The Past and Present of Secretory Otitis Media in Children

Secretory otitis media (SOM) refers to the accumulation of fluid in the middle ear without acute inflammatory symptoms, also known as non-suppurative otitis media, exudative otitis media, catarrhal otitis media, serous otitis media, serous mucoid otitis media, middle ear effusion, and glue ear. It is more common in winter and spring and is classified as acute or chronic based on whether the duration exceeds 3 months. If the onset time can be determined, the duration starts from the onset; if the onset time is unclear, the duration starts from the date of diagnosis.

The incidence of SOM in children varies across different age groups and regions, with detection rates ranging from 1.16% to 30.7%, predominantly affecting preschool children. Risk factors for SOM in children include Down syndrome, cleft palate, and autism.

01
Etiology and Pathology

Eustachian Tube Dysfunction

(1) Anatomical Factors: The Eustachian tube in children is short, flat, wide, straight, measuring 15-20mm in length, and matures around 7 years of age, with an angle to the horizontal plane of ≤10-20°. Therefore, nasal (pharyngeal) inflammation can easily enter the middle ear through the Eustachian tube, leading to SOM.

The Past and Present of Secretory Otitis Media in Children

Eustachian tube anatomical diagram

(2) Eustachian Tube Obstruction: Hypertrophy of adenoids or nasopharyngeal masses can compress the orifice of the Eustachian tube, affecting middle ear drainage and gas exchange, leading to negative pressure in the tympanic cavity and effusion.

The Past and Present of Secretory Otitis Media in Children

Adenoid hypertrophy and other obstructive diseases leading to mouth breathing

(3) Mucosal Changes in the Eustachian Tube: The “mucociliary transport system” in the Eustachian tube continuously expels pathogens and secretions to the nasopharynx. Conditions like congenital ciliary dyskinesia, bacterial exotoxins, inflammatory secretions from the middle ear and Eustachian tube, and acute or chronic sinusitis or bronchitis can cause abnormal mucus secretion and ciliary movement disorders, leading to blockage of the Eustachian tube.

(4) Local Developmental Abnormalities: Children with cleft palate may have abnormal development of the levator veli palatini muscle, preventing effective contraction, or the fibers of the tensor veli palatini muscle may be underdeveloped, reducing the Eustachian tube’s drainage and pressure-equalizing functions, leading to prolonged negative pressure in the middle ear and fluid accumulation.

Infectious Factors

SOM was once thought to be a sterile inflammation of the middle ear, but recent findings indicate that it is related to infections, with the most common bacteria being Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, as well as viruses like respiratory syncytial virus, adenovirus, rhinovirus, and coronaviruses. Patients may have varying degrees of bacterial biofilms on the nasopharyngeal and middle ear mucosal surfaces, leading to recurrent SOM and chronic suppurative otitis media.

Immune Factors

(1) Allergic Reactions: The proteins and enzymes in the effusion of the tympanic cavity are secretions rather than exudates, possibly belonging to immune complex (III) diseases; patients with allergic rhinitis have a higher incidence of SOM due to mucosal edema at the Eustachian tube orifice caused by rhinitis, which may be due to an immediate hypersensitivity (I) reaction or a delayed hypersensitivity (IV) reaction mediated by T cells.

(2) Immunoglobulin Deficiency: Secretory IgA produced by the upper respiratory mucosa can prevent pathogen adhesion and clear resident flora in the nasopharynx. In children, the immune system is not fully developed, and the lack of secretory IgA may lead to a higher incidence and recurrence of SOM.

Other Factors: Passive smoking, obesity, endocrine diseases, improper breastfeeding positions, excessive use of pacifiers, and gastroesophageal reflux in infants can trigger SOM.

02
Clinical Symptoms

1. Hearing Abnormalities:

(1) Some children may complain of hearing loss, often manifesting as ignoring calls or being inattentive in class, which is noticed by parents or teachers; they may also experience noises in the ear, enhanced self-hearing, and/or changes in hearing with position changes;

(2) It is also possible for one ear to be affected while the other remains normal, going unnoticed for a long time until a comprehensive examination during a check-up reveals it;

(3) Infants may show delayed responses to speech and environmental sounds, and prolonged hearing loss can lead to speech development disorders in preschool children.

2. Ear Fullness:: Children may feel a sense of fullness or blockage in the ear, which can be temporarily relieved by repeatedly pressing on the ear.

3. Ear Pain:: Usually transient and mild, this characteristic increases the subtlety of SOM.

4. Tinnitus:: Often low-pitched and intermittent, such as “crackling” sounds, “buzzing” sounds, and “water flow” sounds, with sounds of air passing through water when moving the head or yawning.

5. Dizziness and Unsteadiness: A few children may exhibit vestibular symptoms and balance abnormalities.

03
Examination and Signs
1. Otoscopic Examination and Tympanic Membrane Imaging
(1) Acute Phase: The tympanic membrane may show congestion and retraction (the light reflex disperses or disappears, the handle of the malleus shifts backward and upward, and the short process of the malleus protrudes), and may even show retraction pockets in the anterior superior quadrant of the tympanic membrane.

The Past and Present of Secretory Otitis Media in Children

Acute phase tympanic membrane congestion in SOM, light reflex shallow or absent

(2) Effusion and Air Bubble Signs: The tympanic membrane may appear dark or amber, with enhanced reflection, and air-fluid levels or bubbles may be visible; when the effusion is substantial, the tympanic membrane may bulge.

The Past and Present of Secretory Otitis Media in Children

Tympanic membrane with effusion and air bubble signs

(3) Pneumatic Otoscopy: Dynamic changes in the tympanic membrane can be observed.

(4) Chronic Phase: The tympanic membrane may appear milky white or gray-blue; prolonged negative pressure in the tympanic cavity or adhesions may cause retraction of the tympanic membrane, which may even adhere to the tympanic ridge.

The Past and Present of Secretory Otitis Media in Children

Chronic phase of SOM: amber effusion in the tympanic cavity; retraction of the tympanic membrane, protrusion of the short process of the malleus, and formation of retraction pockets in the upper tympanic cavity.
2. Behavioral Audiometry
Choose according to the child’s age; infants aged 7 months to 2.5 years can undergo visual reinforcement audiometry, children aged 2.5 to 5 years can undergo play audiometry, and children over 5 years can undergo pure tone audiometry, with the average air conduction thresholds at 500, 1000, 2000, and 4000 Hz used to assess the degree of hearing loss. Hearing loss exceeding 50 dB HL is rarely caused solely by SOM and is usually associated with other middle or inner ear lesions.

The Past and Present of Secretory Otitis Media in Children

Pure tone audiometry threshold values for SOM
3. Acoustic Impedance Testing: The tympanic cavity admittance curve at 226 Hz is recommended for children over 6 months of age, mainly classified into types A, B, C, and D. Among them, type B indicates tympanic cavity effusion or significant middle ear adhesion, which is a typical manifestation of SOM, with a positive predictive value of 86% to 96%; type C indicates middle ear negative pressure or Eustachian tube dysfunction, which is an excessive type between normal and effusion ears. The 1000 Hz probe is more sensitive for detecting SOM in infants under 6 months of age; the tympanic curves can be classified into unimodal, bimodal, flat, and indeterminate types, with unimodal and bimodal types used as standards for determining normal acoustic impedance, while SOM presents without a positive peak.

The Past and Present of Secretory Otitis Media in Children

Typical “B” type image of acoustic impedance testing for SOM

Wideband acoustic impedance (WBA) can monitor whether the tympanic cavity fluid is completely drained during tympanostomy, evaluate the efficacy post-tubing, check if the tube is patent, and whether there is residual fluid in the middle ear.

The Past and Present of Secretory Otitis Media in Children

WBA images indicating middle ear effusion and negative pressure

4. Objective Audiometry

(1) Auditory Brainstem Response (ABR) Testing: For children who cannot cooperate with subjective hearing threshold tests, ABR testing can be performed under sedation, with SOM presenting as elevated ABR thresholds, prolonged I-V wave latencies, and a difference in bone conduction thresholds of >10 dB.

The Past and Present of Secretory Otitis Media in Children

ABR and AABR test result reports

(2) Otoacoustic Emissions (OAE): OAE is not a specific diagnostic indicator for SOM but is directly influenced by external and middle ear functions, thus can assist in diagnosing SOM and evaluating its condition and efficacy.

5. Nasopharyngeal Examination: The ear, nose, and throat cavities are interconnected, and inflammation can affect one another; thus, clinical practice often requires examination of the nasal and pharyngeal areas and simultaneous treatment of related diseases.

The Past and Present of Secretory Otitis Media in Children

SOM associated with adenoid hypertrophy, acute sinusitis, allergic rhinitis, acute tonsillitis, and other conditions.

6. Imaging Examination: Not routinely recommended, but CT scans of the temporal bone may be performed if necessary.

04
Diagnosis and Differential Diagnosis

Based on the medical history and clinical presentation, combined with otoscopy and audiometric examinations, diagnosing SOM is not difficult. Clinically, it is often necessary to differentiate it from acute suppurative otitis media, nasopharyngeal masses, cholesterol granulomas, cerebrospinal fluid otorrhea, acute middle ear barotrauma, and jugular bulb tumors.

05
Treatment
1. Medical Observation

SOM is a self-limiting disease with a high spontaneous recovery rate; children with a history of less than 3 months and without high-risk factors should avoid unnecessary medical interventions and have regular follow-ups.

2. Pharmacotherapy
(1) Corticosteroids: Due to the adverse effects of oral steroids, nasal spray formulations are generally recommended.
(2) Antibiotics: Antibiotics have adverse reactions, resistance issues, and SOM is self-limiting; routine use is not recommended in the absence of clearly associated infectious diseases such as acute sinusitis or upper respiratory infections.
(3) Antihistamines: Can suppress the release of inflammatory mediators, reducing edema and effusion in the tympanic and Eustachian tube mucosa; routine use is not recommended in the absence of significant allergic reactions such as allergic rhinitis.
(4) Mucolytics: Can promote the synthesis and secretion of surfactant-like substances in the Eustachian tube, adjusting the ratio of the mucus blanket’s sol phase and gel phase, facilitating mucociliary transport and drainage of middle ear fluid.

(5) Decongestants: Can reduce nasal mucosal swelling but have no definitive effect on improving SOM symptoms and may have adverse effects; routine use is not recommended.

3. Surgical Treatment
(1) Tympanostomy
  • Indications: Unilateral or bilateral SOM lasting more than 3 months, tympanometry showing type B or C, meeting one of the following conditions: ① Hearing loss in the affected ear ≥25 dB HL, with an air-bone gap, or affecting speech communication and learning; ② Significant retraction, adhesion, and/or effusion of the tympanic membrane; ③ ≥3 episodes within 6 months or ≥4 episodes within 1 year.

  • Ventilation tubes: When choosing, consider the possibility of SOM recurrence and the patient’s compliance with follow-up; they are usually placed in the anterior or posterior inferior part of the tympanic membrane, away from the annulus. Recommendations: ① For children ≤6 years, choose T-tubes; for >6 years, choose button tubes; ② For those unable to follow up on time, button tubes are recommended; ③ For those with allergic rhinitis, T-tubes may be used initially; ④ For retracted tympanic membranes, button tubes are preferred; ⑤ For completely retracted tympanic membranes or narrow tympanic cavities, T-tubes may be selected.

The Past and Present of Secretory Otitis Media in Children

Different types of middle ear ventilation tubes

  • Complications include ear discharge, tympanic membrane perforation, retraction, and cholesteatoma formation, and tympanic sclerosis. The management principles are: ① Keep the ear canal clean and dry postoperatively; ② If ear discharge occurs, local infection control with antibiotic or corticosteroid + antibiotic ear drops is recommended; routine systemic antibiotics are not recommended, and removal of the ventilation tube is not advised during discharge; ③ For persistent tympanic membrane perforations, tympanoplasty may be scheduled; ④ For retraction pockets and cholesteatoma formation, surgery should be scheduled; ⑤ Tympanic sclerosis is generally not treated.

  • Postoperative matters: Follow-up every 3 months after tube placement to observe tube patency, displacement, or dislodgement. The retention time is 12-18 months, with longer retention times considered for younger children or those with multiple recurrences; some tubes may fall out naturally, while those that do not must be removed after the due date. If SOM has not resolved despite tube blockage or premature dislodgement, re-tubing is necessary.

(2) Adenoidectomy

Indications:

Children ≥4 years who meet one of the following conditions are recommended to undergo adenoidectomy concurrently with tympanostomy or tympanic membrane incision:

① Associated with recurrent sinusitis or nasopharyngitis; ② Recurrent SOM; ③ Re-tubing; ④ Other indications for adenoidectomy.

Children under 4 years have poor clinical benefits from adenoidectomy unless they meet operative indications (such as adenoid hypertrophy, obstructive sleep apnea, or sinusitis); surgery is generally not recommended.

(3) Myringotomy and Incision

Myringotomy can quickly drain tympanic cavity effusion, but it is difficult to perform without pain, and the puncture opening has a short retention time; hence, it is not recommended. Simple myringotomy typically heals in 7-10 days and is not routinely recommended for children with SOM; laser myringotomy can coagulate the edges of the incision, making healing less likely in the short term and can be used selectively.

(4) Eustachian Tube Balloon Dilation

Should be avoided in conjunction with acute upper respiratory infections, chronic sinusitis, and acute otitis media. Children over 2 years can use a balloon or automatic Eustachian tube balloon dilator with parental assistance for dilation, with follow-up after 2-4 weeks.

(5) Hearing Aids

Hearing aids may be considered for children with other related diseases whose hearing cannot be improved despite standard treatment, posing a potential risk for speech development; however, they are not recommended for children with isolated SOM.

4. Follow-Up and Assessment

High-risk children with SOM should be followed up every 1-2 months, while non-high-risk children should be assessed every 3 months.

06
Impact and Harm
1. Middle Ear Structure and Function
The negative pressure and effusion in SOM can lead to hearing loss, initially characterized by low-frequency hearing loss due to negative pressure, gradually developing into both low-frequency and high-frequency hearing loss due to effusion. Prolonged SOM may lead to adhesive otitis media, persistent negative pressure can form retraction pockets in the tympanic membrane, and may ultimately lead to cholesteatoma of the middle ear.

The Past and Present of Secretory Otitis Media in Children

Retracted pocket in the upper tympanic cavity associated with SOM

2. Auditory and Speech Development

SOM primarily leads to conductive hearing loss, but can also involve sensorineural hearing loss, with an average hearing threshold of about 28 dB HL, which can result in unclear speech or age-inappropriate speech errors in children; good family care can mitigate this impact.

The Past and Present of Secretory Otitis Media in Children

Recurrent SOM after tympanostomy, with healed puncture site and remaining effusion in the tympanic cavity; thin and retracted tympanic membrane with visible tympanic calcification.

3. Vestibular Function

Prolonged SOM may lead to decreased balance ability in children, but balance and motor skills can often return to normal after the middle ear effusion resolves.

4. Behavioral and Learning Abilities

Persistent SOM can lead to sluggish responses, lack of concentration, decreased reading and communication skills, and even an inability to complete tasks and homework independently.

5. Quality of Life

Hearing loss, ear discharge post-tubing, sleep disturbances, behavioral issues, and balance disorders can affect children’s health-related quality of life (HRQL), with the degree of impact related to the severity and frequency of SOM.

07
Prevention and Care

The high incidence of SOM in children, diverse causes, insidious onset, prolonged course, and significant harm necessitate active diagnosis and treatment, along with knowledge dissemination to ensure early detection, diagnosis, and rehabilitation.

1. Control of Causes

Inform parents that the occurrence of SOM is related to various factors such as allergic rhinitis, adenoid hypertrophy, upper respiratory infections, air pollution, passive smoking, and pharyngeal reflux; primary diseases should be actively treated to reduce recurrence.

2. Compliance with Follow-Up

Most children can relieve or heal themselves after 3 months of observation, while some require follow-up. Those who have undergone tympanostomy should be informed to avoid getting water in the ear and to have regular follow-ups.

3. Provide Counseling

Inform parents that hearing loss can lead to delayed speech development, difficulties in learning and communication, and behavioral abnormalities. During follow-ups, inquire about the treatment process and any changes in hearing, speech, and quality of life, and provide appropriate counseling.

[References]
[1] Editorial Board of Chinese Journal of Otolaryngology-Head and Neck Surgery. Guidelines for Diagnosis and Treatment of Secretory Otitis Media in Children (2021) [J]. Chinese Journal of Otolaryngology-Head and Neck Surgery, 2021, 56(6): 556-567
[2] Huang Zhaoxuan, Kong Weijia, Wang Jibao. Practical Otolaryngology-Head and Neck Surgery [M]. Beijing: People’s Health Publishing House, 2018, 2nd ed: 1169-1170
[3] Zheng Yiqing, Zhang Zhigang, Yang Haidi. Endoscopic Treatment and Diagnostics [M]. Beijing: People’s Health Publishing House, 2018, 1st ed: 35-41

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