has voiced some objections. During this current crisis of antibiotic resistance, the observation option has become a point of contention.     

Bacterial eradication in the treatment of otitis media

Drugs differ in their ability to eradicate various pathogens from the middle-ear cavity during acute otitis media (AOM), and these differences clearly affect clinical outcome. Outcome is derived from differences in the association between concentrations of the drugs at the site of infection and the antimicrobial effect (termed pharmacodynamics). These differences are even more marked in the present era of antimicrobial resistance. However, since AOM is a self-limiting disease in most cases, difference in clinical outcome is more difficult to ascertain than that of bacteriological outcome, which is measured within 3-5 days. A favourable clinical outcome regardless of the bacteriological effect of the drug can result in false optimism when less-effective antibiotic drugs are used. Inappropriate study design and manipulation of clinical results add to this confusion. In this review we attempt to highlight the evidence regarding bacteriological response to antibiotics in AOM and to draw attention to potential flaws that may mislead clinicians.     

Purulent otitis media in adults.

While the bacterial origin of otitis media has been studied extensively in children, there are few data regarding adults with this disease. We undertook this study to identify the incidence, prevalence, and bacteriologic origin of purulent otitis media in adults. This was accomplished through a review of the English-language literature on adult otitis media and a retrospective review of adult patients with this disease who were hospitalized at our institution. Results of literature review indicate that Streptococcus pneumoniae and Haemophilus influenzae are the most common causes of otitis media in ambulatory adults, but this illness is uncommon, with an incidence of only 0.25%. Hospitalized patients in whom this diagnosis was established suffered a variety of serious suppurative complications such as mastoiditis, meningitis, or brain abscess. Otalgia and fever were the most common symptoms noted in this patient population. Further studies of adult otitis media need to be performed to determine bacteriologic, symptomatic, and high-risk patient groups.     

Immunochemistry of otitis media with effusion.

For investigation of the nature and origin of middle ear effusions, immunochemical studies were performed on more than 400 patients diagnosed as having otitis media with effusion. Although results of cellulose acetate and disc electrophoretic analyses and quantitation of IgG, IgA, and IgM suggested that proteins found in the effusions were derived for the most part from the serum, quantitative analysis of secretory IgA revealed the existence of appreciable amounts of secretory IgA in both serous and mucoid effusions. The antigenicity and subunit structure of the secretory IgA isolated from middle ear effusions were identical or very similar to those of secretory IgA obtained from other external secretions. Radioactive single radial diffusion analysis of IgE showed that the mean concentrations of IgE in effusions and sera were within normal ranges. Findings of this study suggest that the middle ear maintains the local immunologic defense system, that the middle ear effusion is at least partially an external secretion, and that IgE in middle ear effusions obtained from old patients, rather than being a local product, may be derived from the serum.     

Viral otitis media

Acute otitis media (AOM) and viral upper respiratory tract infections (URIs) represent the two most common diseases affecting the human population, and account for substantial patient morbidity and health care costs. Epidemiologic and experimental studies suggest that URIs play a causal role in the pathogenesis of AOM. Specifically, viruses can either invade the middle ear (ME) space and invoke an inflammatory response that culminates in ME effusion formation and consequent symptoms, or URIs might cause eustachian-tube dysfunction, resulting in negative ME pressures and subsequent ME effusion (hydrops ex vacuo theory). The events responsible for the inflammatory response of the human ME following viral exposure have not been well characterized. Although many prophylactic and therapeutic interventions have been evaluated for the treatment of AOM, the information on virusspecific interventions is sparse. In this article, the epidemiology, pathogenesis, diagnosis, and management of viral otitis media are reviewed.     

Intracranial complications of chronic suppurative otitis media.

Twenty-nine patients with chronic suppurative otitis media with intracranial complications are reviewed. The complications occurred predominantly in young patients with a mean age of 17 years. The most common complication was brain abscess (n = 20). The others were meningitis (n = 3), subdural abscess (n = 3), perisinus abscess (n = 2) and otitic intracranial hypertension (n = 1). The common pathogens were Gram-negative bacilli, especially Proteus and anaerobic organisms, respectively. The mortality rate was 7%.     

Diagnosis and treatment of acute otitis media: evaluating the evidence

Acute otitis media (AOM) is one of the most common illnesses for which children in the United States receive an antimicrobial agent. Of the six recommendations offered in recent guidelines for treatment of AOM, only one, the assessment and treatment of pain with analgesics, is based on strong evidence. This article reviews the diagnosis of AOM and the accuracy of various signs and symptoms in indicating a bacterial origin, the data on the effect of antimicrobial agents compared with placebo in the treatment of AOM, and the gaps in knowledge that should be addressed by future research and clinical trials.     

The genetics of otitis media

Almost every child will suffer at least one episode of otitis media (OM). Therefore, it is not immediately obvious that there is a genetic predisposition to the development of the disease. However, evidence from a variety of studies has shown that there is a clear genetic component to susceptibility to OM. Methodologies for discovering these genes are described within this article. The identification of OM susceptibility genes allows the development of molecular diagnostic assays that will inform the clinician as to which child is at increased risk and warrants more aggressive intervention. Delineating the OM genes not only provides a deeper understanding of the pathophysiology of this common disease, but also of acute and chronic bacterial disease in general.     

The genetics of otitis media

There is significant evidence from epidemiologic, anatomic, physiologic, and immunologic studies that susceptibility to recurrent episodes of acute otitis media (OM) and persistent OM with effusion is largely genetically determined. The genetics of OM are most likely complex, ie, many genes are probably contributing to the overall phenotype. The knowledge of a hereditary component has important implications because closer surveillance of children at risk for OM could result in earlier detection and treatment. Further, once OM susceptibility genes have been identified it may be possible to develop molecular diagnostic assays that could enable the clinician to identify the child at high risk for OM and to develop more focused treatments in the future.     

Immunologic aspects of otitis media

The middle ear cleft is a modified gas pocket which functions normally when the gas contents are regulated by a normal eustachian tube, resulting in equalization of middle ear pressure to that of the environment. The most important regulator of this middle ear pressure is the eustachian tube, a critical passageway from the nasopharynx into the middle ear. Any alteration of eustachian tube mucociliary function caused by virus, allergy, pollutants, or alteration of the normal homeostasis of the nasopharynx will result in eustachian tube obstruction. This, in turn, leads to underventilation of the middle ear, and transudation of fluid. If bacteria or virus or viral-bacterial interaction leads to infectious disease of the middle ear, an immune response is produced as a result of the inflammatory response, allowing lymphocytes and antigen-presenting cells to enter into the middle-ear mucosa. This article summarizes the immunologic reactivity in the middle ear following a viralbacterial inflammatory reaction in the middle-ear mucosa. Although secretory IgA is critical for protection of the nasopharynx, its function in the middle ear has still not been resolved. The evidence strongly suggests that IgG1 and IgG3 subclasses are responsible for eradication of middle ear pathogens. Finally, a review of alternative approaches to the prevention of otitis media is briefly discussed in this critical period of emergence of resistant bacteria to available antibiotics.