Role of adenoids in the pathogenesis of otitis media: a bacteriologic and immunohistochemical analysis

Otitis media with effusion: an effort to understand and clarify the uncertainties

Otitis media with effusion--defined as the accumulation of middle-ear effusion behind an intact tympanic membrane without signs or symptoms of acute infection--is one of the most common causes of hearing loss in children in developed countries, potentially leading to language deficits. Although treatment of chronic or relapsing otitis media with effusion is considered imperative, none of the preventative or nonsurgical management measures currently available have proven effective. Tympanostomy tube placement remains the recommended treatment option for high-risk children or for cases of unresponsive otitis media with effusion. This can be attributed to the uncertainties surrounding its pathogenesis. Multiple factors and several possible pathogenetic models have been proposed to explain the production and persistence of middle-ear effusion; only a few of them are supported by sufficient evidence. In this review, the authors will present current knowledge on the pathogenesis, consequences, diagnosis and management of otitis media with effusion. An effort will be made to clarify those aspects sufficiently supported by evidence-based studies, and to underline those that remain unfounded.

Cytokine levels in groups of patients with different duration of chronic secretory otitis

Chronic secretory otitis relates to the permanent presence of secretion in the middle ear for more than 3 months. The reason why applied therapy is often ineffective is that, for now, etiopathogenic molecular mechanisms responsible for the cause and the course of the secretory process in the mucus of the middle ear have not been precisely defined. Cytokines are the key mediators in middle ear inflammation with secretory otitis and regulating different inflammation states can add to the cause of the molecular processes that lead to hystopathological changes in mucus and submucus characteristically for the chronic state of secretory otitis. The aim of our work was to define the pro-inflammatory, immunoregulatory and allergy-associated cytokine levels in middle ear secretion samples of diseased children and to compare the defined values with the secretory process continuance in groups of patients who were diseased for more or less than 3 months. According to the results that have showed higher concentration of all ten examined cytokines in the secretion samples of the children who had secretory otitis for a longer time, it can be concluded that the disturbance expression regulation of the pro-inflammatory TNFalpha, TNFbeta, IL1beta, IFNgamma, IL-6 and IL-8, as well as immunoregulatory IL-2 and IL-10, and allergy associated cytokines IL-4 and IL-5 relating to the hyper production can add to the conversion of the inflammatory process to the chronic state, which has been maintained for longer than 3 months.

High frequency of Alloiococcus otitidis in the nasopharynx and in the middle ear cavity of otitis-prone children

OBJECTIVE

Colonization of middle ear pathogens is facilitated in the nasopharynx of otitis-prone children, and is associated with the development of otitis media. Recently, a new species of bacterium, Alloiococcus otitidis, is considered as one of the major middle ear pathogens. However, as far as we know, no study has been reported concerning the prevalence of A. otitidis in the nasopharynx of otitis-prone children. And, no study has been conducted on the association of A. otitidis in the nasopharynx with otitis media.

METHODS

The frequency of A. otitidis in 83 middle ear effusions (MEE) and 56 nasopharyngeal swab (NPS) specimens from 56 children with otitis media was investigated by culture and polymerase chain reaction (PCR).

RESULTS

A. otitidis was detected in 24 (28.9%) of MEE and in 6 (10.7%) of NPS specimens. When the frequency was investigated in relation to proneness to otitis media, A. otitidis was detected in 16 (64%) of 25 MEE and in 5 (29.4%) of 17 NPS specimens from otitis-prone children, whereas it was detected in 8 (13.8%) of 58 MEE and in 1 (2.6%) of 39 NPS specimens from non-otitis-prone children. The frequency of A. otitidis in both NPS and MEE specimens was significantly higher in otitis-prone than in non-otitis-prone children.

CONCLUSIONS

Our results suggest that colonization of A. otitidis is facilitated in the nasopharynx of otitis-prone children. And, nasopharyngeal colonization of A. otitidis may be associated with the frequency of otitis media.

Difference in cytokine production and cell activation between adenoidal lymphocytes and peripheral blood lymphocytes of children with otitis media

We evaluated the immunological potential of adenoidal lymphocytes from children with recurrent otitis media. Interleukin-4 release and CD69 expression were lower in adenoidal lymphocytes than in peripheral blood lymphocytes (PBL). Our results suggest that there may be a difference between the immunological potential of adenoidal lymphocytes and that of PBL in children with otitis.

Tympanostomy tube sequelae in children with otitis media with effusion: a three-year follow-up study

Tympanostomy tube (TT) insertion is one of the most frequently performed procedures in otolaryngology. Otorrhea, tympanosclerosis, retraction, perforation, and cholesteatoma are complications reported in the literature after its application. Aim: To determine the incidence and the type of TT insertion sequelae/complications in children presenting with recurrent otitis media and chronic otitis media with effusion undergoing myringotomy and tube placement. Study Design: prospective cohort study. Material and Method: A total of 75 children (150 ears) aged 11 months to 10 years were regularly followed up for up to 38 months after TT insertion. Results: Incidence of sequelae/complications: otorrhea - 47.3% of the ears; perforation - 2.1%; retractions - 39.7%; tympanosclerosis - 23.3%. Average length of stay: 12.13 months. Mean age at initial tube placement of children not requiring a second set of tubes = 35.9 months and mean age at initial tube insertion of children requiring an additional set of tubes = 25.6 months (P=0.04). TT stayed longer in the ears that had more episodes of otorrhea (P=0.01). TT insertion with adenoidectomy was associated with a smaller number of otorrhea episodes (P=0.02) Conclusions: Otorrhea was the most frequently found complication. TT placement with adenoidectomy was associated with fewer otorrhea episodes. TT extruded later in those ears that had more episodes of otorrhea. Younger age at the time of the initial tube placement is associated with higher incidence of additional tube placement. One in six patients will probably require a second set of ventilation tubes.

The immunoregulatory and allergy-associated cytokines in the aetiology of the otitis media with effusion

Inflammation in the middle ear mucosa, which can be provoked by different primary factors such as bacterial and viral infection, local allergic reactions and reflux, is the crucial event in the pathogenesis of otitis media with effusion (OME). Unresolved acute inflammatory responses or defective immunoregulation of middle inflammation can promote chronic inflammatory processes and stimulate the chronic condition of OME. Cytokines are the central molecular regulators of middle ear inflammation and can switch the acute phase of inflammation in the chronic stage and induce molecular-pathological processes leading to the histopathological changes accompanying OME. In this review we present cytokines identified in otitis media, immunoregulatory [interleukin (IL)-2, IL-10, transforming growth factor-beta]) and allergy associated (IL-4, IL-5, granulocyte-macrophage colony-stimulating factor), as crucial molecular regulators, responsible for chronic inflammation in the middle ear and the chronic condition of OME.

Antibody production directed against pneumococci by immunocytes in the adenoid surface secretion

OBJECTIVE

In previous studies of the adenoid surface secretion we revealed the presence of activated T cells, granulocytes engaged in phagocytosis and immunocytes that produce IgG, IgA and IgM. In the present study the objective was to assess the ability of these immunocytes to produce antibodies directed at S. pneumoniae.

METHOD

Nine children subjected to adenoidectomy due to adenoid hypertrophy, secretory otitis media or recurrent otitis media were enrolled in the study. Samples of adenoid surface secretion were obtained by an imprint method and for comparison samples of adenoid tissue and peripheral blood were also obtained as well as a nasopharyngeal culture. Double-colour enzyme-linked immunospot (ELISPOT) assays were performed to detect total and pneumococci-specific IgG- and IgA-antibody secreting cells (ASC). In the adenoid tissue, the presence of H. influenzae type b specific ASC was also examined.

RESULTS

ASC were present in all nine samples of adenoid surface secretion with a dominance of IgG-ASC as compared to IgA-ASC. The proportion of ASC relative to the total number of lymphocytes was always greater in the secretion than in the corresponding adenoid tissue. The adenoid surface secretion samples from three of nine children contained IgG-ASC directed against S. pneumoniae. IgG-ASC directed against S. pneumoniae were detected in six of eight adenoids and IgA-ASC directed against S. pneumoniae were detected in two of eight adenoids. IgA-ASC directed against H. influenzae type b (Hib) were detected in one of seven adenoids.

CONCLUSION

The immunocytes in the adenoid surface secretion and the adenoid tissue itself hold the property to produce antibodies specific for known pathogens of the upper airways. These ASC are probably engaged in the immunologic defence of the nasopharyngeal mucosa and further studies are therefore called upon.

Otitis media: concepts and controversies

PURPOSE OF REVIEW

Otitis media is the most common bacterial infection among children, accounting for as many as 30 million office visits annually. Proper treatment has become critical as offending pathogens become increasingly resistant to antibiotics and the cost of managing the disorder has exceeded 3 billion dollars per year. However, data suggest that many practitioners still struggle with the diagnosis of otitis media and often recommend medical and surgical intervention inappropriately. This article presents recent advances in the otitis media literature and an evidence-based approach to its management.

RECENT FINDINGS

Recent investigations have resulted in the following findings: (1) bacterial biofilms may account for the persistence of middle ear disease; (2) there is increasing evidence that heredity and reflux are risk factors for otitis media; (3) primary care providers may be receiving poor otitis media training, leading to inadequate diagnostic skills; (4) medical and surgical therapy are of limited utility in the management of acute and recurrent acute otitis media; (5) antibiotics and steroids are of limited value in the treatment of chronic middle ear effusion; (6) delayed management of effusion may not adversely affect development in children; (7) vaccination for pneumococcus may alter the serotypes responsible for otitis media; and (8) vaccine candidates for other middle ear pathogens are under investigation.

SUMMARY

Management of otitis media is constantly evolving, based on research from a variety of medical subspecialties. It is incumbent on the otolaryngologist and primary care providers treating otitis media to keep pace with and synthesize these findings into a rational approach to treatment.

Evaluation of the virulence of a Streptococcus pneumoniae neuraminidase-deficient mutant in nasopharyngeal colonization and development of otitis media in the chinchilla model

Considerable evidence has implicated Streptococcus pneumoniae neuraminidase in the pathogenesis of otitis media (OM); however, its exact role has not been conclusively established. Recently, an S. pneumoniae neuraminidase-deficient mutant, DeltaNA1, has been constructed by insertion-duplication mutagenesis of the nanA gene of S. pneumoniae strain D39. The relative ability of DeltaNA1 and the D39 parent strain to colonize the nasopharynx and to induce OM subsequent to intranasal inoculation and to survive in the middle ear cleft after direct challenge of the middle ear were evaluated in the chinchilla model. Nasopharyngeal colonization data indicate a significant difference in the ability of the DeltaNA1 mutant to colonize as well as to persist in the nasopharynx. The neuraminidase-deficient mutant was eliminated from the nasopharynx 2 weeks earlier than the D39 parent strain. Both the parent and the mutant exhibited similar virulence levels and kinetics during the first week after direct inoculation of the middle ear. The DeltaNA1 neuraminidase-deficient mutant, however, was then completely eliminated from the middle ear by day 10 postchallenge, 11 days before the D39 parent strain. Data from this study indicate that products of the nanA gene have an impact on the ability of S. pneumoniae to colonize and persist in the nasopharynx as well as the middle ear.

Evaluation of factors affecting outcome of surgery for otitis media with effusion in clinical practice

In discussing surgery for otitis media with effusion (OME), tympanostomy tubes and adenoidectomy are important. Sinus surgery is less important and cleft palate surgery needs to be mentioned for completeness sake. There is no evidence supporting the value of tonsillectomy in the treatment of OME. Tympanostomy tubes are possibly best regarded as artificial eustachian tubes, which remain in position for a variable amount of time. It is therefore apparent that resolution of OME from tympanostomy tube placement largely depends on whether underlying aetiological factors have either resolved or been corrected when the tympanostomy tube was in position.

Role of nasopharyngeal bacterial flora in the evaluation of recurrent middle ear infections in children

OBJECTIVE: To study the nasopharyngeal colonization in otitis-prone children before and after adenoidectomy. METHODS: The study population consisted of 35 children between 11 months and 4 years of age, undergoing adenoidectomy and tube placement for recurrent acute otitis media. All these children were otitis prone (OP). During general anesthesia, bacteriologic samples were obtained from the nasopharynx and the middle ear fluid, if present. During the follow-up visit, a new nasopharyngeal culture was taken. The control population consisted of 35 children undergoing surgery for non-ear-nose-throat pathology. These children had no history of recurrent upper respiratory tract infections. RESULTS: Colonization of the nasopharynx with potential pathogens (Streptococcus pneumoniae, Moraxella catarrhalis, Haemophilus influenzae) occurred significantly more in the OP children than in the non-OP children. Adenoidectomy resulted in a substantial decrease of potential middle ear pathogens in the nasopharynx and an increase of normal commensal flora. In about half of the patients, middle ear fluid was still present at the time of tube placement; in most instances, H. influenzae was cultured. Typing with arbitrarily primed PCR indicated substantial genetic diversity among the H. influenzae isolates studied. CONCLUSIONS: Both cross-colonization (between sampling sites within the same patient and between siblings) and turnover appeared to be high.

Clinical, bacteriological, and histological study of adenoids in children

PURPOSE

The adenoid has long been recognized as an important factor in the pathogenesis of otitis media with effusion (OME). However, there is still considerable debate concerning how the condition of the adenoid tissue is involved in the cause of OME. The purpose of this study is to investigate whether the adenoid is an active agent of OME.

PATIENTS AND METHODS

One hundred forty-six patients aged from 3 to 6 years who underwent adenoidectomy at Oita Medical University (Japan) were retrospectively compared with patients with and without OME regarding macroscopic size of the adenoid, adenoidal-nasopharyngeal ratio (AN ratio), incidence of sinusitis and nasal allergy, bacteriological examination of adenoid tissues, reticular formation of the epithelium, and the percent of ciliated epithelium.

RESULTS

There was no significant difference in the size of adenoids. Haemophilus influenzae (HI) was cultured more frequently in adenoid specimens from patients with OME. A tendency toward increased stratified squamous epithelium and decreased ciliated epithelium was apparent in patients with OME. Reticular epithelium extension was greater in patients with than without OME.

CONCLUSION

Adenoid inflammation is implicated in the pathogenesis of OME and the adenoids have an important role in the cause of OME by being a reservoir for HI.