Otitis media: Interactions between host and environment, immune and inflammatory responses.

OBJECTIVE: To review and highlight progress in otitis media (OM) research in the areas of immunology, inflammation, environmental influences and host-pathogen responses from 2019 to 2023. Opportunities for innovative future research were also identified. DATA SOURCES: PubMed database of the National Library of Medicine. REVIEW METHODS: Key topics were assigned to each panel member for detailed review. Search of the literature was from June 2019 until February 2023. Draft reviews were collated, circulated, and discussed among panel members at the 22nd International Symposium on Recent Advances in Otitis Media in June 2023. The final manuscript was prepared and approved by all the panel members. CONCLUSIONS: Important advances were identified in: environmental influences that enhance OM susceptibility; polymicrobial middle ear (ME) infections; the role of adaptive immunity defects in otitis-proneness; additional genes linked to OM; leukocyte contributions to OM pathogenesis and recovery; and novel interventions in OM based on host responses to infection. Innovative areas of research included: identification of novel bacterial genes and pathways important for OM persistence, bacterial adaptations and evolution that enhance chronicity; animal and human ME gene expression, including at the single-cell level; and Sars-CoV-2 infection of the ME and Eustachian tube.

Niche- and Gender-Dependent Immune Reactions in Relation to the Microbiota Profile in Pediatric Patients with Otitis Media with Effusion.

Otitis media with effusion (OME) is a common inflammatory disease that primarily affects children. OME is defined as a chronic low-grade inflammation of the middle ear (ME), without any signs of infection and with effusion persisting in the ME for more than 3 months. The precise pathogenesis is, however, not fully understood. Here, we comprehensively characterized and compared the host immune responses (inflammatory cells and mediators) and the overall microbial community composition (microbiota) present in matched middle ear effusion (MEE) samples, external ear canal (EEC) lavages, and nasopharynx (NPH) samples from children with OME. Female patients had significantly increased percentages of T lymphocytes and higher levels of a wide array of inflammatory mediators in their MEE compared to that of male patients, which were unrelated to microbiota composition. The relative abundances of identified microorganisms were strongly associated with their niche of origin. Furthermore, specific inflammatory mediators were highly correlated with certain bacterial species. Interestingly, some organisms displayed a niche-driven inflammation pattern in which presence of Haemophilus spp. and Corynebacterium propinquum in MEE was accompanied by proinflammatory mediators, whereas their presence in NPH was accompanied by anti-inflammatory mediators. For Turicella and Alloiococcus, we found exactly the opposite results, i.e., an anti-inflammatory profile when present in MEE, whereas their presence in the the NPH was accompanied by a proinflammatory profile. Together, our results indicate that immune responses in children with OME are highly niche- and microbiota-driven, but gender-based differences were also observed, providing novel insight into potential pathogenic mechanisms behind OME.

Subperiosteal abscesses in acute mastoiditis in 115 Swedish children.

OBJECTIVES: To study the outcome of different surgical methods of treating subperiosteal abscesses resulting from acute mastoiditis. METHODS: Medical records for all children from a Swedish retrospective multicentre study, conducted between 1993 and 2007, with acute mastoiditis and subperiosteal abscess, but without predisposing diseases or other complications, were studied. A total of 115 children aged 0-16 years were identified. All patients had received intravenous antibiotics and most had undergone myringotomy. RESULTS: Thirty-three children had been treated with only minor interventions such as retroauricular needle aspiration and/or incision, while 67 had undergone mastoidectomy. Fifteen had undergone both needle aspiration and mastoidectomy. The group treated with needle aspiration/incision was compared with those treated with mastoidectomy. One of the few significant differences found between the groups was a longer hospital stay in the group that had undergone mastoidectomy. CONCLUSIONS: Retroauricular needle aspiration and/or incision combined with intravenous antibiotics and myringotomy was an effective first-line treatment for subperiosteal abscesses resulting from acute mastoiditis. In this retrospective study, no greater risk of further complications was seen in this group compared to the group in which mastoidectomy was performed.

Recurrent acute mastoiditis - a retrospective national study in Sweden.

CONCLUSIONS: Recurrences were seen in 5% of all patients with acute mastoiditis (AM). Mastoidectomy had been performed in the majority of the patients with recurrences at their first episode of AM. Compared with the group with a single episode of AM, the recurrent group exhibited more subperiosteal and ear canal abscesses, although they were not more severely ill. It appears from this study that previous mastoidectomy itself could predispose patients to recurrent AM (rAM), perhaps due to easier access to the mastoid cavity and/or due to a reduction in mucosal lining. OBJECTIVE: To retrospectively study the incidence and characteristics of rAM in Sweden. METHODS: Data from patients with rAM were reviewed and compared with data from patients with a single episode of AM during 1993-2007 in 33 ear, nose and throat departments in Sweden. RESULTS: Of 798 cases fulfilling the criteria for AM, 36 patients (5%) had experienced one or more recurrences, of which 4 patients (11%) had concurrent cholesteatoma. More than 50% of the patients had their first episode of AM before the age of 2 years. There was a highly significant difference between the two groups concerning the frequency of mastoidectomies and subperiosteal/retroauricular abscesses. However, other clinical characteristics, including severe complications, did not differ significantly. The majority of recurrences were treated conservatively with myringotomy and intravenous antibiotics, and also with aspiration/incision if a subperiosteal/retroauricular abscess was present.

Acute mastoiditis in children aged 0-16 years--a national study of 678 cases in Sweden comparing different age groups.

OBJECTIVE: To compare the characteristics of acute mastoiditis in children in different age groups in order to identify risk groups and risk factors for acute mastoiditis. METHODS: Records for all children aged 0-16 years treated for acute mastoiditis during 1993-2007 at 33 Ear, Nose and Throat departments in Sweden were reviewed retrospectively according to defined criteria for acute mastoiditis. RESULTS: A total of 678 cases fulfilled the inclusion criteria. Acute mastoiditis was most common in children younger than two years of age and this group was characterized by less prior history of other diseases and ear diseases, fewer visits to health care centers and less antibiotic treatment before admission, shorter duration of symptoms before admission, hospitalization for fewer days and lower frequency of complications and mastoidectomies. These children also showed a higher incidence of clinical findings, increased inflammatory markers such as fever and heightened counts of C-reactive protein and white blood cells compared with older children. They also tested positive for significantly more samples of Streptococcus pneumoniae while the older children more often exhibited growth of Streptococcus pyogenes or Pseudomonas aeruginosa or no microbial growth. CONCLUSIONS: The characteristics of pediatric acute mastoiditis differed significantly between age groups. Acute mastoiditis was most common in children younger than two years of age. They showed more rapid progress of symptoms and more distinct signs of acute mastoiditis. This is probably the reason why parents rapidly seek medical care for small children and hospital treatment thus starts earlier in the youngest children, which may in turn explain the excellent outcome. This study showed that younger children have neither more severe acute mastoiditis nor more complications than older ones. The differences between age groups suggest that there are distinctions in the pathophysiology behind the onset and course of acute mastoiditis in younger and older children.

Acute mastoiditis in children in Sweden 1993-2007--no increase after new guidelines.

OBJECTIVE: To study whether the incidence and characteristics of acute mastoiditis in children changed in Sweden following the introduction of new guidelines for diagnosis and treatment of acute otitis media advocating "watchful waiting" as an option in children 2-16 years of age with uncomplicated acute otitis media. METHODS: The records for all patients treated for mastoiditis during 1993-2007 at all Ear, Nose and Throat departments in Sweden were reviewed retrospectively according to defined criteria for acute mastoiditis. In this study the data from children aged 0-16 years were analyzed and compared 71/2 years before and 71/2 years after the introduction of the new guidelines in 2000. RESULTS: A total of 577 cases aged 0-16 years fulfilled the inclusion criteria during the whole study period. Cases involving cholesteatoma were excluded. The number of children affected by acute mastoiditis did not increase after the introduction of new guidelines. Acute mastoiditis was most common in children younger than two years of age. The proportion of acute mastoiditis increased after 2000 in the group aged 2-23 months although they were not affected concerning treatment by the new guidelines. No decrease was found in the frequency of prehospital antibiotic treatment among the children admitted with acute mastoiditis, and no increase was seen in the duration of ear symptoms before hospital admission, duration of hospital stay, or in the frequency of complications or mastoidectomies, after the introduction of the new guidelines in either group of children. CONCLUSIONS: The incidence of acute mastoiditis in children in Sweden did not increase following the introduction of new guidelines in 2000 for the diagnosis and treatment of acute otitis media. This is despite the fact that a significant decrease in antibiotic prescriptions for otitis media has been reported during the same time period. The characteristics of acute mastoiditis reflecting severity of illness did not change over time. Acute mastoiditis was most common and increased after 2000 only in children younger than two years of age in which antibiotics were still recommended in all cases of acute otitis media.