Clinical and audiological findings in children with acute otitis media

Surfactant proteins and innate immunity of otitis media

Otitis media (OM) is the most common disease among young children and one of the most frequent reasons to visit the pediatrician. Development of OM requires nasopharyngeal colonization by a pathogen which must gain access to the tympanic cavity through the eustachian tube (ET) along with being able to overcome the defense mechanisms of the immune system and middle ear mucosa. OM can be caused by viral or bacterial infection. The three main bacterial pathogens are Streptococcus pneumoniae, nontypeable Haemophilus influenzae (NTHi), and Moraxella catarrhalis. Innate immunity is important in OM resolution as the disease occurs in very young children before the development of specific immunity. Elements of innate immunity include natural barriers and pattern recognition receptors such as Toll like receptors (TLRs), and Nod like receptors (NLRs). Surfactant proteins A (SP-A) and D (SP-D) act as pattern recognition receptors and are found in the lung and many other tissues including the ET and the middle ear where they probably function in host defense. Surfactant has a potential for use in the treatment of OM due to surface tension lowering function in the ET, and the possible immune functions of SP-D and SP-A in the middle ear and ET.

Innate immunity of surfactant protein A in experimental otitis media

Surfactant protein A (SP-A) plays an important role in innate immune response and host defense against various microorganisms through opsonization and complement activation. To investigate the role of SP-A in non-typeable Haemophilus influenzae (NTHi)-induced acute otitis media, this study used wild type C57BL/6 (WT) and SP-A knockout (KO) mice. We divided mice into an infection group in which the middle ear (ME) was injected with NTHi and a control group that received the same treatment using normal saline. Mice were sacrificed on d 1, 3, and 7 after treatment. Temporal bone samples were fixed for histological, cellular, and molecular analyses. Ear washing fluid (EWF) was collected for culture and analyses of pro-inflammatory cytokines and inflammatory cells. SP-A-mediated bacterial aggregation and killing and phagocytosis by macrophages were studied in vitro. SP-A expression was detected in the ME and Eustachian tube mucosa of WT mice but not KO mice. After infection, KO mice showed more severe inflammation evidenced by increased ME mucosal thickness and inflammatory cell infiltration and higher NF-κB activation compared to WT mice. The levels of IL-6 and IL-1β in the EWF of infected KO mice were higher compared to infected WT mice on d 1. Our studies demonstrated that SP-A mediated NTHi aggregation and killing and enhanced bacterial phagocytosis by macrophages in vitro and modulated inflammation of the ME in otitis media in vivo.

Prevalence of Hearing Loss Among Children 9 to 11 Years Old: The Generation R Study

Importance

Hearing loss (HL), a major cause of disability globally, negatively affects both personal and professional life.

Objective

To describe the prevalence of sensorineural hearing loss (SNHL) among a population-based cohort of 9- to 11-year-old children, and to examine potential associations between purported risk factors and SNHL in early childhood.

Design, Setting, and Participants

The study was among the general, nonclinical, pediatric community within the city of Rotterdam, the Netherlands, and was conducted between 2012 and 2015 as a cross-sectional assessment within the Generation R Study, a population-based longitudinal cohort study from fetal life until adulthood. Participants are children of included pregnant women in the Generation R Study with an expected delivery date between April 2002 and January 2006. They form a prenatally recruited birth cohort.

Main Outcomes and Measures

Pure-tone air-conduction hearing thresholds were obtained at 0.5, 1, 2, 3, 4, 6, and 8 kHz, and tympanometry was performed in both ears. Demographic factors and parent-reported questionnaire data, including history of otitis media, were also measured.

Results

A total of 5368 participants with a mean age of 9 years 9 months (interquartile range, 9 years 7 months-9 years 11 months) completed audiometry and were included in the analyses. A total of 2720 were girls (50.7%), and 3627 (67.6%) were white. Most of the participants (4426 children [82.5%]) showed normal hearing thresholds 15 dB HL or less in both ears. Within the cohort, 418 children (7.8%) were estimated to have SNHL (≥16 dB HL at low-frequency pure-tone average; average at 0.5, 1, and 2 kHz or high-frequency pure-tone average; average at 3, 4, and 6 kHz in combination with a type A tympanogram) in at least 1 ear, most often at higher frequencies. In multivariable analyses, a history of recurrent acute otitis media and lower maternal education were associated with the estimated SNHL at ages 9 to 11 years (odds ratio, 2.0 [95% CI. 1.5-2.8] and 1.4 [95% CI, 1.1-1.7], respectively).

Conclusions and Relevance

Within this cohort study in the Netherlands, 7.8% of the children ages 9 to 11 years had low-frequency or high-frequency HL of at least 16 dB HL in 1 or both ears. A history of recurrent acute otitis media and lower maternal education seem to be independent risk factors for presumed SNHL in early childhood.